Low-Emission CO₂-Rich Natural Gas Processing Plant with Hybrid Decarbonization: Techno-Economic and Marginal Abatement Cost Analyses

Natural gas processing plants (NGPP) contribute considerably to greenhouse-gas emissions, especially when processing carbon dioxide rich (CO₂-rich) natural gas. Therefore, it is urgent and of general interest to study the decarbonization of such plants through new combined technologies and to estimate its economic–environmental performance through up-to-date metrics like the Marginal Abatement Cost (MAC). Comprehensive techno-economic and MAC analyses were conducted in the decarbonization of a NGPP through hybrid membrane permeation plus aqueous-monoethanolamine post-combustion capture. The NGPP processes 6.6 MMSm³/d of 44%mol CO₂-rich gas. Hybrid decarbonization captured 94.05% of carbon dioxide abating carbon emissions from 2.69 t to 0.11 t per ton of treated gas, while power demand, investment, and manufacturing costs increased from 31.7 MW to 69.5 MW, 177.2 MMUSD to 325.4 MMUSD, and 238.8 MMUSD/y to 327.3 MMUSD/y, respectively. Simultaneously, revenues increased from 255.82 MMUSD/y to 421.78 MMUSD/y when 100% of carbon dioxide is utilized in enhanced oil recovery (EOR), leading to a 25-year net value increase from −1097 MMUSD to +441 MMUSD. For 80% carbon dioxide to EOR, the 25-year net value surpasses the counterpart of the carbon-emitting plant by 96.56 MMUSD with the same payback time (12 years). MAC decreased from 20.9 USD/t^CO2 to −12.4 USD/t^CO2 as carbon dioxide utilization changed from 0% EOR to 100% EOR. Since better net values and MACs were obtained for hybrid decarbonization with EOR, these retrofitted alternatives are more recommendable as they effectively reduce the carbon footprint by 54.53 MMt^CO2 for 25 years of a profitable campaign.