METHOD OF CONVERSION OF MUNICIPAL SOLID AND OTHER

CARBON-CONTAINING WASTE INTO SYNTHESIS GAS

AND THE EQUIPMENT BASED ON THIS METHOD

This invention consists of the method of thermochemical conversion into the synthesis gas of municipal solid waste (MSW) and other carbon-containing waste with large tar content into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized- bed updraft gasification of the carbon-containing residue of the process of pyrolysis.

"Slow fluidized bed" is a layer of heated ground mass of carbon-containing residue of raw waste resulting from the process of low-temperature pyrolysis and fed into internal container of a gasification reactor. On the surface of this layer occurs movement of particles under the impact of gases generated in the in the zone of burning and gasification of the gasification reactor. This movement is similar to the process of slow boiling in a liquid, with the velocity of movement of generated synthesis gas over the surface of slow fluidized bed does not exceed 0.8 meters per second.

This invention is also a basis for a device realizing the method of thermochemical conversion into the synthesis gas of municipal solid waste (MSW) and other carbon- containing waste with large tar content into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized-bed updraft gasification of the carbon-containing residue of the process of pyrolysis.

PREREQUISITES FOR THIS INVENTION

Deficiencies of modern technologies of thermochemical conversion of MSW and other hydro-carbon materials into the synthesis gas.

An acute and global need in the sources of renewable energy and alternative raw materials for the synthesis of nitrate fertilizers, like urea, exists today. These renewables could minimize environmental impact and display maximal economic effectiveness. Demand for energy and raw materials for synthesis of hydrocarbons generated from fossil fuels grows with continuing growth of population. This intensifies negative impact on the environment.

Some gasification technologies have recently shown significant progress in the conversion of residential waste, especially in generation of thermal energy, although it constitutes comparatively small segment of energy markets of the developed nations. A number of technological and economic obstacles to the extension of this segment exist, and they should be removed.

The use of the majority of technologies of MSW conversion into synthesis gas have not until now reached industrial scale owing either to their low efficiency, or to their inadequacy to the ever more strict environmental norms and standards, or a combination of these two factors.

The matter is that currently existing technologies of thermochemical conversion of MSW and other hydrocarbon-rich materials into synthesis gas for further generation of electricity and synthesis of chemical products have until now used the so-called traditional updraft and traditional downdraft principles of gasification. These two principles are based on the three theories of gasification (reviewed in more details further on) that were developed in previous century and were meant for the conversion into the synthesis gas of the traditional types of materials, like charcoal, coke and low-tar dry wood. These materials contain small amount of hydrocarbons (10-20%) in gas phase and large amount of residual carbon (80- 90%).

As MSW and other types of hydrocarbon materials with large amounts of tar belong to an entirely different category of fuels with high amounts of hydrocarbons in gas phase (60- 70%) and small amounts of residual carbon (30-40%), they are not suitable for traditional methods of their conversion into synthesis gas. That is to say that all current technologies attempt to convert these types of materials into synthesis gas applying those old traditional principles of gasification based on the theories of gasification oriented for the conversion of materials that have entirely different thermochemical characteristics.

This approach entails negative outcomes in the form of the barriers that slow down the development and usage of new thermochemical technologies of recycling of domestic waste.

Technical barriers

" Imperfect technologies

■ Low efficiency of synthesis gas production, hence low efficiency of electricity generation and synthesis of hydrocarbons

■ High selectivity of composition of solid waste

■ Complex and cumbersome design of conversion plants and a large number of the units of equipment, including those for synthesis gas and smoke gases purification

■ Low scaling capacity of existing technologies

■ High thermal and electric energy consumption of conversion process

■ Use of fossil fuels in the process of conversion

■ Use of combined generating cycles in generation of electricity

■ Complexity of service and maintenance of equipment

■ Other technological deficiencies Economic barriers

^■ Long periods of cost recovery of conversion plants owing to the high capital and maintenance expenditures

Environmental barriers

^■ Excessive emissions into the atmosphere of NO _x , COS, NH ₃ , SO2, ¾S, HC1, dioxides, furans, various aromatic hydrocarbons and many other substances

^■ High levels of tars and oxides of heavy metals in synthesis gas, hence the need to recover them after costly purification of gases resulting from conversion

■ High content of carbon in the ash residue of conversion process. Ash residue being toxic due to high concentration of heavy metals, hence the need to dispose of it at special landfills for hazardous and toxic discards

In addition to the abovementioned, traditional updraft and traditional downdraft methods of gasification employed in the technologies of conversion of traditional fuels into synthesis gas have substantial deficiencies of their own.

Deficiencies of the traditional updraft method of gasification:

• Impossibility to use plasticizing and coking types of feedstock;

• Limited use of feedstock with high content of tars because of them polluting recovered synthesis gas and high costs of the system of gas cleaning;

• Impossibility to use small or very large fraction feedstock, heterogeneous or compressed mass, as well as high ash content feedstock and feedstock with low melting temperature of ash;

• Heterogeneity of the volumes, temperatures and composition of recovered gases due to instability of the process of gasification;

• The need to maintain very high temperatures at the gasification reactor exhauster in order that relatively clean synthesis gas be obtained. This reduces significantly the efficiency of the technology in terms of «cool gas»;

• Insufficient use of the heat of recovered synthesis gas in gasification process. Its better use increases overall efficiency of gasification process;

• Low efficiency of gasification reactors due to the need of comparatively slow air inflow avoiding initiation of the process of formation of fluid ash;

• Instability of gasification process because of the need to terminate completely the process of gasification to avoid the feedstock suspension inside gasification reactor;

• The need to periodically stop gasification process to clean internal surfaces of gasification reactors of feedstock, ash and slag formations; • Difficult disposal of toxic carbon-containing slag residue;

• Large losses of heat due to designs of gasification reactors.

In an attempt to overcome these shortcomings a new theory (referred to further in the text as Theory 4) of gasification was developed for feedstock with high content of hydrocarbons in gaseous phase and low content of residual carbon.

This theory is the foundation of a new method of conversion of MSW and other types of hydrocarbon feedstock with high content of tars into synthesis gas. The process consists of two-stage pyrolysis with subsequent gasification in the air-and-gas flow of slow fluidized-bed carbon residue and is called SFGP4 (Slow Fluidized-Bed Gasification Process 4). Gasification plant was developed based on this method.

Subsequently, these discoveries have been embodied in the new gasification technology with working pre-patent name SYNTENA 1-SFGP4 (Slow Fluidized-Bed Gasification Process 4).

Gasification technology SYNTENA 1-SFGP4

Technology SYNTENA 1-SFGP described hereinafter is based upon method of thermochemical conversion into the synthesis gas of municipal solid waste (MSW) and other carbon-containing waste with large tar content into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized-bed updraft gasification of the carbon- containing residue in the air-and-gas flow using updraft process of gasification of slowly boiling layer of feedstock. Because of this it is classified as two-stage pyrolysis and gasification technology realized in a single or double container technological design.

Method of thermochemical conversion into the synthesis gas of municipal solid waste (MSW) and other carbon-containing waste with large tar content into synthesis gas described in this application is materialized through the two-stage process of pyrolysis and subsequent slow fluidized-bed gasification of the carbon-containing residue in the air-and-gas flow using updraft process of gasification of slowly boiling layer of feedstock has enabled to develop additional technological and environmental advantages of gasification reactors using the principle of updraft gasification:

► Main technological advantages:

^■ Horizontal positioning of key gas generating equipment;

■ Simplicity of design and minimal amount of the units of equipment including synthesis and smoke gas cleaning equipment;

■ Good scalability of technology enabling conversion of up to 1000 tons of MSW per day;

■ Only the heat of exothermal reactions of the process of gasification itself is used for the process of thermochemical conversion of domestic waste into synthesis gas;

■ This technology makes possible thermochemical conversion of MSW of different composition, fractions and highly humid, conversion of various materials that was not possible before;

■ Increased productivity thanks to intensified reactions of gas formation;

^■ Improved quality and homogeneity, increase of the quantity of generated synthesis gas;

^■ No need for additional sources of heat for pre-treatment drying of domestic waste as all necessary heat is provided by smoke gases from gas reciprocating machines of electricity generating cycle or from the process of synthesis of nitrogen fertilizers. This makes possible to convert domestic waste with humidity higher than 50% without any additional energy input;

^■ Simplicity of technological maintenance, the need for overhauls and preventive maintenance is minimal thanks to special design of gasification reactor. Besides, costs of synthesis gas cleaning are reduced substantially due to the fact that major cleaning of synthesis gas occurs within the process of gasification;

^■ 78-86% "cool gas" output efficiency of gasification process with the amount of gas double that of other technologies having output of only 40-50% as compared to technology SY TENA 1-SFGP;

■ Possibility to use synthesis gas in gas reciprocating machines or gas turbines with 35-42% efficiency for electricity generation, which is two times higher than the efficiency steam turbines with the efficiency of about 20%.

■ This technology makes possible intense synthesis of nitrate fertilizers like urea with no need for natural gas;

■ Oxygen and steam mixture can be used instead of air;

■ Other alternative fuels can be used, including hazardous.

► Environmental advantages

■ Efficient utilization of domestic waste as a source of renewable energy for generation of environmentally clean electric power and synthesis of nitrate fertilizers;

■ No need to use any external fuel as the process is based on the heat of exothermal reactions only generated within the process of gasification;

Prevention of formation of NOx, COS, NH ₃ , SO¾ H ₂ S, HC1 thanks to special features of technology and design of gasification process;

■ Recovered synthesis gas does not contain any compounds of aromatic hydrocarbons, volatile organic compounds (VOCs) or tars, because they are destroyed in the course of thermochemical process. This simplifies significantly the system of gas cleaning and guarantees that they are not emitted in the environment;

^■ Non-hazardous silica slags are formed in the process of gasification of nonorganic fractions of MSW. Heavy metals from the MSW are encapsulated within those slags, which are insoluble in water and can be used for industrial purposes.

^■ In compliance with the provisions of Kyoto Protocol and Paris Climate Convention emissions of C0 ₂ are reduced two to three times per every kilowatt of electricity in comparison with now existing technologies.

All the advantages listed above permit to efficiently convert MSW and other hydrocarbon-rich feedstock into synthesis gas with its further use for the generation of electric power and /or synthesis of nitrate fertilizers. This advanced technology achieves a new level of economic efficiency as compared to the existing technologies of gasification.

LIST OF FIGURES

Fig. 1 shows the scheme of calculation characteristics referred to in the part "Relative Calculation of the Amount of Pyrocarbon Formed in the Process of Thermal Conversion of Hydrocarbons and Tars Making Part of Pyrolysis Gases".

Fig. 2 shows schematic diagram of gas generator.

Fig. 3 shows the sketch of gas generator unit.

Fig. 4 demonstrates the sketch of pyrolysis part.

Fig. 5 shows the sketch of gasification part.

Fig. 6 shows configuration of gasification zone of carbon-containing residue of feedstock.

Fig. 7 demonstrates the scheme of computations describing the principle of operation of gas generator based on the method of thermochemical conversion into synthesis gas of MSW and other carbon-rich feedstock with high content of tars executed through two-stage process of pyrolysis and subsequent gasification in the air and gas flow of slow fluidized bed of carbon residue.

Fig. 8 in the form of Table 1.1 shows morphological content of solid waste used in this computation.

Fig. 9 in the form of Table 1.2 shows element composition of MSW.

Fig. 10 in Table 1.3 shows the products of the drying of feedstock.

Fig. 11 shows in Table 2.1 the feedstock residue after drying.

Fig. 12 demonstrates Table 2.2 with element composition of feedstock residue after the feedstock moisture recovery process. Fig. 13 illustrates in Table 2.3 what gases are recovered in the process of moisture recovery.

Fig. 14 compares in Table 2.4 design data and literature data of changed elementary composition of fuel before and after the process of the recovery of moisture.

Fig. 15 shows in Table 3.1 of the feedstock residue entering the zone of low temperature pyrolysis.

Fig. 16 lists in Table 3.2 the products of low temperature pyrolysis.

Fig. 17 demonstrates in Table 3.3 the distribution of solid feedstock residue after the zone of low temperature pyrolysis.

Fig. 18 shows in Table 3.4 the part of residue of solid feedstock conveyed into the zone of high temperature pyrolysis.

Fig. 19 shows in Table 3.5 the part of solid feedstock conveyed into filtering zone.

Fig. 20 in Table 3.6 refers to the aggregate composition of gases of drying process, moisture recovering and low temperature pyrolysis conveyed into the channel of pyrolysis gases of gasification reactor.

Fig. 21 with Table 3.7 refers to the design and literature data of the products of low temperature pyrolysis.

Fig. 22 compares in Table 3.8 design and literature data on gases of low temperature pyrolysis.

Fig. 23 compares in Table 3.9 design and literature data on tar of low temperature pyrolysis (primary tar oil).

Fig. 24 in Table 3.10 gives the composition of the tar of semi-coking of the coal.

Fig. 25 in Table 4.1 gives aggregate composition of gases conveyed into the channel of pyrolysis gases (gases of drying, feedstock moisture and liquid release and of low temperature pyrolysis).

Fig. 26 in Table 4.2 lists the tars entered into the channel of pyrolysis gases.

Fig. 27 in Table 4.3 describes thermal conversion of primary tar oil (tar) in the channel of pyrolysis gases.

Fig. 28 in Table 4.4 demonstrates the gases resulting from break down of primary tar oil.

Fig. 29 in Table 4.5 gives the aggregate composition of tars formed in the channel of pyrolysis gases.

Fig. 30 in Table 4.6 quotes the data of conversion of hydrocarbons, contained in the gas mixture of the channel of pyrolysis gases.

Fig. 31 in Table 4.7 shows the products of conversion of hydrocarbons contained in the producer gas of low temperature pyrolysis.

Fig. 32 in Table 4.8 illustrates the gases after conversion in the channel of pyrolysis gases.

Fig. 33 in Table 4.9 shows gas mixture and pyrocarbon formed in the channel of pyrolysis gases.

Fig. 34 in Table 4.10 shows the tars in the channel of pyrolysis gases.

Fig. 35 shows in Table 5.1 solid feedstock residue conveyed into the zone of additional gasification from the zone of burning and gasification.

Fig. 36 in Table 5.2 shows gas mix and pyrocarbon conveyed from the channel of pyrolysis gases into the zone of additional gasification.

Fig. 37 demonstrates in Table 5.3 the tars conveyed from the channel of pyrolysis gases into the zone of additional gasification.

Fig. 38 in Table 5.4 quotes the data on thermal conversion of tars at their contact with hot burning slag residue.

Fig. 39 in Table 5.5 illustrates the gases resulting from the breakdown of tars.

Fig. 40 in Table 5.6 shows combined composition of tars in the zone of additional gasification.

Fig. 41 in Table 5.7 gives the data on carbon that makes part of the reactions of gasification.

Fig. 42 in Table 5.8 gives the data on the gasification of the carbon.

Fig. 43 in Table 5.9 describes gas mix resulting from gasification of carbon.

Fig. 44 in Table 5.10 contains the data on gas mix formed in the zone of additional gasification.

Fig. 45 in Table 6.1 lists the products entering the zone of burning and gasification from the zone of high temperature pyrolysis.

Fig. 46 in Table 6.2 illustrates thermal conversion of solid carbon-rich residue at its entering the zone of burning and gasification.

Fig. 47 gives in Table 6.3 the data on the combustion of a part of solid carbon-rich residue.

Fig. 48 in Table 6.4 shows the composition of carbon-rich residue after its partial combustion.

Fig. 49 shows in Table 6.5 the composition of carbon residue after its partial combustion.

Fig. 50 describes in Table 6.6 the gas mix formed as a result of conversion of the products conveyed from the zone of high-temperature pyrolysis. Fig. 51 demonstrates in Table 6.7 gas mix entering from the zone of additional gasification into the combustion and gasification zone.

Fig. 52 in Table 6.8 lists the tars entering from additional gasification zone into the zone of combustion and gasification.

Fig. 53 in Table 6.9 has the data on combustion of the tars in the zone of combustion and gasification.

Fig. 54 in Table 6.10 describes with the data the tar not burnt in combustion and gasification zone.

Fig. 55 in Table 6.11 gives the data on combustion of gases conveyed from the zone of additional gasification.

Fig. 56 in Table 6.12 shows the data on gases that have not burnt in the zone of combustion and gasification.

Fig. 57 in Table 6.13 shows gas mix formed after combustion of the products that entered from the zone of additional gasification.

Fig. 58 in Table 6.14 describes gas mixture formed in the zone of combustion and gasification.

Fig. 59 in Table 6.15 displays the data on the tar exiting zone of combustion and gasification.

Fig. 60 in Table 6.16 shows the total amount of air consumed.

Fig, 61 in Table 6.17 shows carbon residue in zone of combustion and gasification.

Fig. 62 in Table 6.18 shows composition of the gases of high temperature pyrolysis and gases of combustion and gasification.

Fig. 63 shows in Table 6.19 the mixture of the tars of high temperature pyrolysis and tars conveyed from the zone of combustion and gasification.

Fig. 64 demonstrates in Table 6.20 carbon residue of feedstock after high temperature pyrolysis.

Fig. 65 gives in Table 6.21 the data on partial decomposition of tars rising from high temperature zones.

Fig. 66 produces in Table 6.22 the data on the continuation of the process of high temperature pyrolysis in the zone of filtration.

Fig. 67 shows in Table 6.23 the data on thermal breakdown of the tar going down from the zone of filtration into the zone of high temperature pyrolysis.

Fig. 68 shows in Table 6.24 carbon-rich residue that participates in the reactions of gasification.

Fig. 69 produces in Table 6.25 the data on thermal conversion of solid carbonaceous residue.

Fig. 70 demonstrates in Table 6.26 the mixture of gases entering into reaction of gasification.

Fig. 71 displays in Table 6.27 the reactions of C0 ₂ .

Fig. 72 displays in Table 6.28 reactions of C.

Fig. 73 lists in Table 6.29 reactions of CO.

Fig. 74 shows in Table 6.30 reactions of CH ₄ .

Fig. 75 lists in Table 6.31 reactions of C ₂ H ₄ .

Fig. 76 describes in Table 6.32 the gas mix after gasification.

Fig. 77 illustrates in Table 7.1 composition of solid carbonaceous residue (semi -coke) entering the zone of high temperature pyrolysis.

Fig. 78 shows in Table 7.2 products of high temperature pyrolysis.

Fig. 79 describes in Table 7.3 relative distribution of solid residue of the feedstock in high temperature zone.

Fig. 80 shows in Table 7.4 the part of solid feedstock residue that goes into the zone of combustion and gasification.

Fig. 81 shows in Table 7.5 the part of the solid carbonaceous residue that remained in the zone of high temperature pyrolysis and is consumed in reaction of gasification.

Fig. 82 compares in Table 7.6 effective and literature data on the products of high temperature pyrolysis.

Fig. 83 makes comparison in Table 7.7 effective and literature data on the gases of high temperature pyrolysis.

Fig. 84 shows in Table 7.8 comparison between the effective and literature data on the tars of high temperature pyrolysis.

Fig. 85 compares in Table 7.9 effective and literature data on solid feedstock residue of high temperature pyrolysis (coke).

Fig. 86 refers in Table 8.1 the data on gas mix of the products of gasification and high temperature pyrolysis.

Fig. 87 contains in Table 8.2 the data on reaction of methanization.

Fig. 88 contains Table 9.1 with the data on tars discharged from the gasification reactor.

Fig. 89 produces in Table 9.1 the data on the gas mix exiting the gasification reactor. Fig. 90 refers in Table 10.1 the data on slag residue discharged from gasification reactor.

Fig. 91 represents basic technological scheme of the process of synthesis of urea. Fig. 92 presents structural scheme of technological complex.

THEORETICAL FOUNDATION OF THE INVENTION

In their simplified form the processes of gasification of carbon feedstock can be viewed as the interaction only of carbon with oxygen and water steam. This is characteristic of traditional gasifiers used for the conversion into synthesis gas of traditional feedstocks like charcoal, coke and dry wood with low content of tars. These are the kinds of feedstocks, whose thermochemical parameters correspond to low content of hydrocarbons (10-20%) in gas phase and high content of residual carbon (80-90%),

Similar model describes quite accurately real processes occurring in these devices, because feedstock containing up 96% of carbon goes into gasification zone.

At present three theories exist that describe thermochemical interaction of carbon and oxygen, the so-called three theories of gasification. They can be symbolically designated Theory 1, 2 and 3:

Theory 1

The theory of primary formation of carbon oxide through reaction:

2c+0 ₂ =2CO (1)

According to this theory, carbon dioxide is a secondary product of the following oxidation of carbon oxide through reaction:

2CO+0 ₂ -2C0 ₂ (2)

This theory is taken as the basis for the design of the majority of gasification devices. Theory 2

The theory of primary formation of carbon dioxide through reaction:

C+0 ₂ =C0 ₂ (3)

In accordance with this theory carbon oxide is a secondary product of the recovery of carbon dioxide by heated up carbon of the fuel as a result of reaction:

C0 ₂ + C = CO (4)

Theory 3

The theory of intermediary formation of complex carbon-oxygen compound from the reaction:

xC+y/20 ₂ =CxOy (5)

This theory assumes that CO and C0 ₂ are formed in different proportions from the CxOy compound depending on the conditions in which occur the reactions:

CxOy=mC0 ₂ +nCO (6)

C0 ₂ conversion occurs according to the equation: Cx+yC0 ₂ =CxOy+yCO (7)

Thus part of resulting CO is a product of primary reactions of gasification and another part is a product of secondary reactions.

It was established that with the temperature rising gasification process is ameliorated owing to the reactions balance shifting towards formation of larger amount of CO and also towards intensification of the reactions of water gas:

H ₂ 0+C =CO+H ₂ (8)

2H2O+C = C0 ₂ +¾ (9)

There are three theories describing interaction between steam and hot carbon of solid feedstock. All three are based on the same principles that are valid for the interaction of carbon with oxygen.

Of these three theories of carbon gasification the third theory is most viable, that of an interim formation of a complex carbon-oxygen compound and subsequent transformation of this compound into simple gaseous products, carbon dioxide (C0 ₂ ) and carbon oxide (CO).

Despite that, it was Theory 1 on which the design of the majority of gasification devices was based. In this theory reactions of "primary gasification" (Formula 1) are considered main ones and reactions of "secondary gasification" auxiliary (Formula 4). In the designs of some gasification reactors secondary reactions (Formula 4) are not taken into consideration at all.

In major part of gasification reactors the main process of primary oxygen gasification occurs through the so-called "incomplete burning" (Formula 1), to which carbon of the fuel is mainly subjected. The amount of carbon sufficient for this process is achieved by the usage of carbon-rich fuels, such as coke, wood charcoal, firewood, peat. Reactions of gasification are in this case heterogeneous, and, due to low intensity of those reactions, they do not develop high temperatures. This, in its turn, generates producer gas with low calorific value and with high content of the C0 ₂ .

The use of MSW and other carbonaceous types of waste with high tar content as a feedstock that are the types of fuel thermochemical characteristics of which correspond to high content of hydrocarbons (60-70%) in gas phase and low content of residual carbon in gasification reactors of classic design result in even higher content of C0 ₂ the gases thus generated. This is caused directly by the amount of carbon insufficient for the reactions of gasification.

