Experimental study on CO2 solubility in aqueous Piperazine/alkanolamines solutions at stripper conditions

摘要

Vapor liquid equilibrium (VLB) experiments using pressurized vessel operated at wide range of temperatures from 40 °C to 120 °C were conducted with four binary solutions of Piperazine (PZ) and alkanolamines, which are 2-Isopropylaminoethanol (IPAE), Monoethanolamine (MEA), Diethanolamine (DBA) and Methyldiethanolamine (MDEA). Effective CO2 loadings of some PZ based binary solutions, which meant the difference between the CO2 loadings at the consistent absorber and stripper conditions, increased in comparison with the PZ only solution and especially, PZ/MDEA showed the largest effective CO2 loading. CO2 loadings at the stripper condition did not depend on additive amount of MDEA to PZ and was the same CO2 loading as PZ only solution, while those increased with increase in MDEA concentration at the absorber condition. According to the reaction products analysis for PZ/MDEA samples operated at different temperature by using ~(13)C-NMR spectroscopy, the bicarbonate in the solution decreased significantly with increase in temperature, but the PZ carbamate dissociated CO2 much less than the carbamate even at 120 °C.