Zero discharge treatment process of saline sewage produced by refining

Abstract

The invention provides a zero discharge treatment process of saline sewage produced by refining. The treating process comprises the steps that saline sewage produced by flue gas desulfurization is conveyed to an evaporation chamber after undergoing two-stage filtration and heat exchange, evaporated steam is mixed with fresh steam after being pressurized and the steam mixture enters the shell pass of a heater to be condensed and discharged; saline water in the tube pass of the heater is heated to be evaporated and crystallized in the heater, the steam enters a compressor and salt crystals are deposited in a salt leg at the bottom of the evaporation chamber and are swirled and centrifugally concentrated; salt crystal filter cakes are dried in a drying machine, moisture is volatilized and is discharged from the top of the drying machine, gases pass through a two-stage cyclone separator to separate salt solid particles and the salt solid particles are emptied by a drying draught fan, and the salt solid after dehydration and drying is packaged to prepare sodium sulfite or ammonium sulfate products. The process provided by the invention has the effects of overcoming the defects of the prior art, really achieving zero discharge treatment of sewage and producing sodium sulfite or ammonium sulfate with economic value and has the beneficial effects of high energy efficiency, low investment, short flow, small floor area, low failure rate and satisfaction of long period operation.

Description

technical field [0001] The invention relates to a process for implementing "zero discharge" treatment of high-salt flue gas desulfurization sewage produced by petrochemical and coal chemical enterprises, and producing economically valuable sodium sulfite or ammonium sulfate, which belongs to the technical field of sewage treatment engineering. Background technique [0002] At present, with the improvement of environmental protection requirements of petrochemical and coal chemical enterprises, flue gas desulfurization facilities have been put into use one after another. Concentrated brine with a mass concentration of about 7.5% sodium sulfate produced by flue gas desulfurization is generally mixed into sewage treatment plants after clarification and oxidation. Straight discharge after the exit monitoring pool; for many inland petrochemical plants and coal chemical plants, without setting up evaporation ponds, a large amount of high-salt sewage is continuously discharged outsid...

AI Technical Summary

Problems solved by technology

[0004] Mechanical recompression evaporator overview Steam mechanical recompression evaporator is referred to as MVR. Compared with traditional multi-effect evaporation, MVR energy efficiency is equivalent to four-effect evaporation. It is a new type of high-efficiency evaporation equipment developed in the late 1990s in the world. Its working principle is that after the secondary steam generated by the evaporator is acted on by a mechanical heat energy compressor, the temperature rises by 5-15°C and returns to the heating heat source for the evaporator. The fresh steam is only used to supplement heat loss and supplement the heat enthalpy of the incoming and outgoing materials. , so as to greatly reduce the consumption of external fresh steam by the evaporator, the steam that was originally to be discarded has been fully utilized, the latent heat has been recovered, the demand for external heating and cooling resources has been reduced, energy consumption has been reduced, and pollution has been reduced. It has been applied in food, pharmaceutical, chemical, salt and other industries, but there is no precedent for the treatment of salty sewage from flue gas desulfurization

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