Multiobjective Optimization of CO₂ Capture from Varied CO₂ Point Sources: An Evolutionary Algorithm Approach to Economic, Engineering, and Environmental Performance

CO2 capture involves treating and purifying carbon dioxide emitted from industrial processes for either conversion into value-added chemicals through carbon utilization or long-term storage via carbon storage─together termed Carbon Capture, Utilization, and Storage (CCUS). Different CO2 point sources exhibit varying flow rates, compositions, and thermodynamic properties. Understanding the relationship between the CO2 source characteristics and the design of the CO2 capture process is thus crucial. This study compares the engineering, economic, and environmental (3E) performance of CO2 capture from different point sources via a multiobjective optimization approach. First, process models for capturing CO2 from a bulk source (>80% CO2) and a diluted source (<5% CO2) were developed using Aspen Plus v14, employing the commercially used chemical absorption-stripping process with a piperazine–methyl diethanolamine (PZ-MDEA) solution. A multiobjective optimization model was developed in Python, leveraging the PYMOO package alongside an in-house Python-based cost library. The model simultaneously optimized three key performance indicators: CO2 capture rate, Total Annual Cost (TAC), and Negative Net Carbon Emission (NNCE), ensuring a balanced trade-off between environmental impact and economic viability. Results show that, for bulk CO2 sources, a higher CO2 capture rate is favorable as it leads to an increase in NNCE. On the other hand, for diluted CO2 sources, a higher capture rate leads to lower NNCE due to increased indirect emissions. Moreover, the capture of CO2 from the bulk source achieves a standardized NNCE six times greater and a TAC of four times lower than the diluted CO2 source. These findings emphasize the need to design specific capture strategies based on the CO2 source properties, suggesting that future research should explore various source-specific capture technologies to enhance sustainability and economic feasibility.