Method and system for removing volatile organic compounds (VOCs) by ozone microwave excitation of magnetically separable catalyst

Abstract

The present invention provides a method and system for removing volatile organic compounds (VOCs) by ozone microwave excitation of a magnetically separable catalyst. After VOCs-containing exhaust gasis dedusted and cooled, a portion of the VOCs in a flue can be pre-oxidized by ozone. Peroxides can be activated by the microwave synergistic magnetically separable catalyst in a microwave spray reactor to generate hydroxyl groups and sulfate radical free radicals, and the remaining VOCs and intermediates resulting from the preoxidation are finally converted into a gas-solid mixture comprising themagnetically separable catalyst, H2O, CO2 and solid residues. The gas-solid mixture is washed by a tail spray washing tower to form a gas-liquid-solid mixture. The gas-liquid-solid mixture containingthe magnetically separable catalyst, the H2O, the CO2 and the solid residues enters into a catalyst magnetic separation tower for magnetic separation recovery regeneration. The system can achieve 100% removal of the VOCs, has no secondary pollution in the removal process, and has broad market use prospects.

Description

technical field [0001] The invention relates to the field of flue gas purification, in particular to a system for removing VOCs based on advanced oxidation of ozone, hydroxyl and sulfate radicals. Background technique [0002] VOCs is the English abbreviation of Volatile Organic Compounds. After entering the human body through the respiratory tract and skin, VOCs can cause temporary and permanent lesions to human breathing, blood, liver and other organs (such as causing various blood diseases and cancers). Waste incineration and industrial production will produce various organic waste gases, mainly including various hydrocarbons, alcohols, aldehydes, acids, ketones and amines, etc. These organic waste gases will cause air pollution and endanger human health. With the rapid development of the economy and the improvement of people's awareness of environmental protection, the problem of VOCs removal in exhaust gas has attracted more and more attention. At the same time, the c...

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Problems solved by technology

[0004] Chinese patent (ZL 201410247572.X) proposed a VOCs removal method and process using adsorption, condensation and membrane separation. industrial application

[0005] Chinese patent (ZL201210263021.3) proposes a VOCs removal method and process based on adsorption, desorption, rectification and pervaporation separation, but this method also has the disadvantages of complex process and high application cost, making it difficult to realize industrial application

[0006] Chinese patent (ZL201210431594.2) proposes a method for removing VOCs by electrolytic process, but the system and process of this method are complicated, the electrode material is easily corroded and deactivated, and the power consumption and operating cost are high

It has been reported that even in pure water, the effective propagation distance of 254nm short-wave ultraviolet light is only a few centimeters, which will make it difficult to scale up the reaction device

In addition, impurities such as particulate matter in the actual coal-fired flue gas will seriously hinder the transmission of ultraviolet light, thereby affecting the safe and efficient operation of the photochemical removal system.

Therefore, the above deficiencies seriously restrict the industrial application of photochemical removal systems.

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