Method for producing isotropic oil coke on the basis of shale-oil

Technical field

The invention relates to the field of chemical industry and is provided for producing isotropic oil coke on the basis of shale-oil to be used in manufacturing of construction graphite and on its basis devices to be operated in chemically active and radioactive environments and also in environments having high temperatures.

Prior art

From prior art producing coke from organic raw materials is known. For example, a method for producing petroleum-coke in a horizontal coke cube is known, according to which heavier fractions, obtained in thermal treatment of petroleum, are used as raw material for producing coke. The method provides pre-heating of the coke cube during 5-10 minutes to vaporize water possibly present in the cube. At the same time steam is fed into the cube to remove air from the cube, thus avoiding forming of the explosive mixture of air and vaporized fractions of raw material fed into the cube. After that the raw material for coke is fed into the cube to fill up 33% of the volume and the temperature of the raw material is raised to start the coking process of the raw material. When the temperature of the raw material reaches up to 445-460 ⁰ C, the temperature in the cube starts to drop, meaning that the process of forming of the coke bulk has come to an end and from this moment drying of the coke starts, which process is also called heating through of the coke. Drying lasts for 2-3 hours after which the burners heating the cube are switched off and in 0,5-1 hours the steam is fed into the cube in order to remove residual gases and to cool the coke. Further the prepared coke is removed from the cube and a new cycle is started again as explained above (see also A.φ.Kpacκ>κoB. ,,HeφτflH0M KOKC". M3flaτenbcτB0 «XMMM?I», 1968, pp 72-81 ).

Also a method for producing coke on the basis of petroleum is known. The coke produced this way is used for making anodes and other products from graphite. According to the method the raw material is fed into the coke container at a temperature of 475-485 ⁰ C to be coked for 14-36 hours and then the coke is removed from the coke container (see also Russian Federation Patent No.

2296151 ).

Due to the rapid growth of the price of petroleum, also the price of the coke produced on the basis of petroleum has increased and therefore efforts are made to produce coke from other organic raw materials, including also shale-oil which is the product of thermal treatment (dry distillation) of shale. For example, a method for producing oil coke on the basis of shale-oil is known, whereas as a raw material for oil coke residual products with BP starting from 350 ⁰ C and obtained in distilling of shale-oil at atmospheric pressure, as well as heavy fraction with BP starting from 320 ⁰ C and separated from the same residual product in the process of coking are used, at that either residual products or heavy fraction are used as raw material but not both of them at the same time. The raw material for producing coke is heated up to 150-200 ⁰ C in order to make it sufficiently fluid for transportation through pipelines and further the process of preparing coke in the coke cube is carried out in a series of identical cycles, whereas each cycle works as follows: the temperature in the coke cube furnace is raised at least up to 250 ⁰ C, when the temperature in the cube reaches 150 ⁰ C the water possibly remaining in the cube vaporizes and all inlets and outlets of the cube are closed hermetically, after which steam having temperature of 150 ⁰ C is fed into the cube for the purpose of checking its impermeability. When during a specified period of time, for example 3-5 minutes, the pressure in the cube does not decrease, the cube has been tested for impermeability, after what the steam is removed from the cube and the raw material is introduced into the cube to fill up 25-35% of its volume. After that the temperature of the raw material in the coke cube is raised by burners allocated under the bottom of the cube. When the temperature is being raised, lighter evaporating fractures are led out of the cube and when the temperature of the raw material left in the cube reaches BP, active vaporization of lighter fractions to be led out of the cube is starting. After reaching of BP the raw material goes on boiling until there is a rapid raise in temperature of the boiling raw material. This indicates the start of active coking. When the raw material is boiling and coke is forming, heavier evaporated fractions are led out of the cube and when being condensated, they produce heavy fraction with a BP starting from 320 ⁰ C, which is used as raw material for coke. When the process of forming of coke has terminated, the temperature in the cube drops rapidly and the temperature of

the furnace is increased to ensure the necessary temperature for the following heating through of the coke. The heating through of the coke lasts 1 ,5-2 hours, whereupon the burners under the bottom of the cube are switched off and the heat stored in the coke keeps on annealing it up to 2 hours. During this time interval the structure of the coke reaches the requested strength on account of residual heat stored in the coke.

After termination of annealing the ready coke is removed from the container (the described method is applied by an Estonian company VKG Oil Ltd in Kohtla-Jarve, Estonia).

