A flue gas purification method and device for ozone-activated persulfate

Abstract

The invention discloses a method for purifying flue gas through activating persulfate by ozone, and an apparatus thereof. Ozone in the flue gas contacts with persulfate in a solution in a bubbling-spray two stage reactor to generate sulfate radicals and hydroxy groups having strong oxidizability in order to oxidize and remove SO2, NOx, mercury, H2S and VOCs in the flue gas; and a reaction product solution enters a mercury separation tower to remove mercury, a mercury removed sulfuric acid and nitric acid solution enters an ammonia feeding tower, an ammonium sulfate and ammonium nitrate solution generated through the above reaction enters a product crystallization tower, and a flue gas waste heat utilizing device is used to evaporate and crystal recyclable agricultural fertilizers ammonium sulfate and ammonium nitrate. In the invention, ozone is adopted to induce persulfate to generate the sulfate radicals and hydroxy groups having extremely strong oxidizability, and the oxidbillities of the sulfate radicals and the hydroxy groups are second to that of fluorine, and are far higher than that of single ozone or persulfate, so the five pollutants can be efficiently simultaneously removed.

Description

technical field [0001] The invention relates to the control of flue gas emission pollutants in the combustion process, in particular to an ozone-activated persulfate flue gas purification method and device. Background technique [0002] SO produced by combustion 2 ﹑NO x ﹑Hg﹑H 2 S and VOCs can cause serious hazards such as acid rain, photochemical smog, carcinogenicity, and teratogenicity. Therefore, the development of effective flue gas desulfurization, denitrification, mercury removal, VOCs and H removal 2 Method S is one of the important tasks of environmental protection scientists and technicians in various countries. [0003] In recent years, although people have developed a large number of flue gas desulfurization, denitrification, mercury, VOCs and H 2 S technology, but due to the limitations of human cognition process and the gradual development of science and technology, the existing various desulfurization, denitrification, mercury, VOCs and H 2 At the beginni...

AI Technical Summary

Problems solved by technology

Although these two methods can desulfurize and denitrify separately, they cannot achieve simultaneous removal in one reactor.

For example, the invention patent, 201010296492.5, is named "a simultaneous desulfurization and denitrification system based on photochemical advanced oxidation", which can only perform desulfurization and denitrification, but cannot simultaneously remove the above five pollutants

[0004] Although the joint superimposed use of the two processes can achieve simultaneous desulfurization and denitrification, it also causes the whole system to be complex, occupy a large area, and have high investment and operating costs.

In addition, with the continuous improvement of human requirements for environmental protection, for mercury, VOCs and H in flue gas 2 Laws and regulations on S emission control are gradually introduced, but there is no economical and effective flue gas mercury removal, VOCs removal and H removal. 2 S technology obtains large-scale commercial application

For example, in invention patents 201010296492.5 and 201310683135, ultraviolet light is used as an inducer to catalyze the decomposition of hydrogen peroxide and ammonium persulfate to generate free radicals, but the penetration distance of ultraviolet light is extremely short, especially in the actual coal-fired flue gas containing a large amount of particulate matter, Will seriously affect the effective radiation distance of ultraviolet light

In addition, after long-term use, a large amount of dirt will be deposited on the surface of the UV lamp, which will deteriorate the long-term operating efficiency of the system, and may even cause the system to fail

[0005] If separate flue gas mercury removal, VOCs removal and H removal are added at the end of the existing desulfurization and denitrification system 2 The S system will inevitably cause a further sharp increase in the initial investment and operating costs of the entire system, and it will be difficult to obtain large-scale commercial applications in developing countries.

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