A new theory of gasification has been developed to resolve this problem. If we use numbers to mark the existing theories of gasification, this new theory can be tentatively called "Theory 4". Based on Theory 4 a new method of thermochemical conversion of municipal solid waste (MSW) and other carbon-containing waste with large content of tars into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized-bed updraft gasification of the carbon-containing residue in the air-and-gas flow SFGP4 (Slow Fluidized- bed Gasification Process 4) using updraft principle of gasification. This method has become a foundation of technology SYNTENA 1-SFGP4, developed for conversion into synthesis gas of the MSW and other carbon-containing feedstock with thermochemical characteristics corresponding to high content of hydrocarbons in gas phase and low content of residual carbon.

Unique aspects of the new method of thermochemical conversion of municipal solid waste (MSW) and other carbon-containing waste with large content of tars into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized-bed updraft gasification of the carbon-containing residue in the air-and-gas flow made it possible to alter the classic scheme of gasification. A new device has been created that constitutes this invention representing a new design of a gasifier, which was given a tentative name SYN1- GG (SYNTENA 1 Gas Generator). The latter makes it possible to reach the content of carbon sufficient for full scale gasification of the abovementioned types of feedstock.

Theory 4 of gasification of MSW

The concept of the new theory of gasification, Theory 4, which is a foundation of the method of thermochemical conversion into synthesis gas of MSW and other carbon- containing waste with large content of tars into synthesis gas through the two-stage process of pyrolysis and subsequent slow fluidized-bed gasification of the carbon-containing residue in the air-and-gas flow is as follows. Gaseous products that are formed at the initial stage of thermochemical conversion of feedstock through its drying, removal of moisture, low- and high-temperature pyrolysis, contain large amount of various hydrocarbons and tars. They are conveyed into the zone of combustion and gasification, where part of them are burnt and thermally decomposed in a layer of carbonaceous residue resulting from the pyrolysis of this feedstock.

Partial combustion of pyrolysis gases occurs because the amount of oxygen conveyed into the fuel input unit of gasification reactor is insufficient for complete burning of these gases, which is the main condition for entire process of gasification.

As the speeds of homogenous reactions is one or two orders of value higher than the speeds of those heterogeneous, homogenous reactions of the combustion of gaseous products of pyrolysis first occur in the zone of combustion and gasification. Heterogeneous reaction between oxygen and solid carbon can only be secondary. The carbon resulting from a preliminary pyrolysis of the feedstock, and pyro-carbon resulting from incomplete combustion of pyrolysis gases with high calorie values, are subjected to intense heating-up during the combustion of pyrolysis gases. This causes the intensification of the "secondary" reactions of gasification (Formula 4).

Reactions of water gas (8) are also enhanced by high temperatures, resulting in the increase of H ₂ , CO content in the gas, and respective decrease of N ₂ . Because of these processes synthesis gas is formed, which in fact consists of simple combustible gases CO and H ₂ , with small content of CH ₄ and C _x H _y . Content of C0 ₂ remains minimal.

In conjunction with above mentioned, Theory 4 can be construed as a based on Theory

2.

Given the existing three theories of gasification, the new Theory 4 can be presented in most general terms as follows:

CxH _y Oz + ((2(x-a)+b-z)/2)0 ₂ - x-aC0 ₂ + bH ₂ 0 + (y/2-b)H ₂ + aC (10)

2H ₂ 0 + C = C0 ₂ + H ₂ (9)

C0 ₂ + C = CO (4)

First equation (Formula 10) describes the process of incomplete burning of a part of pyrolysis gases in the zone of combustion and gasification with formation of carbon dioxide and water vapor, as well as partial thermal conversion of the residue of these gases with formation of hydrogen and residual pyro-carbon, generated by the reaction of de-hydration (Formula 11 and Formula 12):

CnH _2n+2 →C _n H _2n + H ₂ (11)

C _n H _2n H C _m H2 _m+2 -» (n+m)C + (2n+2m+2)H ₂ (12)

Three subsequent reactions (Formula 4, Formula 8 and Formula 9) are the reactions of conversion of smoke gases into conventional flammable gases CO and H ₂ occurring inside a layer of red-hot carbonaceous residue. Formula 8 and Formula 9 are the reactions of hydro- gasification of carbon, and Formula 4 is the reaction of the reduction of C0 ₂ into CO.

Another variant of the implementation of this invention is possible with another formulation of Theory 4:

CxHyOz→ C0 ₂ + CO + H ₂ 0 + CaH _b + H ₂ + C (13)

H ₂ + CO + CaHb + 0 ₂ → CO2 + H ₂ 0 + H ₂ + C (14)

H ₂ 0 + C = CO + H ₂ (8)

2H ₂ 0 + C = C0 ₂ + H ₂ (9)

C0 ₂ + C - CO (4)

The equation of Formula 13 describes schematically the process of pyrolysis of hydrocarbon feedstock - C _x H _y O _z . In their simplified form the products of this pyrolysis are C0 ₂ , H ₂ 0, CO, H ₂ , hydrocarbons C _a H„ and pyro-carbon C.

Hydrogen, carbon monoxide and hydrocarbons partially burn in the process of gasification generating carbon dioxide and water vapor. Their residues become subjects of partial thermal conversion generating hydrogen and residual pyro-carbon, as schematically described by the equation of Formula 14.

Thus generated CO2 and H ₂ 0 are converted into the conventional flammable gases CO and H2 within the layer of red-hot carbonaceous residue through the reactions of "secondary" gasification (Formula 4) and reactions of hydro-gasification (Formula 8 and Formula 9). The three latter equations (Formula 4, Formula 8 and Formula 9) are analogous to the previous scheme.

It is worth to note that pyro-carbon resulting from incomplete combustion and thermal conversion of pyrolysis gases (Formula 12) makes up for the overall deficiency of carbon in carbonaceous residue of the feedstock and is the first to enter the reactions of gasification and hydro-gasification (Formula 4, Formula 8 and Formula 9).

It must be noted also that in up-draft gasification highly wet feedstock can be used, or an additional amount of water together with air can be fed, resulting into an increase of methane CH ₄ as in the reaction of methanization:

2H ₂ 0 + 2C = CH4 + CO (15)

This scheme of gasification makes it possible to process highly damp feedstock with high content of volatile substances, utilization of which in classic design gasification reactors can be problematic due to the lack of carbon for the reactions of reduction. As a result, producer gas in them can have higher content of hydrocarbons, tars, C0 ₂ , H ₂ 0 and, respectively, N ₂ .

For the sake of clarity of description of the benefits of the method of pyrolysis and subsequent gasification of viscous layer of feedstock in thermochemical conversion into synthesis gas of solid waste and other carbonaceous feedstock with high content of tars, it can be described with design parameters of "black box", as presented in Fig. 1 , This scheme corresponds to the estimated parameters referred to in the chapter "Relative estimate of the amount of pyro-carbon formed in the process of thermal conversion of hydrocarbons and tars being part of pyrolysis gases".

Brief description of the method of thermochemical conversion into synthesis gas of MSW and other carbon-based feedstock with high content of tars, applied through the two-stage process of pyrolysis and subsequent slow fluidized-bed gasification of carbon-rich residue in the air-gas flow.

Method of thermochemical conversion into synthesis gas of MSW and other carbon- based feedstock with high content of tars, applied through the two-stage process of pyrolysis and subsequent slow fluidized-bed gasification of carbon-rich residue in the air-gas flow is used in the gas generator SYNl-GG, in which the entire process of generation of synthesis gas is relatively divided into the ten separate temperature zones.

The first three zones are the zones of low-temperature processing of the feedstock. They are located in the pyrolysis part of gas generator SY l-GG that is a specially designed rotary kiln (is referred to as SY l-RK in the description annexed to this application) slightly inclined towards the horizon. In other embodiment, it can have horizontal location. It is heated by the heat of synthesis gases resulting from the process of gasification of the feedstock.

The other seven zones are the zones of high temperature processing of feedstock. They are located in gasification section of gas generator SYNl-GG, which is an updraft gasification reactor (can be referred to in this description as SYNl-SFG) of special design. The gasification reactor SYNl-SFG is connected to the rotary kiln SYNl-RK by a body connector or by tubes. Design of the SYNl-GG is presented in Fig. 2.

Zones of low-temperature processing of feedstock:

Zone 1 - Zone of feedstock drying

Temperatures: T - 30- 120°C.

Operations in this zone are:

• sizing of feedstock through crushing of its lumps into smallest primary fractions, its drying and poking inside revolving internal body of rotary kiln;

• homogenization of feedstock:

• primary heating up of the feedstock with the heat of the synthesis gas conveyed through the walls of the body of the rotary kiln;

• final drying of the feedstock and intense formation of vapor with boiling of recovered moisture;

• partial removal from the feedstock of the water tied in colloids and of adsorbed gases;

• beginning of the process of conversion of the state of the fusible elements of feedstock in the form of the softening of outer zones of these elements;

• initiation of the process of gasification.

Main feature of this zone is that during the pre-treatment of feedstock the largest part of its moisture and of the water tied in colloids are evaporated. Adsorbed gases are also released and decomposition of feedstock under these low temperatures is manifested in a weak manner, only through hardly noticeable formation of gases.

Zone 2 - Zone of moisture removal from the feedstock

Temperatures: T - 120 - 300°C.

In this zone:

• final drying of the feedstock takes place and colloid water is removed;

• conversion of the state of matter of the feedstock occurs;

• processes of decomposition and destruction of organic polymers starts;

• initial formation of tars and of saturated and unsaturated hydrocarbons occurs. It is in this zone that gas starts to be released from the feedstock. This gas mainly consists of carbon dioxide and water. Amount of gas released under the temperature of 250°C can reach 2% - 2,5% of the total weight of feedstock fed into a gasification reactor. This conversion results in the loss of oxygen that is taken away from the feedstock in the form of water vapor, carbon dioxide and monoxide. Feedstock residue starts being enriched by carbon.

Zone 3 - Zone of low-temperature pyrolysis

Temperatures: T - 300 - 700°C.

In this zone the following processes occur:

• formation of saturated and non-saturated hydrocarbons, release of the vapors of light resinous substances;

• structural changes in the mass of feedstock, its conversion into homogenous crushed mass of carbonaceous feedstock residue;

• disintegration of some organic salts with formation of respective oxides;

• beginning of the process of reduction of oxides into metals.

This zone is characterized by increased formation of gases. Gases formed here have larger content of C0 ₂ and of saturated and unsaturated hydrocarbons. Under the temperature of 350°C non-condensing gases start to be released. Condensing products start to be released at the same time, such as vapors of oil tar. Their amount increase and reaches maximum at the temperatures of 500° - 550°C. Large amount of the so-called pyroligneous water is also released from the feedstock, and the feedstock residue enriches significantly with carbon.

Zone of high-temperature processing of feedstock:

Zone 4 - Zone of the channel of pyrolysis gases of gasification reactor

Temperatures: T - 700 - 900°C

In this zone: • additional heating of gases of low-temperature pyrolysis takes place;

• conversion of hydrocarbons in gases of low-temperature pyrolysis intensifies;

• the gas of low-temperature pyrolysis is divided into two flows going in different directions.

Thus in this zone the mixture of gases of low- temperature pyrolysis formed in the zones of low-temperature treatment of feedstock are divided into two flows and are subjected to additional thermochemical conversion.

Zone 5 - Zone of additional gasification

Temperatures: T - 900 - 1350°C

In this zone:

• additional heating of gases of low-temperature pyrolysis occurs, these gases conveyed into this zone through an open ingress of the channel of pyrolysis gases of the gasification reactor;

• the process of thermal conversion of hydrocarbons continues in gases of low- temperature pyrolysis. These gases enter the zone through an open ingress of the channel for pyrolysis gases of the gasification reactor;

• the process of gasification of a part of red-hot carbon residue occurs, the residue coming from the zone of combustion and gasification under the impact of the gases of low-temperature pyrolysis conveyed into this zone through an open ingress of the channel of pyrolysis gases of the gasification reactor;

• slag is formed and it is partially cooled down.

This zone needed to be organized because one part of burning-hot carbon from the zone of combustion and gasification, not having gasified, falls down into the slag zone from where it is removed from the gasification reactor together with the slag.

Zone 6 - Zone of combustion and gasification

Temperatures: T - 1100-1350°C.

The following processes take place in it:

• partial combustion of pyrolysis gases formed in the zone of low temperature processing of feedstock;

• conversion of carbon residue of the feedstock into the state of a "boiling" bed due to the dynamic of partial combustion of pyrolysis gases;

• gasification of carbonaceous residue of feedstock;

• thermal conversion of hydrocarbons and tars entering the zone of combustion and gasification; • melting of inorganic component of carbonaceous residue;

• reactions of oxidation and reduction in inorganic component of carbonaceous residue;

• cleaning of the gases with the removal of hazardous components of gas;

• formation of slag.

The main processes in this zone are partial combustion in the oxygen of air flown inside, and thermal decomposition of gaseous products of pyrolysis. There is also intense interaction between burning-hot carbonaceous residue of feedstock with oxidizing gases resulting from combustion of some part of pyrolysis gases conveyed from the zones of low- temperature processing of feedstock.

All the processes occur directly inside the bed of carbonaceous residue conveyed from the zone of high-temperature pyrolysis of feedstock.

Zone 7 - Zone of high-temperature pyrolysis of feedstock

Temperatures: T - 900 - 1100°C.

In this zone:

• gasification process of carbonaceous residue of the feedstock finishes;

• reactions of high-temperature pyrolysis take place;

• decomposition and melting of some part of inorganic salts occurs, and their interaction with carbon and mineral components of carbonaceous residue of feedstock;

• reduction of metals from the oxides occur;

• reduced metals are oxidized under the influence of C0 ₂ and H ₂ 0;

• hazardous components are cleaned from the gases;

• separation of carbonaceous residue occur;

• conversion of the feedstock residue into a friable porous bed of carbon take place.

In this zone end gasification processes that occur in the zone of combustion and gasification. Also volatile hydrocarbons and tars are released some part of which are converted into simple gases H ₂ and CO under the impact from high temperatures, H ₂ 0 and C0 ₂ .

Amount of carbon in feedstock residue reaches its maximal value as a result of these processes.

Zone 8 - Zone of gas filtering

Temperatures: T - 700-900°C.

In this zone: • the ending of the process of low-temperature pyrolysis occurs;

• high temperature pyrolysis ends;

• generated gas is cleaned of tars and other hazardous gas components;

• hot synthesis gas is formed completely.

In this zone generated gas is cleaned of tars and other hazardous components of gas with the help of carbonaceous feedstock residue conveyed from the zone of low temperature pyrolysis. At this time all pyrolysis processes end and the gas generated so far are finally converted into synthesis gas.

Zone 9 - Gas zone

Temperatures: T- 500 - 700°C.

In this zone:

• Hot synthesis gas is separated from slag-carbon dust.

In this zone owing to the low speed of gas flow in the internal space of gas zone and natural gravitation hot synthesis gas is separated from slag-carbon dust of carbonaceous feedstock residue.

Zone 10 - Slag zone

Temperatures: T - 150 - 900°C.

In this zone:

• slag cools;

• slag is mechanically crushed;

• slag is removed from the gasification reactor.

In this zone the slag conveyed from the zone of additional gasification is cooled with the air flown into the gasification reactor and subsequent mechanical crushing and removal from the gasification reactor.

Description of the design and of the principle of operation of the device of this invention

The main device is gas generator SYN1-GG, representing a device executing pyrolysis and gasification, thermochemically converting solid waste and other carbon containing feedstock with high content of tars into synthesis gas. Detailed design of the device is presented in Fig. 3.

Gas generator SYN1-GG consists of two parts:

A. Pyrolysis unit, which is a inclined rotary kiln SYN1-RK for sloping heating. It has original design shown in Fig. 4, consisting of the following devices:

1. Input unit for feeding the feedstock into the rotary kiln.

2. Inclined rotary kiln for indirect heating SYN1-RK. 3. Device for unloading dust gas residue from rotary kiln.

B. Gasification unit, which is gasification reactor SYN1-SFG of updraft gasification of the slow fluidized-bed of feedstock, shown in Fig. 5 and consisting of the following devices:

4. Unit for the feeding of carbonaceous feedstock residue into the gasification reactor.

5. Gasification reactor S YN 1 -SFG.

6. Device for unloading the slag from the gasification reactor.

Input unit conveying the feedstock into the inclined rotary kiln

Device that loads the feedstock into the inclined rotary kiln (1) presented in Fig. 3 loads the feedstock (solid waste) into the rotary kiln for indirect heating (2).

It consists of the following components:

1. Bunker.

2. Vertical piston mechanism.

3. Slide gate.

4. Vertical loading channel.

5. Horizontal loading channel.

6. Horizontal piston mechanism.

PI . Hydraulic cylinder of vertical piston mechanism.

P2. Hydraulic cylinder of slide gate.

P3. Hydraulic cylinder of horizontal piston mechanism.

Design of the device that loads the feedstock into the inclined rotary kiln for indirect heating

Device that feeds the inclined rotary kiln (1) consists of the bunker 1 that has rectangular cross-section with vertical back wall and sloping side and front walls. Vertical piston mechanism 2 of the loading device with hydraulic cylinder PI is fastened to the vertical back wall of the bunker 1.

Vertical loading channel 4, divided into the upper and lower pipes of the vertical loading channel 4 that has rectangular or round cross-section, is weld onto the lower part of bunker 1. Between these two pipes there is slide gate 3 that has hydraulic cylinder P2. Lower part of the lower pipe of vertical loading channel 4 is weld on horizontal loading channel 5 that has round or rectangular cross-section and a mounting flange at its front end. Inside horizontal loading channel 5 there is horizontal piston mechanism 6 equipped with hydraulic cylinder P3 and attached to horizontal loading channel 5 with the bolt joining of coupling flange of horizontal piston mechanism 6 and horizontal loading channel 5. Operation of the loading device of the inclined rotary kiln for indirect heating

Pre-treated feedstock having passed through the system of feedstock pre-treatment (Fig. 3) of the technological complex SYN1-TC is conveyed by a conveyor belt to bunker 1 of the feedstock loading device (1), equipped with the vertical piston mechanism 2. In bunker 1, under the impact of movement of the piston of vertical piston mechanism 2, moved by hydraulic cylinder PI, the feedstock is compacted and conveyed through the vertical loading channel 4 into horizontal loading channel 5. In horizontal loading channel 5 under the impact of horizontal movement of the piston of horizontal piston mechanism 6, moved by hydraulic cylinder P3, the feedstock is conveyed into the tilted inclined rotary kiln of indirect heating (2). At this time in horizontal loading channel 5, between the front end of the piston of horizontal piston mechanism 6 and back end of horizontal loading channel 5 a plug is formed by the feedstock. This plug prevents pyrolysis gases escape from the inclined rotary kiln of indirect heating (2) into the atmosphere through the feedstock loading device (1).

In order to completely prevent the release of pyrolysis gases into the atmosphere from the inclined rotary kiln of indirect heating (2), there is in the vertical loading channel 4 the slide gate 3. It is shut at all times and is only opened by hydraulic cylinder PI, when the piston of the vertical piston mechanism 2 moves down. When the piston of the vertical piston mechanism 2 moves up, the slide gate 3 shuts down, totally eliminating a possibility of escape of pyrolysis gases from the inclined rotary kiln (2) into the atmosphere.

Inclined rotary kiln of indirect heating

Inclined rotary kiln of indirect heating (2) is presented in Fig. 4. It is used for drying, moisture recovery and low temperature pyrolysis of feedstock.

Inclined rotary kiln of indirect heating (2) is tilted at 2-22 degrees vis-a-vis the horizon and consists of two bodies:

7. The inner body of the inclined rotary kiln

8. The outer body of the inclined rotary kiln

The inner body of the inclined rotary kiln

The inner body of the inclined rotary kiln is composed of the two elements:

9. Round rib of the inner body

10. Outlets for pyrolysis gas and carbonaceous residue

11. External guide vanes

12. Front oil seal hub of inner body

13. Back hub

14. Central hub

15. Supporting front wheel 16. Front supporting blocks

17. Supporting back wheel

18. Back supporting block

19. Back toe block

20. Ring gear

21. Pinion gear

P4. Motor of rotary kiln

Design of the inner body of the inclined rotary kiln

Design of the inner body of the inclined rotary kiln 7 includes round rib of the inner body 9. Spiral shape outer guide vanes 11 are welded to the outer surface of the rib. They are slightly inclined towards the rib's axis. In the back part of the rib of the inner body 9 there are outlets for pyrolysis gases and carbonaceous residue. Front oil seal hub 12 is welded to the front end of the rib of the inner body 9. In the headstock there is a channel for the installation of the feedstock loading unit, inside which there is an oil seal. In the front part of the front oil seal hub of inner body 12 there is a site for the supporting front wheel 15 bearing in its lower part on two supporting blocks 16. Ring gear 20 is welded to the central part of the front oil seal hub of inner body 12. Ring gear 20 meshes with the pinion gear 21 moved by electric or hydraulic motor of the rotary kiln P4.

Central hub 14 is welded to the central part of the rib of the inner body 9.

Back hub of the inner body 13 is welded to the back end of the rib of the inner body 9. Inside the tailstock there is a site, where back supporting wheel 17 is installed. In its lower part supporting wheel bears on the two back supporting blocks 18 and the side of the back supporting wheel 17 bears on the back toe block 19.

Outer body of the includes rotary kiln

Outer body of the includes rotary kiln (2) consists of the following components:

22. Front rib of the outer body

23. Front flange of the front rib of the outer body

24. Back oil seal flange of the front rib of the outer body

25. Front oil seal flange of the front rib of the outer body

26. Hot synthesis gas inlet tube

27. Cold synthesis gas outlet tube

28. Outlet tube for dust residue

29. Back rib of the outer body

30. Front oil seal flange of the back rib of the outer body

31. Back flange of the back rib of the outer body 32. Back oil seal flange of the back rib of the outer body

33. Hot pyrolysis gas outlet tube

34. Valve for emergency pressure relief

35. Carbonaceous residue outlet tube

36. Supporting feet of the front rib of the outer body

37. Supporting feet of the back rib of the outer body

38. Thermal insulation jacket of inclined rotary kiln

39. Outer casing of inclined rotary kiln

Design of the outer body of includes rotary kiln

Design of the outer body 8 of the inclined rotary kiln includes the front rib of the outer body 22 and back rib of the outer body 29 having the heat insulation jacket of inclined rotary kiln 38 and outer coat of inclined rotary kiln 39.

Front flange of front rib of outer body 23 is welded to front end of front rib of outer body 22. Front oil seal flange of the front rib of outer body 25 is attached to front flange of front rib 23 with the bolts. Back oil seal flange of the front rib of outer body 24 is welded to back end of front rib of outer body 24. To the upper front part of the front rib of the outer body 22 cold synthesis gas outlet tube 27 is welded, in the back part of front rib of outer body 22 there is tangentially welded the hot synthesis gas inlet tube 26 and the outlet tube of dust residue 28, which is welded in the lower part of the back of front rib of outer body 22.

Four support feet are welded to the front rib of outer body 22. It is with these feet that it is attached to the frame structure of inclined rotary kiln.

Front oil seal flange of the back rib of outer body 30 is welded to the front end of the back rib of outer body 29, and at the part of back rib of outer body 29 the back flange of the back rib of outer body 31 is welded, to which the back oil seal flange of back rib of outer body 32 is attached with the bolts. In the upper central part of back rib of outer body 29 the hot pyrolysis gas outlet tube 33 is welded. It is equipped with the valve for emergency pressure relief 34. In the lower central part of the back rib of outer body 29 carbonaceous residue outlet tube 35 is welded. Also, four supporting feet of the back rib of the outer body 37 are welded to the back rib of outer body 29. It is with these feet that it is attached to the frame structure of inclined rotary kiln.

