Process method of purifying and recycling mixed organic waste gas

Abstract

The invention belongs to chemical industry and waste gas process field, in particular providing a process method which mixes organic waste gas purifying and resource recovery. The specific procedure is that: make the mixed waste gas pass through a filter to be filtered, and then enters into a single-seat multilevel absorption tower and contacts with a packing layer and a liquid distribution device; when the series of the single-seat tower is 3, the second-grade liquid distribution device adopts a kind of absorbent which is a mixing liquid comprising the mixing liquid which is pumped in after cooled by a heat interchanger at the bottom of the adsorption tower and the mixing liquid which generates in the middle groove of the third-grade; the third-grade liquid distribution device adopts a kind of absorbent which is a mixing liquid comprising fresh absorbent, the regenerating liquid recycled by a mixing liquid separation device and the collecting liquid collected by a collecting hopper of third-grade; when the series of the single-seat tower is N and is larger than 3, all grades of absorbent from the second grade to the N minus 2 is a mixing liquid comprising a mixing liquid generated in the middle groove of the next grade and a collecting liquid collected by the collecting hopper on the same grade, the absorbent of the N minus grade is the colleting liquid collected by the collecting hopper of the N minus 1 grade, the absorbent of the N grade is a mixing liquid comprising of pumped fresh absorbent and the regenerating liquid recycled by the mixing liquid separation device. The fresh absorbent is an environment-protected organic solvent with high boiling point, strong lipophilicity and low volatility. The invention can recycle a plurality of organic infectant in waste gas, the technics procedure is simple, practical, and the operation cost is low.

Description

technical field [0001] The invention belongs to the fields of chemical industry and waste gas treatment, and specifically provides a method for purifying and recycling mixed organic waste gas. Background technique [0002] At present, for mixed organic waste gas, such as waste gas containing organic pollutants such as dimethylformamide (DMF), toluene and methyl ethyl ketone in the synthetic leather industry, the purification of waste gas is mainly concentrated in the terminal treatment. The mature technologies mainly include: catalytic combustion technology, Activated carbon adsorption technology and water and DMF solvent absorption purification technology. Among them, the catalytic combustion technology can simultaneously treat DMF, toluene, and methyl ethyl ketone in the exhaust gas, but the operating cost is high, and it belongs to the elimination type technology, which cannot realize the resource recovery of organic matter. Although activated carbon adsorption technolog...

AI Technical Summary

Problems solved by technology

Among them, the catalytic combustion technology can simultaneously treat DMF, toluene, and butanone in the exhaust gas, but the operating cost is high, and it belongs to the eradication technology, which cannot realize the recycling of organic matter resources

Although activated carbon adsorption technology can simultaneously adsorb the above three pollutants from exhaust gas, due to the high boiling point of DMF, a perfect activated carbon regeneration technology has yet to be developed.

Although some experts and scholars have improved the above-mentioned process technologies in recent years, such as improved carbon adsorption, improved direct combustion, improved catalytic combustion, etc., these technologies are still based on exhaust gas purification at the end of treatment, and cannot recycle useful components in exhaust gas. Recycling causes a great waste of resources

Conventional absorption technology, such as using water as absorbent, can only effectively recycle DMF, but cannot recycle low water solubility or insoluble toluene, methyl ethyl ketone, etc., such as the patent No. 200510061856.0 "Dry Synthetic Leather DMF Exhaust Gas The absorption process mentioned in "Recycling method"

The absorption process for recovering DMF in waste gas developed in Italy has a total recovery rate of DMF of up to 90%, but it cannot meet the requirements of the environmental emission standards for toluene and methyl ethyl ketone in my country's leather process waste gas.

The application number is 200410053246.1 "Recovery method of toluene, butanone and dimethylformamide in waste gas from wet synthetic leather production", although the technology mentioned in can simultaneously recycle DMF, toluene and butanone in waste gas, but there are still problems Problems mentioned above: (1) recovery efficiency is low

The recovery rates of toluene and acetone in this process are 83.5% and 49.2% respectively, and the toluene and butanone in the treated gas obviously exceed the standard, which cannot meet the environmental protection emission requirements; (2) large investment and high operating cost

The process adopts a double-tower and two-stage absorption device. The one-time investment of the process is large. At the same time, the pressure drop of the process tower equipment is large, the system energy consumption is high, and the concentration of DMF in the exhaust gas at the outlet of the primary absorption device exceeds 10000mg / Nm 3 , resulting in a high adsorption load of the secondary absorption device, a large amount of absorbent, and a high cost of recovering DMF solution purification

(3) There are serious security risks in the operation of the system

When the absorption unit operates in summer, the exhaust gas at the outlet of the primary absorption tower is at high O 2 , high DMF concentration, and high exhaust gas temperature (up to 60°C in summer, close to the flash point of DMF), the treatment process has serious fire or explosion hazards

(4) The process is complicated, the operation requirements are high and difficult, and it is not suitable for the practical application and promotion of environmental protection projects

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