A kind of mdea composite absorbent for acid gas separation and separation method

Abstract

The invention discloses an MDEA compound absorbent for acid gas separation and a separation method, and belongs to the technical field of gas separation. The MDEA compound absorbent comprises MDEA, alcohols immiscible with water and water, wherein the weight percentage of MDEA is 10-60%, the weight percentage of alcohols immiscible with water is 10-60%, and the weight percentage of water is 10%-80%; due to the solubilization assisting effect of MDEA, the compound absorbent has a homogeneous phase before absorbing acid gas, and is formed into liquid-liquid phases after absorbing acid gas, the upper liquid phase is the barren liquid phase loaded with acid gas, the lower liquid phase is the rich liquid phase loaded with acid gas, and only the rich liquid phase enters a desorption unit, so that the desorption energy consumption is reduced. The compound absorbent is formed into liquid-liquid phases after absorbing acid gas, the liquid-liquid phases are easy to separate, and the composition proportion of the absorbent is adjusted to adapt to the optimal volume ratio of the upper liquid phase and the lower liquid phase and loading capacity of the absorbent in the process, so that amount of the rich liquid phase entering the desorption unit is reduced, and the desorption energy consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of gas separation, and in particular relates to an MDEA composite absorbent for acid gas separation. Background technique [0002] The energy demand brought about by the rapid development of industrialization and my country's energy structure dominated by fossil fuels such as coal have resulted in a large amount of CO 2 The emissions have seriously affected the ecological environment and caused the global greenhouse effect. Extreme weather continues to appear. Problems such as melting glaciers, rising sea levels, and species extinction are becoming more and more serious. reduce CO 2 Emissions are an effective way to curb global warming. will CO 2 Efficient capture and storage (CCS) is currently the most feasible CO 2 emission reduction methods. [0003] Chemical absorption is currently the most commonly used CCS technology. Since the energy consumption of the desorption process accounts for a large pro...

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Problems solved by technology

[0005] Chinese patent application "An amine absorbent and CO capture 2 Method" (application number 201280031688.9, published on May 28, 2014) proposes an amine absorbent and captures CO 2 method, absorbents DIPAE / MAPA, DIPAE / DAB, N-TBDEA / DiAP, DEEA / DMPDA absorb CO 2 After forming two phases, the load CO 2 The enriched phase enters the desorption unit to reduce the amount of desorption liquid and reduce the energy consumption of desorption. The method of this patent application can simultaneously reduce the energy consumption of water evaporation and the energy consumption of absorbent heating, but the concentration of absorbent is high, the viscosity is high and the Expensive, difficult to synthesize, not conducive to its application in industry

Chinese patent application "for CO 2 Combined CO for split systems 2 Phase Change Absorbent" (Application No. 201310212240.3, published on December 28, 2013) proposes an amino-silicone absorbent that absorbs CO 2 After that, solid-liquid two phases are formed, and the solid is carbamate. The regeneration of the absorbent can be realized by heating the solid carbamate during the desorption process. Since the solid is generated during the absorption process, it is easy to block the pipeline, which brings great advantages for industrial applications. Inconvenience

U.S. Patent "PHASE TRANSITRONAL ABSORPTION METHOD" (Application No. 11 / 279095, Patent No. US7541011B2, Publication No. September 2, 2009) discloses a process that uses an absorbent that contains at least one activator and at least one solvent to convert a gas mixture The method for separating gas in the middle, the absorbent of only example is the water-containing mixture of DEA and potassium carbonate, above-mentioned patent does not specify the phase separation solvent that causes expectation, and does not make clear absorbent composition and the concentration of each component in the embodiment, experiment shows, Most of the absorbents with different compositions cannot phase-separate after absorbing the gas to be absorbed, so it is impossible to implement

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