Techno-economic and environmental process evaluation of biogas upgrading via amine scrubbing

This study presents a techno-economic and environmental analysis of biogas upgrading processes. Biogas upgrading, with the removal of acid gases (CO2, H2S) from biogas produced from municipal solid wastes, can reduce air pollutant emission and increase the heat of combustion of the final product, thus promoting biogas use as a transport fuel while mitigating landfill disposal in urban areas. Among technically feasible routes, amine scrubbing results in relatively low methane loss and a renewable methane-enriched product. In this study, diglycolamine and methyldiethanolamine with diethanolamine were considered as solvents. Simulations were carried out using Aspen Plus, in which process variables were evaluated for different process conditions, with the restriction to attend product regulatory specifications. The results indicate that the diglycolamine-based upgrading route can remove up to 99% of the carbon dioxide from the biogas, generating a biomethane product with 91% methane. Net present value (NPV) was calculated for both cases, under economically feasible conditions, considering a biomethane price of 0.38 US$/Nm(3). An environmental evaluation based on Life Cycle Assessment (LCA) estimates a reduction of ca. 95% in CO2 equivalent emissions for the upgraded biomethane. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study provides a techno-economic and environmental analysis of biogas upgrading processes, highlighting the effectiveness of diglycolamine-based upgrading route in removing carbon dioxide and producing methane-enriched biomethane. The study also evaluates the net present value under economically feasible conditions and estimates a significant reduction in CO2 equivalent emissions for the upgraded biomethane based on Life Cycle Assessment (LCA).