A method for microwave coupled ultraviolet photocatalytic oxidative desulfurization and denitrification

Abstract

The invention discloses a method for microwave-coupled ultraviolet photocatalytic oxidation desulfurization and denitrification, which belongs to the technical field of flue gas purification. The method is to combine NO and SO 2 The gas is diluted by a mixture of nitrogen and oxygen into SO 2 pre-absorption system, the SO 2 After preliminary removal, the gas enters the microwave reactor, which provides microwaves and excites the inorganic lamp. This process simultaneously raises the temperature, which improves the oxidation efficiency of the liquid-phase oxidant; Catalytic activation produces a variety of highly active free radicals, and then the highly active free radicals oxidize NO. The newly formed nitrogen oxides are absorbed by the subsequent absorption unit. The tail gas that has been absorbed and treated is finally discharged into the atmosphere; the invention can meet the latest ultra-low emission pollutant standards of thermal power plants. The infrastructure and operation costs of this treatment system are lower, and the desulfurization and denitrification process can be carried out at the same time, reducing the occupied area, and the operation is simple and the desulfurization and denitrification effect is faster and more efficient.

Description

technical field [0001] The invention belongs to the technical field of flue gas purification, in particular to a method for microwave-coupled ultraviolet photocatalytic oxidation desulfurization and denitrification Background technique [0002] Coal-fired power plants release a large amount of NO and SO in the process of coal-fired power generation 2 Such toxic gases have caused serious adverse effects on humans and the environment. China is a big coal-burning country, NO and SO 2 Toxic gas pollution is extremely serious, so the Chinese government promulgated the "Emission Standards of Air Pollutants for Thermal Power Plants" (GB 13223-2011) to reduce NO X , SO 2 , emissions. On July 27, 2014, a new ultra-low emission concept was implemented, that is, the emission concentration of soot, sulfur dioxide, and nitrogen oxides (baseline oxygen content 6%) not to exceed 5mg / m 3 、35mg / m 3 , 50mg / m 3 . Therefore, it is necessary to seek an efficient desulfurization and deni...

AI Technical Summary

Problems solved by technology

However, these technologies still have some disadvantages in application, such as high cost, high energy consumption for free radical excitation, and by-products such as toxic gases may be produced during the process.

[0004] According to the research of other researchers, the oxidation method has been proved to be one of the effective ways to remove NO, the key is to oxidize NO into water-soluble NO 2 , the oxidants that can be used include hydrogen peroxide, sodium persulfate, sodium chlorite and some free radicals, and ozone is also a very effective substance for oxidizing NO, which can oxidize it in a short time ( less than one second), but further improvement is needed due to the large energy consumption required for conventional ozone generation

[0005] In order to reduce the problems of high cost and large floor space of the existing SCR denitrification system, the present invention strives to achieve efficient oxidation of NO in coal-fired flue gas through microwave coupling with ultraviolet light. X , SO 2 common removal, and the removal products are recycled and reused

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