| 摘要 |
PROBLEM TO BE SOLVED: To prevent over-denitration and to avoid the deviation of outlet NOx concn. from a lower limit by controlling denitration on the basis of adsorbed NH3 quantity necessary after the elapse of (n) hr from the present point of time. SOLUTION: In a denitration control apparatus injecting NH3 into exhaust gas to react the same with NOx in the exhaust gas on a catalyst and controlling a flow rate of NH3 so that the outlet NOx concn. of the catalyst enters a predetermined range, a necessary NH3 flow rate correcting device 300 calculating the necessary NH3 flow rate at the present point of time on the basis of the inlet NOx flow rate of the catalyst, an outlet NOx concn. set value and the deviation between both measured values and correcting a necessary NH3 flow rate 111 so that a necessary denitration rate is obtained after the elapse of (n) hr from the present point of time is provided. The necessary NH3 flow rate correcting device 300 adds the reacted NOx flow rate at the present point of time and the reacted NOx flow rate after the elapse of (n) hr and substrates the estimate value of adsorbed NH3 quantity to the catalyst at the present point of time from the necessary adsorbed NH3 quantity to the catalyst after the elapse of (n) hr and calculates a correction value 310 correcting a necessary NH3 flow rate on the basis of the added value and the substracted value. |
