Quality-divided crystallization device and process capable of realizing zero discharge of high-salinity wastewater

Abstract

The invention discloses a simple and highly-efficient quality-divided crystallization device and process capable of realizing zero discharge of high-salinity wastewater. The quality-divided crystallization device comprises a highly-efficient concentration unit, an evaporative crystallization unit, a freezing crystallization unit, a nitrate recrystallization unit and a mixed salt crystallization unit, wherein all the units are connected with a liquid pump and a solid conveyor through pipelines. By adoption of the treatment process provided by the invention, the purpose of zero discharge of thehigh-salinity wastewater with a salt-nitrate ratio (the mass ratio of sodium chloride to sodium sulfate) of no less than 10: 1 or no larger than 1: 1 is achieved; meanwhile, valuable salts like sodiumchloride and sodium sulfate are recycled; the process of the quality-divided crystallization device is simplified; the operation difficulty of quality-divided crystallization is reduced; the qualityof crystallized salt is improved; the operation cost is reduced; and significant economic benefits and social benefits are achieved.

Description

technical field [0001] The application relates to the field of high-salt wastewater treatment, in particular to a simple and efficient high-salt wastewater zero discharge and fractional crystallization device and process. Background technique [0002] The coal chemical industry uses coal as a raw material to produce oil and gas, and derivatives to produce downstream products with higher added value. Coal chemical industry is a "big water consumer". The water consumption per ton of products is as high as 9-12.6 tons, and the amount of wastewater discharged from production is also relatively large. The above problems are particularly serious in the water-scarce areas of Northwest China where coal resources are concentrated. Therefore, modern coal chemical industry places great emphasis on the degradation and reuse of pollutants in production wastewater, and even zero-discharge treatment, thereby greatly reducing the overall water intake and sewage discharge, and realizing the ...

AI Technical Summary

Problems solved by technology

Although the existing zero-discharge technology at home and abroad can basically realize the evaporation and crystallization of high-salt wastewater, there is often a large gap between the quality and yield of crystallized salt and the new standards and environmental protection requirements, and the existing fractional crystallization The process is relatively complicated and the operating costs are high, which makes it difficult to meet the needs of enterprises to respond to increasingly stringent environmental protection policies

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