System and method for treating waste gas containing VOCs (volatile organic compounds)

Abstract

The invention discloses a system and method for treating waste gas containing VOCs (volatile organic compounds). The system comprises adsorption-desorption apparatuses which are connected in series in multiple levels, wherein each adsorption-desorption apparatus comprises an adsorption tank and a desorption tank, which are connected in parallel. The method comprises the following steps: synchronously performing adsorption, desorption and drying processes, and drying desorbed active carbon by utilizing the waste gas containing VOCs in the drying process. By adopting the system and method for treating the waste gas containing the VOCs, the recovery rate of the VOCs can be remarkably increased, the atmospheric emission of the VOCs can be reduced, the environmental pollution is alleviated, the service life of active carbon is prolonged, and the production cost is reduced.

Description

technical field [0001] The invention relates to waste gas treatment technology, in particular to a treatment system and a treatment method for waste gas containing VOCs. Background technique [0002] VOCs is the abbreviation of volatile organic compounds, mainly including hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, esters, amines, organic acids, etc., mostly flammable, explosive, volatile and highly toxic Substances that are directly discharged into the atmosphere will cause serious harm to the environment and human health. [0003] Industrial emissions are the main source of VOCs. Treating VOCs to reduce and eliminate VOCs industrial emissions is an effective means to control VOCs pollution. At present, the use of activated carbon to adsorb and recover VOCs is a common method. High-pressure water vapor can be used for desorption to recover VOCs and regenerate activated carbon to achieve recycling. [0004] In the prior art, a single-stage parallel a...

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Problems solved by technology

[0004] In the prior art, a single-stage parallel adsorption-desorption device is often used to treat waste gas containing VOCs. VOCs are discharged to the atmosphere after one adsorption. The adsorption of VOCs is incomplete, and the amount of atmospheric emissions is large. The recovery rate of VOCs is only 80-90%; The process of desorbing activated carbon with high-pressure water vapor takes a long time and consumes a lot of energy. In order to coordinate the alternation of the adsorption-desorption process, the desorption time is usually reduced, resulting in incomplete desorption of VOCs on activated carbon. Generally, the desorption rate of VOCs is only In addition, during the drying process after desorption of activated carbon, high-temperature nitrogen or air is often introduced from the lower part of the desorption tank and directly discharged to the atmosphere, which is costly. At the same time, after desorption of activated carbon by high-pressure water vapor, some Gaseous VOCs exist in the desorption tank, and the undesorbed VOCs and residual gaseous VOCs on the activated carbon will be directly discharged to the atmosphere with high-temperature nitrogen or air, and the concentration can reach 200-500ppm, causing serious air pollution

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