Coal-fired power plant desulfurization wastewater treatment system and method based on flue gas synergistic treatment

Abstract

The invention discloses a coal-fired power plant desulfurization wastewater treatment system and method based on flue gas synergistic treatment. The system comprises a boiler, a denitration reactor, an air preheater, a flue gas cooler, a dust remover, an induced draft fan and a desulfurization tower which are sequentially communicated in the flue gas flow direction. A desulfurization wastewater outlet of the desulfurization tower is sequentially communicated with a multi-effect flash evaporation concentrator and a drying tower, and a pH value adjusting port is formed in a path from the desulfurization tower to the multi-effect flash evaporation concentrator; a concentrated solution outlet of the multi-effect flash evaporation concentrator is communicated with the drying tower, and a water vapor outlet of the multi-effect flash evaporation concentrator is communicated with the desulfurizing tower; a working medium inlet of the drying tower is communicated with a flue gas outlet of the denitration reactor, an outlet of the drying tower is communicated with the dust remover, desulfurization wastewater is concentrated while flue gas temperature reduction and pollutant cooperative treatment are achieved, water vapor generated by treating concentrated liquid through high-temperature flue gas is directly conveyed to the desulfurization tower system, crystallized fly ash is reinjected into a front flue of the dust remover, and finally, the desulfurized wastewater is recycled along with ash of the dust remover, so that zero emission of the desulfurized wastewater is realized.

Description

technical field [0001] The invention belongs to the technical fields of energy, chemical industry and environmental protection, and in particular relates to a coal-fired power plant desulfurization wastewater treatment system and method based on flue gas collaborative treatment. Background technique [0002] Flue gas collaborative treatment technology refers to the maximum control of pollutant emissions through the collaborative treatment capabilities of equipment without changing the original flue gas system. Among the existing synergistic technologies, the most widely used synergistic treatment technology is the low-temperature dust collector as the core. 3 , Hg and other pollutants are precipitated and adsorbed on the fly ash, and finally collected and discharged by the dust collector together with the fly ash. Therefore, most coal power plants have added an eye cooler cooling device between the air preheater and the dust collector. After the flue gas temperature drops,...

AI Technical Summary

Problems solved by technology

Among them, the chemical precipitation method will produce secondary pollutants such as sludge and secondary waste liquid, and the disposal cost is high

The membrane concentration method has a high degree of automation, but because the membrane is prone to fouling and needs to be replaced regularly, it has high operating costs and is difficult to promote; the evaporation crystallization method consumes a lot of heat, and the crystals after crystallization have many impurities and are difficult to reuse, and there are difficulties in stacking and disposal. Difficult problem; the flue injection method can better evaporate the desulfurization wastewater into fine particles and mix it with the dust, and finally recycle it together with the fly ash. However, the continuous injection of desulfurization wastewater into the flue gas system will lead to an increase in the humidity of the flue gas , which will eventually lead to equipment corrosion and threaten the safety of system operation

[0005] In summary, the existing zero-discharge treatment technologies for desulfurization wastewater have their own advantages and disadvantages, and the economy, safety and environmental protection cannot be fully considered

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