Electric Power ›› 2020, Vol. 53 ›› Issue (7): 197-202.DOI: 10.11930/j.issn.1004-9649.201910029

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Precipitation Characteristics of Chlorine in the Process of Desulfurization Wastewater Spray Before and After Treatment

ZHANG Qian1, NI Li2, DOU Chaozong2, XIAO Haiping2   

  1. 1. Shenhua Guohua Electric Power Research Institute Co., Ltd., Beijing 100069, China;
    2. School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China
  • Received:2019-10-08 Revised:2020-02-28 Published:2020-07-05
  • Supported by:
    This work is supported by the National Key Research and Development Program of China (No.2018YFB0604301)

Abstract: Desulfurization wastewater contains high concentrations of chloride salts, which affects the safe operation of the desulfurization system. The Factsage thermodynamic calculation software was used to simulate the precipitation characteristics of chlorine in a single chloride solution and the desulfurization wastewater before and after treatment through the tail flue spray. The results showed that the precipitates were observed in the form of chlorine-contained gas if CaCl2, MgCl2 and NH4Cl solutions were sprayed. While if NaCl solution was sprayed, all of the chlorine content were precipitated as NaCl(s) without any gas evolution. In the process of spray evaporation with untreated desulfurization wastewater, more than 75% of chlorine were precipitated as NaCl(s). After the removal of Ca2+, Mg2+, NH4+, etc., no HCl gas was formed in the flue gas spray evaporation process of the desulfurization wastewater, and the product NaCl(s) would be removed by electric dust removal device. Therefore, the pretreatment of the desulfurization wastewater has effectively reduced the precipitation of chlorine-contained gas and therefore the corrosion of the tail flue is mitigated.

Key words: desulfurization wastewater, pretreatment, thermodynamic equilibrium, Cl, precipitate