The fault of desulfurization system about the SO2 removal efficiency losses and the calcium sulphite content in gypsum above standards in 600 MW generator set was analyzed in details.The decrease of slurry spray flux

which was caused by the blockage of circulating pump nozzles and the higher slurry pH value

were the main reasons.The fault was treated by using HEE-1 desulfurization additive.The application results show that the additives presents unique performance

such as raising the desulfurization efficiency quickly

improving the operation conditions of desulphurization system and promoting the oxidation rate of calcium sulphite.HEE-1 desulphurization additive can be used in the fault treatment of the desulfurization system.