General description of the design of inclined rotary kiln for indirect heating

Inclined rotary kiln for indirect heating (2) consists of rotating inner body of inclined rotary kiln 7 and of outer body of inclined rotary kiln 8 that is stationary and is fixed on the frame of its own.

Rotation of inner body of inclined rotary kiln 7 occurs inside stationary outer body of inclined rotary kiln 8. These are connected by gasproof oil seal systems located on the inner surfaces of the front oils seal flange of the front rib of outer body 25, of the back oil seal flange of the front rib of outer body 24, of the front oil seal flange of back rib of outer body 30 and of back oil seal flange of back rib of outer body 32. These gasproof oil seal systems make it possible to separate working zone of inclined rotary kiln inside inner body of inclined rotary kiln 7 from gas jacket located between inner body of inclined rotary kiln 7 and outer body inclined rotary kiln 8, and insulate both these zones from the atmosphere.

Calculation of dimensions of inner body of inclined rotary kiln 7 and of outer body of inclined rotary kiln 8, as well as calculations of all gas zones, is based on amounts of feedstock, its composition and moisture content.

Depending on installation of external compressor equipment, gas zones of inclined rotary kiln can experience either heightened or lowered pressure of gas.

General dimensions of inclined rotary kiln for indirect heating (2), and an angle of its inclination with respect to the horizon and velocity of its rotation are calculated upon parameters of maximal thermal processing of feedstock in the inside zone of inner body of rotary kiln 7 by the heat of hot synthesis gas, generated in gasification reactor (5) and moving in the gas jacket located between inner body of inclined rotary kiln 7 and its outer body 8.

Operation of inclined rotary kiln for indirect heating

Feedstock is fed into the inside zone of rotating inner body 7 of inclined rotary kiln for indirect heating (2) through an open end of horizontal loading channel 5 of the feeding unit (1) installed in the oil seal headstock of inner body 12.

Front oil seal hub of outer body 12 has gasproof oil seal hub system preventing the gases formed in the inside zone of inner body of inclined rotary kiln 7 to be released into the atmosphere through a gap between the inner wall of the front oil seal hub of inner body 12 and the outer wall of horizontal loading channel 5 of the feeding unit of the kiln (1).

Inner body of inclined rotary kiln 7 rotates due to the impact from electric or hydraulic engine of rotary kiln P4 conducted to inner body of inclined rotary kiln 7 via pinion gear 21 and ring gear 20. While rotating, inner body of inclined rotary kiln 7 bears with its supporting front wheel 15 on the two revolving front supporting blocks 16 and with its supporting back wheel 17 on the two back supporting blocks 18.

As inclined rotary kiln of indirect heating (2) is inclined at 2-22 degrees vis-a-vis horizon, in its lower part there is back toe block 19, against which rotating inner body 7 is set, making it possible to fix its back part relative to outer body of inclined rotary kiln 8.

Feedstock fed into the working zone of inclined rotary kiln (2) moves in there longitudinally thanks to the 3-5 degrees inclination of inclined rotary kiln relative to the horizon and to the rotation of the inner body of inclined rotary kiln 7. The feedstock is subjected to thermal processing by the heat conducted to it through the walls of the inner body of rotary kiln 7 from hot synthesis gas generated in gasification reactor (5), and moving in a gas jacket between the inner body 7 and outer body 8 of inclined rotary kiln.

Inner body of inclined rotary kiln 7 has on its outside external guide vanes 11 welded at some angle to inner body. They increase the area of heat transfer of the inner body of inclined rotary kiln 7 and direct the movement of hot synthesis gas in gas jacket along spiral trajectory along the surface of inner body of inclined rotary kiln 7. These two factors significantly increase heat transfer and time of contact of hot synthesis gas with inner body of inclined rotary kiln 7 and with feedstock, reducing at the same time the overall size of inclined rotary kiln.

Hot synthesis gas is brought at the temperature of 500-700°C into the gas jacket between inner body 7 and outer body 8 of inclined rotary kiln through the inlet tube of hot synthesis gas 26. Having moved in spiral trajectory along the surface of inner body of inclined rotary kiln 7 and having given its heat to feedstock, synthesis gas is cooled down to 120- 150°C and taken out of gas jacket through the cold synthesis gas outlet tube 27 and conveyed further through heat-insulated gas pipes into gas cleaning system.

Besides, in gas jacket placed at small inclination relative to horizon, due to gravitational and centrifugal constituents of spiral movement of synthesis gas, its primary cleaning of dust brought out of gasification reactor (5) together with synthesis gas occurs. The dust at that time falls out along the walls of gas channel and in its lower part.

While in operation, the inner body of inclined rotary kiln 7 makes revolving movement inside the outer body of inclined rotary kiln 8 and with its vanes welded to the outer surface of its rib cleans the walls and all the space of gas jacket of dust residue. It also transports dust residue along the lower part of outer body of inclined rotary kiln 8 to outlet tube of dust residue 28, located in the lower down part of the front rib of outer body 22, through which dust residue is taken out of inclined inclined rotary kiln.

This unit operates as horizontal cyclone with mechanical cleaning of inside walls of the dust using rotation of the inside part, which is the inner body of inclined rotary kiln 7.

As the feedstock is moving inside the working zone of inclined rotary kiln, the process of its thermochemical conversion takes place that can be relatively divided into the three temperature zones:

Zone 1 - Zone of feedstock drying: T 30 - 120°C;

Zone 2 - Zone of moisture removal from the feedstock: T 120 - 300°C;

Zone 3 - Zone of low-temperature pyrolysis: T 300 - 700°C. As a result of thermal processing of feedstock, in these zones hot pyrolysis gases are formed and hot carbonaceous feedstock residue, which are removed from the working zone of inner body of inclined rotary kiln 7 through outlets for pyrolysis gas and carbonaceous residue 10. At this stage hot pyrolysis gases pass through gas interstice between inner body of inclined rotary kiln 7 and outer body of inclined rotary kiln 8 and are conveyed into gasification reactor (5) through the hot pyrolysis gas outlet tube 33, and hot carbonaceous feedstock residue is put into vertical channel 49 of the device feeding carbonaceous feedstock residue into the gasification reactor (4). Hot pyrolysis gas outlet tube 33 has an outer heat insulation jacket. At upper end of the tube's vertical portion there is the valve for emergency pressure relief 34, through which excessive gas pressure in the working zone of the inner body of inclined rotary kiln 7 can be relieved in the atmosphere or in a separate gas channel should there be any unconventional or emergency situations during the operation of inclined inclined rotary kiln of indirect heating (2).

Inclined inclined rotary kiln of indirect heating (2) has thermal insulation jacket 38 and outer casing 39, minimizing heat loss into atmosphere. The work of the drive of inclined rotary kiln P4 is synchronized with the work of all mechanisms of the input unit (1), of the device for unloading dust gas residue (3) and of unit for the feeding of carbonaceous feedstock residue into the gasification reactor (4). This makes it possible to manage the efficiency of gas generator SYN1-GG, make its operation uninterrupted and guarantee maximal low-temperature processing of feedstock in inclined inclined rotary kiln for indirect heating (2).

Device for unloading dust gas residue from inclined rotary kiln

Device for unloading dust gas residue from inclined rotary kiln (3) presented in Fig. 4 is used for the removal of dust from the synthesis gas channel, located between inner body of rotary kiln 7 and outer body of rotary kiln 8.

It consists of the following components:

40. Sluice

41. Upper slide gate

42. Lower slide gate

43. Vertical channel

44. Horizontal channel

45. Screw mechanism

P5. Hydraulic cylinder of upper slide gate

P6. Hydraulic cylinder of lower slide gate

P7. Drive of screw mechanism Design of the device for unloading dust gas residue from the inclined rotary kiln

Device for unloading dust gas residue from inclined rotary kiln (3) consists of sluice 40, equipped with upper slide gate 41, lower slide gate 42, put in motion by hydraulic cylinders P5 and P6. Sluice 40 is in its upper part attached by the bolts to the flange of outlet tube for dust residue 28. In its lower part sluice 40 is attached by its lower flange to the flange of the pipe of vertical channel 43 with the bolted-on attachment for a pair of flanges. The pipe of vertical channel 43 may have rectangular or round cross-section. The lower part of the pipe of vertical channel 43 is welded to horizontal channel 44 that has round cross-section and attachment flange at its front end. Its back end is welded to an opening in the carbonaceous residue outlet tube 35. Inside horizontal channel 44 there is a screw mechanism 45 equipped with an electric or hydraulic drive P7 and connected with horizontal channel 44 with the bolted-on attachment for a pair of flanges of screw mechanism 45 and horizontal channel 44. Operation of the device for unloading dust gas residue from inclined rotary kiln

Dust residue of synthesis gas goes from gas jacket of inclined rotary kiln of indirect heating (2) into the device for unloading dust gas residue of rotary kiln (3) via the outlet tube for dust residue 28. Upper slide gate 41 and lower slide gate 42 are in the shut position in the initial stage of loading. Because upper slide gate 41 is shut, dust residue accumulates in the outlet tube foe dust residue 28 in the amount equal or smaller than the volume of inner chamber of sluice 40.

After calculated amount of dust residue has accumulated in the outlet tube for dust residue 28, upper slide gate 41 opens under the impact of the movement of hydraulic cylinder of upper slide gate P5. Dust gas residue goes down from outlet tube for dust residue 28 into the internal space of the chamber of sluice 40. After that upper slide gate 41 shuts down under the impact of hydraulic cylinder of upper slide gate P5. After it is shut, lower slide gate 42 opens under the impact of the movement of hydraulic cylinder of lower slide gate P6, and all dust residue from the inner chamber of sluice 40 is unloaded through vertical channel 43 into horizontal channel 44. From there, under the impact of spiral movement of screw mechanism 45, driven by electric or hydraulic drive P7, dust residue moves into the carbonaceous residue outlet tube 35. Afterwards this process is repeated automatically.

Unit for the feeding of carbonaceous feedstock residue into the gasification reactor

Unit for feeding of carbonaceous feedstock residue into the gasification reactor (4) outlined in Fig. 5 is used for loading into gasification reactor (5) of carbonaceous feedstock residue of MSW after thermal conversion of feedstock in rotary kiln for indirect heating (2).

It consists of the following parts: 46. Sluice

47. Upper slide gate

48. Lower slide gate

49. Vertical channel

50. Horizontal channel

51. Screw mechanism

P8. Hydraulic cylinder of upper slide gate

P9. Hydraulic cylinder of lower slide gate

P10. Motor of screw mechanism

Design of the unit for the feeding of carbonaceous feedstock residue into the gasification reactor

Unit for the feeding of carbonaceous feedstock residue into the gasification reactor (4) consists of the sluice 46 equipped with upper slide gate 47, lower slide gate 48, put in motion by hydraulic cylinders P8 and P9. Sluice 46 in its upper part is attached with its upper flange by bolts to the flange of the carbonaceous residue outlet tube 35.

In its lower part sluice 46 is attached by its lower flange to the flange of the pipe of vertical channel 49 with the bolted-on attachment for a pair of flanges. Cross-section of the pipe of vertical channel 49 can have rectangular or round cross-section. Lower part of the pipe of vertical channel 49 is welded to horizontal channel 50 that has round cross-section and securing flange at its front end. In its central part horizontal channel 50 has securing flange, with which it is attached by the bolts to the flange of the pipe of the gasification reactor feeding unit 56.

Inside horizontal channel 50 there is screw mechanism 51 equipped with electric or hydraulic drive P10. The mechanism is attached to horizontal channel 50 with the bolted-on attachment for a pair of flanges of screw mechanism 51 and horizontal channel 50.

Operation of the unit for the feeding of carbonaceous feedstock residue into the gasification reactor

After low-temperature pyrolysis of feedstock in inclined rotary kiln of indirect heating (2) carbonaceous residue of feedstock goes through carbonaceous residue outlet tube 35 into the unit for feeding of carbonaceous feedstock residue into the gasification reactor (4).

In the initial stage of feeding the upper slide gate 47 and lower slide gate 48 are shut. Because upper slide gate 47 is shut, carbonaceous feedstock residue accumulates in carbonaceous residue outlet tube 35 in the amount equal or smaller than the volume of inner chamber of sluice 46.

After calculated amount of carbonaceous feedstock residue has accumulated in the carbonaceous residue outlet tube 35, upper slide gate 47 opens under the impact of the movement of hydraulic cylinder of upper slide gate P8. Carbonaceous residue goes down from carbonaceous residue outlet tube 35 into the internal space of the chamber of sluice 46. After that upper slide gate 47 shuts down under the impact of hydraulic cylinder of upper slide gate P8. After it is shut, lower slide gate 48 opens under the impact of the movement of hydraulic cylinder of lower slide gate P9, and all carbonaceous residue from the inner chamber of sluice 46 is unloaded through vertical channel 49 into horizontal channel 50. From there, under the impact of spiral movement of screw mechanism 51, driven by electric or hydraulic drive P10, carbonaceous residue moves inside gasification reactor (5) through the open end of horizontal feeding channel 50.

Afterwards this process repeats automatically.

Design of gasification reactor

Gasification reactor (5) is schematically presented in Gig. 5. It is used for generation of synthesis gas from pyrolysis gases and carbonaceous feedstock residue, resulting from low- temperature pyrolysis of MSW in inclined rotary kiln for indirect heating (2).

It consists of the following components:

52. Body of the gasification reactor

53. Upper flange

54. Lower flange

55. Branch pipe for the input of pyrolysis gases

56. Branch pipe for installation of feeding unit

57. Outlet branch pipe for hot synthesis gas

58. Heat insulation jacket

59. Outer protective casing

60. Fuel chamber

61. Inner wall of the fuel chamber

62. Outer wall of the fuel chamber

63. Cone

64. Inner wall of the cone

65. Outer wall of the cone

66. Diffusors

67. Air channel

68. Inner wall of the air channel

69. Concentric insert of air channel

70. Air lances 71. Pyrolysis gases channel

72. Lid of the gasification reactor's body

73. Flange of the lid of the gasification reactor's body

74. Branch pipe for installation of mechanism of mechanical mixer

75. Mechanical mixer

76. Shaft with the blades of mechanical mixer

77. Supporting feet

PI 1. Motor of mechanical mixer

Design of gasification reactor

Gasification reactor (5) consists of the body 52 with outer heat insulation jacket 58 covered by outer protective casing 59. To the lower part of the rib of the gasification reactor 52, branch pipe for the input of pyrolysis gases 55 is welded by its end. Branch pipe for installation of feeding unit 56 is welded to the central part of the rib of the gasification reactor 52.

Upper flange 53 is welded to the upper end of the rib of the body of the gasification reactor 52. Heat-insulated lid of the body of gasification reactor 72 is attached to upper flange 53 by the flange of the lid of the body of gasification reactor 73. Outlet branch pipe for hot synthesis gas 57 is welded to one side of the gasification reactor's lid 72, and the branch pipe of the mechanism of mechanical mixer 75 is welded to the lid's central part.

Lower flange 54 is welded to the lower end of the rib of the gasification reactor 52, and device for unloading the slag (6) from the gasification reactor (5) is welded to the lower flange 54.

In the lower part of gasification reactor's body 52 fuel chamber 60 is located. It is hollow structure, the body of which consists of the inner wall of the fuel chamber 61 and its outer wall 62, connected in the lower part by concentric insert.

In the upper part of the fuel chamber 60 diffusors 66 are located. They are specially designed inserts, located between the inner wall of the fuel chamber 61 and the outer wall of the fuel chamber 62.

Over the fuel chamber 60 a cone 63 is located, representing a hollow structure, the body of which consists of the cone's inner wall 64 and outer wall 65.

Inner wall of the fuel chamber 61 is connected to the rib of the body of the gasification reactor 52 with the inner wall of the cone 64. The upper end of the inner wall of the gasification reactor 64 is welded inside to the middle part of the rib of the body of the gasification reactor 52. The lower end of the cone's inner wall 64 is welded to the upper end of the inner wall of the fuel chamber 61, whose lower end is welded to concentric insert. Outer wall of the fuel chamber 62 is connected with the rib of the body of the gasification reactor 52 with the outer wall 65 of the cone and concentric insert 69. The upper end of the cone's outer wall 65 is welded to the inside part of concentric insert 69, the outside part of which is welded from the inside to the middle part of the rib of the body of the gasification reactor 52. The lower end of the outer wall of the cone 65 is welded to the upper end of the inner wall of the body of the fuel chamber 62, whose lower end is welded to concentric insert.

In the lower part of the body of the gasification reactor 52 there is air channel 67 located between lower part of the inner wall of the rib of gasification reactor's body 52 and inner wall of air channel 68, limited at its bottom part by lower flange 54, in which there are air flange channels 83. Air channel 67 in its upper part has a projection in the hollow between inner wall of the cone 64 and outer wall of the cone 65, and further between inner wall of fuel chamber 61 and outer wall of fuel chamber 62 up to concentric insert in the bottom part of the fuel chamber 60.

Air channel 67 ends in C-shaped branch pipes in the upper part of which there are air lances 70 located at the centre of the opening of the diffusor 66 and in their lower part welded into the bottom part of the outer wall of the fuel chamber 62.

Inside bottom part of the body of the gasification reactor 52 there is a channel of pyrolysis gases 71, connected with the inlet pipe for pyrolysis gases 55 and located between the inner wall of air channel 68 at one side, and the outer wall of the cone 65 and outer wall of the fuel chamber 62 at its other side.

Inside upper part of gasification reactor's body 52 there is mechanical mixer 75 installed into a branch pipe for installation of mechanism of mechanical mixer 74 and connected to the lid of the body of the gasification reactor 72 by joining their flanges.

Mechanical mixer 75 is mechanical structure equipped with the shaft with blades of mechanical mixer 76, driven by a hydraulic or electric motor PI 1.

Four supporting feet 77 are welded from the outside to the lower part of the rib of the body of the gasification reactor 46. The gasification reactor (S) is attached to supporting structure that has the same base frame with supporting structure of inclined rotary kiln for indirect heating (2).

Operation of gasification reactor

Gasification process in gasification reactor (5) occurs inside working zone of the body of gasification reactor 52.

Carbonaceous feedstock residue resulting from low-temperature pyrolysis of feedstock in inclined rotary kiln for indirect heating (2) is transferred inside middle part of the body of the gasification reactor 52 through open end of horizontal channel 50 of the feeding unit for carbonaceous feedstock residue (4) installed in the branch pipe for installation of gasification reactor's feeding unit 56.

Automatic control system maintains the level of carbonaceous feedstock in the body of gasification reactor 52 at the level of the top edge of horizontal channel 50 of the unit that feeds carbonaceous feedstock residue (4).

Atmospheric air pumped into the gasification reactor (5) is initially heated up in the air channel 86 of the device for unloading the slag from the gasification reactor (6), heated to 250-300°C in the air channel 66 of the gasification reactor due to the cooling of internal parts of the gasification reactor, and is channeled through air lances 70 and diffusors 66 inside fuel chamber 60.

At the same time pyrolysis gases formed in inclined rotary kiln for indirect heating (2) are channeled through branch pipe for the input of pyrolysis gases 55 and channel for pyrolysis gases 71 into the gasification reactor (5).

Moving down the channel for pyrolysis gases 71, pyrolysis gases are additionally heated up by IR radiation of red-hot slag that there is at the bottom of the channel for pyrolysis gases 71.

Under the impact of the flow of air pumped into the fuel chamber 60 through air lances 70, ejecting suction of hot pyrolysis gases occur from the channel for pyrolysis gases 71 through the diffusors 66 inside fuel chamber 60. Velocity of heated air passing through air lances is up to 50 meters per second and its volume is calculated so that optimal amount and composition of synthesis gas is reached.

This process is structured as a system of ejecting devices, the number of whieh is equal to number of air lances 70 and respective number of diffusors 66 in the body of fuel chamber 60.

Part of pyrolysis gases that have not been ejected inside fuel chamber 60 move down along outer wall of fuel chamber 62 and go inside fuel chamber 60 through the open end of the channel for pyrolysis gases 71.

Contacting with carbonaceous feedstock residue and between themselves, heated air and hot pyrolysis gases create gasification process that can be relatively divided into seven temperature zones.

Zone 4 - Zone of the channel of pyrolysis gases of the gasification reactor: T 700 -

900°C;

Zone 5 - Zone of additional gasification: T 900 - 1350C ⁰ ;

Zone 6 - Zone of gas filtration: T 700 - 900°C; Zone 7 - Zone of high-temperature pyrolysis: T 900 - 1100°C;

Zone 8 - Zone of combustion and gasification: T 1100 - 1350°C;

Zone 9 - Slag zone: T 150 - 900°C.

Zone 10 - Gas zone: T 500 - 700°C;

Main process of gasification takes place inside fuel chamber 60 in the zone of combustion and gasification, due to exothermal reactions from combustion of some part of gases in low-temperature pyrolysis. In the torch of combustion of some part of pyrolysis gases the temperature of T 1100-1350°C is developed. This leads to thermal conversion of some part of pyrolysis gases that were not combusted and to the heating up to the same temperatures of released pyro-carbon and of the layer of carbonaceous feedstock residue that directly contacted the torch.

It must be noted that maximal temperature is only developed in the central part of the fuel chamber 60 in the area of torch combustion of pyrolysis gases. The hollow structures of the fuel chamber 60 and cone 63 are not overheated thanks to their inner cooling by relatively cool air passing through air channel 66.

It should also be mentioned that in the process of gasification only part of pyrolysis gases is combusted of those that enter the zone of combustion and gasification. Another part of these gases is subjected to thermal conversion resulting in the formation of conversion gases and residual pyro-carbon, which together with smoke gases of combustion take further part in the process of formation of synthesis gas in the bed of red-hot carbonaceous residue.

Fuel chamber's internal diameter is calculated for a throughput of 500-700 kilogram of feedstock per 1 square meter of cross section of fuel chamber 60 depending on the intensity of the flow of air and intensity of boiling of the bed of carbonaceous feedstock residue, caused by the process of formation of synthesis gas.

Hot synthesis gas formed in the fuel chamber 60 rises to the top, to the area of broad part of the cone 63, where the zone of high-temperature pyrolysis is located. In this zone hot synthesis gas is partially cooled down to the temperature T 900-1 100°C, heating to the same temperature carbonaceous feedstock residue that there is in this zone. Its high-temperature pyrolysis occurs at that time. In the process of high-temperature pyrolysis of carbonaceous feedstock residue the gases of high-temperature pyrolysis are formed. They, mixed with synthesis gas, rise through the layer of slow boiling carbonaceous residue into filtration zone. Filtration zone, where the temperature is T 700-900°C, is located in upper part of cone 63 and partially in the zone of gasification reactor's body 52. In this zone takes place the process of the cleaning of synthesis gas of the tars of high-temperature pyrolysis. Cleaning is done by their sorbing with relatively cold carbon of feedstock residue. Lowering of the temperature in this zone occurs due to the relatively cold carbonaceous residue conveyed into filtration zone from inclined rotary kiln for indirect heating (2) through the open end of horizontal feeding channel 44 of the feeding unit that loads carbonaceous feedstock residue into the gasification reactor (5).

Outer diameter of the cone 63, and diameter of gasification reactor's body 52 respectively, are calculated , relative to diameter of fuel chamber 60, so that synthesis gas that has formed and perform intense boiling of the bed of carbonaceous residue in the zone of fuel chamber 60, would slow the intensity of the boiling of the layer of carbonaceous feedstock residue due to its increasing surface in the zone of high-temperature pyrolysis, and, in particular, in filtration zone.

