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Feasibility of Evaporation Crystallization for Waste Water from Pulverized Coal Gasification Author/Source: Gasification World Date: 2021-11-27 Clicks: 20 Is evaporation crystallization feasible for waste water from pulverized coal gasification? Can evaporative crystallization be used for wastewater from pulverized coal gasification? Is it feasible to use evaporation crystallization for treating gasification wastewater? I. Sources of wastewater from shredded coal gasification: During the production process of shredded coal gasification, a large amount of wastewater is generated when the raw coal gas is cooled and washed; this wastewater has a complex composition and high concentrations of pollutants. II. Characteristics of wastewater from pulverized coal gasification: In the pulverized coal gasification process, the wastewater generated still exhibits characteristics such as oil content, high ammonia nitrogen levels, high phenol concentrations, high COD values, a complex composition of pollutants, poor biodegradability, and high biological toxicity, even after phenol and ammonia have been recovered from it. III. Waste water treatment process from pulverized coal gasification: At present, the biological treatment of waste water from pulverized coal gasification, the reuse of treated water, and membrane concentration processes have become increasingly mature; however, the evaporative crystallization products obtained at the end of this process consist only of mixed salts. The wastewater from coal gasification is subjected to biochemical treatment, recycled water reuse, and membrane concentration; thereafter, nanofiltration membranes are used to separate chloride and sulfate ions. The water produced by nanofiltration is evaporated and crystallized using the MVR process, while the concentrated stream from nanofiltration is evaporated and crystallized through a combination of MVR thermal and cold crystallization processes. Nanofiltration membranes can effectively separate and concentrate monovalent salts (mainly sodium chloride) and divalent salts (mainly sodium sulfate) in water, which is beneficial for subsequent crystallization and salt separation. The evaporation crystallization test apparatus operates stably and reliably, producing qualified crystalline salt products. The entire process consists of a biochemical treatment section, a recycled water treatment section, a membrane concentration section, and a crystallization and salt separation section.