PURPOSE: To rapidly remove the reaction products of SOX and NH3, crystallized on catalyst at low temperatures, by controlling the amount of NH3 to inject to less than an equimolar amount on the basis of NOX present in waste gas in a NH3 catalytic reduction type denitration method.
CONSTITUTION: Waste gas containing SOx is treated at 300°C or lower in an NH3 catalytic reduction type denitration apparatus, where SOX is reacted with NH3 injected as a reducing agent to crystallize the reaction products of SOX and NH3 on a catalyst, whereby lowering the activity of the catalyst. When the activity of the catalyst is lowered, the injection of NH3 to the apparatus is temporarily stopped or the amount of NH3 to inject is controlled to less than an equimolar amount on the basis of NOX present in waste gas. Thus, NH3 present in the reaction products of SOX and NH3, deposited inside the pores of the catalyst, is selectively and rapidly reacted with NOX in the waste gas and the NOX is therefore decomposed into N2 and sulfuric acid and removed.
KONISHI KUNIHIKO
IMAHASHI ATSUKO
OOTA MASAO
| JPS5428789A | 1979-03-03 |