Research and Application of Zero Discharge Technology for Desulfurization Wastewater of 660MW Coal-fired Unit

Abstract

In this paper, the pretreatment, concentration reduction and evaporation crystallization stages of desulfurization wastewater in zero discharge technology were studied and engineering applications were carried out, and the performance of 660MW coal-fired unit zero discharge desulfurization wastewater was evaluated. The results showed that for desulphurization wastewater with a total dissolved solid of about 48768.9 mg/L and a Cl content of about 12507.2mg/L, the pass flue gas evaporation process could realize zero discharge treatment of desulphurization wastewater. The hot smoke content introduced into the drying tower was about 52351.0m3/h, the inlet and outlet smoke temperatures of the drying tower were 374°C and 130°C respectively, the influence on boiler efficiency was about 0.0676%, and the moisture content of drying products was only 0.15%. The content of HCl in the flue gas at the inlet and outlet of the drying tower was 53mg/L and 165mg/L, the mass fraction of Cl removal and volatilization of desulfurized wastewater were 93.10% and 6.90%, the average content of chlorine in fly ash was about 0.225%, which meet the requirements of relevant standards for the comprehensive utilization of fly ash.