Toluol-benzene solvent recovery technology from vent gas

A tail gas recovery and toluene technology, applied in the direction of absorption purification/separation, organic chemistry, dispersed particle separation, etc., to achieve the effect of improving the economic and social benefits of enterprises and solving the problem of atmospheric environmental pollution

Inactive Publication Date: 2008-07-30
河北美邦工程科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the invention is to provide a toluene-benzene tail gas recovery process in the production process of caprolactam to solve the problems in the prior art

Method used

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  • Toluol-benzene solvent recovery technology from vent gas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Embodiment 1: As shown in Figure 1, the toluene-benzene-containing tail gas discharged from the toluene oxidation device is sent into the extraction and absorption tower from the bottom through the pipeline using the pressure of the tail gas itself, and the fresh toluene-benzene special liquid sprayed from the top of the extraction and absorption tower The absorbent is in gas-liquid countercurrent contact with the above-mentioned tail gas at 30°C and 0.8Mpa to absorb toluene and benzene. The above-mentioned absorbent is a special liquid absorbent for toluene and benzene produced by Hebei Ruitong Meibang Company with the model number RTMB102. The boiling point is higher than 200°C. When the absorption rate of toluene-benzene tail gas reaches 95%, the gas after absorbing toluene and benzene is discharged from the top of the tower, and then sent to the subsequent catalytic combustion treatment system for further power generation, catalytic combustion, and then discharged int...

Embodiment 2

[0017] Embodiment 2: The difference between this embodiment and Embodiment 1 is that the toluene-benzene-containing tail gas discharged from the toluene oxidation device is sent into the extraction and absorption tower from the bottom through the pipeline using the pressure of the tail gas itself, and the fresh fresh water injected from the top of the extraction and absorption tower The special liquid absorbent for toluene-benzene carries out gas-liquid countercurrent contact with the above-mentioned tail gas at 20°C and 0.5Mpa to absorb toluene and benzene. When the absorption rate of toluene-benzene tail gas reaches 90%, the gas after absorbing toluene and benzene is discharged It is discharged from the top, and then sent to the subsequent catalytic combustion treatment system for further power generation and catalytic combustion, and then discharged into the atmosphere. The content of toluene and benzene in the gas discharged into the atmosphere reaches the emission standard;...

Embodiment 3

[0018] Embodiment 3: The difference between this embodiment and Embodiment 1 is that the toluene-benzene-containing tail gas discharged from the toluene oxidation device is sent into the extraction and absorption tower from the bottom through the pipeline using the pressure of the tail gas itself, and the fresh fresh gas injected from the top of the extraction and absorption tower The special liquid absorbent for toluene-benzene carries out gas-liquid countercurrent contact with the above-mentioned tail gas at 50°C and 1.0Mpa to absorb toluene and benzene. When the absorption rate of toluene-benzene tail gas reaches 98%, the gas after absorbing toluene and benzene is discharged It is discharged from the top, and then sent to the subsequent catalytic combustion treatment system for further power generation and catalytic combustion, and then discharged into the atmosphere. The content of toluene and benzene in the gas discharged into the atmosphere reaches the emission standard; ...

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Abstract

The invention discloses a toluene-benzene vent gas recovery process during hexanolactam production by adopting toluene oxidation method, which comprises the following steps: toluene-benzene vent gas discharged from a toluene oxidation device is introduced into an adsorption tower to carry out gas-liquid countercurrent contact with absorbent that is injected form the tower top under the temperature of 20-50 DEG C and pressure of 0.5-1.0MPa; when the adsorption rate of the toluene-benzene vent gas is up to 90-98 percent, the solution absorbed with toluene-benzene is introduced to a desorption tower and desorption is carried out under temperature of 90-108 DEG C and pressure of 0.1-0.12MPa; when the adsorption rate is higher than 95 percent, desorbed toluene-benzene mixture air is cooled to 20-40 DEG C, the adsorbent after desorption is cooled to 20-50 DEG C and recycled. The recovery rate of toluene and benzene of the process of the invention can be more than 90 percent, and the gross content of toluene and benzene after the recovery process can reach more than 95 percent; therefore, not only the toluene and benzene can be effectively recovered, but also the discharged gas can be up to national and industry emission standards; in addition, economic and social benefits of enterprises are improved.

Description

technical field [0001] The invention relates to waste gas recovery in the field of producing caprolactam by a toluene oxidation method, in particular to a toluene-benzene tail gas recovery process. Background technique [0002] At present, the first reaction unit in the process of producing caprolactam by toluene oxidation in China is the oxidation of toluene to produce benzoic acid. The reaction is carried out in a tank reactor with air as the oxidant. Due to the limitation of reaction characteristics and system physical properties, the single-pass conversion rate of toluene oxidation reactor is generally maintained at about 13-17%, and the gas phase load is very large. The nitrogen and unreacted oxygen in the air must be discharged from the tail gas system. These Even if the exhaust gas is cooled to 5°C (design value) by the cooler, toluene vapor will inevitably be carried out. At present, the content of toluene-benzene in the tail gas emission of the toluene oxidation un...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/14C07C7/11C07C15/04C07C15/06
Inventor 张利刚刘东高文杲张玉新张卫国金作宏
Owner 河北美邦工程科技股份有限公司
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