Desulfurization wastewater treatment apparatus and desulfurization wastewater treatment method

Abstract

The invention relates to the field of environmentally-friendly water treatment, and discloses a desulfurization wastewater treatment apparatus and a desulfurization wastewater treatment method. The desulfurization wastewater treatment method comprises that wastewater enters a wastewater collection tank and is precipitated by an electronic flocculator; after the wastewater is precipitated, sludge enters a sludge pool and is dewatered, and the dewatered sludge is externally transported; the supernatant liquid on a clarifying pool enters a softening system; after the softening system removes Ca<2+> and Mg<2+> from the wastewater, the produced water enters a microfiltration membrane system; after the microfiltration membrane system removes the suspended solids from the produced water, the obtained produced water enters an efficient heat exchanger and is subjected to complete heat exchange, and the obtained material enters a membrane distillation system and is subjected to water vapor separation; and the concentrated liquid in the membrane distillation system is preheated, the preheated concentrated liquid enters an MVR system and is continuously concentrated, centrifugal salt dischargeis performed after the concentrating, and the condensed water in the MVR system is reused for a power plant water system. According to the present invention, through the integrated arrangement, the manual operation is saved, the discharge of the sludge is reduced, the cost is reduced, and the wastewater treatment efficiency is improved.

Description

technical field [0001] The invention relates to the field of environmental protection water treatment, in particular to a treatment device for desulfurization wastewater and a treatment method thereof. Background technique [0002] The impurities in limestone wet desulfurization wastewater mainly come from flue gas and desulfurizer, among which the impurities in the flue gas come from the combustion of coal, and the impurities in the desulfurizer come from the dissolution of limestone (most of the desulfurizers for wet desulfurization use limestone); It may contain a variety of elements including heavy metal elements, such as F, Cl, Cd, Pb, Ni, As, Se, Cr, etc. These elements undergo a series of chemical reactions under high temperature conditions in the furnace, resulting in a variety of different compounds. A part of the compounds are discharged from the furnace with the slag, and the other part enters the absorption tower of the desulfurization unit with the flue gas, ...

AI Technical Summary

Problems solved by technology

[0009] 1. Desulfurization wastewater has high SS content, complex water quality components, and large fluctuations in water volume and water quality. For the traditional three-box process, it is necessary to meet the changes in various indicators of incoming water, automatically (manually) adjust the time interval of dosing, dosing Quantity, reaction time, sedimentation time, etc. are difficult to achieve, and the quality of effluent water is poor, which increases the difficulty and burden of subsequent treatment

[0010] 2. The amount of flocculant added by different flocculant manufacturers is quite different

[0011] 3. Chemical flocculation additives increase the ions in the water and change the pH balance, which makes the water more corrosive and increases secondary pollution

[0012] 4. Excessive addition of flocculant can produce an opposite reaction in the absorption process of iron or aluminum ions on the particles, reducing the flocculation efficiency

[0013] 5. Due to the addition of a large amount of PAC, PAM and other chemicals to the desulfurization wastewater, the sludge in the dewatered wastewater increases, which also causes the load of the subsequent treatment process and increases the cost of sewage treatment.

[0014] 6. The outlet water of the triple box needs to go through two-stage precipitation before entering the multi-effect evaporation system to reach the zero-emission standard. The two-stage sedimentation covers a large area, high operation and maintenance costs, and unstable water outlet. It is necessary to add filtration equipment, otherwise it will easily cause multi-effect evaporation. System fouling

The operation cost of the multi-effect evaporation system is high. After evaporation, a large amount of evaporated mother liquor will be discharged and returned to the two-stage precipitation system. The dosage of the system will increase significantly, which will increase the operating cost and difficulty.

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