A method and system for vocs degradation of ozone and microwave-induced free radicals

Abstract

The invention relates to a VOCs free-radical degradation method and system induced by cooperation of ozone and microwave. The system is equipped with a microwave spraying reactor. VOCs-containing exhaust gas coming from an emission source is dedusted and cooled, and ozone is adopted to pre-oxidize a part of VOCs in a flue to an intermediate; the microwave activates persulfate to generate hydroxy and sulfate free radicals in the microwave spraying reactor, wherein the hydroxy and sulfate free radicals can oxidize the left VOCs and the intermediate produced from pre-oxidization to a mixed solution of H2O, CO2 and solid residue; H2O and CO2 in the mixed solution are subjected to centrifugal separation in a solid residue separation tower and then are directly discharged, and the obtained solidresidue enters a drying tower and is dried through a smoke waste heat utilization system for resource utilization. The system can completely remove VOCs, doesn't cause secondary pollution, and has bright market application prospects.

Description

technical field [0001] The invention relates to the field of exhaust gas purification, in particular to a VOCs degradation method and system for ozone-assisted microwave-induced free radicals. Background technique [0002] After VOCs (volatile organic compounds) enter the human body through the respiratory tract and skin, they can cause temporary or permanent lesions in the human respiratory tract, 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 country has also formulated ...

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Problems solved by technology

Among them, the catalytic combustion method is to heat the exhaust gas and convert it into harmless and odorless carbon dioxide and water through catalytic combustion. This method has low ignition temperature, energy saving, high purification rate, convenient operation, and less floor space. Concentration of organic waste gas, but the catalyst is easily poisoned and deactivated, and the stability is poor; the removal efficiency of activated carbon adsorption method can reach 95%, the equipment is simple, and the investment is small, but the activated carbon is replaced frequently, which increases the working procedures of loading, unloading, transportation, replacement, etc. The cost increases; the direct combustion method uses auxiliary fuel such as gas or oil to burn, and heats the mixed gas to decompose harmful substances into harmless substances under the action of high temperature. Exhaust gas, but has high requirements for safety technology and operation; plasma degradation method has the advantages of simple process, convenient operation, and thorough pollutant degradation, but the high energy consumption of the plasma reactor and the stability and reliability of key devices need to be improved; condensation The recovery method is suitable for working conditions with high concentration of organic waste gas, low temperature, and small air volume, and requires auxiliary refrigeration equipment. It is mainly used in the pharmaceutical and chemical industries, while printing companies seldom use it, and the scope of application is limited; the absorption method is commonly used physical absorption , that is, the waste gas is introduced into the absorption liquid for purification, and after the absorption liquid is saturated, it is heated, decomposed, and condensed for recovery. This method is suitable for large volume, low temperature, and low concentration waste gas, but it needs to be equipped with a heating and desorption recovery device. The equipment is large in size and investment higher

Therefore, so far, although a variety of VOCs removal technologies have been developed and utilized, each technology has almost limited application range and many disadvantages.

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