Phase change behavior and kinetics of CO2 absorption into DMBA/DEEA solution in a wetted-wall column

Coal-fired flue gas is a major source of greenhouse gas CO2. Phase-change absorbents can be used to reduce energy consumption associated with regeneration during CO2 capture. In this study, N,N-dimethylbutylamine (DMBA) and N,N-dimethylbutylamine (DEEA) were mixed to develop phase-change absorbents, and the reaction kinetics of CO2 absorption in the absorbents were examined. A bubbling device was used to prepare phase-change absorbents with different CO2 loading levels. The physico-chemical parameters of the absorbents under different conditions were specified, and the changes in the CO2 loading of the upper and lower layers of the absorption solutions after a liquid-liquid separation were analyzed. A wetted-wall column was subsequently used to investigate the effects of temperature, CO2 loading, gas flow rate, and DMBAMEEA composition ratio on CO2 absorption rate. This study determined that the flow velocity, reaction temperature, and CO2 loading affected the CO2 absorption rates to a certain extent. In addition, comparing the reactive properties of the 4M DMBA + 2M DEEA and 2M DMBA + 4M DEEA absorbents under the same experimental conditions revealed that the 4M DMBA + 2M DEEA absorbent exhibited higher absorption rate and reaction stability. A kinetics Model also indicated that the CO2 absorption of the phase-change absorbents used in this study was mainly affected by the liquid film diffusion process. This study contributes theoretically to the development of CO2 absorption technologies. (C) 2016 Elsevier B.V. All rights reserved.