Rate-based process modeling technology has matured and is increasingly gaining acceptance over traditional equilibrium-stage modeling approaches. [Taylor et al. Chem. Eng. Prog. 2003, 99, 28−39] Recently comprehensive pilot plant data for carbon dioxide (CO2) capture with aqueous monoethanolamine (MEA) solution have become available from the University of Texas at Austin. The pilot plant data cover key process variables including CO2 concentration in the gas stream, CO2 loading in lean MEA solution, liquid to gas ratio, and packing type. In this study, we model the pilot plant operation with Aspen RateSep, a second generation rate-based multistage separation unit operation model in Aspen Plus. After a brief review on rate-based modeling, thermodynamic and kinetic models for CO2 absorption with the MEA solution, and transport property models, we show excellent match of the rate-based model predictions against the comprehensive pilot plant data and we validate the superiority of the rate-based models over the traditional equilibrium-stage models. We further examine the impacts of key rate-based modeling options, i.e., film discretization options and flow model options. The rate-based model provides excellent predictive capability, and it should be very useful for design and scale-up of CO2 capture processes.

No abstract

No abstract

in Wiley InterScience (www.interscience.wiley.com).Intercooling was evaluated as a process option in CO 2 absorption by piperazine (PZ) promoted potassium carbonate. The system performance with 4.5 m K þ /4.5 m PZ was simulated by a model in Aspen PlusThe absorber was evaluated for use with a double matrix stripper by optimizing the position of the semilean feed and intercooling stages to maximize CO 2 removal. Additionally, a simple absorber system was modeled to observe the effect of intercooling on systems with variable CO 2 lean loading. Intercooling increases CO 2 removal by as much as 10% with the double matrix configuration. With a simple absorber, the effectiveness of intercooling depends on solvent rate. Near a critical liquid/gas ratio (L/G) there is a large improvement with intercooling. This is related to the position of the temperature bulge. An approximation is proposed to estimate the critical L/G where intercooling may maximize removal. V V C 2009 American Institute of Chemical Engineers AIChE J, 56: [905][906][907][908][909][910][911][912][913][914] 2010