Liquid-Solid Phase-Change Behavior of Diethylenetriamine in Nonaqueous Systems for Carbon Dioxide Absorption

摘要

Conventional amine scrubbing systems for carbon dioxide capture require a large amount of energy to regenerate the absorbent. Theoretically, if CO2-captured product can be separated from the liquid counterpart, and only this product need to be heated for desorption, the energy efficiency for CO2 capture can be improved greatly. In the present work, diethylenetriamine (DETA) dissolved in ethanol, diethylene glycol dimethyl ether, N-methyl-pyrrolidone, or dimethyl carbonate can absorb CO2 to result in liquid-solid phase-change in addition to making the reaction to achieve its stoichiometric maximum. The results show that the different organic solvents have no influence on the formation of precipitate. Single-crystal structure analysis indicates a DETA-carbamate is formed with equimolar CO2 absorption. The absorption-desorption cycles using microwave heating shows that the system has a relatively stable cycling performance.