Techno-economic analysis of biogas upgrading through amine scrubbing: A comparative study of different single amines

Abstract

Bioenergy is gaining increasing prominence globally, highlighting the significant potential of biogas energy recovery for producing biomethane and capturing CO2 within the energy sector. Amine scrubbing stands out as a promising technology for achieving this goal by minimizing methane slippage and efficiently removing acid gases like CO2 and H2S. Despite extensive research on amine-based systems, a direct comparative analysis of various amines for biogas upgrading remains unexplored. This study provides a comprehensive evaluation of the techno-economic feasibility of biogas upgrading using five different amine solvents: monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), methyldiethanolamine (MDEA), and aminomethyl propanol (AMP). Simulations were conducted using Aspen Tech software to assess the performance of each system. The results show that to achieve a 91 % biomethane mass fraction, MEA, AMP, DIPA, DEA, and MDEA require 9, 11, 12, 13, and 25 stages, respectively. Additionally, the mass fraction of CO2 output from the stripper tower varies across the amines, with MEA, DIPA, DEA, MDEA, and AMP yielding values of 0.964, 0.938, 0.939, 0.933, and 0.999, respectively. From an economic perspective, total capital costs for implementing these systems are estimated at 110.72, 80.49, 66.57, 65.61, and 64.56 MUSD for MEA, MDEA, DIPA, DEA, and AMP, respectively. Operating profits of AMP, DEA, DIPA, MDEA, and MEA systems are projected at 18.55, 17.80, 17.62, 17.60, and 17.44 MUSD/year, respectively. The novelty of this work lies in the direct comparison of five distinct amine systems, providing a robust analysis of their performance, validation, and economic viability for biogas upgrading.