The research on the coordinative and competitive relationship between MEA and DEA absorbing CO2 into aqueous blended amine solution

摘要

In this work, ~(13)C NMR spectroscopy was used to study the reaction process of the 2.0M blended amine of MEA-DEA (1:1) with CO2. The concentrations of free amines, the carbamates of amines, protonated amines, HCO3~- and CO3~(2-) in the solutions were generated over the CO2 loading range from 0 to 0.7mol CO2/mol amine at the temperature of 301K in order to understand the specific process of the reaction between the blended amine and CO2. The results show that only the carbamate of MEA was generated under lower CO2 loading, which means that MEA is more competitive than DEA, while when the CO2 loading, the carbamate of DEA (namely, DEACOO~-) was also generated, which means that when the CO2 loading reached 0.231 mol CO2/mol amine and the concentration of MEA was decreased a certain extent, the abilities of MEA and DEA to react with CO2 were well-matched.