Synthetic gas fluidized bed methanol production process based on interstage absorption and separation

Abstract

The invention provides a synthetic gas fluidized bed methanol production process based on interstage absorption and separation. The reaction system is composed of a methanol fixed bed pre-reactor and a two-stage or multi-stage methanol fluidized bed reactor in series. The converted CO / H 2 The 1:2 purified syngas passes through the methanol fixed-bed pre-reactor and then enters the first-stage methanol fluidized-bed reactor with heat extraction pipes, part of CO and / H 2 With the fine powder methanol catalyst at 200-280℃ and 3.0-7.0Mpa, the homogeneous methanol synthesis reaction occurs through the heat exchange of the heat pipe. After the product gas is passed through the gas-solid separator to remove the catalyst, it is cooled by a water cooler and enters the methanol absorption and separation tower. ; After demethanolization, the product gas enters the methanol fluidized bed reactor with heat pipes at subsequent stages, and repeats the above process; finally, part of the separated tail gas is held and partly pressurized and returned as a raw material for synthesis gas; the upper part of the absorption tower is rich in methanol The absorption liquid is depressurized and flashed to recover methanol, which is used as an absorbent in the lower section of the tower to absorb methanol and remove fine powder; methanol is removed from the bottom of the tower and collected to remove impurities before entering the rectification system.

Description

[0001] 1. Technical field [0002] The invention provides a synthetic gas fluidized bed methanol production process based on interstage absorption and separation, which belongs to the field of coal chemical industry. [0003] 2. Background technology [0004] Methanol synthesis at medium and low pressure is an advanced technology commonly used in the world at present. According to the form of catalyst reactor, it can be divided into three types: fixed bed, gas-solid fluidized bed and three-phase slurry bed. Since methanol synthesis is a strong exothermic reaction, for fixed-bed reactors, due to the difficulty in heat removal, in order to ensure that the reactor does not overheat locally, the single-pass conversion rate of methanol synthesis is generally not high at present, about 10%-15%. Methanol content is only 3%-4%. In order to solve local over-temperature and achieve isothermal operation, foreign countries have also developed a super-conversion methanol fixed-bed synthesi...

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Problems solved by technology

[0010] The purpose of the present invention is to provide a syngas fluidized bed methanol process based on interstage absorption and separation in order to overcome the shortcomings of the existing syngas to methanol technology, and solve the full mixing characteristics of the fluidized bed reactor through the methanol fixed bed pre-reactor The defects of rapid catalyst poisoning and deactivation and short service life are caused. The graded reaction reduces the heat extraction load of the heat extraction pipe of the fluidized bed and increases the effective reaction cross-sectional area of ​​the fluidized bed; It promotes the positive reaction of methanolylation and improves the one-way conversion rate of synthesis gas; the concentration of methanol removal is high, the concentration of impurity removal is high, the energy consumption is low, and the harmless treatment of catalyst powder does not contain secondary harmful wastewater containing heavy metals.

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