CO2 trapping method combining dimethyl carbonate absorption and membrane desorption

Abstract

The invention discloses a CO2 trapping method combining dimethyl carbonate absorption and membrane desorption, belonging to the technical field of chemical engineering. The method comprises the following steps of: decarbonizing feed gas containing CO2 by dimethyl carbonate absorption; then carrying out two-stage throttling expansion and membrane desorption regeneration on CO2-absorbed absorbent rich liquor, and discharging CO2 gas generated by the throttling expansion and the membrane desorption out of the battery limit. Compared with a decarbonizing process of the inventor, which adopts the dimethyl carbonate as the absorbent, the new process of the dimethyl carbonate decarburization and the membrane desorption can reduce the comprehensive energy consumption by 5-20 percent. Compared with the propylene carbonate method maturely applied in industry at present, the energy consumption can be reduced by 30-40 percent; compared with the polyethylene glycol dimethyl ether method, the price of a solvent is lower, and polymerization losses are reduced by 40-60 percent; and compared with the low-temperature methane swabbing process, the operating temperature is milder, and the equipment investment is reduced by 30-40 percent. The CO2 removing efficiency can reach 95 percent or above.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering. Especially related to the absorption and removal of CO from the medium and high pressure mixed gas of synthesis gas, shift gas and IGCC gas 2 A CO2 that combines dimethyl carbonate absorption and membrane desorption 2 capture method. Background technique [0002] Global warming has become an undisputed fact. Greenhouse gas CO 2 emissions are a major contributor to climate warming. from rich CO 2 Capture and separation of CO in the gas mixture of synthetic gas, shift gas and IGCC gas 2 It is an important measure to deal with global warming. [0003] According to different applications and the pressure of raw gas, CO removal 2 Methods can be divided into dry method and wet method. Dry methods include adsorption methods and membrane methods, and are generally applicable to CO 2 Where the concentration is low; the wet method can be divided into chemical absorption method and ph...

AI Technical Summary

Problems solved by technology

However, nitrogen stripping is used in the regeneration process of the absorbent. On the one hand, the use of nitrogen increases the cost, and on the other hand, it is necessary to add a tail gas purification tower to recover the dimethyl carbonate in the desorbed gas. The equipment investment increases. For this process Due to the shortcomings and defects of long process, high cost, and large equipment investment, a CO 2 capture methods to further simplify the process and reduce costs

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