The known method enables to produce oil coke which may successfully replace petroleum coke in many ways of usage, for example for making welding electrodes to be used in aluminium industry and metallurgy and when producing devices operating in less aggressive environments. Unfortunately, the oil coke produced on the basis of shale-oil according to the method as described, is not fine enough to be used in the devices which operate in high temperature environments, in chemically active and also in radioactive environments. The reason for this is that the microstructure of the oil coke produced according to the known method is very non-uniform.

Object and subject matter of the invention

Taking into account the aforesaid, the object of present invention is to propose a method for producing oil coke on the basis of shale-oil, whereby the oil coke produced according to such a method has an isotropic microstructure. The oil coke having isotropic microstructure allows to substantially broaden the fields of use of such coke and to use it in devices which operate in high temperature environments, in chemically aggressive environments and also in radioactive environments, for example in linings of nuclear reactors.

In order to achieve the objective according to the method, i.e. to obtain isotropic oil coke on the basis of shale-oil, the raw material is introduced into the coke cube and thereafter coked, for which purpose the raw material is heated until forming of the coke bulk and the oil coke obtained is heated through, annealed and when

annealing has been completed, the prepared oil coke is removed from the coke- cube,

prior to starting the coking process, the raw material in the coke-cube is thermo- oxidated by introducing air into the cube, but keeping the temperature of thermo- oxidation lower than the BP of the raw material,

thermo-oxidation is terminated when the softening temperature of the raw material, determined by the ball and ring method, is in the range of 100-140 ⁰ C,

for forming of the coke the temperature of the raw material is raised up to 390-430 ⁰ C and after forming of the oil coke it is further heated through within 2-3,5 hours.

In order to ensure the heat necessary for heating through of the oil coke in the cube, the temperature of the furnace of the cube is kept within the range of 720- 820 ⁰ C.

Air is introduced into the coke cube with the intensity of 12,5-21 m ³ /h per one ton of raw material in the cube and the thermo-oxidation is carried out at a temperature of 270-290 ⁰ C.

Prior to being introduced into the cube, the raw material is heated up to at least 18O ⁰ C.

Brief description of the drawings

The invention has been illustrated by the drawings, whereby:

Fig 1 shows a flow chart of realization of the method according to the invention.

Fig 2 shows the principal structure of the main unit - coke cube - of the apparatus for realization of the method according to the invention. The arrows next to the valves indicate the direction in which the material in the pipeline flows when the respective valve is in an opened position.

Fig 3 shows the schematic diagram of the apparatus for carrying out the method according to the invention.

Fig 4 shows the temperature curves of the process for obtaining oil coke in the coordinate "time-temperature", whereas the curve A depicted by a continuous line shows the temperature within the raw material being coked, a curve depicted by a continuous line B shows the temperature within the furnace and a curve depicted by a dotted line shows the temperature within the gas outlet pipe of the cube.

Detailed description of the exemplary embodiment of the invention

In Figure 1 there is shown a flow chart of carrying out of the method according to the invention.

For producing isotropic oil coke a residual product with BP starting from 350 ⁰ C and obtained by distilling of shale-oil at atmospheric pressure, as well as heavy fraction with BP starting from 320 ⁰ C and separated from the same residual product in the process of coking are used as raw materials. At that either residual product or heavy fraction is used as raw material, but it is not possible to use their mixture as a raw material because of their different boiling points. The temperature of the raw material in the reservoir is kept at least at 180 ⁰ C to assure its normal flow through the pipelines.

Further process of preparing coke is cyclic, whereas each cycle starts with delivering the raw material into the coke cube and ends with discharging the prepared coke from the cube. Next one cycle of the process is described whereby a residual product with BP starting from 350 ⁰ C and obtained in by distilling of shale-oil at atmospheric pressure is used as raw material.

Prior to introducing raw material into the coke cube, impermeability of the cube is checked. For that purpose the temperature in the empty coke cube is raised at least up to 250 ⁰ C, all inlets and outlets of the cube are closed and pre-heated steam having a temperature of at least 150 ⁰ C is fed into the coke cube. When the pressure of the steam in the cube during a certain period of time, for example in 2- 5 minutes, does not decrease, it is concluded that the cube is air-tight. After that the steam is removed from the coke cube.

