Evaluating the Energy Performance of a Hybrid Membrane-Solvent Process for Flue Gas Carbon Dioxide Capture

• Published in: Industrial & engineering chemistry research Vol. 55; no. 43; pp. 11329 - 11337
• Main Authors: Kusuma, Victor A, Li, Zhiwei, Hopkinson, David, Luebke, David R, Chen, Shiaoguo
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.11.2016; American Chemical Society (ACS)
• Subjects: amine solvent; CO2 absorption; ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ENVIRONMENTAL SCIENCES; gas pressurized stripping; membrane
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.6b01656

A particularly energy intensive step in the conventional amine absorption process to remove carbon dioxide is solvent regeneration using a steam stripping column. An attractive alternative to reduce the energy requirement is gas pressurized stripping, in which a high pressure noncondensable gas is used to strip CO2 off the rich solvent stream. The gas pressurized stripping column product, having CO2 at high concentration and high partial pressure, can then be regenerated readily using membrane separation. In this study, we performed an energetic analysis in the form of total equivalent work and found that, for capturing CO2 from flue gas, this hybrid stripping process consumes 49% less energy compared to the base case conventional MEA absorption/steam stripping process. We also found the amount of membrane required in this process is much less than required for direct CO2 capture from the flue gas: approximately 100-fold less than a previously published two-stage cross-flow scheme, mostly due to the more favorable pressure ratio and CO2 concentration. There does exist a trade-off between energy consumption and required membrane area that is most strongly affected by the gas pressurized stripper operating pressure. While initial analysis looks promising from both an energy requirement and membrane unit capital cost, the viability of this hybrid process depends on the availability of advanced, next generation gas separation membranes to perform the stripping gas regeneration.