VOCs waste gas treatment method combining absorption and adsorption

Abstract

The invention provides a VOCs waste gas treatment method combining absorption and adsorption. The method includes the following steps: absorbing VOCs exhaust gas in a first absorption tower under normal temperature and normal pressure, extracting non-standard gas from the top of a tower, introducing the non-standard gas into a rotating wheel for concentration or other adsorption systems, discharging purified gas reaching the standard directly, discharging concentrated gas with VOCs into a second absorption tower after residual VOCs in the non-standard gas is concentrated by absorption-adsorption, discharging the gas absorbed and purified in the second absorption tower after the gas reaches the standard, combining a first absorbent pregnant solution of the first absorption tower and a second absorbent pregnant solution of the second absorption tower, exchanging heat between the combination and the regenerated lean liquid extracted from a desorbing tower, then introducing the combinationinto the desorbing tower after overheating for steam stripping and regeneration in the tower. The treatment method is suitable for exhaust gas in low, medium and high concentration, and has remarkable effects on treatment of the exhaust gas with VOCs concentration below 5000 mg / m3.

Description

technical field [0001] The invention belongs to the technical field of waste gas treatment, and in particular relates to a VOCs waste gas treatment method combining absorption and adsorption. Background technique [0002] Industrial waste gas containing volatile organic compounds (VOCs) is one of the main sources of air pollution. At present, there are three main methods of VOCs treatment terminal control: adsorption-regeneration method, absorption-desorption separation method and oxidation destruction method. At present, the adsorption method widely uses activated carbon as the adsorbent. When the adsorption reaches the saturation of VOCs, the activated carbon needs to be desorbed by hot air, steam or pressure swing. After desorption, the steam or hot air containing VOCs is then subjected to other rectification, extraction or pervaporation operations, so that VOCs can be recycled. The adsorption method has the characteristics of high purification standard rate, but the ad...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a VOCs waste gas treatment method that combines absorption and adsorption, which can solve the problems of low absorption efficiency, large amount of absorbent, interference of water content in the air, high regeneration energy consumption, and absorbent selectivity in traditional absorption methods. , especially when the VOCs concentration is 5000mg / m 3 The effect of the following exhaust gas is remarkable, and the concentration after treatment is reduced to 50mg / m 3 The following emission standards are met, and the recovery rate of VOCs is not less than 99%.

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