System and method for carrying out electrolysis treatment on high-chlorine desulfurization wastewater and coupling denitration and mercury removal

Abstract

The invention discloses a method and system for carrying out zero-emission treatment on high-chlorine desulfurization wastewater and promoting flue gas to be subjected to denitration and mercury removal. The method comprises the following steps: firstly, carrying out reverse refluxing concentration on the desulfurization wastewater and part of the flue gas; after pre-treating the wastewater, pumping the wastewater into a cathode chamber of an electrolysis system, so as to obtain alkaline slurry containing high-concentration chlorine ions; refluxing the alkaline slurry into a pre-treatment coagulation precipitation tank; enabling the high-concentration chlorine ions to penetrate though an anion exchange membrane to enter an anode chamber; electrolyzing in the anode chamber to generate chlorine gas and oxygen gas; after mixing the chlorine gas, the oxygen gas, anode electrolyte and air, conveying a mixture into a prepositioned SCO system to participate in oxidization of Hg<0> and part ofNO. According to the method disclosed by the invention, high-chlorine desulfurization wastewater treatment and the denitration and mercury removal of the flue gas are subjected to ectopic coupling, so that the zero-emission aim of the desulfurization wastewater is realized, the problem of Hg<0> pollution also can be solved through simultaneous oxidation and the content of NO2 in the flue gas is improved; denitration reaction of rapid SCR (Selective Catalytic Reduction) is promoted and simultaneous denitration and mercury removal of the flue gas are realized.

Description

technical field [0001] The invention belongs to the field of desulfurization wastewater treatment, and in particular relates to a zero-discharge treatment of high-chloride desulfurization wastewater and a method and system for promoting simultaneous demercury and denitrification of flue gas. Background technique [0002] Coal-fired boiler wet flue gas desulfurization system (WFGD) discharges desulfurization wastewater during the desulfurization process. The wastewater contains a large amount of suspended solids, gypsum components, silica and heavy metals. This part of the discharged wastewater is desulfurization wastewater. The mass concentration of suspended solids in desulfurization wastewater is 9000-12700 mg / L. Generally, desulfurization wastewater containing heavy metals such as mercury, lead, nickel, zinc, cadmium, chromium, and non-metallic pollutants such as arsenic and fluorine is weakly acidic (pH 4~ 6) contains a large amount of chloride ions (concentration 8000-2...

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Problems solved by technology

However, the use cost of this kind of modified activated carbon is high, and it will affect the quality of fly ash and increase the difficulty of its disposal.

Noble metal catalysts for Hg 0 It also has a good oxidation removal effect, but the composition of coal-fired flue gas is complex, and most of the coal-fired coal in my country is low-chlorine coal, resulting in a decrease in its activity, and its cost is self-evident

Various other methods are currently in the research stage, and each has a certain scope of application and advantages and disadvantages

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