Integrated adsorption and absorption process for post-combustion CO 2 capture
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RESEARCH ARTICLE
Integrated adsorption and absorption process for post-combustion CO2 capture Gongkui Xiao (✉)1, Penny Xiao2, Andrew Hoadley3, Paul Webley2 1 Department of Chemical Engineering, The University of Western Australia, Perth WA 6009, Australia 2 Department of Chemical Engineering, University of Melbourne, Victoria 3010, Australia 3 Department of Chemical Engineering, Monash University, Victoria 3800, Australia
© Higher Education Press 2020
Abstract This study explored the feasibility of integrating an adsorption and solvent scrubbing process for postcombustion CO2 capture from a coal-fired power plant. This integrated process has two stages: the first is a vacuum swing adsorption (VSA) process using activated carbon as the adsorbent, and the second stage is a solvent scrubber/ stripper system using monoethanolamine (30 wt-%) as the solvent. The results showed that the adsorption process could enrich CO2 in the flue gas from 12 to 50 mol-% with a CO2 recovery of > 90%, and the concentrated CO2 stream fed to the solvent scrubber had a significantly lower volumetric flowrate. The increased CO2 concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber, bringing the size of the absorber from uneconomically large to readily achievable domain. In addition, the VSA process could also remove most of the oxygen initially existed in the feed gas, alleviating the downstream corrosion and degradation problems in the absorption section. The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO2 capture and thus accelerate the deployment of such technologies to reduce carbon emissions. Keywords vacuum swing adsorption, monoethanolamine, post-combustion, CO2 capture, integrated process
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Introduction
Post-combustion CO2 capture (PCC) is an important Received April 10, 2020; accepted May 27, 2020 E-mail: [email protected]
approach to reducing carbon emissions from power plants, especially from low rank coal fired power stations [1,2]. Solvent scrubbing with ethanolamine based solvents, such as monoethanolamine (MEA) and methyl diethanolamine, are likely to be most ready technology for full scale CO2 capture from post combustion gases [3,4]. However, several issues associated with solvent absorption technologies such as large absorber size, corrosion of the capture plant and solvent degradation, need to be addressed to enable these technologies to be widely deployed for full scale post-combustion CO2 capture: the unusually large absorber size presents considerable technical and economic challenges for full scale coal-fired power plant PCC applications [4,5], the corrosion of the absorber (and associated piping) and degradation of the amines increase the on-going maintenance cost [6,7] and may cause health and environmental hazards [8,9]. The diameter of an absorber is mainly determined by the volume of the gas flow, and for PCC the extreme volume of gas is attributed pr
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