Method for zero emission treatment of desulfurization waste water based on flue gas waste heat evaporation

Abstract

The invention discloses a method for zero emission treatment of desulfurization waste water based on flue gas waste heat evaporation. In the method, three systems, namely a double-alkali method pretreatment system, a membrane filtration desalination concentration decrement system and a flue gas bypass evaporation tower evaporation zero emission system, are used. The method is characterized in that the double-alkali method pretreatment is adopted to soften, flocculate and clarify the desulfurization waste water, membrane filtration desalination is utilized to perform desalination concentration decrement for clarified liquor, demineralized water is recyclable, concentrated liquor is sent to the flue gas bypass evaporation tower to be evaporated by boiler flue gas waste heat, gas state vapor enters a desulfurizing absorption tower along with the flue gas to perform condensation recovery, crystal substances and coal ash are discharged together, the purpose of completely recycling the desulfurization waste water is achieved, and the zero emission of the desulfurization waste water and high salinity wastewater is achieved. The method has the advantages that the technology is simple, the boiler flue gas waste heat is utilized to perform evaporation, and the method is low in investment and operation cost and high in practicability. The method achieves low cost zero emission of the desulfurization waste water and has wide popularization and utilization value.

Description

technical field [0001] The invention relates to a zero-discharge treatment method for high-salt wastewater such as electric power, metallurgy, and chemical industry, and belongs to the technical field of high-salt wastewater treatment, in particular to a zero-discharge treatment method for desulfurization wastewater based on waste heat evaporation of flue gas. Background technique [0002] Wet desulfurization is currently the only large-scale commercial desulfurization method in the world, and it is the main technical means to control sulfur dioxide emissions from coal-fired power plants. Limestone-gypsum wet desulfurization is the most widely used flue gas desulfurization method at home and abroad. [0003] The flue gas produced by the boiler enters the wet desulfurization system after being dedusted by the electrostatic precipitator, and is washed and desulfurized in the absorption tower. After the mist is removed by the demister, it is discharged into the atmosphere throu...

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Problems solved by technology

For example, the waste water treatment system of Heyuan Power Plant in Guangdong pioneered desulfurization waste water treatment technology in China. It is the first power plant in my country to adopt the desulfurization waste water "pretreatment + evaporation + crystallization" process. The desulfurization waste water treatment capacity is about 20t / h, and the investment is about ~9800 10,000 yuan, but this method has the disadvantages of high investment cost, operating cost, and high energy consumption, and this technology has not been widely promoted

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