Slurry circulation process based on SDA process desulfurization system

The invention relates to a slurry circulation process based on an SDA (Spray Drying Absorption) process desulfurization system. The slurry circulation process comprises the steps that (1) desulfurized fly ash of a desulfurization tower enters an accident pool, is mixed and stirred together with digestive water to prepare circulation slurry, the circulation slurry enters a slurry top tank after being filtered, and finally the filtered circulation slurry enters an atomizer to participate in desulfurization reaction; (2) when the desulfurization system fails or is maintained, slurry which overflows from or is discharged from the top tank, a digestion tank and a slurry tank is discharged into the accident pool; and (3) when the desulfurization system recovers to normally work, the slurry is re-circulated. Compared with the prior art, the slurry circulation process has the beneficial effects that (1) the desulfurized fly ash directly enters the accident pool, a dust producing point caused by fly ash discharging and transporting of the desulfurized tower is eliminated, and the environment quality of a desulfurization island is effectively improved; (2) the accident pool in an original desulfurization system is combined with a mixing tank and a circulation slurry tank in a circulation slurry system into a whole, the functions of the accident pool, the mixing tank and the circulation slurry tank are integrated, the quantity of equipment and the occupation area are reduced, and the input cost is lowered; (3) the process route is shortened, the structure is simple, and the operation and the maintenance are convenient.