In this zone a process of the so-called "slow boiling" of the bed of carbonaceous feedstock residue occurs that allows maximal cleaning of synthesis-gas of the tars of high- temperature pyrolysis and other hazardous components. It also makes it possible to minimize the release of a large amount of feedstock dust in gas zone and further into the pipes of gas flue and in the gas jacket of inclined rotary kiln for indirect heating (2).

As synthesis gas is moving through the bed of carbonaceous feedstock residue, vertical gas channels can form in it. Synthesis gas can get through these channels from the zone of combustion and gasification, bypassing the zone of high-temperature pyrolysis and filtration zone, directly into the gas zone. This phenomenon is called "gas breakthroughs". It negatively affects gasification process and worsens the composition of generated synthesis gas.

To eliminate any possibility of formation of these gas channels in the bed of carbonaceous feedstock residue, mechanical mixer 75 is located inside upper part of gasification reactor's body 52. This mixer has a shaft with blades 76 that is put in motion by a hydraulic or electric motor Pl l . Making rotating movements around the shaft, the blades of mechanical mixer 76 mix the bed of carbonaceous feedstock residue, making impossible formation of vertical gas channels in it.

Besides, hot synthesis gas, when rising, carries along a part of carbonaceous feedstock residue from the centre of gasification reactor's body 52. Hot lower layers of carbonaceous feedstock residue tend to go up together with synthesis gas. This process is interrupted by the movements of the blades of mechanical mixer 76 that throw hot layers of carbonaceous feedstock residue to peripheral area, where they are somewhat cooled by inner wall of the cone 64. The wall is cooled down from the inside by the cold air going through air channel 67. Carbonaceous feedstock residue at that time starts moving down along inner wall of the cone 64, thus circulating inside the body of the gasification reactor 52. Having passed filtration zone, synthesis gas enters free upper part of the body of the gasification reactor 52, where there is gas zone of the gasification reactor. In this zone, due to the low speed of movement, not exceeding 0,3 - 0,8 m/s, and due to natural gravitation, synthesis gas is partially cleaned of feedstock dust. Then, through the outlet branch pipe for hot synthesis gas 57, located in the lid of the gasification reactor's body 72, it goes out of gasification reactor and transfers along heat-insulated channel into the gas jacket of the inclined rotary kiln for indirect heating (2).

Hot slag, formed in the process of gasification of carbonaceous feedstock residue in the zone of combustion and gasification, goes into the zone of additional gasification, where it is partially cooled while contacting cooler pyrolysis gases, entering this zone via lower open end of the channel for hot pyrolysis gases 71. Besides that, the cooling of hot slag occurs due to endothermal reactions of the interaction of hot pyrolysis gas with residual carbon in this zone, and through its cooling by the inner wall of air channel 68 cooled by colder air passing through air channel 67. Then the slag from the zone of additional gasification goes into the slag zone located in the device for unloading of slag from the gasification reactor (6), where it is cooled even more, is crushed and unloaded through the sluice 88.

The gasification reactor (5) has thermal insulation jacket 58 and outer protective casing 59 that minimize heat losses into the atmosphere while gasification reactor is in operation.

Device for unloading the slag from the gasification reactor

Device for unloading the slag from the gasification reactor (6) is a part of gasification reactor (5). It is presented in general in Fig. 5 and is used to remove the slag formed during gasification of carbonaceous feedstock residue in the gasification reactor (5).

It consists of the following components:

78. Outer body

79. Bottom

80. Inner body

81. Lower cone

82. Upper flange of the device for unloading the slag

83. Flange air channels

84. Crushing machine

85. Upper branch pipe of the slag unloading channel

86. Branch pipe of the air input channel

87. Air channel

88. The sluice 89. Upper slide gate

90. Lower slide gate

91. Lower branch pipe of the slag unloading channel

PI 2. Hydraulic cylinder of the upper slide gate

P13. Hydraulic cylinder of the lower slide gate

Design of the device for unloading the slag from the gasification reactor

Device for unloading the slag (6) from the gasification reactor (5) consists of the rib of the outer body 78, inside which there is the rib of the inner body 80 and upper flange 82, to which upper part of the rib of inner body 80 and upper part of outer body 78 are welded. To the lower part of the inner body's rib 80 lower cone 81 is welded, to lower part of which the upper branch pipe of the slag unloading channel 85 is welded.

In the lower part of the device for unloading the slag from the gasification reactor (6) there is the bottom 79, to which lower part of the rib of the outer body 78 and lower part of the lower cone 81 are welded.

Both outer body 78, and the bottom 79 of the device for unloading the slag from the gasification reactor (6) can be fitted with thermal insulation jacket and protective casing.

To make the inside of the gasification reactor (5) airtight, there is a sluice 88 in the lower part of the upper branch pipe of the slag unloading channel 85. The sluice 88 is equipped with the upper slide gate 89 and lower slide gate 90, driven by hydraulic cylinders P12 and P13.

The sluice 88 is joined in its upper part by its upper flange with the flange of the branch pipe of the slag unloading channel 85 with the bolts.

In its lower part the sluice 88 is joined by its lower flange with the flange of the lower pipe of the slag unloading channel 91 by the bolt joining of flange pair.

Crushing machine 84 is placed inside the rib of outer body 80. Crushing machine is equipped with the set of revolving disc mills mounted on water-cooled shafts.

Branch pipe of the air input channel 86 is welded tangentially to the bottom 79. Between the rib of outer body 78 and the rib of inner body 80 there is air channel 87, connected with gasification reactor's air channel 67 by flange air channels 83, located in upper flange 83 of the slag unloading device (6) and lower flange 54 of the gasification reactor (5).

Crushing machine 84 has a system of oil seals and bearings, and its own electric or hydraulic motor (not shown on the figures).

Operation of the device for unloading the slag from the gasification reactor

At the bottom of the gasification reactor (5) there is a device for unloading the slag (6), in the lower part of which there is tangentially placed air input branch pipe 86, through which cold air is supplied into the gasification reactor (5). Cold air, moving through air channel 87 between the lower cone 81 and the bottom 79, and between outer body 78 and inner body 80 cools down their surfaces heated by hot slag that there is inside inner body 80 and lower cone 81. This supply air is heated.

Similarly, upper flange 82 is cooled down by supplied cold air. Inside the flange there are flange air channels 83, connected with the same flange channels of lower flange 54 of the gasification reactor (5). Slightly heated air from air channel 87 of the device for unloading the slag (6) goes through flange channels 83 into the air channel 67 of the gasification reactor (5).

In the process of gasification of carbonaceous feedstock residue in the gasification reactor (5), the slag formed in fuel chamber 60 becomes hot monolith silicate formation and is transferred into the slag unloading device (6), where it is crushed by the disc mills of crushing machine 84.

Crushed slag is dropped into lower cone 81 and the upper branch pipe of the slag unloading channel 85, where it is cooled further by supplied cold air. Then, cooled and milled slag is removed through the sluice 88 from the device for unloading the slag (6) through lower branch pipe of the channel for unloading the slag 91.

Crushing machine 84 of the device for unloading the slag (6) operates in sync with all the mechanisms and devices of gasification technology complex SYNl-TC. This makes it possible to manage its efficiency, operate it uninterruptedly and achieve maximal thermochemical conversion of feedstock into synthesis gas in required composition, amount and quality.

DETAILED DESCRIPTION OF THE METHOD

Technological Complex SYNl-TC (SYNTENA 1) was developed for the implementation of technology SYNTENA 1- SFGP4, using gasification process SFGP4 (Slow Fluidized-bed Gasification Process 4). The main component of technological complex SYNl-TC (Technological Complex SYNTENA 1) is gas generator SYN1-GG (Gas Generator SYNTENA 1), in which phased thermochemical conversion of feedstock into synthesis gas occurs. Entire gasification process is relatively divided into ten separate temperature zones.

Zones of gas generator SYN1-GG for ermochemical conversion of feedstock into synthesis gas

The first three zones are the zones of low-temperature processing of the feedstock. Low-temperature pyrolysis of the feedstock (T<700°C) occurs in them. They are located in the pyrolysis part of gas generator SYN1-GG, which is a specially designed inclined rotary kiln for indirect heating SY 1-RK (Rotary Kiln SYNTENA1), installed at some angle to the horizon and heated by synthesis gas resulting from gasification of the feedstock. Remaining seven zones are the zones of high-temperature processing of the feedstock (T>700°C). These zones are located in gasification part of gas generator SYN1-GG, which is a gasification reactor for updraft gasification of the slow fluidized bed SYN1-SFG (Slow Fluidized-Bed Gasification reactor SYNTENA1). Its design is based on the new theory of gasification (Theory 4). The gasification reactor is connected with inclined rotary kiln SYN1-RK by a body junction or by tubes.

Zones 1, 2, 3, 4, 7 and 8 are parts of pyrolysis area, and zones 5, 6, 7, 8, 9 and 10 pertain to the area of gasification process. Zones 7 and 8 are parts at the same time the areas of both pyrolysis, and gasification processes.

Processes of heating, drying, low-temperature and high-temperature pyrolysis occur in gas generator SYN1-GG at the same time. Gasification processes of interaction between oxidizing gases and the products of thermal break-down of the feedstock take place in it too. Division of the process of gasification into the zones is relative, as well as the subdivision of the processes that take place in these zones. Many gasification processes proceed in different zones with varying intensity, so this idealization is done for the purpose of theoretical computations and better understanding of the processes, occurring inside gas generator.

It needs to be noted that the sequence of parts in this chapter does not correspond to the numbers of zones of gas generator, but is oriented towards succession of the processes of conversion of the solid part of municipal solid waste (MSW).

Municipal solid waste processed in the gas generator as its feedstock are incredibly diverse and multicomponent in their organic and mineral parts, and also have varying moisture contents. These are the key aspects of their conversion, largely affecting the amount and composition of generated synthesis gas, and formation of slag residue.

In order to describe the process of gasification SFGP4, a MSW of the so-called "bottom" residue resulting from sorting of solid waste is used. Morphology and element structure of MSW referred to further in the description and theoretical calculations are shown in Tables 1 and 2.

Table 1. Morphological composition of MSW

metals (Al + Fe) 0,30

particulate waste (dust, sand, etc.) 6,25

food waste 7,50

Total 100,00

Table 2 Element composition of MSW

Morphology and elements presented in the tables above are real and were used in the tests of technological complex PGP-ITPD, described in the Gasifier Draft Test Report of the University of California Riverside (UCR), USA.

With regard to mineral part, not only its composition has an effect, but also the form of inorganic components in the feedstock.

Two categories can be distinguished among inorganic components: mechanical inclusions, and components that are chemically related with the feedstock.

• First category is the main one and can include 6% to 25% of inorganic components relative to the total mass of feedstock. These are mechanical inclusions such as ferrous and non-ferrous metals, ceramics, building refuse, particulate waste, glass, etc., forming its mineral part that includes such important elements as: CaC0 ₃ , MgC0 ₃ , FeC0 ₃ , CaSC>4, Na ₂ S0 ₄ , FeS0 ₄ , FeS ₂ , Si0 ₂ , silicates with varying content of main oxides A1 ₂ 0 ₃ , S1O2, CaO, Na ₂ 0, K2O and small content of the oxides of other metals.

These components can be relatively arranged by their lowering content in the feedstock in the following order:

o S1O2 - dozens of percents of the total mass;

o Al, Al ₂ 03, MgO, Fe, F ₂ 0 ₃ , CaSi0 ₃ , CaC0 ₃ - a few percents, dozens of percents;

o Cu, Zn, S, Ti0 ₂ , FeO, Ni, Pb, Na ₂ Si0 ₃ , Sn, CaS0 ₄ , MgS0 ₄ , CI ^" , S ^2' , Na ₂ C0 ₃ - few percents, tenths of a percent;

o BaO, ZnO, Cd, NaCl, NaP0 ₄ , MgC0 ₃ , MgSQ ₄ , MgSi0 ₃ , K ₃ P0 ₄ , CaCl ₂ , MgCl ₂ , K ₂ C0 ₃ , Cr, Sb, SbO - tenths, hundredths of a percent;

o NaOH, LiOH, W, V ₂ 0 ₅ , Cr ₂ 0 ₃ , Ni ₂ 0 ₃ , PbO, ZnSi0 ₃ , F ^" , SO3 ^2" , Mn, V, Mo, As, Co, Hg, As ₂ 0 ₃ , BeO - less than hundredths of a percent;

• Second category includes fewer compounds and may reach from 0,47% to 2,81 ) of the total mass of the feedstock. They are present in the feedstock as components that are chemically related with the feedstock, e.g. the metals, their oxides and salts making parts of paper, cardboard. They are present in the wood, dyes in textile refuse, polymeric materials.

Zones of low-temperature processing of feedstock

Zone 1 - Zone of feedstock drying

Zone 1- Zone of feedstock drying is one of the zones of low-temperature processing of feedstock. The temperatures in it are: T 30 - 120 °C. It is located in the first section of the inner body of the inclined rotary kiln for indirect heating SYN1-R .

The following processes take place inside this zone:

• Fragmentation of the lumps of grinded feedstock formed while being fed. It is grinded to the fraction of primary grinding due to its drying and mixing inside the inner body of the rotary kiln;

• Homogenization of the feedstock;

• Initial heating of feedstock by the heat of exiting synthesis gas, conveyed through the walls of the inner body of rotary kiln;

• Final drying of the feedstock and intensive formation of vapor during the boiling of released moisture;

• Partial removal of colloid-bound water and adsorbed gases from the feedstock;

• Beginning of the process of the change of the state of matter of the low melt components of feedstock in the form of the softening of their surfaces;

• Beginning of the process of formation of gases.

In the drying process there distinction can be made between the free moisture, hardly related with the feedstock because absorbed during direct contact of the feedstock with water, and the moisture related to the structure of the feedstock, hygroscopic and acquired through adsorption of the water vapors.

During feedstock's drying by the heat of outgoing synthesis gas conveyed through the inner walls of the body of inclined rotary kiln, the speed of the drying grows rapidly, reaching its constant speed. The drying is accompanied by intensive formation of vapor caused by the boiling of free moisture in the feedstock.

Then the period of constant speed of the drying begins, and after feedstock reaches hygroscopic condition, the speed starts falling. This process is very dependent on the fraction composition of feedstock, on the load fed, and on the dynamic of its shuffling.

Thermal conductivity of feedstock constantly diminishes in the process of drying. Coefficient of thermal conductivity also reduces with diminishing moisture content, starting from critical point. Moisture content reduces due to deepening of the zone of evaporation and increase of thermal resistance of the dry outer layer of feedstock. These developments worsen the heating of inside layers of the feedstock, thereby prolonging the time of complete drying of internal layers of the feedstock.

But constant shuffling of the feedstock through rotation of the inner body of inclined rotary kiln allows to level the temperature and homogenize the feedstock, distribute these processes through all the feedstock loaded, improving therewith the process of its drying.

Water vapor released during the drying goes into the upper part of inside body of inclined rotary kiln, where it is partially heated up during the contact with the wall of the inner body of inclined rotary kiln.

Natural moisture and part of colloid-tied water is removed from the feedstock, but most of colloid-bound water remains in the feedstock.

Adsorbed gases are also released from the feedstock during its drying. Decomposition of the feedstock is at this time manifested weakly with these temperatures, it is only expressed in hardly noticeable formation of gases.

Beginning of the process of the change of the state of the low-melting-point components of feedstock in the form of the softening of their surfaces is also seen.

The feedstock's mass reduces during the drying, but without shrinkage, that is to say that its volume does not diminish, and only its further heating causes more profound structural changes.

Zone 2 - Zone of moisture removal from the feedstock

Zone 2 - Zone of the removal of moisture from the feedstock is one of the zones of low-temperature processing of the feedstock with the temperatures of T 120 - 300°C. It is located in the second section of the inner body of the inclined rotary kiln for indirect heating SYN1-RK.

The following processes take place inside this zone:

• final drying of the feedstock and removal of colloid-bound water from it;

• conversion of the state of matter of the feedstock occurs;

• processes of decomposition and destruction of organic polymers starts;

• initial formation of tars and of saturated and unsaturated hydrocarbons occurs.

Final drying of the feedstock and removal of colloid water from it

Complete drying of the feedstock and removal of colloid-bound water from it occurs at the temperature approximately T 200 °C. Splitting off of the functional categories occurs at this time accompanied by the reactions of condensation of the radicals thus formed:

As a result of this process, mineral colloids go into the vapor phase and water vapors thus formed go into the upper part of the inner body of inclined rotary kiln.

Change of the state of matter

Along with this, fusible materials of organic and inorganic origin change their state into plastic or fluid. At the temperature of T 120°C polyethylene starts melting, then the other polymers representing low-melting-point part of the feedstock. At the temperature of T 200- 250°C all the polymers turn fluid, and owing to conglutination of the particles of the feedstock, all its mass turn into separate plastic lumpy formations, slowly revolving inside the second section of the inner body of inclined rotary kiln.

Structural changes that occur in this zone make all the mass of the feedstock shrink significantly and reduce its volume. Its thermal conductivity grows, helping quicker heating of the lumpy structures of the feedstock, including their inner strata. But, despite this, internal parts of the lumpy structures of the feedstock heat up slower than their outer parts.

Beginning of the processes of decomposition and destruction of organic polymers

Decomposition of organic polymers (breakup of polymer chains) starts at approximately T - 250 °C:

(-CH ₂ -CH ₂ -) _n → (-CH ₂ -CH ₂ -)n- _{X l} + (-CH ₂ -CH ₂ -)n-x ₂ + (-CH ₂ -CH ₂ -)n-x ₎₎ (17)

Initial formation of saturated and unsaturated hydrocarbons and some other substances

The following processes occur in parallel with decomposition of polymers:

o Formation of saturated and unsaturated hydrocarbons, the reactions not being intensive:

R→CnH ₂ n + C _m H _2m+2 (18)

o Release of nitrogen, mainly molecular, in the form of ammonia and some other compounds containing nitrogen.

o Initiation of oxidation of hydrocarbons to phenols (Formula 21), acids (Formula 19, Formula 20) and other compounds containing oxygen, owing to release of oxygen from the feedstock.

o Formation of considerable amount of phenols:

C„H _2n + 0 ₂ → C _n- lH2n-2COOH (19)

(Formula 22)

C„H _2n + H ₂ 0→ C„H ₂ „ ₊ iOH (22)

This reaction is not sizeable.

As a result of these processes gases start to be released from the layer of feedstock in the form of oxide, carbon dioxide and tar. Methane, heavy hydrocarbon gases and hydrogen are released with further heating. The gases thus formed go into the upper part of the inner body of rotary kiln, where they mix up with water vapors.

At T 250°C the amount of released gas can be 2-2,5% of the weight of the feedstock loaded into the kiln.

These conversions result in feedstock losing both its weight and volume, and feedstock residue begins to be enriched by carbon.

Zone 3 - Zone of low-temperature pyrolysis of the feedstock

Zone 3 - Zone of low-temperature pyrolysis is one of the zones of low-temperature processing of feedstock. The temperatures in this zone are: T 300 - 700°C.

Zone of low-temperature pyrolysis of the feedstock is located in the third section of the inner body of inclined rotary kiln for indirect heating SYN1-RK.

Processes inside this zone are:

• formation of saturated and non-saturated hydrocarbons, release of the vapors of light resinous substances;

• structural changes in the mass of feedstock, its conversion into homogenous crushed mass of carbonaceous feedstock residue;

• disintegration of some organic salts with formation of respective oxides;

• beginning of the process of reduction of oxides into metals.

Formation of saturated and non-saturated hydrocarbons, release of the vapors of light resinous substances Reactions forming saturated and unsaturated hydrocarbons with small content of the atoms of C are predominant in this zone:

where n and m mainly have values 1-4.

Primary aromatic compounds are formed along with this process:

C„H _2n+ 2→ C„H„ +n/2H ₂ (25)

It is caused by the fact that, when the temperatures reach T -500°C, the process of condensation and aromatization of organic molecules intensifies, and its intensity peaks at the temperatures of 600 -700°C.

Among main reactions of this process are reactions of dehydration (Formula 11 and Formula 12) that can be divided into two parts:

o Primary reactions - reactions of milder dehydration with the release of unsaturated hydrocarbons (Formula 11).

o Final ones - reaction of total dehydration with formation of carbon and hydrogen (Formula 12).

Intensive formation of methane also occurs:

o Water vapors, released from the central part of the lumps of feedstock react with the carbon, formed on their surfaces and the walls of the device:

2C + 2H ₂ 0 CH ₄ + C0 ₂ (26)

o Methane as a consequence of interaction between carbon and hydrogen:

C + 2H ₂ <» CH (27)

Equilibrium of this reaction in these conditions is shifted towards formation of methane by 60 % only. Therefore reverse reaction is also considerable.

o Methane forms as a result of catalytic decomposition of various hydrocarbons (Formula 28). Different metals are catalysts. These metals are always present in feedstock. It also occurs because of the contact with metal walls of inner body of rotary kiln:

CnH _2n and/or C _m H _2m+ 2 ^Fe '' > CH ₄ (28)

Structural changes in the mass of feedstock

The following processes take place under the impact of rising temperature:

• Plastic material of the lumpy formations of feedstock solidifies and then carbonizes starting from its outer layers; • Carbon structure forms due to removal of hydrogen and formation of carbon- carbon bonds;

• Plastic lumps of feedstock residue disintegrate and all its mass turns into homogeneous ground mass of carbonaceous feedstock residue.

Metals and their salts contained in original feedstock and melt are incorporated into the forming carbon structure, producing significant impact on the process of pyrolysis, and later, on the process of gasification.

Decomposition of some organic salts with formation of related oxides

Initial temperature of decomposition of feedstock is determined mainly by its individual properties, and to some extent by the conditions in which its heating occurs.

The more there is bound oxygen the lower is the primary temperature of its decomposition. At initial stages of the heating of feedstock the first components that are released are components containing oxygen, and the last released are least oxidized tarry substances.

Large amount of oxygen in the feedstock causes exothermal effect in the process of the feedstock's heating. This happens because of reactions of oxidization, the feedstock is heated even more, which accelerates its destruction. This process is also sustained by decomposition of some inorganic salts, accompanied by formation of respective oxides in the process of heating of the feedstock loaded. H ₂ 0, C0 ₂ and NO2 also decompose according to reactions cited in Formulas 29-33:

o Bases

Me(OH) ₄ — '→ MeO + H ₂ 0, (29)

where Me = Ca(580°C), Be, Mg(550°C), Sr(500-850°C), A1(575°C), Cu(200°C) ₅ Zn(100-250°C), Cd(170-300°C), Mn(220°C), Co(170°C), Ni(230-360°C), others,

o Nitrates

MeNOs— i-> MeO + N0 ₂ , (30)

where Me = Ni(500°C), Cu(250°C), Mg(300 ^D C), Sr(570°C), Ba(670°C), and others, o Carbonates

MeCOs—→ MeO +C0 ₂ , (31 )

where Me = Mg (350-650°C), Pb (315°C), Be (180°C), Mn (100°C), Zn (357°C), Fe

(282°C), Cd (207°C) and others.