The quantity of the raw material to be fed into the coke-cube constitutes 23-33% of the volume of the cube. It is not to the purpose to insert a greater amount of the

raw material, inasmuch as it expands several times during the coking process and when a greater amount is inserted, the raw material may fill up the coke cube, thus making it impossible for the process to carry on.

After the necessary quantity of the raw material has been introduced into the cube, the temperature of the raw material is raised to 270-290 ⁰ C for the purpose of thermo-oxidation. When the temperature is being raised, vaporized lighter fractions are removed from the cube and after condensation they are put to further use. The thermo-oxidation temperature is the same irrespective of which of the two aforesaid raw materials is used.

When the temperature of the raw material has been raised up to the necessary level, air is introduced into the coke-cube with the intensity of 12,5-21 m ³ /h per one ton of the raw material in the cube. At the same time the fractions being vaporized are removed from the cube, condensed and are put to further use or utilization.

In the course of thermo-oxidation the melting point of the raw material is regularly checked by the ball and ring method. In the course of thermo-oxidation the melting point of the raw material constantly increases and the experiments have established that when the melting point of the raw material is in the range of 100- 140 ⁰ C, the density of the raw material in the coke-cube is at the necessary level for the coke to start forming and the thermo-oxidation is terminated by stopping adding air into the coke-cube. At said temperature thermo-oxidation is terminated irrespective of which of the two aforesaid raw materials is used. According to the data obtained by experiments, the duration of the thermo-oxidation is different in case of different raw materials: when a residual product with BP starting from 350 ⁰ C and obtained in distilling of shale-oil at atmospheric pressure is used, then thermo-oxidation lasts up to 40 hours, but when heavy fraction with BP starting from 320 ⁰ C and separated from the same residual product in the process of coking is used, then thermo-oxidation lasts up to 50 hours.

After the thermo-oxidation has terminated, the temperature of the raw material in the coke-cube is raised up to 410-420 ⁰ C, at which temperature the raw material boils and forming of the coke starts. After coking the temperature in the cube drops rapidly to 330-355 ⁰ C and the temperature of the furnace is raised to 720-

820 ⁰ C to ensure the necessary heat for the further heating through of the formed coke. Heating through of the coke lasts for 2,5-3 hours.

When heating through of the coke has come to an end, the burners heating the cube are switched off and the heat stored in the coke keeps on annealing it for at least 2 hours. After that the coke is ready to be removed from the coke-cube.

Next an integrated embodiment of the method according to the invention for producing oil coke on the basis of shale-oil by means of particular apparatus is described. This embodiment enables residual products (vaporized fractions, water, etc.) formed during the production process to be utilized or to be directed back into the production process if needed.

A coke cube, the principal structure of which is shown in Fig 2, is the main unit of the apparatus. The coke cube 1000 comprises a cylindric horizontal reservoir 1100 and a furnace 1200 underneath it. In the upper part of the reservoir there are four openings 1101 , 1102, 1103 and 1104, whereby openings 1101 -1103 are inlets, through which steam, air and raw material are respectively introduced into the coke cube, and opening 1104 is an outlet, through which gases and vapours emerging during coke formation process are removed. The outlet pipe starting from opening 1104 is split into two - an outlet 1105 for removing vapours and gases and an outlet 1106 for removing air used in the coke cube. In the non-split part of the outlet pipe, originating from opening 1104, there is installed a thermocouple 1107 for measuring the temperature of gaseous residues leaving the coke cube. The temperature of gaseous residues is used for monitoring of the burning process going on in furnace 1200. In the region 1105 of the outlet pipe there is valve 1108 and in the region 1106 there is valve 1109, which are necessary for introducing emerging vapours and gases into different processing units. Inlets 1101 -1103 are also equipped with valves 1110-1112. In the cylindrical reservoir of the coke cube (approximately 90 cm from the lowest point of its bottom) there is also a thermocouple for measuring the temperature of raw material.

