Separation process for preparing low-carbon olefin gas through methanol conversion

Abstract

The invention discloses a separation process for preparing low-carbon olefin gas through methanol conversion, aiming at overcoming the defects that products such as high-purity hydrogen, methane, ethane and propane cannot be obtained, dimethyl ether and oxygen and carbon monoxide in flue gas impurities are not effectively removed and the like in the prior art. A carbon monoxide and oxygen removal step is added in the process. Methanol-to-olefin gas with the carbon monoxide and the oxygen being removed passes through six separation tanks and then enters a high-pressure demethanation tower, a deethanization tower, an acetylene hydrogenation reactor, an ethylene rectifying tower, an allylene hydrogenation reactor, a propylene rectifying tower and the like for separation, wherein liquid which comes out from the bottoms of the first five separation tanks sequentially enters the middle-to-upper part of the demethanation tower. By adopting the separation process, polymer-grade ethylene and propylene products can be obtained and products such as high-purity hydrogen, methane, ethane and propane can also be obtained.

Description

Technical field: [0001] The invention relates to a separation process for preparing low-carbon olefin gas by converting methanol. In particular, the present invention relates to a mixture of materials comprising 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 light olefins (light olefins) such as ethylene and propylene, are required as raw materials for the production 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 of ethylene and propylene. The cracked gas produced by cracking hydrocarbons is a mixture containing hydrogen, methane, ethane, ethylene, propane, propylene, mixed...

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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