In other cases parts of organic salts break up and related oxides and oxygen 0 ₂ are formed:

o Peroxides

Me ₂ 0 ₂ — i_> Me ₂ 0 + 0 ₂ , (32) where Me = K(500°C), Na(400°C), Li(200-400°C), and others,

o Sulphides

MeS0 ₄ —!→ MeO + S0 ₂ + 0 ₂ , (33)

where Me = Fe"(700°C), Fe'"(600°C), Co(700°C), Ni(500°C), Sn(360°C), Cu(720°C), Ti(600°C), and others.

With the oxygen released, reactions of oxidation in the layer of feedstock intensify, augmenting temperature increase in this zone and intensifying the release of various products of destruction of feedstock, mainly such as water vapor, carbonic gas, carbon oxide, acetic acid, methyl alcohol, formaldehyde, tar, methane, ethylene, propylene and hydrogen, as well as some other products of decomposition, amounts of which depend on the morphologic composition of the feedstock.

Beginning of the process of reduction of metals from the oxides

In this zone starts the process of reduction of metals from oxides that were fed with the feedstock. This reduction results from the reactions shown in Formulas 34-36:

MeO + CO— ^→ Me + C0 ₂ , (34)

where Me = Fe "Fe2 ^IM (700°C), Pb(400°C), Cu(550°C), and others.

MeO + C—!→ Me + CO, (35)

where Me = Mn(600°-700°C), and others.

MeO + H ₂ — !→ Me + H ₂ 0, (36)

where Me = Sn(500-600°C), Pb(350°C), Cu(250°C), Cd(300°C), Mo(700°C), Co(500°C), Ni(400°C), and others.

Large amounts of polymeric materials in the feedstock causes respective growth of output of saturated and unsaturated hydrocarbons. The polymers at this stage decompose practically entirely and no carbon residue is formed.

With the temperature reaching T - 350°C, along with non-condensing gases condensing products start to be released in the form of the vapors of tar oil (tar), their mass increasing with growing temperature of the feedstock, reaching the maximum at T - 500- 550°C. Abovementioned processes of destruction of the feedstock and of formation of gases cause significant shrinkage of the feedstock's volume and to the conversion of its structure to a porous dry carbon form.

With further heating the process of the release of tarry substances and other products that may condense, if cooled, terminates entirely. Formation of gases though continues, albeit less intensively.

The products resulting from low-temperature pyrolysis and the products of decomposition of the feedstock rise into the upper part of the inner body of the inclined rotary kiln where they mix with water steam and with gases from the drying zone and zone of moisture recovery.

Pyrolysis gas thus obtained is subjected to heating with thermal radiation coming from the wall of the inner body of inclined rotary kiln, or by direct contact with the wall. The tars and particles of carbon residue deposited on the inner wall of inner body of inclined rotary kiln are removed under the impact of outside temperatures and water vapor coming from the zone of drying and zone of moisture removal, and through mechanical contact with carbonaceous feedstock residue occurring in the process of rotation of the inner body of inclined rotary kiln.

After that, carbonaceous feedstock residue from the zone of low-temperature pyrolysis of the feedstock located inside inner body of inclined rotary kiln SYN1-RK, goes into gasification reactor SYNl-SFG, where its high-temperature pyrolysis and subsequent gasification take place.

Gases of low-temperature pyrolysis go out of inner body of inclined rotary kiln SYN1- RK and go through a special channel into gasification reactor SYNl-SFG, where they are subjected to thermal conversion, partial combustion and further conversion into synthesis gas.

Zones of high-temperature treatment of the feedstock

Zone 8 - Zone of gas filtration

Zone 8 - Zone of gas filtration is one of the zones high-temperature processing of feedstock at the temperatures of T - 700 - 900°C.

In the gas filtration zone generated gas is cleaned of tars and other hazardous components of gas with the help of carbonaceous feedstock residue conveyed from the zone of low temperature pyrolysis. At this time all pyrolysis processes end and the gases generated so far are finally converted into hot synthesis gas.

The following processes take place within this zone:

• the process of low-temperature pyrolysis terminates;

• high temperature pyrolysis ends;

• generated gas is cleaned of tars and other hazardous gas components;

• composition of hot synthesis gas becomes complete.

Temperature in the gas filtration zone lowers to T - 700 - 900°C as compared to the temperatures of T - 900 - 1100°C in the zone of high-temperature pyrolysis mainly occurs due to relatively cold carbonaceous feedstock residue, continuously coming into this zone from the zone of low-temperature pyrolysis, situated in inclined rotary kiln for indirect heating. Carbonaceous feedstock residue coming from the zone of low-temperature treatment has the structure of dry substance consisting of carbonaceous elements in various fractions. It is predominantly small fraction containing carbons in the form of semi-coke, and solid mineral elements of the feedstock.

In the upper strata of the zone of gas filtration the processes completing low- temperature pyrolysis can occur, accompanied by the release of the residue of light hydrocarbons and tars only in case when carbonaceous feedstock residue was in the zone of low-temperature pyrolysis for a short time.

In the lower strata of filtration zone final processes of high-temperature pyrolysis can occur with the release of the residue of heavy hydrocarbons and tars.

As the gases formed in combustion and gasification zone move through the layer of carbonaceous feedstock residue, in the central section of the zone of gas filtration and of the zone of high-temperature pyrolysis vertical gas channels may form, and gases from the zone of combustion and gasification can get through these channels directly into the gas zone. This phenomenon is called "gas breakthroughs". These worsen the composition of generated synthesis gas.

Besides that, the hot gases formed in the zone of combustion and gasification trying to rise through the central part of the zone of high-temperature pyrolysis and into the zone of gas filtration draw with them a part of red-hot carbonaceous feedstock residue. This, along with the impact from hot gases, adds to the overheating of central parts of these zones. This circumstance causes an imbalance in temperature regimes in gas filtration zone and in high- temperature pyrolysis zone, negatively affecting entire gasification process.

In order to prevent the overheating of the central parts of these zones and formation of gas channels there, mechanical mixer is placed inside upper part of the gasification reactor. This mixer with horizontal movements of its vanes shuffles the layers of carbonaceous feedstock residue inside temperature zones. This makes impossible the formation of vertical gas channels and enables the formation of the zone of filtration of gas, using relatively cold carbonaceous residue, coming constantly from the zone of low-temperature pyrolysis.

Under the impact of the movement of the gases coming from the zone of high- temperature pyrolysis and of the movements of the vanes of mechanical mixer, all of the mass of the carbonaceous feedstock residue in the filtration zone starts moving in the manner resembling the process of "slow boiling", which allows to clean to maximal extent the gases resulting from the tars of high-temperature pyrolysis and other hazardous components by sorbing them with carbonaceous residue. Besides that, the process of "slow boiling" of carbonaceous feedstock residue also allows to minimize exit of any large amount of feedstock dust into the gas zone.

Because of this circumstance, gasification process described above was called Updraft Slow Fluidized-bed Gasification Process, created on the basis of Theory of Gasification 4 with the working not yet patented title SYNTENA1- SFGP4 (Slow Fluidized-bed Gasification Process 4).

Additionally, in entire volume of carbonaceous feedstock residue circulation process takes place, caused by upward movement of hot gases and the work of the vanes of mechanical mixer, throwing the layers of carbonaceous feedstock residue with sorbed tars and other hazardous components in the peripheral area, where they are cooled somewhat contacting cold wall of the cone of the gasification reactor. Carbonaceous feedstock residue starts at his point to move downwards along relatively cold inner wall of the cone of the gasification reactor into the zone of combustion and gasification. There under the impact of high temperatures sorbed tars and other hazardous components are released from it and further decompose. H ₂ 0 and C0 ₂ convert into primary combustible gases H ₂ and CO.

These processes proceeding in gas filtration zone make it possible to form final structure of synthesis gas, best clear it from the tars and other hazardous components, and minimize the release of feedstock dust together with it into the gas zone.

Zone 7 - Zone of high-temperature pyrolysis

The zone of high-temperature pyrolysis gasification reactor SYN1-SFG is one of the zones of high-temperature processing of the feedstock. Temperatures there vary between 900 and 1100°C.

The process of high-temperature pyrolysis of carbonaceous feedstock residue takes place in the zone of high-temperature pyrolysis, as well as the termination of all reactions of the process of gasification.

The following processes take place within this zone:

• reactions of high-temperature pyrolysis;

• gasification process of carbonaceous feedstock residue starts;

• part of inorganic salts break down and melt. They interact with carbon and mineral components of carbonaceous feedstock residue;

• reduction of the metals from the oxides;

• oxidation of reduced metal after C0 ₂ and H ₂ 0 act on them;

• feedstock residue turn into compressed, viscous mass of carbon.

Zone of high-temperature pyrolysis is formed out of solid feedstock residue transferred from inclined rotary kiln SY 1-RK in gasification reactor SY 1-SFG and heated up to the temperature of T - 900 - 1100°C due to thermal radiation coming from the zone of combustion and gasification and from the heat of hot gases rising from this zone.

Hot gases from the zone of combustion and gasification, passing through the zone of high-temperature pyrolysis, interact with carbonaceous feedstock residue and partially cool down to the temperature T 700 - 1100°C.

Essential processes in this zone occur at the T - 700 - 1100°C, at this time continues the release of volatile hydrocarbons and tars, part of which, affected by high temperatures, convert into simple gases H ₂ and CO. Another part is sorbed by carbonaceous residue formed in filtration zone, and a small part only gets into the gas zone. As a result of these processes the amount of carbon in feedstock residue reaches its maximum.

Also in this zone reactions of oxidation and reduction start. They take place in combustion and gasification zone. The process of high-temperature pyrolysis, in addition to the formation of primary gases H ₂ and CO, is generally characterized by the formation of small amounts of methane, hydrogen, carbon dioxide, water vapor, and traces of some other hydrocarbon gases.

Termination of the process of gasification of the feedstock

In the lower part of the zone of high-temperature pyrolysis, which has higher temperature, reactions of gasification continue, these reactions occurring in the zone of combustion and gasification.

Reactions of gasification (Formula 8, Formula 9 and Formula 4) that take place in this zone have clear endothermal nature, which is one of the factors facilitating the lowering of general temperature in this zone to T - 900 - 1100 °C:

H ₂ 0 + C = CO + H ₂ - 30 044 kcal/mole (8)

2H ₂ 0 + C = C0 ₂ + H ₂ ~ 20 195 kcal/mole (9)

C0 ₂ + C = CO - 39 893 kcal/mole (4)

Development of the process of high-temperature pyrolysis

Volatile hydrocarbons and tars continue to be released from carbonaceous feedstock residue in the entire volume of the zone of high-temperature pyrolysis. Predominant reactions are those, in which saturated and unsaturated hydrocarbons are formed (23) and tars with high content of the atoms of C:

R-> CnH _2n + C _m H _2m+ 2, (23)

where n and m equal 4 and more.

Hydrocarbons and tars generated in this zone as a result of high-temperature pyrolysis of carbonaceous feedstock residue, and those of them, which arrived from the zone of low- temperature pyrolysis, when acted on by high temperatures, remaining water vapors and carbon dioxide, begin conversion through the reactions of dehydration (Formula 11 and Formula 12), and vapor (Formula 37) and carbon dioxide conversion (Formula 38), during which primary flammable gases H ₂ and CO are formed:

CnH ₂ „ ₊₂ → C„H _2n + H ₂ (11)

C _n H _2n a CmH ₂ m+2→ (n+m)C + (2n+2m+2)H ₂ (12)

C _x H _y + XH ₂ 0— '→ XCO + (X + Y/2)H ₂ (37)

C _x H _y + X/2C0 ₂ — '→ (X + X/2)CO + Y/2H ₂ (38)

Reactions of Formula 37 and Formula 38 are catalytic, the catalyzer being different metals present in carbonaceous feedstock residue.

Residual part of heavy hydrocarbons and tars together with the rest of the gases go down into the zone of combustion and gasification, where they partially combust and are finally converted into primary flammable gases H ₂ and CO.

Besides formation of simple gases H ₂ and CO, the process of high-temperature pyrolysis is characterized by formation of small amount of methane, and of the traces of some other hydrocarbon gases.

Methane is formed in this process as a product of interaction of carbon with water vapor and hydrogen through the reactions:

2C + 2H ₂ 0 » CH ₄ + C0 ₂ (26)

C + 2H ₂ o CH ₄ (27)

This reactions is catalytic, its catalyzer, as in reactions with Formula 37 and Formula 38, are various metals present in carbonaceous feedstock residue.

Equilibrium of this reaction is in these conditions tipped towards formation of methane 60% only. Therefore reverse reaction is also tangible.

Methane is also formed during catalytic cracking of various hydrocarbons (Formula 28). The catalyzer, as in reactions with Formula 26 and Formula 27, are different metals present in carbonaceous feedstock residue, for example, iron (Fe):

CnH _2n and/or CmH _2m + ₂ ^Fe > CH ₄ (28)

Breakup of some part of inorganic salts and their interaction with carbon and other mineral components of carbonaceous feedstock residue

There is originally in solid urban refuse a large mineral component, whose concentration grows at its entering the zone of high-temperature pyrolysis due to the reduction of volume of carbonaceous feedstock residue, caused by extraction of moisture from it alonfg with gaseous products and tars in the zones of low-temperature processing.

Some inorganic salts are decomposed through the reactions with Formulas 29-33. These are the salts that have not broken up in the zone of low-temperature pyrolysis with formation of respective oxides and of H ₂ 0, C0 ₂ , NO2 and O2 through the reactions with Formulas 29-33:

Me(OH) ₄ —!→ MeO + H ₂ 0 (29)

MeN0 ₃ — '→ MeO + N0 ₂ (30)

MeC0 ₃ —!→ MeO +CO2 (31 )

Me ₂ 0 ₂ —!→ Me ₂ 0 + 0 ₂ (32)

MeS0 ₄ -^→ MeO + SO2 + 0 ₂ (33)

As a result of the processes in this zone, oxides of various metals are formed from the mineral part of the feedstock. These metal oxides have impurities of carbon and insignificant amounts of salts that have not yet decomposed, and some pure reduced metals. Depending on feedstock's original composition, some amount of metal alloys is formed. The basis of these alloys are iron, copper and silicon.

It needs to be mentioned that in these processes take part mineral components of feedstock that are both chemically bound with organic components (second category), and constitute mechanical impurities (first category).

Reduction of metals from oxides

Some part of metal oxides breaks up in the zone of high-temperature pyrolysis under the impact of high temperatures, especially in the lower part of this zone that borders on the zone of combustion and gasification:

MeO—!→ Me + O, (39)

where Me = CdO (900°C), CuO (1026°C), and others.

Part of the metals is reduced from the oxides while contacting red-hot carbon:

MeO + C— ^! → Me + CO, (40)

where Me = Na(900-1000°C), Ca(800-850°C), Ba(1000°C), Li(800°C), Sn(800- 900°C), Cd, Mn(600°-700°C), Cd, Ni, and others.

Oxidation of reduced metals under the impact of CO2 and H2O.

The process of oxidation of reduced metals brought into the zone of high-temperature pyrolysis together with carbonaceous feedstock residue from the zone of low-temperature pyrolysis and zone of gas filtration (Formulas 34-36), and of those formed in this zone as a result of reactions with Formulas 39-40 can occur under the impact of remaining water vapors (H ₂ 0) and carbon dioxide (CO2), formed in this zone:

where Me = Ti(800°C), Cr(700°C), Mo(700°C), and others.

Me + C0 ₂ = MeO + CO, (42)

where Me = Zn(600-700°C), and others. Then the metals oxidized to oxides as a result of reactions with Formulas 41-42 are reduced again from the oxides in the reactions with Formulas 39-40. Alternating reactions of oxidation and reduction continue through all the period of the metals presence in the zone of high-temperature pyrolysis.

Reduced metals become acceptors of oxygen in the molecules of C02 and H ₂ 0 in the reactions of Formulas 41-42, converting them in simple flammable gases CO and H ₂ .

Alternating processes of the reduction of metals from the oxides (Formulas 39-40) and subsequent oxidation of reduced metals (Formulas 41-42) reduces the content of C0 ₂ and H ₂ 0 in the gases obtained in the zone of high-temperature pyrolysis and conveyed from the zone of combustion and gasification. Additional amounts of CO and H ₂ are also generated in the process.

With gasification reactor working, this process expands down to the zone of combustion and gasification, where these reactions intensify.

Cleaning of the gases by removing NOx, SO2, HC1, E S, NELt and COS.

In the zone of high-temperature pyrolysis the process of cleaning of the obtained gases of hazardous gas components. This process occurs mainly in the zone of combustion and gasification.

Cleaning of obtained gases by removing S0 ₂ and NO _x can also be done with reactions with the carbon:

Me + H ₂ S = MeS + H ₂ (45)

Me + HC1 = MeCl + H ₂ (46)

After that C0 ₂ can be restored to the CO with reaction of Formula 4:

C0 ₂ + C = 2CO (4)

Under high temperatures parts of the metals in the form oxides, as well as pure metals and their salts, may be transformed into gases. But even in this case the larger part of those volatile metals and their compounds remain solid or liquid. The reasons for that are either insufficient residence time in the zone of high-temperature pyrolysis, or the formation of the other less volatile compounds in the form of oxides, or other substances, e.g. sulfides, nitrides or chlorides.

Both metal oxides and reduced metals can be a part of the cleaning of the gases obtained of such materials as HC1, H ₂ S, NH and COS. The metals can be both solid, or melt, or in a gas state.

With the oxides this process occurs through the reactions of Formulas 43-44; with reduced metals the reactions are described in Formulas 45-48:

MeO + H ₂ S = MeS + H ₂ 0 (43) eO + 2HC1 = MeCl ₂ + H ₂ 0 (44)

Me + H ₂ S = MeS + H ₂ (45)

Me + HCl = MeCl + H ₂ (46)

Me + COS = MeS + CO (47)

Me + NH ₄ = MeN+ 2H ₂ (48)

As a result of the reactions above, the gases resulting from the processes of combustion and gasification are cleaned of hazardous components, and additional amounts of the CO and ¾ are obtained with respective amounts of sulfides, chlorides and nitrides.

Further on, all these gases rise through the "slow fluidized bed" of carbonaceous feedstock residue into filtration zone, where they are additionally purified.

Elutriation of carbonaceous residue

Slow boiling, or "fluidization" of the bed of carbonaceous feedstock results in the development of the process elutriation of carbonaceous feedstock by weight and fractions.

This process is natural, as it is caused by Archimedean force of rising gases in the layer of carbonaceous feedstock from one side, and by the force of gravitation of the Earth, from the other side.

This process results in the separation of entire mass of carbonaceous feedstock residue into the fractions, and low speed of gas flow facilitates the rise of only small and light fractions upwards into the zone of gas filtration. Large and heavy fractions tend to go down into the lower part of the bed, in the zone of combustion and gasification.

Large inorganic components of the feedstock of the first category, and the small ones shielded by carbon inside big lumps of feedstock, may quickly go into the zone of high- temperature pyrolysis because of their large size and weight. They may go down into the zone of combustion and gasification, affected only weakly by high temperatures in that zone.

Transformation of carbonaceous feedstock residue into compressed viscous mass of carbon

The process of melting of some mineral salts occurs in the zone of high-temperature pyrolysis.

All the chlorides are melted in this process (CaCl ₂ - 787 °C, NaCl - 801 °C, and others), some carbonates (Li ₂ C0 ₃ - 618°C, Na ₂ C0 ₃ - 851°C, K ₂ C0 ₃ - 89 C, and others) and some oxides (K ₂ 0 - 740°C, Mn0 ₂ - 847°C, PbO - 890°C, CdO - 900°C, SnO - 1040°C, and others).

Mineral components of feedstock undergo melting, both those bound with organic components (second category), and those that are mechanical impurities (first category). Small mechanical inclusions of the first category, and particularly mineral components of the second category, evenly dispersed in the organic part of carbonaceous feedstock residue, are strongly shielded by carbon from the impact of high temperatures, so in the upper part of the zone of high-temperature pyrolysis they do not melt considerably. In the lower part of the zone of high-temperature pyrolysis bordering on the zone of combustion and gasification the melting of some part of inorganic salts largely intensifies, this melting being caused by general rise in temperatures and reduction of the shielding of the salts by carbon. This happens due to their higher concentration provoked by the process of secondary gasification.

General rise in temperature in the lower area of the zone of high-temperature pyrolysis and high concentration of mineral components with low melting point resulting from the reactions of reduction creates along with high-melting point components of feedstock also eutectic alloys with low melting points.

Due to high concentration of melted mineral salts these processes in the lower part of high-temperature pyrolysis zone cause transformation of carbonaceous feedstock residue into a red-hot crumbly porous mass of carbon.

Zone 4 - Zone of the channel for pyrolysis gases of the gasification reactor

The zone of the channel for pyrolysis gases of gasification reactor SYN1-SFG is one of the zones of high-temperature processing of the feedstock. The temperatures in the zone are T 700 - 900°C.

Zone of the channel for pyrolysis gases of the gasification reactor is located in the inner volume of the body of gasification reactor SY 1-SFG.

In this zone:

• additional heating of gases of low-temperature pyrolysis takes place;

• process of conversion of hydrocarbons in gases of low-temperature pyrolysis intensifies;

• the gas of low-temperature pyrolysis is divided into two flows going in different directions.

Thus in this zone the mixture of gases of low-temperature pyrolysis formed in the zones of drying, moisture recovery and low-temperature pyrolysis of inclined rotary kiln SYNl-RK go through a special gas channel into the channel for pyrolysis gases of gasification reactor SYN1-SFG. Moving down this channel along vertical part of gasification reactor's body, gases of low-temperature pyrolysis are divided into two flows:

• The first flow is distributed through the diffusors of nozzle devices of the fuel chamber and transfers through them into the zone of combustion and gasification; • Second flow goes downwards and exits into the zone of additional gasification through the open end of the channel for pyrolysis gases of the gasification reactor, thus entering the zone of combustion and gasification.

Going through the channel for pyrolysis gases, the low-temperature pyrolysis gases undergo thermochemical conversion. Both hydrocarbons, and tars that they contain are subjected to this conversion.

Reactions of dehydration (Formula 11 and Formula 12) presented earlier are the main reactions of this process:

C„H ₂ n ₊ 2→ C„H _2n + H ₂ (11)

C _n H ₂ „ H CmH _2m +2→ (n+m)C + (2n+2m+2)H ₂ ( 12)

The reason why these transformations take place is the impact of high temperatures conveyed from the red-hot rib of the feed channel into this zone through the lower open end of the channel for pyrolysis gases from the zone of combustion and gasification. These temperatures are conducive to the reactions of conversion of hydrocarbons.

High content of water vapors in the composition of low-temperature pyrolysis gases is one of the reasons for reactions of conversion of hydrocarbons in this zone.

Tar vapors in the form of "primary tar oil" formed in the colder zones of low- temperature pyrolysis also undergo partial pyrolysis in this zone.

But, because gas mix remains in the zone of the channel for pyrolysis gases for only a short time, only a part of gaseous hydrocarbons and tar vapors are subjected to thermal conversion.

Zone 6 - Zone of combustion and gasification

Zone of combustion and gasification of gasification reactor SYNl-SFG is one of the zones of high-temperature treatment of the feedstock with the temperatures: T 1100 - 1350°C.

The process of gasification of carbonaceous residue is a very complex process. It is a part of high-temperature processing of the feedstock. It is executed simultaneously in all the seven zones of gasification reactor SYNl-SFG, but the main process of gasification of carbonaceous feedstock residue generating very high quality synthesis gas takes place in the zone of combustion and gasification under the temperature T 1100 - 1350°C.

