Solubility, absorption heat and mass transfer studies of CO_2 absorption into aqueous solution of 1-dimethylamino-2-propanol

摘要

In this work, the CO_2 absorption performance of aqueous 1-dimethylamino-2-propanol (1DMA2P) was comprehensively investigated in terms of CO_2 equilibrium solubility, CO_2 absorption rate, CO_2 absorption heat, and mass transfer efficiency. The CO_2 equilibrium solubility in 2 M 1DMA2P was measured over the temperature range of 298-333 K and CO_2 partial pressure range of 8-101 kPa. The results showed that the CO_2 equilibrium solubility of 1DAM2P was higher than those of conventional amines, MEA and MDEA. The CO_2 absorption heat of 1DMA2P based on the Gibbs-Helmholtz equation was found to be -30.5 kJ/ mol, which suggests that 1DMA2P needs a lower regeneration energy as compared with MEA and MDEA. Ion speciation (including 1DMA2P, 1DMA2PH~+, HCO_3~-, CO_3~(2-)) plots obtained from the pH method were also generated at the temperatures of 298 K and 313 K. In addition, the overall mass transfer coefficient (K_Ga_v) of 1DMA2P in a packed column was also experimentally obtained and compared with those of MEA and MDEA. The ranking was: MEA ＞ 1DMA2P ＞ MDEA.