Cracking gas separation method and cracking gas separation apparatus

Abstract

The invention belongs to the field of chemical industry gas separation, and relates to a cracking gas separation method and a cracking gas separation apparatus. The method comprises: (1) pressurizingcracking gas; (2) cooling the compressed gas, and conveying to an absorption tower; (3) making the stream on the top of the absorption tower enter a re-absorption unit or be cooled, and conveying thestream on the tower kettle to a desorption tower; (4) obtaining C2 concentrated gas from the top of the desorption tower, obtaining a lean solvent from the tower kettle, and returning the lean solventto the top portion of the absorption tower; (5) making the C2 concentrated gas enter a purification unit, and purifying; (6) making the purified C2 concentrated gas enter a methane removing tower, and conveying the material from the kettle of the methane removing tower to an ethane removing tower; (7) obtaining crude ethylene gas from the top of the ethane removing tower, conveying the crude ethylene gas to an ethylene rectification tower, and extracting the material from the kettle of the ethane removing tower as a liquefied gas product or conveying to a propane removing tower; and (8) extracting a polymerization-grade ethylene product from the top / side line of the ethylene rectification tower, wherein the material from the tower kettle is an ethane-rich product. According to the presentinvention, the method and the apparatus have advantages of simple process, high recovery rate, low energy consumption and the like.

Description

technical field [0001] The invention belongs to the field of chemical gas separation, and more specifically relates to a cracking gas separation method and a cracking gas separation device. Background technique [0002] Ethylene and propylene are important basic chemical raw materials. In the industrial production process, ethylene and propylene are mainly produced by steam cracking (ie thermal cracking) process. In the steam cracking production device, after the cracking raw materials such as light hydrocarbons, naphtha, hydrogenated tail oil, light diesel oil are mixed with water vapor, a thermal cracking reaction occurs in the cracking furnace to generate hydrogen, methane, C2, C3, C4, C5, pyrolysis gasoline, pyrolysis fuel oil and coke and other pyrolysis products. The pyrolysis products are separated and purified in the subsequent separation system to obtain fractions with different carbon numbers, and then the ethylene and propylene products are separated from the car...

AI Technical Summary

Problems solved by technology

At present, the C2C3 concentrated gas recovered from the tail gas of the refinery is mainly sent to different sections of the ethylene plant to increase the production of ethylene propylene. However, for refineries without ethylene production facilities nearby, the concentrated gas The whereabouts is a major problem, resulting in the C2C3 resources in the dry gas not being fully utilized, resulting in a large waste

If the traditional pyrolysis compression cryogenic separation method is used to process saturated resources and ethane propane in dry gas, the investment recovery rate is low and the energy consumption is high

[0005] In summary, the existing separation process for cracked gas containing methane, hydrogen and light hydrocarbons has the problems of large investment and high energy consumption.

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