The principle of selective catalystic reduction(SCR) denitrification process has been briefly expounded

pointing out the harmfulness of ammonium bisulfate(ABS) occurred in SCR denitrification process.The main affecting factors for ABS formation

such as the mole ratio of NH3/NOx

the SO3 concetration

and the dew point of ABS etc.

have been analysed in detail.According to the properties of ABS

the measures for controlling formation of ABS and recducing negative impacts of ABS have been put forward:through controlling the amount of ammonia escape in the SCR process and the oxidation rate of SO2 in the flue gas

the formation amount of ABS is to be reduced;in order to prevent the catalyst to lose its activity due to hold-up of ABS

the operating time of SCR under low load has to be reasonably controlled;for effectively decreasing the formation rate of ABS on heat-exchanging elements in the preheater

the ceramic coating has to be selected for said elements.