Biogas upgrading through blends of deep eutectic solvents and monoethanol amine: 4 E analysis (energy, exergy, environmental, and economic)

Abstract

Blends of monoethanol amine (MEA) with an aqueous deep eutectic solvent (DES), with MEA present in various proportions of 5, 10, and 15 wt%, are used in process design for biogas upgrading. To the best of our knowledge, this is the first study that presents process analysis based on 4 major performance indicators, namely energy, exergy, environmental, and economic analysis, for biogas upgrading using a hybrid solvent. The process is modeled in Aspen Plus V10 commercial software. MEA and DES based configurations were considered as the base cases for the sake of performance comparison with the proposed configurations. Process evaluation determined that the addition of MEA to ChCl/urea not only reduces the amount of DES (≥40%), but also improves the functionality of MEA itself together with overall solvent characteristics. As a result, the reduction in energy consumption in each proposed case is ≥72% compared to the MEA-based base case. While the process efficiency in terms of exergy destruction is the highest in the 15 wt% MEA case, the 5 wt% MEA case exhibits more potential in terms of environmental aspects. However, the economic factor is in favor of the 10 wt% MEA case with TAC savings of up to 27.8%. The overall process evaluation based on performance indicators revealed that the choice of hybrid solvent improves the efficiency of the process and the hybrid solvent has the potential to replace conventional solvents.