Several processes take place in the zone of combustion and gasification. They occur in the inner volume of gasification reactor's fuel chamber. These processes are the result of the complex interaction of hot pyrolysis gases coming from the channel for pyrolysis gases inside fuel chamber, of the oxygen of heated air conveyed into fuel chamber through air lances, and of red-hot carbonaceous feedstock residue.

These processes can be tentatively broken into a few closely tied processes going on in parallel:

• conversion of carbon residue of the feedstock into the state of a "boiling" or "fluidized" bed;

• partial combustion of pyrolysis gases formed in the zone of low temperature processing of feedstock;

• gasification of carbonaceous residue of feedstock;

• thermal conversion of hydrocarbons and tars entering the zone of combustion and gasification;

• melting of inorganic component of carbonaceous residue;

• reactions of oxidation and reduction in inorganic component of carbonaceous residue;

• cleaning of the gases with the removal of hazardous components of gas;

• formation of slag.

Transformation of carbonaceous feedstock residue into the state of 'fluidized" bed

It needs to be pointed out that the processes of combustion and gasification in the fuel chamber of gasification reactor SYN1-SFG differ in principle from similar processes in conventional gasification reactors. This difference can be shown in the diagram of horizontal cross-section of fuel chambers presented in Fig. 6.

A special feature of gasification reactor SYN1-SFG is that the hot mixture of pyrolysis gases is conveyed into the space under the lances of fuel chamber from the channel for pyrolysis gases and from the zone of additional gasification. This mixture contains large amounts of simple hot gases H ₂ , CO, and CH ₄ , and certain portion of hydrocarbon gases and tars with high calorie value.

At the same time, carbonaceous feedstock residue, heated up to T - 1100°C, comes into the fuel chamber of the gasification reactor from the zone of high-temperature pyrolysis. In this heated bed of the residue rapid combustion take place of a part of pyrolysis gases composed mainly of simple hot gases H ₂ , CO, and some amount of CH ₄ . Combustion occurs under the impact of the flow of hot air blown through the lances at a speed of up to 50 meters per second. This causes considerable local rise of temperature in this zone up to T - 1500°C.

Gas mixture, entering the fuel chamber, also contains water steams ¾0 and carbon dioxide gas C0 ₂ . These actively participate in gasification process and themselves lower the temperature of combustion of gas mixture. This make it possible to control the temperature in the fuel chamber either through the general moisture content of loaded feedstock, or by feeding additional amounts of H ₂ 0 or C0 ₂ into the gasification reactor. Due to the high velocity of the air flow a "zone of combustion of pyrolysis gases" and a "zone of gasification of carbonaceous feedstock residue" are formed in front of the air lances. Their general configuration is presented in Fig. 6.

Thanks to the advantageous design of gasification reactor SYN1-SFG, processes of combustion and gasification occur in virtually all span of the fuel chamber located in front of the air lances.

Combustion process is distributed evenly in the zone of combustion of pyrolysis gases and gasification process is distributed evenly in the zone of gasification of carbonaceous feedstock residue thanks to the large number of air lances and high speed of the air blown through them. This, in turn, makes possible:

• maximally even supply of all the span of the zone of torch combustion of pyrolysis gases with air;

• to increase the depth of combustion to the very centre of the gasification reactor;

• to reduce the size of the segments of carbonaceous feedstock residue in gasification zone, which makes easier their faster heating and subsequent gasification;

• to cut, crush and loosen carbonaceous feedstock residue using powerful torch jets;

• to improve gas dynamic behavior in combustion zone by creating powerful effect of fluidization of carbonaceous residue in the volume of gases resulting from gasification. This, in its turn, allows us to avoid the formation of local stagnating cold areas (1) in this zone;

• elutriate inorganic part of carbonaceous residue, when larger and heavier inclusions (first category) go down into the zone of additional gasification and then in the slag zone, and smaller ones (of the first and second categories) are melted in combustion zone;

• using the high velocity of torch jets, the not melted inorganic particles or the drops of melted slag can be transferred into the central part of the zone of combustion of pyrolysis gases, thus forming a slag cone in its centre (3).

• to raise the temperature not only in the area of air lances, but in all the volume of combustion zone, thus intensifying to maximal extent the process of gasification, to increase the level of conversion of the tars, acids and composite hydrocarbons in this zone.

These actions maximally intensify the processes of combustion of pyrolysis gases, thermochemical conversion of different hydrocarbons and tars, and gasification of carbonaceous feedstock residue in the area of fuel chamber of gasification reactor SYN1- SFG. The process of partial combustion of pyrolysis gases formed in the zone of low- temperature processing of the feedstock

Partial combustion of pyrolysis gases in the bed of carbonaceous feedstock residue occurs in the zone of combustion of pyrolysis gases. Combustion occurs under the impact of oxygen of the air, conveyed into the fuel chamber of the gasification reactor that represents a system of torch combustion of gases shown in Fig. 6.

This is a diffusion process, because the air is fed into the fuel chamber through the air lances, and pyrolysis gases are conveyed through the diffusors or through the lower end of the fuel chamber. Air oxygen, as an oxidizer, and combustible pyrolysis gases are separated from each other in base mixture are transferred into the fuel chamber via diffusion.

Partial combustion of pyrolysis gases occurs due to the fact that the amount of air oxygen supplied into the fuel chamber of the gasification reactor is insufficient for complete burning out of these gases, the latter being key precondition for entire process of gasification.

During the combustion of a part of pyrolysis gases the reactions that occur first of all are homogenous reactions of oxidation with air oxygen of gaseous products specifically. Heterogeneous reactions of oxidation with air oxygen of the solid carbon are less frequent. This phenomenon is explained by the fact that the velocities of homogenous reactions (gas - gas) are higher of one or two orders than of those heterogeneous (gas - solid matter).

Besides, when part of pyrolysis gases combust in an oxygen-depleted environment, simple combustible gases H ₂ , CO and to some extent CH ₄ have priority in combustion due to high velocity of laminar expansion of fire in these gases. Only after combustion of these gases may various hydrocarbon gases and tars partake in combustion, and only after them carbon may combust.

The dynamic of reactions of combustion is branching-chain with progressing self- acceleration owing to the heat released in exothermal reactions, and the volume of air oxygen conveyed into the fuel chamber is calculated on the basis of thermal energy needed to maintain temperature regime in all the zones of the gasification reactor, and for generation of synthesis gas of best possible composition and amounts.

The process of partial combustion of pyrolysis gases in an oxygen-depleted environment can be schematically presented in the equations of Formula 10 and Formula 13:

CxHyO _z + ((2(x-a)+y/2-z)/2)0 ₂ = x-aC0 ₂ + y/2H ₂ 0 + aC (10) or

H ₂ + CO + CaHb + 0 ₂ -→C0 ₂ + H ₂ 0 + H ₂ + C (13) These equations (Formula 10 and Formula 13) describe the process of partial combustion in the zone of combustion and gasification of a part of products of low- temperature, and in part high-temperature pyrolysis with the release of residual pyro-carbon.

Equations of Formula 10 and Formula 13) may also be presented as a complex interaction of simple reactions of oxidation (Formulas 14-18), and of reactions of dehydration (Formula 11 and Formula 12):

C _n H _2n+2 → C„H ₂ „ + H ₂ (11)

CnH _2n H C _ra H ₂ m+2→ (n+m)C + (2n+2m+2)H ₂ ( 12)

2H ₂ + 0 ₂ = H ₂ 0 + 58 kcal/mole (14)

2CO + 0 ₂ = 2C0 ₂ + 136 kcal/mole (15)

CH ₄ + 20 ₂ = C0 ₂ + H ₂ 0 + 193 kcal/mole ( 16)

C ₂ H ₄ + 30 ₂ = 2C0 ₂ + 2H ₂ 0 + 316 kcal/mole (17)

C ₃ H ₆ + 4,50 ₂ = 3C0 ₂ + 3H ₂ 0 + 460 kcal/mole (18)

This presentation is based on the fact that gaseous products of pyrolysis are oxidized, first of all, by air oxygen, and only after that they start interacting with carbon dioxide gas and water steam formed during combustion of pyrolysis gases during pyrolysis of the feedstock. At that time the major part of the hydrocarbons and tars that make part of pyrolysis gases undergoes dehydration in this zone, and large amount of hydrogen (H ₂ ) and finely dispersed pyro-carbon (C) are generated.

To intensify the process of combustion and gasification hot air is conveyed at high speed into combustion and gasification zone. This air is heated as a result of the cooling of the components and parts of gasification reactor. If need be, water steam (H ₂ 0) and/or carbon dioxide (C0 ₂ ) may be fed into this zone.

High speed of the air exiting air lances permits to loosen the carbonaceous feedstock residue mass in entire span of the fuel chamber, and in particular, in the area of the band of air lances. It makes possible to create in this zone a powerful effect of "boiling" of carbonaceous feedstock residue in the volume of gases formed in the process.

This circumstance makes possible considerable acceleration of the diffusion for interacting gases, and significant increase of the area of the surface of heterogeneous phase for carbonaceous residue. Velocity of adsorption of oxidizing gases and velocity of desorption of reaction products may be increased too. This substantially enhances reactions of oxidation, hence reactions of reduction in this zone, and, in turn, considerably improve the composition of generated synthesis gas.

Air oxygen in the process of combustion is virtually totally expended in the reactions of oxidation of a part of pyrolysis gases, in which mostly carbon dioxide, water steam and pyro-carbon are released. These then become the main agents together with carbonaceous feedstock residue in the process of gasification. In this same zone the nitrogen (N) and sulphur (S) are oxidized to the oxides NO _x and S0 ₂ . Their amount depends on initial content of these elements in the feedstock and on the gas dynamic during diffusion combustion of the part of pyrolysis gases inside fuel chamber.

In the zone of combustion of pyrolysis gases reactions that form NH ₄ , COS, H ₂ S, HC1 and other gases also occur. These, being hazardous components, shall be removed from generated gas.

Gasification of carbonaceous feedstock residue

Gasification of carbonaceous feedstock residue is executed in the zone of gasification of carbonaceous feedstock residue. This process constitutes the conversion of combustion gases C0 ₂ and H ₂ 0 into the simple combustible gases H ₂ and CO due to their restoration in the fluidized bed of carbonaceous feedstock residue.

High velocity of homogeneous reactions of partial combustion of pyrolysis gases results in virtually all supplied oxygen reacting in a narrow space around air lances of fuel chamber. Thermal energy released in the process causes local overheating of carbonaceous feedstock residue in the area of the band of air lances, and significant rise in temperature in all the zone of combustion and gasification. This circumstance enables maximal intensification of gasification process, to raise the level of conversion of tars, acids and hydrocarbon compounds in this zone.

All the gases conveyed into the zone of combustion and gasification and formed as a result of the process of combustion as they interact with red-hot carbonaceous residue are mainly reduced to simple combustible gases in the reactions represented by Formula 4, Formula 8 and Formula 9:

H ₂ O + C = CO + H ₂ - 30 044 kcal/mole (8)

2H ₂ 0 + C = C0 ₂ + H ₂ - 20 195 kcal/mole (9)

C0 ₂ + C = CO - 39 893 kcal/mole (4)

These three reactions are main reactions of gasification, the first two (Formula 8 and Formula 9) being reactions of hydrogasification, and the last (Formula 4) is a reaction of carbon dioxide gasification when carbon monoxide is released.

Rising of the temperature in the zone of combustion and gasification accelerates and increases the rate of reactions of hydrogasification (Formula 8 and Formula 9) by additional heating of carbonaceous residue and water steam resulting both from combustion of pyrolysis gases (Formula 10), and from low-temperature processing of the feedstock. Increase of the rates of reactions of hydrogasification (Formula 8 and Formula 9) makes possible the use of the feedstock with high moisture content without its deep drying pre-treatment or additional feeding of water or water steam into the gasification reactor from the outside. Under the impact of initial high temperatures the rate of reaction of carbon dioxide gasification of carbonaceous residue (Formula 4) also grows. This makes theoretically possible to use carbon dioxide fed from outside the gasification reactor as an additional oxidizer.

Reactions of Formula 4, Formula 8 and OopMyjia 9) primarily occur at a boundary of the process of torch combustion of pyrolysis gases in the bed of carbonaceous residue and at the periphery of this process.

Because these reactions are reductive and are explicitly endothermal, the temperatures of the gases formed in the zone of combustion and gasification decrease to T - 1100-1350°C, limiting the overheating in this zone to T - 1500°C only in the area of torch combustion of pyrolysis gases.

Hot gases resulting from the process of gasification move upwards, thus towards a layer of carbonaceous feedstock residue moving down from the zone of high-temperature pyrolysis, heating it and setting it in motion in the form of suspension layer. At this time the temperature in the upper part of the zone of combustion and gasification rises to T - 1100 - 1200 °C.

Reactions of reduction (Formula 4, Formula 8 and Formula 9) continue in this part of the zone of combustion and gasification. These reactions result in continuing gasification - with remaining carbon dioxide and water steam - of the bed of the heated carbonaceous residue, rising into the zone of high-temperature pyrolysis.

In high-temperature pyrolysis zone the hot synthesis gas is additionally cooled to T 700 - 1100°C, heating to the same temperature carbonaceous feedstock residue in this zone, subjecting it to partial gasification and high-temperature pyrolysis.

Intensification of the reactions of gasification (Formula 4, Formula 8 and Formula 9) due to high temperatures and intense gas dynamic inside the bed of carbonaceous feedstock residue results in the gases with high content of H ₂ and CO, thus lower content of C0 ₂ and N ₂ .

The process of thermal conversion of hydrocarbons and tars coming into gasification and combustion zone

In the zone of combustion and gasification a very important process occurs besides the processes of combustion of pyrolysis gases and of gasification of carbonaceous feedstock residue. This process has serious impact on the composition of the gases obtained in this zone. This process is thermal conversion of hydrocarbons and tars that within pyrolysis gases come into the zone of conversion and gasification from the channel of pyrolysis gases of the gasification reactor, from the zone of additional gasification and partially from the zone of high-temperature pyrolysis.

It should be noted that various hydrocarbons and tars in the pyrolysis gases going into the zone of combustion and gasification from aforementioned zones, have more carbon and hydrogen as compared to other combustible gases that are parts of pyrolysis gases.

Given the fact that during the combustion of pyrolysis gases simple combustible gases H2, CO and to some extent CH4 have a priority in combustion in a depleted oxygen environment, and that conditions of gas dynamics in the fuel chamber of the gasification reactor intensify combustion process and heighten the temperature of combustion to 1500 °C in the area of fuel chamber, where the air lances are situated, favourable conditions for thermal conversion are created in the zone of combustion of pyrolysis gases and in the zone of gasification of carbonaceous feedstock residue (Zone 6.1 and Zone 6.2 in Fig. 6), as well as in all of the gasification reactor.

Because of that the hydrocarbons and tars entering the zone of combustion and gasification from the channel for pyrolysis gases of the gasification reactor undergo dehydration through the reactions of Formula 11 and Formula 12):

C _n H _2n+ 2→ C _n H _2n + H ₂ (11)

C„H ₂ „ H C _m H _2m +2→ (n+m)C + (2n+2m+2)H ₂ (12)

The largest part of hydrocarbons and tars that are part of pyrolysis gases are subjected to the process of dehydration in this zone. At this stage large amount of hydrogen (H ₂ ) and of fine-dispersed pyro-carbon (C) are released.

These capabilities of gasification reactor SYN1-SFG and gasification process SYN1- SFGP4 in general are well correlated for the processing of various types of feedstock with high content of hydrocarbons and chars in gas phase, and with low content of residual carbon. Municipal solid waste is exactly this kind of feedstock.

Besides the process of dehydration, the hydrocarbons and tars that are part of pyrolysis gases can undergo in this zone the steam and carbon dioxide conversion through the reactions shown in Formulas 37-38:

C _x H _y + X 2C0 ₂ (X + X/2)CO + Y/2H ₂ (37)

CxH _y + XH ₂ 0 XCO + (X + Y/2)H ₂ (38)

Large amounts of water steam (H ₂ 0) and carbon dioxide (C0 ₂ ) that enter the zone of combustion and gasification along with pyrolysis gases, or resulting from combustion enhance this process.

Reactions of Formula 37 and Formula 38 are catalytic, the metals in carbonaceous feedstock residue serving as catalyzers.

Remaining part of the heavy hydrocarbons and tars not subjected to thermal conversion rise together with gases formed in the zone of combustion and gasification into the zone of high-temperature pyrolysis, and then into filtration zone, where they go on undergoing various thermochemical processes.

In the filtration zone simple combustible gases H ₂ and CO and fine-dispersed pyro- carbon are formed as a result of the thermal conversion of carbons and tars going into the zone of combustion and gasification from the channel for pyrolysis gases as a part of gases of low-temperature pyrolysis and carbons and tars of high-temperature pyrolysis sorbed by carbonaceous residue.

Melting and breakdown of inorganic ingredients of carbonaceous residue

Inorganic ingredients of the feedstock come into the zone of combustion and gasification from high-temperature pyrolysis zone in the state differing from initial as a result of thermochemical transformation they have undergone in the zones preceding combustion and gasification zone.

Despite the fact that all inorganic ingredients in these zones were shielded by newly formed carbon and might have been subjected to only a weak impact from high temperature, one can assume that major part of them underwent structural changes within the range of the temperatures typical for various inorganic components.

This assumption is based on the following factors:

• continuous presence of inorganic components in these zones, hence their possible heating to relevant temperatures even when shielded by carbonaceous formations of feedstock;

• Mechanical impact on the feedstock inside rotary kiln due to its rotation and movements of the blades of the mixer in the gasification reactor;

• destruction of large carbonaceous lumps due to the gas dynamic inside gasification reactor's body.

High temperature impact results in structural transformations of the feedstock. Inorganic ingredients thus proceed from the zone of high-temperature pyrolysis into the zone of combustion and gasification in the form of:

o the oxides resulting from the reactions shown in Formulas 29-33 :

Me(OH) ₄ —!→ MeO + H ₂ 0 (29)

MeN0 ₃ — '→ MeO + N0 ₂ (30)

MeC0 ₃ -→ MeO +C0 ₂ (31 )

Me ₂ 0 ₂ — '→ Me ₂ 0 + 0 ₂ (32)

MeS0 ₄ —→ ' MeO + S0 ₂ + 0 ₂ (33) o pure metals resulting from the reactions of Formulas 34-36 and Formulas 39-

40):

MeO + CO—!→ Me + C0 ₂ (34)

MeO + C—!→ Me + CO (35)

M _E0 +H ₂ —!→ Me + H ₂ 0 (36)

MeO— '→ Me + O (39)

MeO + C— i→ Me + CO (40)

o sulphides, nitrides and chlorides resulting from the reactions in Formulas 43- 48, with practically all the chlorides coming in melted form:

MeO + H ₂ S = Me S + H ₂ 0 (43)

MeO + 2HC1 = MeCl ₂ + H ₂ 0 (44)

Me + H ₂ S = MeS + H ₂ (45)

Me + HC1 = MeCl + H ₂ (46)

Me + COS = MeS + CO (47)

Me + NH ₄ - MeN+ 2H ₂ (48)

o certain amount of other inorganic ingredients (first and second categories) coming into the gas reactor together with the feedstock.

Large inorganic components of the feedstock of the first category and small inorganic components shielded by the carbon inside large lumps of the feedstock may go into the zone of combustion and gasification without being affected by temperature in the zone of high- temperature pyrolysis. Therefore, due to high temperatures in the zone of combustion and gasification continue the following processes, initiated yet in the zone of low-temperature pyrolysis:

o decomposition of the salts of the mineral part of carbonaceous residue with relatively low temperature of destruction that were not broken down in the zone of high- temperature pyrolysis (Formulas 29-33);

o decomposition of the carbonates with high temperature of destruction:

MeC0 ₃ — !→MeO +C0 ₂ (49)

where Me = Ca(900-1200°C), Na(1000°C), K(1200°C), Ba(1000°C), Li(730-1230°C), and others;

o melting of some of the carbonates and final melting of all the chlorides. At this stage molten chlorides and carbonates may form eutectic mixtures with more refractory salts, lowering their melting temperature. This phenomenon eventually influences significantly formation of liquid slags with lowered temperature of melting. Reactions of oxidation and reduction in inorganic constituent of carbonaceous residue

The process of reduction of metals from oxides and their subsequent oxidation in the zone of combustion and gasification occurs in exactly the same way as in the zone of high- temperature pyrolysis, albeit at a higher rate owing to higher temperatures and more intense gas dynamic in this zone.

In this process due to the reactions of Formula 39 and Formula 40 the main part of metal oxides conveyed in this zone is either broken down under the impact of high temperatures, or is reduced upon interaction with red-hot carbon. They are then oxidized to oxides while interacting with water steams (H ₂ 0) and carbon dioxide (C0 ₂ ) through the reactions of Formula 41 and Formula 42. Reduced metals are in this process an acceptor of oxygen in molecules CO2 and H ₂ 0, transforming them in simple combustible gases CO and H ₂ .

These reactions alternate at high speed caused by high temperatures and elevated gas dynamic in this zone. This alternation continues until the moment when these metals start interacting with silicon dioxide (S1O2) with formation of silicates and other elements like NH4, H ₂ S and HC1 through reactions of Formula 43 and Formula 44. Respective sulfides, nitrides and chlorides are formed in the process, the latter being resistant to destruction by high temperature.

Cleaning of gases by removing hazardous components

Main and highly efficient cleaning of generated gases takes place in the zone of gasification of carbonaceous feedstock residue. Gases are cleaned of ΝΟχ, S0 ₂ , HC1, H ₂ S, NH ₄ and COS that are hazardous components of gases formed in the zone of combustion of pyrolysis gases with the partial combustion of pyrolysis gases, part of which are all these components and some elements in them.

Three factors present in this zone make cleaning of gases efficient:

o high temperature from combustion of some part of pyrolysis gases;

o the presence of red-hot carbonaceous residue and of burning-hot micro- particles of pyro-carbon turned into the state of "fluidized" bed;

o the presence of various oxides and reduced metals of the first and second categories, deprived of shielding by carbon as a result of gasification.

Cleaning of generated gases of major pollutants like S0 ₂ and NOx occurs through their reactions with burning-hot carbon in the reactions (Formulas 50-51):

S0 ₂ + C = S + C0 ₂ (50)

N0 ₂ + C = N + C0 ₂ (51) After that C0 ₂ can be reduced to CO through the reaction of Formula 4:

C0 ₂ + C = 2CO (4)

Cleaning of generated gases of HC1, H ₂ S, NH ₄ and COS can be executed with metal oxides and reduced metals. The metals can be solid, melted or gaseous.

This process occurs with oxides through the reactions of Formulas 43-44, and with reduced metals through the reactions of Formulas 45-48:

MeO + H ₂ S = MeS + H ₂ 0 (43)

MeO + 2HC1 = MeCl ₂ + H ₂ 0 (44)

Me + H ₂ S = MeS + H ₂ (45)

Me + HC1 = MeCl + H ₂ (46)

Me + COS = MeS + CO (47)

Me + NH ₄ = MeN+ 2H ₂ (48)

Gases obtained as a result of combustion and gasification after going through all these reactions are cleaned of hazardous components and additional volumes of CO and H2 are obtained along with some amounts of sulfides, chlorides and nitrides.

Generated gases are also cleaned of vapors of metals, including heavy metals, during the process of their transformation into respective sulfides, chlorides and nitrides that are resistant to destruction by temperature and subsequently become part of the slags.

