Kinetics Of Carbon Dioxide Absorption By Sulfolane/MEA Phase-change Absorbents

Global warming is a growing problem at present,and the various climate problems which brought by global warming also deserve to be focused.As we all know,CO2 and other greenhouse gas emissions are the main causes of the rising temperature.Carbon capture and sequestration?CCS?is an essential means of mitigating climate change and has received growing attention worldwide.Absorption with alkanolamine solutions is currently the most prevalent CO₂ capture technology.However,this technology cannot be applied cost-effectively on a large scale because it consumes considerable energy for CO₂ regeneration.Therefore,the development of low-cost,low-energy CO₂ capture technologies has been a prominent subject of academic discussion.In this study,Sulfolane and Monoethanolamine?MEA?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 CO₂loading 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 and gas flow rate on CO₂ absorption rate.The kinetic parameters such as mass transfer coefficient,liquid film mass transfer coefficient,total mass transfer coefficient and enhancement factor of reaction were calculated by dynamic model.The 3M MEA+3.5M sulfolane mixed solution system,3M MEA+4M sulfolane mixed solution system and 4M MEA+5M sulfolane mixed solution system all showed obvious liquid-liquid delamination phenomenon after absorbing enough CO₂.However,the comparison shows that the 4M MEA+5M sulfolane mixed solution has the best phase change performance.The CO₂ absorbed after the liquid-liquid layering is mainly concentrated in the upper layer of the solution,and with the increase of CO₂absorption,the CO₂ load of the upper layer solution gradually increases,while the CO₂ load of the lower layer solution is small and little change occurs.The effects of different reaction conditions on CO₂ absorption rate were investigated in a wetted-wall column using 4M MEA+5M sulfolane phase-change solvent as absorbers.This study determined that reaction temperature,CO₂ loading affected the CO₂ absorption rates to a certain extent.Overall,under the experimental conditions,the CO₂ absorption rate increased with increasing temperature and decreased with increasing CO₂ loading,but the performance was different with CO₂load increased to 1.39 mol/L and temperature increased to 60°C.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 mass transfer resistance.This study contributes theoretically to the development of CO₂ absorption technologies.