Method for preparing olefin by dehydration of methanol

Abstract

The invention discloses a method for preparing olefin by dehydration of methanol, which overcomes the shortcoming of low olefin yield in the prior art, the shortcoming that a catalyst is susceptible to inactivation due to carbonization during reaction and the like. The method provided by the invention comprises: heating the methanol to generate vapor; allowing the vapor to enter a catalytic distillation rector to contact with a zeolite molecular sieve (ZSM)-5 catalyst and react; allowing the reaction product to enter a moving-bed reactor to contact with the catalyst and react; separating the reaction products; after ethylene and propylene products are separated out, allowing a material flow containing C4 hydrocarbons and a material flow containing C5-C7 hydrocarbons to enter two fixed-bedrectors respectively to contact with the catalyst and react; regenerating the inactive catalyst in the moving-bed reactor by burning and then recycling the regenerative catalyst. The method provided by the invention has the advantages of high olefin yield, high catalyst activity and high stability.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for preparing olefins by dehydrating methanol. Background technique [0002] Ethylene and propylene are important basic chemical raw materials with huge annual demand, and they are mainly obtained from petroleum processing at present. In recent years, the international oil price has been at a high level above US$50 / barrel. Our country's oil resources are limited, and more than 40% of the oil needed at present depends on imports. Therefore, the catalytic conversion of methanol produced from coal to ethylene and propylene has a good application prospect. [0003] The methanol-to-ethylene-based process (MTO for short) and the propylene-based process (MTP for short) are about to enter large-scale industrialization. German Luqi company has multi-top MTP patents (EP448000, WO192190, WO20061364.33, DE1020050159232, etc.), and has completed the continuou...

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Problems solved by technology

[0006] The present invention aims at the disadvantages of the prior art, such as low yield of olefins, easy carbonization and deactivation of the catalyst in the reaction process, etc., and proposes a new method for methanol dehydration to olefins. The method adopts a catalytic distillation reactor, a continuous reaction regeneration The device constitutes an MTP catalytic reaction system and two adiabatic fixed-bed reactors. Using the method of the present invention, the catalyst can be continuously reacted and regenerated, with less carbon deposition and high olefin yield

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