Coal chemical strong brine zero emission and salt screening technology

Abstract

The invention discloses a coal chemical strong brine zero emission and salt screening technology. Strong brine enters a first special reverse osmosis process pack after being treated by an adjusting pond and a pre-treatment device, freshwater of the strong brine is reused, water produced on the thick water side passes through a softening process pack to remove calcium ions and magnesium ions in wastewater and then enters a first-stage special nanofiltration process pack, water produced on the thick water side of the first-stage special nanofiltration process pack passes through a first evaporation crystallization process pack to obtain industrial-grade sodium sulfate, water produced on the fresh water side enters a second-stage special nanofiltration process pack, water produced on the thick water side of the second-stage special nanofiltration process pack returns to the adjusting pond, water produced on the fresh water side enters a reverse osmosis membrane process pack, the fresh water is reused, water produced on the thick water side enters a second special reverse osmosis membrane process pack, water produced on the fresh water side of the second special reverse osmosis membrane process pack flows back to the adjusting pond or is reused according to water quality, and water produced on the thick water side passes through a second evaporation crystallization process pack to obtain industrial-grade sodium chloride. The technology is simple, cost is low, the automation degree is high, long-time stable operation can be achieved, and secondary pollution is not caused.

Description

technical field [0001] The invention relates to the field of concentrated brine treatment and reuse, in particular to a coal chemical industry concentrated brine zero discharge and salt separation process. Background technique [0002] At present, the pollution and shortage of water resources have become an important reason restricting the economic and social development of our country. Since the State Council put forward "Several Opinions on Promoting the Healthy Development of the Coal Industry" in 2004, the coal chemical industry has developed rapidly, but at the same time, the brine it produces has become a bottleneck for the development of the industry. Degree, high sodium chloride content and other characteristics. [0003] In November 2007, the state promulgated the "National Environmental Protection "Eleventh Five-Year" Plan", which clearly requires key industries such as chemical industry and coal to promote the recycling of wastewater and strive to achieve less or...

AI Technical Summary

Problems solved by technology

Multi-stage flash evaporation is generally used in large-scale evaporation projects, and the treatment effect on wastewater with complex salt content is not ideal; multi-effect evaporation is generally used in small and medium-sized evaporation projects, and its economy is mainly affected by steam prices. It can achieve better results; mechanical vapor compression evaporation is also suitable for small and medium-sized evaporation projects. The disadvantage is that the system needs to run continuously, and the economy is mainly affected by the electricity price.

The crystallized salt produced by the above-mentioned evaporation and crystallization process is miscellaneous salt, which can only be treated as hazardous waste, and it is difficult to ensure that the treatment of concentrated brine meets the requirements of zero discharge

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