| 摘要 |
PROBLEM TO BE SOLVED: To efficiently and surely reduce the concentration of nitrogen oxides in a combustion furnace by precedently controlling atomization rate of ammonia to the furnace on the basis of predicted values of the nitrogen oxides concentration in combustion gas. SOLUTION: Combustion materials are fed from a combustion material feed hopper 16 and gasified and combusted in a refuse layer 12 of a stoker fired furnace 1 through a feeder 17. Exhaust gas is cooled in a boiler 19, removed with poisnous gas, particles or the like at a filter dust collector 20 and discharged from a chimney 23. Real-time measurement of nitrogen oxides concentration is conducted by an NOx measuring means 2 at the upper part of the furnace 1, followed by transferring concentration signals to a predicting means 28 and performing variation prediction of the nitrogen oxides concentration. Then, signals of the predicted variation of a given time later, are sent to a controller 26 to control ammonia flow rate regulating valves 13a, 13b on the basis of the control signals formed in the controller 26, followed by regulating an ammonia injection flow rate, thereby controlling the nitrogen oxides concentration so as to be not more than an arbitrary value.
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