Evaporation characteristics of desulfurization wastewater in low-temperature three effect evaporation process

The evaporation characteristic of desulfurization wastewater is an important indicator for determining the process parameters of three effect evaporation. Through evaporation experiments，the relationship between the evaporation rate of desulfurization wastewater and the solid content，salt content and density of wastewater was studied，and the discharge concentration under the optimal operation state of the system was determined. The experimental results showed that low solid content of desulfurization wastewater was conducive to wastewater evaporation，solid particles in the wastewater could provide crystal seeds for salt crystallization，particle scouring reduces the risk of tube scaling，considering evaporation efficiency and reducing the risk of tube scaling，the recommended solid content of influent water was 4%.The evaporation rate of desulfurization wastewater decreases with the increase of salt concentration. Moreover，the higher the salt concentration was，the faster the evaporation rate decreased，which may be related to solution viscosity，solution surface tension and ion hydration number. The evaporation rate of desulfurization wastewater is negatively related to the solution density. When the solution density exceeded 1 400 kg/m3，the evaporation rate decreased significantly and the energy consumption increased significantly. Considering the efficient operation of the system and the filter press effect，it recommended 1 400 kg/m3 of the discharge density. The concentration ratio was an important indicator of the process design of the low-temperature three effect evaporation system. The concentration ratio was negatively related to the solid content of raw water. The concentration ratio should be determined according to the solid content of raw water and the discharge density to complete the overall design of the three-effect evaporation system.