The Technology And Application Of Flue Gas Desulfurization Based On Wet Limestone-gypsum

With that the world attaches increasing importance to environmental protection, the SO₂ emission control from thermal-electric power stations becomes very important in the treatment for air pollution. Flue gas desulfurization based on wet limestone-gypsum process (WLST-FGD) which has been taken by 90% of FGD devices for thermal-power plant in Japan, Germany, America is most widely used technology in FGD field all over the world.Dongfang boiler (group) Co., Ltd introduced WLST-FGD technology from Lurgi company(Germany) in 2003 and then successfully applied it to the FGD project for Jiangyou 2×300MW units.WLST-FGD system is mainly composed of flue-gas system, absorber system, slurry preparation system, gypsum dewatering system and discharging system etc. The main process is: the flue-gas from boiler flows into absorber after passing deduster, booster fan and GGH, then it flows upward and be washed by countercurrent downward circulating spraying slurry which is sprayed into absorber through many nozzles on the spraying levels so that most of SO₂, HCL and HF can be removed. At the same time, the outgrowth will be oxidated into gypsum by forced oxidation way, and then will be discharged to gypsum dewatering system by gypsum discharging pumps. At the lower part of the absober, the special impulse suspending system is taken to avoid forming sediment and deposit. The clean gas finally is dischaged to atmosphere after being removed water by demister which is arranged at the top of absorber.This article introduces the feature, principle, process and its practical implement of WLST-FGD technology by taking example for Jiangyou FGD project. It has referential mean for same technology introduction and its appliance to practical project.