Optimizing CO2 capture from biogas: a comparative study of amine-based solvents through Aspen Plus simulations

Abstract Biogas is a sustainable energy source with ecological, economic, and societal advantages. Composed mainly of CH 4 and CO 2 , it offers a cleaner alternative to fossil fuels, emphasizing the importance of decarbonization. Chemical absorption effectively captures CO 2 , and process simulations assess separation performance before industrial use. This research aims to explore the potential of three amine-based solvents—AMP, DEA, and MDEA—for CO 2 capture from biogas via Aspen Plus simulations to assess absorption/stripping columns. An improved rate-based model enhances the accuracy of mass and heat transfer simulations, with electrolyte NRTL models used for thermodynamic analysis. The study considers two distinct biogas compositions: biogas 1, which comprises 50% CH 4 , 32.2% CO 2 , 10% N 2 , and 7.8% H 2 O, and biogas 2, which consists of 50% CH 4 , 25% CO 2 , 5% N 2 , 7.8% H 2 O, 5% H 2 , and 7.2% H 2 S. Simulations are conducted to analyze the effects of biogas composition, solvent choice, and thermodynamic models on performance indicators such as the percentage of CO 2 captured and the removal efficiencies of both CO 2 and H 2 S within the absorber. The simulation results indicate that DEA has the highest CO 2 capture effectiveness among solvents for both biogas compositions, followed by AMP, with MDEA showing the lowest. DEA achieves optimal results when the ENRTL-RK model is used. For biogas 1, DEA results in the highest CO 2 removal efficiency, whereas for biogas 2, AMP results in the best H 2 S removal efficacy. The amine-based CO 2 capture simulation suggests viability but highlights the need for further analysis of environmental impacts and costs for sustainability.