Desulfurization wastewater zero discharge system and method based on high-temperature and low-temperature flue gas coupling treatment

Abstract

The invention discloses a desulfurization wastewater zero-discharge system and method based on high-temperature and low-temperature flue gas coupling 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 along the flow direction of a medium, and a desulfurization wastewater outlet of the desulfurization tower is communicated with a desulfurization wastewater integrated treatment device; the desulfurization wastewater integrated treatment device comprises a concentration tower and a drying tower which are communicated with each other, and the concentration tower is provided with a wastewater inlet communicated with a desulfurization wastewater outlet, a steam outlet communicated with a flue gas inlet of the desulfurization tower, a flue gas inlet communicated with an outlet of the dust remover, a flue gas inlet communicated with an outlet of the denitration reactor and a fly ash outlet communicated with an inlet of the dust remover. The integrated process of low-temperature waste heat flue gas concentration and high-temperature flue gas drying crystallization is adopted, waste heat of a power plant is fully utilized, existing equipment of a dust remover and a desulfurizing tower is fully utilized, system safety and cost are both considered, and zero emission of desulfurization wastewater is achieved.

Description

technical field [0001] The invention belongs to the technical field of desulfurization wastewater treatment, and in particular relates to a zero-discharge system and method for desulfurization wastewater based on coupled treatment of high and low temperature flue gas. Background technique [0002] Coal-fired power stations and other coal-fired boilers often use wet desulfurization technology, which refers to the combination of limestone / lime slurry and SO in coal-fired flue gas 2 The reaction forms gypsum (CaSO 4 ) thus reducing SO 2 Emission process. The advantages of this process are mature technology, high desulfurization efficiency, simple operation, low operating cost, and wide application of coal quality; the disadvantage is that some wastewater will be generated after desulfurization. With the continuous improvement of environmental standards, the discharge of desulfurization wastewater has gradually attracted attention. Some regions have clearly required enterpris...

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

[0004] 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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