- Title
- CO₂ absorption into aqueous amine blended solutions containing monoethanolamine (MEA), N,N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA) and 2-amino-2-methyl-1-propanol (AMP) for post-combustion capture processes
- Creator
- Conway, William; Bruggink, Stefan; Beyad, Yaser; Luo, Weiliang; Melián-Cabrera, Ignacio; Puxty, Graeme; Feron, Paul
- Relation
- Chemical Engineering Science Vol. 126, p. 446-454
- Publisher Link
- http://dx.doi.org/10.1016/j.ces.2014.12.053
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2015
- Description
- Presently monoethanolamine (MEA) remains the industrial standard solvent for CO₂ capture processes. Operating issues relating to corrosion and degradation of MEA at high temperatures and concentrations, and in the presence of oxygen, in a traditional PCC process, have introduced the requisite for higher quality and costly stainless steels in the construction of capture equipment and the use of oxygen scavengers and corrosion inhibitors. While capture processes employing MEA have improved significantly in recent times there is a continued attraction towards alternative solvents systems which offer even more improvements. This movement includes aqueous amine blends which are gaining momentum as new generation solvents for CO₂ capture processes. Given the exhaustive array of amines available to date endless opportunities exist to tune and tailor a solvent to deliver specific performance and physical properties in line with a desired capture process. The current work is focussed on the rationalisation of CO₂ absorption behaviour in a series of aqueous amine blends incorporating monoethanolamine, N,N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA) and 2-amino-2-methyl-1-propanol (AMP) as solvent components. Mass transfer/kinetic measurements have been performed using a wetted wall column (WWC) contactor at 40°C for a series of blends in which the blend properties including amine concentration, blend ratio, and CO₂ loadings from 0.0-0.4 (moles CO₂/total moles amine) were systematically varied and assessed. Equilibrium CO₂ solubility in each of the blends has been estimated using a software tool developed in Matlab for the prediction of vapour liquid equilibrium using a combination of the known chemical equilibrium reactions and constants for the individual amine components which have been combined into a blend.From the CO₂ mass transfer data the largest absorption rates were observed in blends containing 3M MEA/3M Am₂ while the selection of the Am₂ component had only a marginal impact on mass transfer rates. Overall, CO₂ mass transfer in the fastest blends containing 3M MEA/3M Am₂ was found to be only slightly lower than a 5M MEA solution at similar temperatures and CO₂ loadings. In terms of equilibrium behaviour a slight decrease in the absorption capacity (moles CO₂/mole amine) with increasing Am₂ concentration in the blends with MEA was observed while cyclic capacity followed the opposite trend. Significant increases in cyclic capacity (26-111%) were observed in all blends when compared to MEA solutions at similar temperatures and total amine concentrations. In view of the reasonable compromise between CO₂ absorption rate and capacity a blend containing 3M MEA and 3M AMP as blend components would represent a reasonable alternative in replacement of 5M MEA as a standalone solvent.
- Subject
- CO₂ capture; carbon dioxide; amine; absorption; kinetics; mass transfer co-efficient
- Identifier
- http://hdl.handle.net/1959.13/1335719
- Identifier
- uon:27484
- Identifier
- ISSN:0009-2509
- Language
- eng
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