A method for absorbing and separating light hydrocarbons from dry gas or industrial tail gas

A technology of industrial tail gas and dry gas, which is applied in the direction of separation methods, dispersed particle separation, chemical instruments and methods, etc., can solve the problems of high energy consumption, environmental and product pollution, difficult recycling and recycling of cryogenic separation methods, and achieve suitable Effects on industrial production, high efficiency removal, high light hydrocarbon separation selectivity

Active Publication Date: 2019-04-02
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Although the existing technology is relatively mature, the cryogenic separation method consumes a lot of energy and is generally suitable for the recovery of large-scale olefins, while the absorbent used in the absorption method is a molecular solvent, which has the disadvantages of being volatile and poor in thermal stability. Complete recycling and recycling, and easy to cause pollution to the environment and products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The absorbent is a deep eutectic solvent mixed with n-decanoic acid and tetrabutylammonium chloride at a molar ratio of 2:1. Refinery dry gas composition (molar ratio): methane 21.8%, ethane 20%, ethylene 17.1%, propane 2.6%, propylene 5.4%, hydrogen 1.6%, nitrogen 22.4% and other components above C4.

[0042] The refinery dry gas is pressurized to 3.8MPa through the compressor, and the temperature is lowered to 15°C by cooling, and it is fed from the bottom of the absorption tower, and the absorbent is added to the top of the absorption tower to ensure that most of the C2~C4 light hydrocarbons are absorbed. Absorption, the absorption liquid rich in C2-C4 light hydrocarbons obtained at the bottom of the tower, and the residual tail gas such as insoluble nitrogen, hydrogen, methane, etc. are obtained at the top of the tower.

[0043] The absorption liquid at the bottom of the tower enters the desorption tower, adopts the method of temperature rise and desorption, the des...

Embodiment 2

[0045] The absorbent is a deep eutectic solvent mixed with n-decanoic acid and trioctylmonomethylammonium chloride at a molar ratio of 2:1. Refinery dry gas composition: 23% methane, 9.5% ethane, 7.4% ethylene, 0.5% propane, 1.2% propylene, 32% hydrogen, 19% air and other components above C4.

[0046] As in Example 1, the dry gas and the absorbent are countercurrently contacted and absorbed at 20°C and 3.0 MPa, the absorbing liquid is desorbed at 65°C to produce C2-C4 light hydrocarbons, and the absorbent is recovered and recycled at the bottom of the tower. The comprehensive recovery rate of C2-C4 light hydrocarbons can reach 93.6%.

Embodiment 3

[0048] The absorbent is a deep eutectic solvent mixed with lauric acid and trioctylmonomethylammonium chloride at a molar ratio of 2:1. Dry gas composition: methane 20.6%, ethane 11.9%, ethylene 14.8%, propane 0.6%, propylene 1.6%, hydrogen 28.3%, air 18.4% and other components above C4.

[0049] As in Example 1, the dry gas and the absorbent are countercurrently contacted and absorbed at 15°C and 3.2 MPa, the absorbing liquid is heated and decompressed at 70°C and 0.3 MPa to desorb C2-C4 light hydrocarbons, and the absorbent is recovered and recycled at the bottom of the tower. The comprehensive recovery rate of C2-C4 light hydrocarbons can reach 95.5%.

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PUM

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Abstract

The invention discloses a method for absorbing and separating light hydrocarbon from dry gas or industrial tail gas. The method comprises the following steps: allowing a deep eutectic solvent used as an absorbent to contact with the dry gas or the industrial tail gas, carrying out absorption so as to obtain an absorption solution containing the light hydrocarbon, and subjecting the absorption solution to desorption and separation so as to obtain the light hydrocarbon, wherein the light hydrocarbon mainly contains C2-C4 alkane or olefin. According to the invention, the deep eutectic solvent is used as the absorbent, and an absorption-desorption method is adopted to recycle and separate the light hydrocarbon, wherein the absorbent has significantly high light hydrocarbon solubility and separation selectivity, so highly-efficient separation and recycling of the light hydrocarbon can be realized.

Description

technical field [0001] The invention relates to the field of separation, recovery and purification of dry gas and industrial tail gas, in particular to a method for absorbing and separating light hydrocarbons from dry gas or industrial tail gas by using a deep eutectic solvent. Background technique [0002] Refinery dry gas produced by heavy oil catalytic cracking, thermal cracking, delayed coking, etc., as well as tail gas discharged from chemical equipment, etc., contain a certain amount of light hydrocarbon resources, but they are usually sent into the gas pipeline network as fuel gas, resulting in Low-grade utilization of resources. Therefore, recovery of light hydrocarbons from dry gas and industrial tail gas has important practical significance. [0003] At present, the industrial separation methods for hydrocarbon mixtures such as dry gas are mainly cryogenic separation method, solvent absorption method, absorption and rectification coupling separation method. The f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/14
CPCB01D53/1425B01D53/1487B01D53/1493
Inventor 杨启炜张依邢华斌任其龙苏宝根鲍宗必张治国
Owner ZHEJIANG UNIV
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