The limestone (CaCO3) is adopted to absorb SO2 in the offgas and the by-product is gypsum. The entire desulfurization system is composed of offgas delivering system, SO2 absorption system, limestone slurry preparation and supply system, gypsum dewatering system and wastewater treatment system.

Main characteristics of this process are that the countercurrent spraying empty tower with simple structure is adopted, and the absorbing, oxidizing and crystallizing are all completed within the tower; SiC centrifugal nozzle is wear-resistant and non-blocking; absorption solution redistribution device of absorption tower makes efficient use of all the recycled slurry, which is mixed in the spraying area, thus reducing the raw material consumption of absorber.