Process method for drying cracking gas

Abstract

A process method for drying cracking gas is provided; the cracking gas passes through a dryer separation tank and then enters a first dryer from the top of the first dryer, wherein the dryer adopts a 3A molecular sieve drying agent to remove moisture; the cracking gas after drying is supplied to a depropanization tower, propane and heavy components with the carbon number of 4 or less are removed from the tower bottom, and propylene, ethylene, ethane, acetylene and methane light components of the tower top enter a compressor section 4 and then enter a second-stage dryer feed tank; cracking gas coming out of the top of the second-stage dryer feed tank flows into a reactor to remove COS, sulfur alcohol, ammonia, H2S and CO2 impurities, and then enters a dearsenication reactor; a dearsenication agent and a catalyst in the dearsenication reactor remove arsenic and mercury impurities, and the cracking gas after treatment enters an acetylene hydrogenation reactor, next enters a second dryer, is dried, and then enters a separation system. The problems of poor drying and purification effects of cracking gas produced by a conventional device for preparing ethylene through catalytic thermal cracking are solved, freezing and blocking of the cryogenic separation system of a CPP device subsequent unit can be effectively prevented, and the economic benefits are improved.

Description

technical field [0001] The invention relates to the technical field of petrochemical technology, in particular to a process method for drying cracked gas in the production process of ethylene production by catalytic thermal cracking. Background technique [0002] Catalytic thermal cracking ethylene unit is a production unit that produces ethylene and propylene from atmospheric residual oil. The cracked gas produced in the production process is a mixed gas, including fuel gas, ethylene, propylene, carbon four, etc., in addition to a certain amount of impurities such as acid gas, tribute, nitrides, water, etc. A series of drying and purification treatments can separate it into qualified fuel gas, ethylene, propylene, carbon four and other products. Ethylene is an important basic raw material of organic chemical industry and the most basic raw material of petrochemical industry. According to the statistics of relevant departments, ethylene products account for more than 75% of...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a process for cracking gas drying in the production process of catalytic thermal cracking to ethylene, so as to solve the problem of cracking gas drying and purification in catalytic thermal cracking ethylene production

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