Because the depth of gas cleaning directly depends on the components of inorganic constituent in carbonaceous residue, this depth can be augmented by special inorganic additives to the feedstock. These additives can be metal oxides, their salts and hydrates of oxides, and silicon dioxide.

Cleaned gases then rise into the zone of high-temperature pyrolysis where their cleaning of hazardous gas components continues. Inorganic components of the slags descend into the slag zone.

Formation of the slag

Inorganic constituent of carbonaceous feedstock residue undergoes cardinal chemical and structural transformations in the zone of combustion and gasification, being at the same time a catalyst of gasification and an acceptor. It takes active part in production of synthesis gas in large amounts and of great quality, and in its cleaning of hazardous impurities of heavy metals, compounds of sulfur and chloride, transforming them into an inactive, insoluble form representing in their major part compounds of silicon slag.

The main process of formation of the slag corresponds to a reaction of interaction of some metal oxides with silicon oxide (Formula 49):

MeO + Si0 ₂ = MeSiOs, (49) where M = Ca, Na, K, Ba, Li, Fe, Cu, Zn, Cr, Mg, Pb, Ti, Cd and others.

These reactions primarily occur with the formation of liquid slag. This process is facilitated by the fact that the chlorides and carbonates present in the zone of combustion and gasification in molten state form eutectic mixtures with more refractory salts, lowering thereby their fusion temperature.

This circumstance considerably affects formation of fluid slags in this zone with reduced fusion temperature, which is T _sq - 1100 - 1150°C.

The temperature of slag formation also directly depends on the components of inorganic constituent in carbonaceous residue, therefore the temperature of slag formation can be changed with special inorganic additives to the feedstock in the form of metal oxides, their salts, hydrate oxides and silicon dioxide.

As a result of the processes occurring in the zone of combustion and gasification, the slag is formed, the main components of which are metal and non-metal oxides, sulphides, chlorides, fluorides, inclusions of metal alloys and unreacted carbon. The slag thus formed represents complex amorphous-crystalline form of the silicates with variable composition with some mechanical inclusions.

The structure of the slag formation in the zone of combustion and gasification is a slag cone with a peak (3) in Fig. 6, located in the centre of fuel chamber at the level of air lances. Slowly cooling melt of the slag descends along the cone's slopes.

Slag cone's solid foundation is formed by unmelt inorganic inclusions (of the first category) of various sizes transferred into the central part of fuel chamber under the impact of high velocity of torch jets.

Smaller inorganic inclusion (of the first and second categories) molten at the boundaries of torch combustion, and those that came into this zone from high-temperature pyrolysis zone as separate drops are also blown into the central part of this zone under the impact of high velocity of torch jets.

Drops of melt slag moved into the central part of fuel chamber combine with unmelt inorganic inclusions having lower temperature. Molten slag cools down somewhat and together with unmelt inorganic inclusion forms a peak (3) in Fig. 6 of slag cone, along the slopes of which the drops of melt slag descend into the slag zone.

In the slag zone the slag continues cooling down, forming a mass of slag in conic shape.

Slag's cooling down in this zone results from the general lowering of temperatures in this zone caused by powerful endothermal reactions of gasification.

The slag then goes down into the slag zone, where it is transformed as it cools into a single mass of slag of a complex amorphous-crystalline form.

Zone 5 - Zone of additional gasification

Zone 5 - zone of additional gasification of gasification reactor SYN1-SFG is one of the zones of high-temperature processing of the feedstock at the temperatures T 900 - 1100°C.

Additional gasification zone is situated inside the inner volume of the body of gasification reactor SYN1-SFG.

Within this zone the following processes occur:

• additional heating of gases of low-temperature pyrolysis, these gases conveyed into this zone through an open ingress of the channel of pyrolysis gases of the gasification reactor;

• the process of thermal conversion of hydrocarbons continues in gases of low- temperature pyrolysis. These gases enter the zone through an open ingress of the channel for pyrolysis gases of the gasification reactor;

• the process of gasification of a part of red-hot carbon residue occurs, the residue coming from the zone of combustion and gasification under the impact of the gases of low-temperature pyrolysis conveyed into this zone through an open ingress of the channel of pyrolysis gases of the gasification reactor;

• slag is formed and it is partially cooled down.

Main gasification process in gasification reactor SY 1-SFG occurs in the zone of combustion and gasification, and in high-temperature pyrolysis zone. But beneath the zone of combustion and gasification in this gasification reactor there is a zone of additional gasification. This zone needed to be organized because one part of burning-hot carbon from the zone of combustion and gasification, not having gasified, can fall down into the slag zone from where it is removed from the gasification reactor together with the slag.

For gasification of this carbon part of hot gas of low-temperature pyrolysis is conveyed into the zone of additional gasification through an open ingress of the channel for pyrolysis gases of the gasification reactor. This part of hot gas contains large portion of water steam and certain amount of C0 ₂ . Carbonaceous feedstock residue that has not been gasified in the zone of combustion and gasification undergoes final gasification under the impact of water steam and C0 ₂ once it is in the zone of additional gasification. Also in this zone the gases and tars of low-temperature pyrolysis not subjected to conversion in the zone of the channel for pyrolysis gases of the gasification reactor undergo additional conversion through reactions of dehydration (Formula 25 and Formula 26) and reduction to the level of simple combustible gases through reactions of gasification (8), (9), (4). This is the result of the impact of high temperatures radiated by burning-hot remaining carbon and newly formed slag.

Reactions of gasification (Formula 8, Formula 9 and Formula 4), occurring in this zone, are clearly endothermal, which contributes to the general lowering of temperature in this zone to T - 700 - 800 °C:

H ₂ O + C = CO + H ₂ - 30 044 kcal/mole (8)

2H ₂ 0 + C = C0 ₂ + H ₂ - 20 195 kcal/mole (9)

C0 ₂ + C = CO - 39 893 kcal/mole (4)

After that the gases formed in this zone go together with a part of pyrolysis gases into the zone of combustion and gasification, where they take part in the process of combustion and gasification.

Summarizing all the above, a conclusion may be made that the impact of water steam H ₂ 0 and of carbon dioxide C0 ₂ in the zone of additional gasification make certain influence on entire process of gasification in gasification reactor SY 1 -SFG, as the heated water steam and partially C0 ₂ gasify residual carbon that came into additional gasification zone from the zone of combustion and gasification.

During these developments:

• thermochemical transformations of pyrolysis gases continue in this zone, the main reactions now being the reactions of dehydration (25) and (26) mentioned earlier in the text;

• relatively cold gases of low-temperature pyrolysis coming to this zone from the channel for pyrolysis gases are heated additionally by the slag that in this zone has the temperature of T - 1000 - 1300°C;

• excessive steam and gas pressure developed in this zone reduces the entry of carbon and small slag formations into it from the zone of combustion and gasification;

• the gases formed in this zone go together with some part of pyrolysis gases into the zone of combustion and gasification, where they take part in the main process of combustion and gasification.

The process of structuring of the slag formed in the central part of the zone of combustion and gasification also occurs in the zone of additional gasification.

The slag comes into this zone mostly in liquid form, descending along the slopes of the slag cone, but also in the form of some solid formations, and more rarely in the form of slag masses. At this stage the slag is affected by:

• relatively cold pyrolysis gases and by reactions of gasification, in which water steam, carbon dioxide and residual carbon take part (Formula 8, Formula 9 and Formula 4). These reactions are endothermal and cool considerably the slag coming into this zone at the temperatures of T - 1000 - 1300°C;

• water steam that partaking in the process of formation of the slag makes its structure crumbly. This positively affects the process of its further breaking up in the slag zone and unloading from the gasification reactor.

In this zone the slag slowly cools after some time to the temperature of T 900 - 1100°C, turning into a complex amorphous-crystalline form of the silicates of variable composition with some mechanical inclusions.

Then solidified slag goes into the slag zone, where it further cools, is crushed and taken out of the gasification reactor.

Zone 10 - Slag zone

The temperatures: T - 150-900°C.

In this zone:

• the slag cools;

• it is mechanically crushed;

• slag is removed from the gasification reactor.

The slag is conveyed into the slag zone of gasification reactor SYN1-SFG from the zone of additional gasification, its temperature being T - 900°C, in the form of monolithic hot slag, but some part of it can also be in liquid form, and some amount of slag may have a shape of separate solid formations. In slag zone the slag is slowly cooled under indirect impact of cold atmospheric air pumped into the gasification reactor, then it is mechanically crushed in an impact crusher by means of disc cutters and subsequently removed from the gasification reactor through a sluice device into a receiving bunker.

The cooling of the slag is slow due to its large thermal capacity, which, in its turn, causes the need for a large volume of the slag zone, where the slag has to be kept for long periods of time.

Remaining in this zone, the slag cools down to the temperature T - 300°C and acquires complex amorphous-crystalline form that depends on the conditions of the cooling, on initial morphological composition of the feedstock, its moisture content and possible inorganic additions to the feedstock, and on possible additional supply of water or water steam into this zone.

Feeding some water or water steam into the slag zone may entirely clean residual carbon from the slag through the reactions of methanization (Formula 26) and may additionally cool the slag down to T - 150°C.

2C + 2H ₂ 0 CH ₄ + C0 ₂ (26) Potential future use of released gases CH ₄ and C0 ₂ includes their participation in the process of combustion and gasification along with the gases of low-temperature pyrolysis.

The sluice device makes possible discharge of the crushed slag, practically excluding the entry of atmospheric air inside gasification reactor, which could cause additional heating of the slag due to a reaction of oxidation of small amount of carbon in it.

Zone 9 - Gas zone

In zone 9 - the gas zone of gasification reactor SYN1-SFG, one of the zones of the low-temperature treatment of the feedstock at T - 500 - 700°C, the process of the cleaning of synthesis gas of feedstock dust.

Hot synthesis gas resulting from all thermochemical processes that occur in the gasification reactor is released from the layer of feedstock in filtration zone at T - 700°C, goes into gas zone situated inside the gasification reactor between the surface of the layer of feedstock and the lid of the body of the gasification reactor. Diameter of this zone and diameter of the body of the gasification reactor are designed so that the speed of the gas flow in it does not exceed 5 m/s. This makes it possible to clean the obtained synthesis gas by the impact of natural gravitation with maximal efficiency.

Generated synthesis gas slowly rises and starts cooling, its temperature possibly falls to T - 700°C due to heat loss caused by the large area of this zone of the gasification reactor.

Hot synthesis gas then goes through the gas outlet branch pipe into the jacket of inclined rotary kiln where it undergoes additional cleaning of slag and carbon dust and cools further to T - 120°C, giving its heat to MSW feedstock loaded inside inclined rotary kiln.

Taking into consideration all the above, a conclusion can be made that gasification of MSW and of other and other carbon-containing feedstock with high content of tars with the method of thermochemical conversion consisting in two-stage process of pyrolysis and subsequent gasification in the flow of air and gas of the slow-fluidized bed of carbonaceous residue are to result in:

• higher intensity of gasification of the feedstock in the fuel chamber of gas generator SYNl-GG, bringing its capacity from 350 kilogram per hour for 1 square meter of the overall cross-section of the fuel chamber (this being a norm for currently existing gasification reactors) to 700 kilogram per hour for 1 square meter of the cross-section of the fuel chamber (based on general intensity of gasification of pre-treated MSW of the gas generator SYNl-GG);

• larger amount of synthesis gas and its better composition thanks to higher content of simple combustible gases CO and H ₂ .

• the reduction in the overall volume of obtained synthesis gas of the unneeded substances like C0 ₂ , H ₂ 0, 0 ₂ , and of N ₂ as of a product of air gasification. This increases the efficiency of obtained gases for the generation of electric power.

• possibility to clean synthesis gas of hazardous gas components ΝΟχ, S0 ₂ , HC1, H ₂ S, NH ₄ and COS, and of heavy metals directly in the process of gasification, including them into silicate slags in which there is practically no residual carbon.

Conditional estimate of the amount of pyro-carbon formed in the process of thermal conversion of hydrocarbons and tars making part of pyrolysis gases

This estimate should be considered conditional, because a computation of the amount of pyro-carbon is extremely complicated. It is conditioned by a multitude of factors that are difficult to take account of, as they are related to the reactions of combustion. This estimate may be computed though, if some conditional assumptions are allowed for.

The basis of this estimate is the process of partial combustion of pyrolysis gases and tars in the zone of combustion and gasification, accompanied by formation of carbon dioxide and water steam, during which their remaining portions are subjected to thermal conversion generating hydrogen and residual pyro-carbon resultant from the reactions of dehydration (1 1):

C„H ₂ „ H CmH _2m +2→ (n+m)C + (2n+2m+2)H ₂ (1 1)

The data for estimated composition of pyrolysis gases and tars is given in Table 3.

Table 3. Gaseous products of feedstock pyrolysis

The estimate of combustion of a part of pyrolysis gases is based on a conditional assumption about priority combustion of simple combustible gases H ₂ , CO and partially CH4 in a depleted oxygen environment, conditioned by high velocity of laminar diffusion of flame in these gases.

The data on the combustion of pyrolysis gases is shown in Table 4.

The estimate of the volume of oxygen (Table 3), needed in the process of gasification of the feedstock derived from the need to maintain certain temperatures in all the zones of gas generator SYN1-GG. In the general estimate of gasification processes however exothermal effect of some of the reactions was not taken into account, specifically of the reactions of thermochemical conversion of inorganic constituent of the feedstock. Neither was taken into account the influence that catalytic effect exerts on the process of obtaining of synthesis gas. Catalytic effect is caused by various metals that have been reduced from their oxides in the process of feedstock processing. As a practical consequence of this fact, the amount of oxygen needed for feedstock gasification may be much smaller than estimated. This brings us to the conclusion that an indicator of the amount of pyro-carbon resulting from incomplete combustion of pyrolysis gases can be much higher than estimated, because it has inverse correlation on the volumes of oxygen needed for feedstock gasification.

As a result of this estimate and with assumptions made hitherto, a conclusion can be made that residual carbon can be obtained in the amount exceeding the estimated 90,15 grams per each kilogram of processed feedstock. Larger amounts can be obtained through reactions of dehydration occurring during partial combustion of pyrolysis gases and tars in the zone of combustion and gasification and subsequent thermal conversion of their residues.

This option makes possible the processing of hydrocarbon feedstock with high content of hydrocarbons in gas phase and with low content of residual carbon. MSW is one of the types of such feedstock, and with this option synthesis gas of better quality and in larger amounts can be obtained from every kilogram of processed feedstock.

Theoretical estimate of the method of thermochemical conversion into synthesis gas of municipal solid waste (MSW) and other carbon-containing feedstock with high content of tars executed in a two-stage process of pyrolysis and subsequent gasification of carbonaceous feedstock in a slow fluidized-bed air-and-gas flow

This theoretical estimate of gasification process is presented in the form of tables with calculations organized in accordance with the chart of the estimate in Fig. 7, where the principle of operation of gas generator SYN1-GG is shown. This operation is based on the method of thermochemical conversion into synthesis gas of municipal solid waste (MSW) and other carbon-containing feedstock with high content of tars executed in a two-stage process of pyrolysis and subsequent gasification of carbonaceous feedstock in a slow fluidized-bed air- and-gas flow.

Description of the theoretical estimate of the method of thermochemical conversion into synthesis gas of municipal solid waste (MSW) and other carbon- containing feedstock with high content of tars executed in a two-stage process of pyrolysis and subsequent gasification of carbonaceous feedstock in a slow fluidized-bed air-and-gas flow

Area of low-temperature processing of the feedstock

Zone 1 - Zone of feedstock drying

The process of drying occurs in the zone of low-temperature processing of the feedstock and takes place in Zone 1 - Zone of feedstock drying at the temperature T 30 - 120°C.

Solid urban refuse (municipal solid waste) in the form of "vat" residue after its sorting was taken as initial feedstock for this estimate.

Fig. 8 shows in Table 1.1 morphological composition of MSW used in this estimate.

This composition was used in the tests of technological complex PGP-1TPD, described in the Gasification reactor Draft Test Report of the University of California Riverside (UCR), USA.

Estimate of gasification process SFGP4

Fig. 9 Table 1.2 demonstrates elemental composition of MSW.

In the drying process physical moisture and colloid water are removed from the feedstock, although the literature data points to the possibility for a part of colloid water to remain in the feedstock.

Percentage of water content that was removed during feedstock drying is taken for this estimate. It is shown in Fig. 10, Table 1.3.

Zone 2 - Zone of moisture removal

Moisture removal zone is one of the zones of low-temperature processing of the feedstock. The process takes place in Zone 2 - Moisture removal zone under the T 120 - 300°C. Fig. 11 Table 2.1 describes feedstock remaining after drying, and Fig. 12 gives in Table 2.2 elemental composition of the feedstock after moisture is removed.

Moisture removal process consists in the removal of remaining moisture and in low intensity release of gases, mainly water vapors and C0 ₂ .

Fig. 13 gives in Table 2.3 an assumed composition of the gases after removal of moisture from the feedstock. It is compared to the data taken from the literature. Fig. 14 refers in Table 2.4 a comparison of estimated and literature data of the changes in elemental composition of the feedstock before and after moisture removal.

Zone 3 - Zone of low-temperature pyrolysis

The process of low-temperature pyrolysis can be attributed to the zones of low- temperature processing of the feedstock. It takes place in Zone 3 - Zone of low-temperature pyrolysis under the T 300 -~ 700°C. Fig. 15 describes in Table 3.1 the feedstock residue, coming into the zone of low-temperature pyrolysis.

According to the literature data and due to peculiarities of the feedstock, massive percentage of the products of low-temperature pyrolysis is included, and composition of generated gases and elemental composition of primary tar oil. Elemental composition of residual solid feedstock that has not undergone pyrolysis is calculated based on the remaining mass of the elements after the other products of pyrolysis (gases, tars, water) have been removed. All this data is shown in Table 3.2 of Fig. 16.

According to the design of gas generator SYN1-GG, feedstock residue after the zone of low-temperature pyrolysis, located in inclined rotary kiln SYN1-RK, comes into gasification reactor SY 1-SFG, where its high-temperature pyrolysis and subsequent gasification ensue. The main part of feedstock residue after low-temperature pyrolysis goes into the zone of high-temperature pyrolysis and then into the zone of combustion and gasification. But some part of feedstock residue gets into filtration zone, where under the lower temperatures the process of its low-temperature pyrolysis continues. Therefore, for the purpose of this estimate, feedstock residue after the zone of low-temperature pyrolysis was provisionally divided into two parts. One part descending into the zone of high-temperature pyrolysis, and the other, that goes into filtration zone and remains in the low-temperature pyrolysis conditions. All this data is presented in Table 3.3 of Fig. 17, Table 3.4 in Fig. 18, and in Table 3.5 in Fig. 19.

Fig. 20 refers in Table 3.6 shows the total composition of the gases of the processes of drying, moisture removal and low-temperature pyrolysis that go into the channel for pyrolysis gases of gasification reactor SYN1-SFG. Fig. 21 Table 3.7 compares estimated and literature data for the products of low-temperature pyrolysis. Fig. 22 Table 3.8 compares estimated and literature data for the gases of low- temperature pyrolysis, Fig. 23 Table 3.9 compares estimated and literature data for the low- temperature pyrolysis tar (primary tar oil). Fig.24 quotes in Table 3.10 literature data [5] for the composition of the tar of semi-coked coal.

Area of thermal conversion of the gases of low-temperature pyrolysis

The process of thermal conversion of gases of low-temperature pyrolysis occurs in the zone of high-temperature processing of the feedstock, in Zone 4 - Zone of the channel for pyrolysis gases of the gasification reactor SYN1-SFG under the T 700 - 900°C, and in Zone 5 - Zone of additional gasification at the T 900 - 1100°C.

Zone 4 -Zone of the channel for pyrolysis gases of the gasification reactor

Gas mixture formed in inclined rotary kiln SYN1-R , in the zones of drying, moisture removal, low-temperature pyrolysis, goes into the channel for pyrolysis gases of gasification reactor SYN1-SFG. For the clarity of this estimate an assumption is made that descending through the channel for pyrolysis gases along the vertical part of the gasification reactor, these gases get into the zone of additional gasification and further into the zone of combustion and gasification. During this process they undergo certain thermochemical transformations described further in the text. Both the gases of low-temperature pyrolysis undergo these transformations, and the tars contained in them.

The transformations start in the zone of the channel for pyrolysis gases of the gasification reactor. There the conditions conducive to the reactions of conversion of hydrocarbons are created thanks to high temperature of burning-hot slag that is in the lower part of the channel for pyrolysis gases, and thanks to high content of water steam in pyrolysis gases.

But because of the short residence time of gas mixture in this zone, only part of hydrocarbons undergoes thermal conversion.

For the purposes of the estimate, percentage of hydrocarbons that entered into the reaction of water or carbon dioxide conversion is introduced. It is shown in Fig. 25, Table 4.1, in which total composition of gases that came into the channel for pyrolysis gases is given (gases of drying, moisture removal and low-temperature pyrolysis).

It is also assumed that in the zone of the channel for pyrolysis gases partial pyrolysis of primary tar oils occurs, these tar oils formed in a colder zone of low-temperature pyrolysis. The estimate assumes that this process occurs predominantly in the channel for pyrolysis gases, where the tar vapors come together with the gases. As the residence time of the gases and tar vapors in this zone is limited, not all the primary tar oil undergo thermal breakdown, therefore relative percentage value of its transformation is introduced into the estimate. On the basis of literature data, in this estimate the elemental composition of the tar obtained after thermal conversion was included. All this data is presented in Tables 4.2-4.10 of Fig. 26-34.

The area of gasification of carbonaceous residue that has not reacted in the zone of combustion and gasification

The process of gasification of carbonaceous residue that has not reacted in combustion and gasification zone occurs in the zone of high-temperature processing of the feedstock, Zone 5 - Zone of additional gasification of the gasification reactor SY 1-SFG under the T 900 - 1350°C, and Zone 10 - Slag zone, under T 300 - 900°C.

Zone 5 - Zone of additional gasification

Melted or burning-hot inorganic residue in the form of slag with impurity of burning- hot carbon descend into the zone of additional gasification from combustion and gasification zone.

In their turn, gaseous products of low-temperature pyrolysis and drying of the feedstock with impurities of volatile tars come into additional gasification zone from the channel for pyrolysis gases of the gasification reactor. At this stage this gas mixture interacts with burning-hot slag residue. As a result, total or partial gasification of residual carbon in the slag occurs, and partial decomposition of resinous substances. Estimated data of these processes are shown in Tables 5.1-5.10 of Fig. 35-44.

Zone 6 - Zone of combustion and gasification

The process of combustion and gasification of carbonaceous residue occurs in the zone of high-temperature processing of the feedstock, in Zone 6 - Zone of combustion and gasification of the gasification reactor SYN1-SFG under the T 1100 - 1350°C, and partly in Zone 7 - Zone of high-temperature pyrolysis, under T 900 - 1 100°C.

Because the process of combustion and gasification is very complex and occurs in the two zones at a time, an assumption was made for the clarity of the estimate that reactions of combustion occur in the Zone of combustion and gasification, and reactions of gasification take place in the Zone of high-temperature pyrolysis.

The process of combustion

The process of combustion of carbonaceous feedstock residue occurs in the zone of high-temperature processing of the feedstock, in Zone 6 - Zone of combustion and gasification of the gasification reactor SYN1-SFG under the T 1100 - 1350°C.

