In order to predict the influence of high calcium viscous fly ash produced from wet-bottom furnace upon the SCR catalyst

through analysis of fly ash concentration

particle size distribution

and composition of fly ash in the flue gas

at the same time

through small sample test of catalyst in flue duct of thermal power plant

it shows that the deposition of products in chemical reaction between active CaO and SO2 in high calcium fly ash

as well as the deposition of viscous fine fly ash

on the surface of catalyst are main causes resulting in inertness of catalyst's activity

for this

some measures

including adaptation of highly effective sootblowers

enhancement of the flue gas' flow speed

and improvement of the cleanliness on catalyst surface

etc.

have been put forward.