| OCR Text |
Show As a result. the discharge NOx is stable and can be controlled lower. (Refer to Fig. 1-26 - 29) Itt) No lIanual operation during the normal operation As lIentioned in I) and Ii) above, the system is siMPle and automatically operated. Therefore, no manual operation will be required in this system under normal operating conditions. tv) Low ma intenance cost (a) Small consumption of reduction agent As the above-mentioned automatic control system operates on the minimum required amount of reduction agent that maintain the NOx below the set value, consumption of reduction agent can be made sma II in amount. (b) Small consumption of electric power As the pump for ammonia water requires only sm~l] power, i.e. smaller than approximately lkW. and th~ pressurp. loss in the exhaust gas system does not increase as in the c~se of catalytic denitrification, consumption of electric pOWf'r can be very small. v) No care about discharge of white smokp. of ammonium chloride Because of the minimum addition of reduct ion agent by automatic control system and the shape of furnace that ~I lows a high reaction efficiency, discharged ammonia is very small. Therefore, white smoke of ammonium chloride cannot be visible. Fig. 1-30 shows ammonia concentration, NOx concentration, etc. at the E.S.P outlet under operating the automatic control system. It can be seen that unreacted ammonia is only several ppm with no white smoke being visible. 1 0 |
