Method and system for purifying flue gas by inducing free radicals by virtue of ozone and hydrogen peroxide

Abstract

The invention discloses a method and a system for purifying flue gas by inducing free radicals by virtue of ozone and hydrogen peroxide. The system is characterized in that a flue of a boiler is connected with one end of a flue gas heat exchanger, wherein the other end of the flue gas heat exchanger is connected to the bottom of a spraying washer; an injection hole of an ozone injection system is formed in a pipeline located between the flue gas heat exchanger and the spraying washer; a solution circulating by-pass system is connected with the top end and lower part of the spraying washer, respectively; the bottom of the spraying washer is sequentially connected with a mercury separation system, an ammonification neutralizing system and a product concentrating and crystallizing system; the top of the spraying washer is connected with a chimney through the pipeline and a flue gas waste heat system. According to the method, hydroxyl free radicals with strong oxidizing property are generated in an induction manner after the ozone in the flue gas is contacted with the hydrogen peroxide in spraying liquid; four main pollutants in the flue gas can be simultaneously removed, equipment is simple and reliable, and no secondary pollution is generated in a removal process. The method and the system are novel and have wide application prospects.

Description

technical field [0001] The invention relates to the control of flue gas emission pollutants in the combustion process, in particular to a flue gas purification method and system for free radicals induced by ozone / hydrogen peroxide double oxidant. Background technique [0002] In the process of industrial production, SO produced by combustion 2 ﹑NO x ﹑Hg and VOCs can cause serious hazards such as acid rain, photochemical smog, carcinogenesis, and teratogenicity. Therefore, research and development of effective flue gas desulfurization, denitrification, mercury and VOCs removal methods is one of the important tasks of environmental protection scientists in various countries. [0003] In recent years, although people have developed a large number of flue gas desulfurization, denitrification, mercury and VOCs technologies, due to the limitations of human understanding and the gradual development of science and technology, the existing various desulfurization, denitrification, ...

AI Technical Summary

Problems solved by technology

But this technology has the following disadvantages: 1. This method can only remove sulfur dioxide and nitrogen oxides, but cannot remove toxic heavy metal mercury and volatile organic pollutants

2. Invention patent 200910095344 mainly uses ozone as a single oxidant to oxidize and remove pollutants, but ozone has a limited ability to oxidize elemental mercury and volatile organic pollutants. In order to meet the removal requirements, it is often necessary to greatly increase the input of ozone, so separate Very expensive to use

This invention (method) has the following deficiencies: 1. The content of this invention is mainly aimed at oxidizing and removing NOx in coal-fired flue gas, and then using the existing tail wet desulfurization system for removal, but it does not involve the removal of elemental mercury and the removal of volatile organic pollutants; 2. The invention sprays hydrogen peroxide and ozone into the flue at the same time, and allows the oxidation reaction to occur in the high-temperature flue, which belongs to a typical semi-dry removal process (this invention belongs to a typical wet removal process), this arrangement will cause flue corrosion and oxidant self-decomposition at high temperature, and the application cost is very high

Wet flue gas purification technology is a traditional flue gas treatment technology. It has the characteristics of small initial investment, simple process flow and easy removal of multiple pollutants at the same time. It is a flue gas purification technology with good development and application prospects. , but the research progress of traditional wet flue gas purification technology has been relatively slow, the main reason is that NO﹑Hg in flue gas 0 and VOCs are difficult to remove

[0010] According to the double-membrane theory, the gas phase molecules must first dissolve into the liquid phase through the process of mass transfer and diffusion from the gas state, and then they can undergo chemical reactions and dissolve into the absorption liquid, while NO﹑Hg 0 The insoluble characteristics of VOCs and VOCs greatly increase its absorption and mass transfer resistance in the liquid phase, and it is difficult to significantly increase NO﹑Hg only by adjusting the pH and temperature of the absorption liquid. 0 And the solubility of VOCs in the liquid phase, this characteristic has caused the traditional wet desulfurization, denitrification and mercury removal technology to generally have high desulfurization efficiency, but the denitrification and mercury removal efficiency is low, and it is actually impossible to achieve real simultaneous desulfurization, denitrification, mercury and demercuration VOCs

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