Methanol purge gas recycling process

Abstract

The invention belongs to the field of chemical waste gas recycle and in particular relates to a methanol purge gas recycling process. The process comprises the following steps of: firstly, reducing the pressure of the methanol purge gases to 1.0-1.5Mpa under normal temperature; secondly, leading the methanol purge gases to a heat exchanger to be heated to 200-450 DEG C; thirdly, leading the methanol purge gases to a reformer, controlling the temperature of the reformer at 620-720 DEG C and reforming the methanol purge gases to a mixture of carbon monoxide, carbon dioxide and hydrogen; fourthly, leading the mixture obtained through reaction to an oxygenation reformer to further reform the incompletely reformed methanol and methane to carbon monoxide, carbon dioxide and hydrogen under the conditions that the temperature is 820-1000 DEG C and oxygen is present; fifthly, re-leading the obtained mixture to the reformer to reform carbon monoxide to carbon dioxide and controlling the temperature of the reformer at 380-450 DEG C; and finally, removing carbon dioxide from the mixture with an MDEA (methyldiethanolamine) solution, thus obtaining hydrogen through separation. The process has the following advantages that the process is little in pollution; the methanol purge gases can be recycled; and the economic and environmental benefits are higher.

Description

technical field [0001] The invention belongs to the field of recovery of chemical waste gas, and in particular relates to a recovery and utilization process of methanol exhaust gas. Background technique [0002] Purge gas usually refers to the gas that does not participate in the reaction in chemical production or the gas that cannot be used because the grade is too low and accumulates in chemical equipment or pipelines. Since the purge gas affects the heat transfer effect of the equipment, affects the reaction speed and progress, reduces the production efficiency, etc., the purge gas must be discharged regularly. [0003] The purge gas in the methanol production process is rich in 52-65% hydrogen, carbon monoxide, carbon dioxide, methane and nitrogen, and also contains some useful components such as methanol and methyl formate. The traditional treatment method for methanol purge gas is to burn it as fuel gas. However, due to the relatively low calorific value of hydrogen i...

AI Technical Summary

Problems solved by technology

The traditional treatment method for methanol purge gas is to burn it as fuel gas. However, due to the relatively low calorific value of hydrogen in it, the value of direct combustion is not high. At the same time, other impurities will be released during the combustion process. The pungent smell pollutes the air environment. Obviously, this traditional methanol offgas treatment method needs to be improved urgently.