In the wall 1201 of the coke cube furnace 1200 there is an opening 1202 through which the burners installed in the furnace (not shown in the figure) are connected

to the tanks of heating gas. These connections are made through valves 1203 and 1204, whereby with the valve 1203 supply of heating gas to the burners is controlled, and gases to be utilized are introduced into the furnace through valve 1204, whereby it is also possible to utilize residual gasses generated in other production processes. The bottom of the furnace is realized as inclined plane 1205 extending until vertical partition wall 1206, the height of which being a little bit smaller than the height of the furnace and which is in proximity to the opposite wall 1207 of the furnace chamber. In this wall near the furnace bottom there is an opening 1208 through which combustion gases leave furnace 1200. Above partition wall 1206 and very close to the bottom of reservoir 1200 there is installed thermocouple 1209 which is used for indirect measurement of the temperature of the bottom of reservoir 1100 - though the thermocouple 1209 measures the temperature in the furnace, due to its closeness to the bottom of the reservoir, this measured temperature, is practically equal to the temperature of the bottom of reservoir 1100. Therefore, the term "temperature of the furnace" used hereinafter practically means also the temperature of the bottom of reservoir 1100.

Fig 3 shows the complex apparatus used for implementing of the present invention. The apparatus includes four main units - the coke cube 1000, the structure of which was in detail described above, unit 2000 for processing air used in the coke cube, unit 3000 for processing gaseous compounds and unit 4000 for collecting processed residues and returning them back into process.

The unit 2000 for processing used air includes a heat exchanger 2010 cooled by water and a separator 2020, whereby inlet 2011 of the heat exchanger 2010 is connected to the valve 1109 of the coke cube 1000 and outlet 2012 is connected to the inlet 2021 of the separator 2020. Separator 2020 has an outlet 2022 for light distillate and an outlet 2023 for air and combustible vapours.

The unit 3000 for processing gaseous compounds includes intermediate tank 3010 and two air coolers 3020 and 3030. Intermediate tank 3010 has an inlet 3011 that is connected to the valve 1108 of the coke cube and two outlets 3012 and 3013. Outlet 3012 is connected to the inlet 3021 of the first air cooler 3020 in order to forward uncondensed gaseous compounds from the intermediate tank 3010 to the air cooler 3020, and outlet 3013 is used for discharging of condensed in the

intermediate tank 3010 heavy distillate into a storage tank for said product (not shown in the figure). Air cooler 3020 has an outlet 3023 for condensed fractions that is connected to the unit 4000 for collecting and returning the processed residues, and outlet 3022 for gaseous fractions connected to the inlet 3031 of the second air cooler 3030. The condensed fractions outlet 3033 of this air cooler is connected to the unit 4000 for collecting and returning the processed residues, and through outlet 3032 for gaseous fractions the coke gas outflows and is directed back into the manufacturing process for heating of the furnace 1200.

The unit 4000 for collecting processed residues and returning them into the manufacturing process includes tanks 4010 and 4020 and pumps 4030 and 4040. Inlet of 4011 of the condensed light distillate tank 4011 is connected to the outlet 2022 of the separator 2020 of the unit 2000, and also to the outlet 3023 of the air cooler 3020 of the unit 3000. Outlet 4012 of the tank 4010 is connected to the inlet 4031 of a pump 4030 that returns light distillate to the production process. Inlet 4021 of the tank 4020 is connected to the outlet 3033 of the air cooler 3030 of the unit 3000, from where condensed petrol and water are removed, and outlet 4022 is connected to inlet 4041 of the pump 4040 returning petrol and water from tank 4020 into the production process.

The method is realized as a cyclic process using the above described apparatus, whereby each cycle is performed as follows.

Prior to introducing raw material into the reservoir 1100 of the coke cube 1000 all the inlet and outlet valves of the reservoir 1100 are closed, except for the valve 1108 through which the reservoir 1100 is connected to the unit 3000 for processing gaseous compounds. Thereafter heating gas is introduced into the furnace 1200 through valve 1203 and heating of the lower surface of the reservoir of the coke cube starts. In Figure 4 the starting moment of heating is indicated by t-i at which point the curve B makes a sharp rise upwards and within a few minutes reaches the temperature of approximately 370 ⁰ C. Residual products remaining in the reservoir 1100 from the previous cycle evaporate, leave the reservoir and are collected in the intermediate tank 3010 of the unit 3000 for processing gaseous compounds. When the temperature in the reservoir 1100 is at least 250 ⁰ C, the valve 1108 is closed and the valve 1110 is opened, through which pressurized

superheated water steam is introduced into the reservoir 1100 with a temperature of at least 150 ⁰ C in order to avoid its condensation in the reservoir 1100. When the necessary pressure level in the reservoir 1100 has been reached, the valve 1110 is closed and within 2 to 5 minutes the change of pressure in the reservoir 1100 is checked. In case the pressure does not drop, meaning that the reservoir 1100 is air tight, the valve 1108 is opened and used steam, which contains also vapours of residual products left in the reservoir 1100 from the previous cycle, is led into the intermediate tank 3010 of the unit 3000 for processing gaseous compounds.

