PURPOSE: To reduce NOx and make the quantity of used ammonia most suitable by adding to an exhaust smoke denitrification control system a most suitable control system which uses the most suitable control means.
CONSTITUTION: The most suitable control means 2 has an AR model controller 21 and a guidance alarm section 22. To the AR model controller 21 the NOx concentration, O2 concentration, exhaust gas flow rate, and the temperature and concentration of ammonia are inputted, and the most suitable ammonia flow rate correction value is outputted based on this input and it is added by an addition calculator 30 to set a final NH3 flow rate. When the control performance of AR model 21 is deteriorated as years go and with the change of season, a guidance alarm section 22 issues alarm signal and displays it on a CRT 23. In this case the AR model tuning is made or it is exchanged for another model. The NOx concentration at the inlet of a denitrification device 55 and NOx concentrations of O2 and NOx at the inlet of a chimney 59 are fedback to the control mechanism 61, and the control mechanism 61 controls the degree of opening of a NH3 flow rate adjusting valve 62, and NH3 is mixed with the air from a forced draft fan and the mixture is thrown into the denitrification device 55.
MANABE HIROYUKI
KAMATAKI YASUNORI
