System and technology for treating unstable large-volume VOCs waste gas

Abstract

The invention discloses a system for treating unstable large-volume VOCs waste gas. The system comprises: a preprocessing device used for preprocessing the waste gas to filter out dusts in the waste gas and removing non-VOCs in the waste gas; an adsorbing and concentrating connected to the outlet of the preprocessing device and used for adsorbing and concentrating the preprocessed waste gas; and ahigh-energy-level photooxidation device communicated with the outlet of the adsorbing and concentrating device through a homogenizing connection device, wherein the outlet end of the high-energy-level photooxidation device is further connected with a discharge pipeline through washing device, the adsorbing and concentrating device is provided with a hot purified gas inlet and a desorbed gas outlet, and the desorbed gas outlet is connected with an oxidation device, the oxidation device is provided with a purified gas outlet, and the purified gas outlet is connected with the discharge pipeline.The invention further provides a corresponding treatment technology of the system. A combined device or process of preprocessing, adsorption concentration, homogenization connection, high-energy-level photooxidation and washing absorption is adopted to make any unstable large-volume VOCs waste gas discharged in an ultra-clean manner.

Description

technical field [0001] The invention belongs to the field of waste gas treatment, and relates to a treatment system and process for VOCs waste gas in an unstable large volume, which is applicable to discharge gas from coal chemical industry, petrochemical enterprise sewage treatment plants, silos, etc., centralized discharge gas from workshops, and other chemical industry discharge scenarios. Background technique [0002] In the process of crude oil processing in refining and chemical enterprises, due to technological requirements, some facilities inevitably emit a large amount of VOCs waste gas, such as biochemical aeration tanks, sewage tanks, equipment-containing workshops, silos and other facilities. These facilities emit a large amount of emissions Low-concentration VOCs (volatile organic compounds) components, low concentration, large air volume, and a wide range of surrounding influences. Staff who have been active in an environment polluted by these substances for a l...

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Problems solved by technology

[0005] Qi Guoqing et al. mentioned in "Engineering Design of Bio-scrubbing + Bio-trickling Filtration Combined Process for Treatment of Odor Gas in Oil Refinery Sewage Fields" that the combined process of bio-scrubbing and bio-trickling filtration can purify 80% of VOCs, according to the input data given in the article 8640ppmv Calculated, the concentration of VOCs at the outlet of the device is 1328ppmv, which is far from meeting the 120mg / m3 stipulated in the "Petroleum Refining Industry Pollutant Discharge Standard" 3

In the "Odor Treatment Engineering Design of Qingdao Large Oil Refinery Sewage Treatment Plant", Gao Youhong set the design index for the biological purification of hydrocarbon waste gas in the sewage treatment plant as the inlet concentration ≤ 3000mg / m 3 , purification rate ≥ 95%, according to this calculation, the concentration of hydrocarbons in the outlet ≤ 150mg / m 3 , cannot meet the requirements of the new standard

[0006] Chinese patent document CN 103463932B adopts the adsorption-hot nitrogen desorption method to treat high-volume low-concentration organic waste gas, but it is suitable for organic matter with a high boiling point. For organic matter with a low boiling point, the desorption gas cannot be condensed and removed, resulting in light hydrocarbons in the circulating nitrogen gas. more and more, causing the adsorption bed to penetrate quickly

Limited by the limitation of the rotor adsorbent, when dealing with the waste gas containing more light hydrocarbon VOCs, the adsorption capacity of the rotor adsorbent is very low, and the concentration of non-methane total hydrocarbons at the outlet of the purified gas of the device is difficult to stabilize to meet the latest national standard requirements

[0008] Chinese patent document CN 106731486B is an optimal method for mixing high-concentration exhaust gas and low-concentration exhaust gas at the outlet of the existing diesel absorption recovery device to achieve suitable conditions for catalytic oxidation. Uneconomical

[0009] CN 108043185A uses a pretreatment-photocatalysis-adsorption combination device and process to treat waste gas containing VOCs. However, when the device and process process waste gas with large fluctuations in VOCs concentration in the petrochemical industry, the concentration of VOCs may reach the explosion limit range. Some components are very easy to generate charged free radicals in the photocatalytic process, resulting in safety problems. In addition, this process does not treat the exhaust gas after desorption and regeneration in the adsorption VOC unit, and there is secondary pollution

In the sewage treatment plants of refining and chemical enterprises, the concentration fluctuation range of VOCs discharged is 0~50000mg / m 3 , the components are very complex, using the patented technical solution to treat this kind of exhaust gas is not only inefficient, it cannot meet the national emission standards, and there are serious safety problems

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