Thereafter the valve 1 108 is left open, in addition the valve 1112 is also opened and introducing of raw material, that in order to assure its trouble-free flow in the pipelines has previously been heated up to the temperature of at least 180 ⁰ C, into reservoir 1100 is started. In Fig 4 the starting moment of filling the reservoir is indicated by t ₂ where the temperature curvature A of raw material rises rapidly (preheated raw material, having a temperature of at least 180 ⁰ C, is fed in). The amount of the raw material introduced into the reservoir 1100 is 23-33% of its volume, whereby when as a raw material residual products with BP starting from 350 ⁰ C and obtained in distilling of shale-oil at atmospheric pressure is used, then the coefficient of charge of the reservoir 1100 is chosen up to 25%, and when heavy fraction with BP starting from 320 ⁰ C and separated from the same residual product in the process of coking is used, then the coefficient of charge of the reservoir 1100 may be increased up to 33%.

After feeding the necessary amount of raw material into the reservoir 1100 the valve 1112 is closed and by intensifying heating of the furnace 1200 the temperature of the raw material starts to raise (during this period the temperature of the furnace and accordingly also of the bottom of the reservoir 1100 exceeds 400 ⁰ C, as is seen in Fig 4 for the time interval t ₂ -t ₃ ). Vapours of lighter fractions formed in the reservoir 1100 during the temperature raise leave the reservoir 1100 through an open valve 1108. Heating of the raw material is continued and when to the moment t ₃ the temperature measured by thermocouple 1113 is within the range of 270-290 ⁰ C, the raw material has reached the temperature needed for the following thermo-oxidation.

In order to start thermo-oxidation the valve 1108 is closed and the valve 1109 connecting reservoir 1100 with the unit 2000 for processing used air is opened. Simultaneously the valve 1111 is also opened and the air needed for thermo- oxidation is fed through it into the reservoir 1100 with the intensity of 12,5-21 m ³ /h per one ton of the raw material inserted into the reservoir. Tests have proved that supplying air with this kind of intensity is suitable for both of the above mentioned types of raw material. The air used during thermo-oxidation leaves the reservoir 1100 through valve 1109 and is fed into the heat exchanger 2010 of the unit 2000 for processing used air, where vapourized light fractions condense and form the so called light distillate as a residual product of thermo-oxidation. The intensity of burning in the furnace 1200 and respectively the temperature of the bottom of the reservoir 1100 are adjusted so that it stays lower than the temperature needed for thermo-oxidation or close to it because during exothermic thermo-oxidation a substantial amount of heat is generated, that can be used for keeping the temperature necessary for the process, thereby reducing the heating costs. In Fig 4 this is illustrated by curves A and B within the time interval t ₃ -t ₄ .

Thermo-oxidation process lasts until the melting point temperature determined by the ball and ring method is in the range of 100-140 ⁰ C. In Fig 4 this instant is indicated as U- At this moment feeding of the air into reservoir 1100 is stopped by closing the valve 1111 and the temperature of the raw material is raised as this is necessary for boiling the raw material and achieving conditions necessary for coking. For that purpose the temperature in the furnace is drastically raised, resulting in a rapid raise of the temperature of the bottom of the reservoir up to 550-600 ⁰ C. The raise of the raw material temperature follows after a short delay and when it has raised to 400-420 ⁰ C, boiling of the raw material starts (in Fig 4 instant t ₅ on curve A). The temperature of the furnace 1200 is adjusted by the burners in a manner that insures maintaining of the temperature of the raw material within the limits indicated above.

Coking starts in the process of the above mentioned boiling. To control the run of the process it is not essential to determine this starting point precisely, instead it is important to fix the instant when coking has finished. When the coke has been formed, the temperature inside the reservoir 1100 falls sharply to the range of 330-

355 ⁰ C (in Fig 4 instant t ₆ on curve A). Thereafter the temperature in the furnace 1200 (and thereby the temperature of the bottom of reservoir 1100) is kept in the range of 720-820 ⁰ C in order to ensure the temperature necessary for heating through the coke in the reservoir 1100 and the coke is heated through for 2,5-3,5 hours. In Fig 4 the end of heating through is indicated by instant t ₇ .

