Treatment system and treatment method for evaporating and crystallizing desulfurization waste water by using cooling tower

Abstract

The invention relates to the field of industrial waste water treatment, in particular to a treatment system and a treatment method for evaporating and crystallizing desulfurization waste water by using a cooling tower. The treatment system for evaporating and crystallizing the desulfurization waste water by using the cooling tower is characterized by comprising a TMF microfiltration unit, a heat exchange unit, a cooling tower unit, a crystallization and precipitation unit, and a running sand filtering unit. The treatment system and the treatment method provided by the invention have beneficial effects of being capable of effectively reducing scale formation of an evaporator and energy consumption, facilitating recycling of carnallitite, being low in investment cost and stable in running, almost achieving zero emission, and the like.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a treatment system and treatment method for evaporative crystallization desulfurization wastewater using a cooling tower. Background technique [0002] Flue gas desulfurization is considered to control SO 2 The most effective and economical way, limestone-gypsum wet desulfurization is the most commonly used flue gas desulfurization process in China. The desulfurization wastewater produced by this wet flue gas desulfurization process contains a large amount of suspended solids (gypsum particles, SiO 2 , aluminum and iron hydroxides), active silicon, COD, chloride ions, fluoride ions, calcium ions, magnesium ions and trace heavy metal ions, such as arsenic, cadmium, chromium, mercury, etc., TDS is generally 25000-60000mg / l , wherein the Cl- content is generally 5000-20000mg / l, and direct discharge will cause serious harm to the environment. The common treatment met...

AI Technical Summary

Problems solved by technology

The desulfurization wastewater produced by this wet flue gas desulfurization process contains a large amount of suspended solids (gypsum particles, SiO 2 , aluminum and iron hydroxides), active silicon, COD, chloride ions, fluoride ions, calcium ions, magnesium ions and trace heavy metal ions, such as arsenic, cadmium, chromium, mercury, etc., TDS is generally 25000-60000mg / l , where the Cl- content is generally 5000-20000mg / l, direct discharge will cause serious harm to the environment

The common treatment method is chemical precipitation treatment, which can partially remove pollutants such as heavy metals, suspended solids, fluoride ions, COD, and sulfide in wastewater, but the Ca in wastewater 2+ , Cl - 、Na + , SO 4 2- Such soluble substances cannot be effectively removed, and the dosage of this method is large, resulting in a large amount of sludge, causing secondary pollution, and the TDS concentration in the supernatant is as high as 25000-60000mg / l, and direct discharge will cause great pollution to the water body

The current popular desulfurization wastewater zero discharge processes mainly include the following types: pretreatment + evaporative crystallization, pretreatment + electrodialysis + evaporative crystallization, pretreatment + butterfly tube reverse osmosis + evaporative crystallization, pretreatment + seawater reverse osmosis + forward osmosis + Evaporation and crystallization, etc. These processes have many problems such as evaporator structure, high energy consumption, difficulty in recycling miscellaneous salts, high investment and operation costs, and unstable operation.

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