Thermal power plant desulphurization wastewater purification system and purification method

Abstract

The invention discloses a thermal power plant desulphurization wastewater purification system including a desulphurization wastewater pretreatment system, a multi-medium filter, a forward osmosis-nanofiltration coupling concentration-desalination system, a multi-stage flash evaporation system and a horizontal crystallization box which are successively connected. The invention also discloses a thermal power plant desulphurization wastewater purification method including wastewater neutralizing treatment, heavy metal precipitation treatment, flocculation treatment, clarification treatment, sludge dewatering treatment, clear water filtration treatment, forward osmosis concentration treatment and multi-effect negative pressure flash evaporation crystallization. With chemical treated desulphurization wastewater as raw material, pretreated wastewater passes through the forward osmosis-nanofiltration coupling concentration-desalination system and then enters the multi-stage flash evaporation system, the flash evaporation efficiency is greatly improved, final products comprise a brick making raw material, industrial salt and distilled water, and the purpose of turning waste into treasure is achieved.

Description

technical field [0001] The invention relates to a thermal power plant desulfurization wastewater purification system and a purification method, belonging to the field of sewage treatment. Background technique [0002] my country is the largest coal producer and consumer in the world, and the proportion of coal in China's energy structure is as high as 76.2%. 2 90% comes from burning coal. In recent years, although my country has adopted a sewage charging policy, the annual SO 2 Emissions still exceed 20 million tons, and the area polluted by acid rain is rapidly expanding, causing huge damage to crops, forests, and human health in my country, and has also become an important factor restricting the sustainable development of my country's economy and society. Therefore, the SO 2 Emission control is imperative. [0003] In January 1998, the National Environmental Protection Agency approved the "Acid Rain Control Area and Sulfur Dioxide Pollution Control Area Division Plan" ...

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Problems solved by technology

[0015] At present, the domestic waste water zero discharge process represented by Heyuan Power Plant mainly adopts the process of coagulation + multi-stage evaporation and crystallization, which can realize zero discharge of waste water and comprehensive utilization of waste water sludge and crystallized salt, but this process has steam consumption and drug consumption The disadvantages of large quantity and low efficiency, and improving the efficiency of multi-effect evaporation crystallization is the key to energy saving and consumption reduction of this process.

[0016] The existing terminal wastewater treatment process is complicated, and the investment and operation costs are high. As far as Heyuan Power Plant is concerned, a four-stage evaporation process is adopted, and multi-effect evaporation pressure and temperature control are not considered, resulting in high steam consumption and equipment corrosion. serious

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