Upon completion of heating through the burners in the furnace 1200 are closed and as a result the temperature of the furnace 1200 starts to fall rapidly. Thereafter the heat stored in the coke in the reservoir 1100 keeps on annealing it approximately for 2 hours.

Annealing is completed at the instant indicated in Fig 4 by t ₈ , after that the valve 1110 is opened and steam is introduced into reservoir 1100 in order to remove residual gases. The mixture of vapour and gases is led through opened valve 1108 into the unit 3000 for processing gaseous compounds. After that the coke is ready to be removed.

Processing and returning of the vapours-gases emerged in the process and of the used air takes place as follows.

From the mixture of gas and vapour led into the tank 3010 of the unit 3000 the heavy fractions (heavy distillate) condense already in that tank and this heavy distillate is led through outlet 3013 in the bottom of the tank 3010 into a special tank and it can be used as a raw material in coke production. Lighter fractions, being still in a vapouhzed state, are led through outlet 3012 into first air cooler 3020, in which they are cooled to 140-150 ⁰ C. At this temperature lighter fractions condense and this light distillate is led from the air cooler 3020 through outlet 3023 into the tank 4010 for light distillate of the unit 4000 for collecting and returning the processed residues, from where they by means of a pump 4030 are returned back into the process. The components (petrol, water and coke gas) staying gaseous at a temperature of 140-150 ⁰ C are led through outlet 3022 into the inlet 3031 of the second air cooler 3030. In this air cooler the introduced gases are cooled to 10-40 ⁰ C, condensed petrol and water are led through outlet 3033 into tank 4020 of the unit 4000 for collecting and returning processed residues, where this mixture settles and petrol and water are separated from each other. Petrol and water are

returned into the process by means of the pump 4040. Using the same pump 4040 for returning both petrol and water anticipates using additional constructional solutions between the tank 4020 and the pump 4040, but as they are not subjects of the present invention, they are not described in detail. They can be realized on the basis of the solutions already known from the prior art.

The air removed from reservoir 1100 during thermo-oxidation is led through valve 1109 into the heat exchanger 2010 of the unit 2000 for processing used air, where it is cooled with water, resulting in condensation of lighter fractions (light distillate) that vapouhzed in reservoir 1100. The formed mixture of light distillate and air is led through outlet 2012 of the heat exchanger 2010 into the separator 2020, where air and light distillate are separated from each other. Light distillate is led through outlet 2022 into the tank 4010, air and combustible gases are returned into reuse through outlet 2023.

The described method for producing oil coke on the basis of shale-oil enables to produce isotropic coke of high quality, the microstructure of which is essentially more uniform than the structure of a oil coke produced according to the known method and is even to a certain degree more uniform than the structure of isotropic coke produced on the basis of petroleum. The microstructure of isotropic oil coke produced according to the method of the present invention makes it possible to substantially broaden the field of application of this oil coke.

The invention is not limited to the above described embodiment and covers all embodiments either directly covered by the claims and also their equivalent embodiments.

The list of reference numbers used in the figures

1000 - coke cube

1100 - reservoir of coke cube

1101 -1104 - inlets of coke cube

1105 - outlet of coke cube for gases and vapours

1106 - outlet of coke cube for used air 1007 - thermocouple 1108-1112 - valve

1113 - thermocouple

1200 - furnace of coke cube

1201 - wall of coke cube

1202 - opening

1203-1204 - valve

1205 - bottom of a furnace

1206 - partition wall of a furnace

1207 - opposite wall of a furnace

1208 - opening

1209 - thermocouple

2000 - unit for processing used air

2010 - heat exchanger

2011 - inlet

2012 - outlet

2020 - separator

2021 - inlet

2022 - outlet

2023 - outlet

3000 - unit for processing gaseous compounds

3010 - intermediate tank

3011 - inlet

3012 - outlet

3013 - outlet

3020, 3030 - air cooler

3021 , 3031 - inlet

3022, 3032 - outlet

3023, 3033 - outlet

4000 - unit for collecting and returning processed residues

4010, 4020 - tank

4011 , 4021 - inlet

4012, 4022 - outlet

4030, 4040 - pump

4031 , 4041 - inlet