Low-Cost Zero Sewage Discharge Strategy in Coal Chemical Industry

Abstract

High salinity in the sewage discharged by coal chemistry companies has become the bottleneck to the development of this industry. In response to the zero discharge standard specified by the Ministry of Environmental Protection, this paper sheds new light on the development of low-cost zero discharge sewage treatment strategy for the coal chemistry industries based on coal chemistry brine TMC hot film coupling separation technology. A pretreatment test is conducted to determine the dosing conditions for any component. On this basis, taking a coal chemistry company as a study case, we conduct a pilot study on the evaporation and crystallization of industrial strong brine on the field. The findings show that PAC and FeSO4 can act as the best flocculant, while the optimal doses of Na2CO3, MgO, CaO, PAM and PAC are 70mg/L, 2500ug/L, 80mg/L, 2mg/L and 120mg/L, respectively; the purity of brine after evaporative crystallization reaches above 95%; the total treatment cost per ton brine is RMB 50.32 /t, so that the economic effect seems obvious. This study provides the clues for coal chemistry companies to reach the zero discharge of sewage and promote the steady development of the coal chemical industry.