The products coming into the zone of combustion and gasification from the zone of high-temperature pyrolysis, and thermal conversion of these products in this zone are described in Table 6.1 in Fig. 45. Carbonaceous feedstock residue descends in the process of its gasification from high- temperature pyrolysis zone (described further in the text) into the zone of combustion and gasification, undergoing processes of thermochemical conversion. In order to make the estimate a little simpler, it is assumed that having passed through high-temperature pyrolysis zone solid feedstock residue consists mainly of carbon when it enters the zone of combustion and gasification. The data for thermal conversion of solid carbonaceous feedstock residue is shown in Table 6.2 of Fig. 46.

While going through the zone of combustion and gasification some part of carbonaceous feedstock residue burns down. The data on this process is presented in Tables 6.3 and 6.4 in Fig. 47 and 48 .

Two parameters are introduced into the estimate:

- Percentage of burned down carbonaceous feedstock residue with formed CO, but without C0 ₂ .

- Percentage of carbonaceous feedstock residue burnt down forming CO and C0 ₂ . Table 6.5 in Fig. 49 shows the composition of gases resulting from combustion of a part of solid carbonaceous residue, and Table 6.6 in Fig. 50 refers to the gas mixture formed after conversion of the products that came from the zone of high-temperature pyrolysis.

The products coming into the zone of combustion and gasification from the zone of the channel for pyrolysis gases of the gasification reactor and from the zone of additional gasification are shown in Table 6.7 of Fig. 51, as well as their conversion in these zones.

Resinous substances that come from the zone of the channel for pyrolysis gases of the gasification reactor and zone of additional gasification into the zone of combustion and gasification are assumed to not combust there entirely. Percentage of combusted tar is introduced along with percentage of combustion, during which CO and C0 ₂ are formed. The data for this process is shown in Tables 6.8, 6.9 and 6.10 in Fig. 52, 53 and 54.

Gaseous products of low-temperature pyrolysis come into the zone of combustion and gasification from the channel for pyrolysis gases of the gasification reactor. It is these products that combust first, and the main part of air fed into the reactor is consumed by interaction with the gases. It is assumed though, that due to the high velocity of gas stream inside the gasification reactor some part of combustible gases passes into the zone of high- temperature pyrolysis without being transformed. Percentage of gases that have reacted with oxygen is introduced into the estimate. Partial, not complete combustion of hydrocarbons is also assumed, and this assumption is presented in the estimate as percentage of hydrocarbons combusted with formation of CO2 and CO. All the parameters of this process are referred in Tables 6.11-6.17 in Fig. 55-61. The sum of the products formed in the zone of combustion and gasification is shown in Table 6.14 of Fig. 58.

Gasification process

The process of gasification of carbonaceous residue occurs in the zone of high- temperature processing of the feedstock, namely in Zone 6 - Zone of combustion and gasification of the gasification reactor SYN1-SFG under the T 1100 - 1350°C, and in Zone 7 - Zone of high-temperature pyrolysis, under T 900 - 1100°C.

But, as was mentioned before, due to the complexity of the process of combustion and gasification and its development in the two zones at the same time, for the purposes of simplifying this estimate it is assumed that reactions of gasification take place in the Zone of high-temperature pyrolysis.

In internal volume of gasification reactor SYN1-SFG gases formed in the zone of combustion and gasification flow upwards, meeting the descending carbonaceous feedstock residue.

This part of the gasification reactor was tentatively defined as an area of high- temperature pyrolysis and zone of filtration, but various thermochemical processes continue in it.

In this zone, as carbonaceous feedstock residue is moving towards the zone of combustion and gasification characterized by high temperature, high-temperature pyrolysis takes place, and in filtration zone under lower temperatures feedstock residue along with high-temperature pyrolysis undergoes further low-temperature pyrolysis. And along this entire area processes of gas conversion and gasification continue.

For the clarity of this estimate an assumption has been made that gases of high- temperature pyrolysis and tars do not reach the zone of combustion and gasification, but rise together with gases coming from combustion zone. At this time their gasification and thermal conversion occur.

While rising, the tars of high-temperature pyrolysis are sorbed in the layer of feedstock residue in filtration zone, where the temperatures are lower.

Feedstock residue, on its turn, descending from filtration zone, gradually carries away with it these tars into the zones of high temperatures, where part of them turn into gas state and rise. The other part decomposes.

Besides that, part of the tars together with carbonaceous residue from high- temperature pyrolysis zone may fly past combustion and gasification zone into the zone of additional gasification, where they are mixed with the tars from the zone of high-temperature pyrolysis. Because of this circumstance relative percentage of decomposed and not decomposed tars is used in the estimate.

Part of carbonaceous feedstock residue that came into gas filtration zone and zone of high-temperature pyrolysis, the layer of feedstock being heated in these zones only to relatively low temperature, remain at a temperature level pertinent to the processes of low- temperature pyrolysis. Gases of low-temperature pyrolysis formed thereby go into gas zone, where they become mixed with the gases of gasification that come there from combustion and gasification zone and zone of high-temperature pyrolysis.

As the part of the feedstock inside the zone of gas filtration has the temperature of low-temperature pyrolysis and is in close proximity to the gas zone, some part of the tars formed at that time goes into gas zone without being seriously changed and is driven by the gases outside the gasification reactor. Part of these tars fall down on the feedstock and gradually descends into the zone of high-temperature pyrolysis, where it breaks down (an assumption is made that in this instance that part of tars decompose entirely). Inaccuracy of this assumption may be compensated by possible breakthroughs of the tars rising from the zone of high-temperature pyrolysis.

Similarly, interaction occurs between the mixture of the tars coming from high- temperature pyrolysis zone and carbonaceous feedstock residue. The tars rising into the zone of gas filtration characterized by lower temperatures are not subjected to thermochemical conversion. Part of these tars may at this time fly into gas zone and be driven from the gasification reactor together with synthesis gas. The other part of the tars is sorbed by the particles of carbonaceous feedstock residue and moves back into the zone of high-temperature pyrolysis, where it undergoes complete thermal decomposition.

All these processes are demonstrated in Tables 6.18-6.32 in Fig. 62-76. Tables 6.24- 6.30 in Fig. 68-74 present the estimate of the process of gasification of carbonaceous feedstock residue under the impact of gas mixture conveyed from the zone of combustion and gasification. According to the estimate, pyrocarbon is used in gasification process as carbon addition to the mass of carbonaceous feedstock residue.

Zone 7 - Zone of high-temperature pyrolysis

The process of high-temperature pyrolysis occurs in the zones of high-temperature processing of the feedstock: in Zone 7 - Zone of high-temperature pyrolysis of the gasification reactor SYN1-SFG under the T 900 - 1100°C, and partially in Zone 8 - Zone of gas filtration, under T 700 - 900°C. Composition of solid carbonaceous residue (semi-coke) coming into the zone of high-temperature pyrolysis is shown in Fig. 77, Table 7.1.

Eventually, solid carbonaceous residue formed in inclined rotary kiln SYN1-RK, in the zones of drying, moisture removal, low-temperature pyrolysis come into internal volume of gasification reactor SYN1-SFG. Main part of that residue descends into the zone of high- temperature pyrolysis with higher temperatures, and some part remain for some time in the zone of filtration, where the temperatures are lower. In this chapter high-temperature transformations of feedstock residue in the zone of high-temperature pyrolysis are specifically reviewed. Table 7.2 of Fig. 78 displays supposed balance of the products of high-temperature pyrolysis, composition of gases and tars based on literature data with special features of consumed feedstock taken into consideration. Composition of solid carbonaceous residue is computed deriving from the mass of the other products of the pyrolysis.

Synthesis gas and part of smoke gases that have not reacted go into the internal volume of gasification reactor SYN1-SFG rising from the zone of combustion and gasification and going through high-temperature pyrolysis zone and zone of filtration. At that time part of carbonaceous feedstock residue interact with them. For the clarity of the estimate the solid feedstock residue obtained in the zone of high-temperature pyrolysis is tentatively divided into a portion of residue that interacts with smoke gases, and a portion of residue that comes into combustion and gasification zone. Table 7.3 of Fig. 79 gives tentative distribution of carbonaceous feedstock residue of high-temperature zone.

Zone 8 - Zone of gas filtration

Gas mixture that has formed moves up through temperature zones cooling in the process, particularly in gas zone. Conditions emerge, especially the temperature, that are conducive to the reactions of methanizion. All these processes are shown in Tables 8.1-8.2 in Fig. 86-87.

Zone 9 - Gas zone

The process of cleaning of synthesis gas of the dust occurs in the zone of low- temperature processing of the feedstock, specifically in Zone 9 - Gas zone gasification reactor SYN1-SFG under the T 500 - 700°C.

Cleaning of synthesis gas with removal of dust takes place in this zone under the impact of gravitation and low speed of synthesis gas in internal volume of gas zone.

All these processes are illustrated in Tables 9.1-9.2 of Fig. 88-89.

Zone 10 - Slag zone

After additional gasification zone the slag cleaned of carbon goes into the slag zone, where it undergoes final cleaning of residual carbon through the reactions of methanization caused by feeding water or water steam into this zone. The slag at this stage cools to T 150°C.

This process is shown in Table 10.1 of Fig. 90.

Energy balance of gasification process In this estimate the highest calorie value of feedstock (MSW) combustion is used. Table 12 demonstrates thermal effect of gasification process, Table 13 shows heat losses due to thermal energy taken away by generated hot gases (wet), and Table 14 shows heat losses due to physical heat taken away by slag residue.

Table JYs 12 Thermal effect of gasification process

Table JYa 13 Heat losses due to thermal energy taken away by resulting hot gases (wet)

thermal effect of the phase transition of water kJ/mole 43,8000 mass of water in gas, g 66,9109

energy needed for moisture evaporation, kJ 162,8166

TOTAL 628,2532

Table JVs 14 Heat losses due to physical heat taken away by slag residue

Table 15 shows heat losses of physical heat, taken away by the tars. Table 16 shows heat losses due to evaporation of original moisture (phase transition), and table 17 refers heat losses into the environment (design losses).

Table 18 shows general energy balance. Table 19 presents estimated energy parameters of the process of gasification SFGP4.

tar (chemically bound thermal

energy) 52,94520025 0,253774466 tar (physically bound thermal

energy) 0,211675945 0,001014595 evaporation of feedstock

moisture 229,092155 1,098073838 design losses 2936,913108 14,077075

TOTAL 20863,092 20863,092 100

thermal losses 4247,288

Description and data of the process of synthesis of urea from synthesis gas resulting from gasification of MSW with the method of thermochemical transformation into synthesis gas of MSW and other carbon-containing feedstock with high content of tars through a two-stage process of pyrolysis and subsequent gasification of carbon residue in the slow-fluidized bed air-and gas flow

In the process of thermochemical conversion into synthesis gas of solid urban refuse and other carbon-containing feedstock with high content of tars in this invention the gases are formed that besides nitrogen N2 contain large amount of hydrogen H2 and monoxide CO, and smaller amount of carbon dioxide C02.

The increase of hydrogen is possible through conversion of CO with addition of water steam. H ₂ and C0 ₂ also form in the process. After the elutriation of the C0 ₂ hydrogen H ₂ together with N ₂ are used for the synthesis of ammonia NH ₃ , and the C0 ₂ released during regeneration of absorbing solution is used for the synthesis of urea C0(NH ₂ ) ₂ .

The chain of the transformations of the CO is described by this sequence of equations:

CO + H ₂ 0 - C0 ₂ + H ₂ (52);

N ₂ + 3H ₂ = 2NH ₃ (ammonia) (53)

C0 ₂ + 2NH ₃ = H ₂ 0 + CO(NH ₂ ) ₂ (urea) (54).

A primary technological scheme of the process of synthesis of urea through the reactions of Formulas 52-54 is shown in Fig. 91.

The composition of the synthesis gas obtained through the gasification technology S YNTENA 1 -SFGP4 is shown in Fig. 89.

According to the technological scheme (Fig. 91), the separation of nitrogen is performed:

Next is steam conversion of CO in synthesis gas.

In this variant of implementation of the invention an assumption is made that only CO undergoes steam conversion through the reaction:

CO+H2O = C0 ₂ +H ₂ +Q (+9,86 kcal) (52)

Conventional two-stage process of CO conversion is considered:

• The first stage is done under T 350-450°C with catalysts (Fe ₃ O ₄ + 8-10% Cr ₂ 0 ₃ ), resulting gases have residual content of CO - 1-3%.

• Second stage is low-temperature 180-250°C of Cu-Zn-Al(Cr) oxide catalyst, with residual content of CO - 0,1-0,6%.

To sustain the temperature in the CO steam converter, relief gases are used. These gases are obtained at membrane separator H ₂ , consisting mainly of CH ₄ and C _n H _m .

Listed below are the gases that take part in the reaction of conversion:

Parameters of conversion

extent of conversion of CO, % 99

excessive H ₂ 0, % (mass) (not accounting for extent of

CO conversion) 5

Gas mixture after CO conversion:

In accordance with technological scheme (Fig. 56), C02 is removed from synt

It makes followin as mixture com osition after CQ ₂ removal:

According to technological scheme (Fig. 56), membrane separation of hydrogen from synthesis gas is done:

NO 0,555 0,432 0,713 0,955

Total 100,000 100,000 165,136 133,982

In accordance with technological scheme (Fig. 56), ammonia NH ₃ is synthesized.

Industrial production of ammonia is based on direct interaction of hydrogen and nitrogen according to the reaction of Formula 53, Gaber process:

N ₂ +3H ₂ = 2NH ₃ +Q (+22,04 kCal) (53)

Standard synthesis of ammonia takes place under the T 500°C and pressure of 350 atmospheres with catalyst porous iron +A1 ₂ 0 ₃ + ₂ 0. Product output in one cycle in ammonia synthesis reactor is approximately 30%, but due to circulation ammonia output is actually 100%.

Below are the gases used for synthesis of ammonia:

Technology also provides (Fig. 56) for the synthesis of urea CO(NH ₂ ) ₂ . Synthesis process is based on traditional Bazarov reaction in two stages:

- Formation of ammonium carbamate: 2NH ₃ +C0 ₂ =NH4COONH ₂ +Q (+38,0 KKan); - Dehydration of ammonium carbamate: NH ₄ COONH ₂ =( FH ₂ ) ₂ CO+H ₂ 0 - Q(-6,8 kcal).

For this reaction liquid ammonia NH ₃ is used and gaseous carbon dioxide C0 ₂ , their proportions being 2,8-3, 1NH ₃ : 1C0 ₂ . The process is done under the temperature 180-185°C and pressure 13,4 - 14,4 mPa. The reagents are in the synthesis tower for 45-60 min. C0 ₂ conversion rate is 60%. For this variant of the invention's execution proportion of NH ₃ : C0 ₂ was chosen to be 3 : 1.

For the 100% urea output various known technologies can be used.

They differ in methods of distillation and use of not reacted NH ₃ and C0 ₂ , and in ways of manufacturing finished urea from its solutions:

a) Partial recycling processes:

- Partial recycle of liquid ammonia;

- Partial recycle of liquid ammonia and solution of carbon-ammonia salts of «Toyo Kazeu» company.

6) Full recycling processes:

- Recycling of dissolved NH ₃ and C0 ₂ ;

- Recycling of suspension of ammonium carbamate;

- Separation of not reacted NH3 and C0 ₂ and their return into a cycle;

- Recirculation of hot gases;

- Stripping, i.e. process of synthesis and distillation.

The following are the substances for the production of urea:

Therefore, one of the options of this invention is a method of pyrolysis and subsequent gasification of fluidized bed of feedstock through thermochemical conversion into synthesis gas of solid urban refuse and various other carbon- and tar-rich feedstock resulting in the output of up to 939,92 grams of urea for each kilogram of prepared solid urban refuse.

In its entirety, this invention is a method of thermochemical conversion into synthesis gas of municipal solid waste (MSW) and other carbonaceous and tar-rich feedstock through a two-stage process of pyrolysis with its subsequent gasification in the air-and gas flow of slow fluidized-bed in an integrated technological process.

This method of thermochemical conversion into synthesis gas and following gasification of MSW and other carbonaceous and tar-rich feedstock through a two-stage process of pyrolysis and gasification in the slow fluidized bed of carbonaceous residue is fulfilled for technological complex SYN1-TC (SFGP4) and is presented in Fig. 92. The technological complex for this invention is a device for thermochemical conversion into synthesis gas of MSW and other carbonaceous tar-rich feedstock, this conversion being a two- stage process of pyrolysis and ensuing gasification of slow fluidized bed of carbonaceous residue of pyrolysis of the feedstock in an air-and-gas flow. It uses an updraft principle of gasification and known technological methods of MSW processing, named here for explanatory purposes with an unpatented title SYN1-TC (SFGP4). Realization described herewith does not in any way limit possible adaptations and equivalents.

Structure of technological complex SYN1-TC (SFGP4).

MSW after its sorting at a refuse sorting plant was identified in the form of the so- called "vat residue" as a key feedstock in terms of the structure of technological complex SYN1-TC, its configuration and technical devices needed for it. MSW is a feedstock that can be processed into producer and synthesis gas, electric power or nitrogen fertilizers. This does not in any way preclude, though, the use by this technological complex of other carbonaceous feedstocks with various structures, ash and moisture contents after its slight re-configuring. In this variant the feedstock is transported to the site of the technological complex by cargo transport in the amounts needed for its uninterrupted operation for 3 days and stored in a storage bunker. Then the feedstock is transferred to the conveyor belt which feeds it into a mill, where it is crushed, homogenized and partially dried. The milled feedstock is transported by conveyor belt into a specially designed rotary dryer of indirect heating, where the feedstock is dried by smoke gases coming from the power unit of technological complex. The temperature of the gases is 400-500°C. The heat of the power unit's radiator can be used in the drying process. It can heat the flowing air fed into internal volume of rotary dryer so that water steam can be removed from it. Depending on the composition of the loaded feedstock limestone, dolomite, depleted iron ores may be added through dosing units. The products from the system of synthesis gas cleaning can be added too, including carbon, slag dust, and chemical cleaning agents, such as Na ₂ S, NaCl, NaOH, FeO, Fe ₂ 0 ₃ , and some others. The feedstock is dried in the rotary dryer from the level of original moisture content of 40-50% to 5-10% moisture content. Smoke gases cool to the temperature of 120-150°C and are released into the atmosphere through smoke pipe. Steam formed in the process of feedstock drying is conveyed together with hot flowing air into the heat exchanger so that moisture is condensed. It can be partially transferred into gasification reactor, where it takes part in the process of gasification. The water condensed in the heat exchanger goes into the system of water cleaning and treatment equipped with cleaning, pre-treatment and accumulation devices for further use in technological complex. The cooled air is conveyed into the gasification reactor for gasification of the feedstock. Dried feedstock is conveyed from rotary dryer by the conveyor to a magnetic separator, where metal is extracted from the feedstock, the metal can be eventually sold as scrap metal. The feedstock is then transferred by the conveyor to the mechanical sifter, where remaining inorganic components are separated from dried feedstock. About 10% of inorganic components remain in the feedstock, and resultant sifting with small amount of organic components is stored in containers for further transportation to landfills. After inorganic ingredients are separated the feedstock is transferred by the conveyor to the daily storage bunker with 12 hours storage capacity. From there the feedstock is fed by the screw feeder into receiving hopper of an input device. It is then fed into gas generator SY 1- GG consisting of inclined rotary kiln for low-temperature pyrolysis of the feedstock SYN1- RK, in which the processes of low-temperature pyrolysis occurs, and of gasification reactor SYN1-SFG for updraft slow fluidized-bed gasification. The slags formed in the process of gasification are crushed inside the gasification reactor SYN1-SFG body and are removed from it for eventual utilization. Hot synthesis gas is conveyed through a heat-insulated channel into the pyrolysis inclined rotary kiln SYN1-R . Synthesis gas that left its excessive heat in pyrolysis inclined rotary kiln SY 1-RK is removed from it with the temperature 120- 150°C and goes through heat-insulated channel into the system of gas cleaning operating on the principle of "wet" cleaning of gas.

One of the main devices of the "wet" gas cleaning system is a water scrubber, in which synthesis gas is cleaned of fine-dispersed dust carbonaceous and slag components. Gas is cleaned by a spray of cold water counter-current to the flow of synthesis gas. Due to the low temperature of the water spray inside water scrubber, synthesis gas is cooled to the temperature of 20-40°C. Synthesis gas goes then into a disintegrator, where it is dried of water dust, and then it goes into a filter of chemical cleaning. In chemical cleaning filter synthesis gas is cleaned of residual hazardous gaseous components - HC1, H ₂ S, S0 ₂ and some others. Filtering element of chemical filter constitutes a solid porous object made of iron oxides Fe ₂ 0 ₃ and FeO. Going through it, synthesis gas is cleaned, and components that include sulfur, chlorine and other noxious components are bound on the surfaces of filtering element. Cleaning and regeneration of filtering element is done by its cyclical washing with NaOH solution. After the washing the alkali solution contains sulfides and chlorides of sodium Na ₂ S, NaCl, and some amount of dissolved iron oxides in the form of compounds of different composition, such as Na[Fe(OH)4], Na4Fe0 ₃ etc. After maximum concentration of these substances is reached in the washing water solution NaOH solution is replaced with a new one. Used solution with the particles of filtering element dissolved in it as Fe ₂ 0 ₃ and FeO and some other compounds are recycled. There is an option of mixing the components of washing solution with other ingredients used in gas cleaning system and transferring this mixture into a storage bunker of a dosing unit (located at the inlet of rotary drier) to be added to feedstock as an additive. After chemical cleaning filter synthesis gas goes into the filter of fine gas cleaning. After its final cleaning there synthesis gas goes into gasholder, where it is stored and homogenized. In Option 1 synthesis gas goes from the gasholder into gas reciprocator of power generator for generation of electric energy, and hot smoke gases with the temperature of 400- 500°C, formed as a result of combustion of synthesis gases in it, go through the heat-insulated channel into the rotary drier for feedstock drying.

In Option 2 synthesis gas goes from the gasholder into a unit for synthesis of chemical products, such as urea, and relief gases that remain after the process of synthesis are conveyed for the burning that can help drying the feedstock in rotary drier.

Technology complex SYN1-TC (SFGP4) operates automatically.

Albeit a description is completed by the formula of an invention that specifies and clearly state an invention, it was though that the options of realization of this invention would be better understood from this description. In all the options of realization of this invention all the mass percentages are presented as mass of the overall mass of the composition, if there are no specific indications otherwise. All the ranges are inclusive and combinable. The number of significant digits is not transferable for limitation of numbers indicated, nor for accuracy of measurements.

Sizes and values used in this document should not be construed as strictly limited by exact numerical values referred herein. Rather, if there are no indications otherwise, each value is supposed to indicate both the value referred to, and functionally equivalent range surrounding that value.

Every document, cited in this description, including any cross-references, is included in this document as a reference in its entirety, if something different is not explicitly excluded or in any way limited. The citing of any document does not acknowledge that it is a known level of technology concerning any invention presented or claimed in this document, or if any reference in itself or combined with any other reference or references informs of, suggests or discovers any such invention. In addition, to the extent that any meaning of a term or its definition in this document contravenes any meaning or definition of the same term in a document used foe reference, the meaning or definition attributed to that term in this document shall prevail.

As a number of specific options of the materialization of this invention are illustrated and described herein, it must be obvious to skilled experts in this field that various other alterations and modifications can be made without major changes to the essence and scope of this invention. Its purpose therefore is to encompass in the enclosed formula of the invention any modifications and improvements that are within the scope of this invention.