An improved open-access steady state model for flue gas CO2 capture with monoethanolamine

The U.S. Department of Energy’s Carbon Capture Simulation Initiative (CCSI) developed a “gold-standard” steady state CO2 capture process model in 2018 for aqueous monoethanolamine (MEA) solvent. The CCSI model is publicly available and has been widely used for CO2 capture studies. However, there are underreported issues with the model which impair its accuracy for some conditions. Here, we show how these limitations affect the accuracy of model predictions compared to large-scale pilot data and present results from an improved MEA-CO2 capture model which utilises a new combination of mass transfer and thermodynamic/chemistry models. The new process model more closely predicts CO2 capture rate across the wide range of process conditions and equipment scale investigated in this study. The root mean square deviation between predicted capture rate and measured data is reduced to 2.1 pp (percentage points) versus 5.3 pp using the CCSI model for 23 test cases from 3 different facilities. The accuracy improvements are particularly substantial (up to 8 pp) for emission sources with low CO2 concentration, such as combined cycle gas turbines, and for absorber designs where mass transfer is not constrained by equilibrium. The Aspen Plus source file for the new process model is provided for other researchers to use and build upon.