Techno-economic analysis of pressurized absorption carbon capture for biogas upgrading

Résumé fourni par la source

Methyldiethanolamine/piperazine (MDEA/PZ) absorbents are widely used in biogas upgrading for simultaneous carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) removal. However, the existing studies predominantly emphasize methane (CH 4 ) purity and overlook stringent industrial impurity limits (particularly H 2 S ≤ 5 mg/Nm 3 ). Pressurized absorption is required for compliance, along with its energy and economic impacts. This study performs an energy-exergy-economic analysis of a pressurized absorption carbon capture for biogas upgrading, which is validated by the data of a demonstrated pilot plant. The objective is to minimize energy consumption and costs while strictly satisfying biomethane purity standards. Under baseline conditions, the system could achieve 97.8 mol% CH 4 purity and 99.9% recovery. The reboiler thermal duty and equivalent electricity consumption are 4.13 GJ/t CO 2 and 0.30 kWh/Nm 3 biomethane, respectively, with 97.8% exergy efficiency and a unit cost of 0.22 $/Nm 3 . Furthermore, the multi-objective optimization identifies the optimal parameters: 48 wt% MDEA with 1 wt% PZ, 4.5 bar absorption pressure, and 6.5 t/h lean solvent flow. H 2 S concentration drops to 4.64 mg/Nm 3 , with unit costs reduced to 0.19 $/Nm 3 . For high-load scenarios (50 mol% CO 2 , 1 mol% H 2 S), absorption pressure rises to 8.5 bar and PZ fraction to 5 wt% for compliance. The electricity consumption reaches 1.04 kWh/Nm 3 and the cost increases to 0.39 $/Nm 3 . This work may offer a viable technical pathway balancing compliance, energy efficiency, and economic feasibility.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.