Separation process for preparing low-carbon alkene gases through conversion of methanol

Abstract

The invention discloses a separation process for methanol conversion to produce low-carbon olefin gas, in order to solve the problem that the prior art cannot obtain products such as hydrogen, methane, ethane and propane with high purity and cannot effectively remove dimethyl ether and flue gas impurities Defects such as oxygen and carbon monoxide in the air. The methanol-to-olefins gas stream in this process adds carbon monoxide and oxygen removal steps, and the methanol-to-olefins gas stream that removes carbon monoxide and oxygen passes through six separation tanks in sequence and then enters the low-pressure demethanizer, deethanizer, and acetylene hydrogenation reactor , ethylene rectification tower, propyne hydrogenation reactor and propylene rectification tower, etc., in which the liquid from the bottom of the first four separation tanks enters the middle and upper part of the demethanizer in turn, and the liquid from the bottom of the fifth separation tank enters the demethanizer The upper part of the tower or return to the compressor section. By using the present invention, polymer grade ethylene and propylene products can be obtained, and products such as hydrogen, methane, ethane and propane with higher purity can also be obtained.

Description

Technical field: [0001] The invention belongs to the field of petrochemical industry and relates to a separation process for preparing low-carbon olefin gas by methanol conversion. Specifically, the present invention relates to a mixture of materials including one or more of hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, acetylene, propane, propylene, cyclopropane, propyne and propadiene Process for recovering ethylene and propylene. Background technique: [0002] Olefins, especially low-carbon olefins (light olefins) such as ethylene and propylene, are required as raw materials for the preparation of higher olefins, polyethylene and polypropylene. The tube furnace cracking unit that uses naphtha as raw material to produce ethylene and propylene through steam cracking is currently the most important industrial production unit for ethylene and propylene. The cracked gas produced by hydrocarbon cracking is a mixture containing hydrogen, me...

AI Technical Summary

Problems solved by technology

[0020] The present invention aims at the disadvantages that the method disclosed in CN1833017A cannot obtain products such as hydrogen, methane, ethane and propane with higher purity and does not effectively remove oxygen and carbon monoxide in dimethyl ether and flue gas impurities. The components and composition characteristics of the production of low-carbon olefin gases, and a new and highly effective separation process for the separation of polymer-grade ethylene and propylene from low-carbon olefin gases

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