Simulation-Based Assessment of Catalytic CO₂ Capture and Conversion in Industrial Flue Gas Streams

The escalating concentration of atmospheric CO₂ attributable to industrial emissions necessitates the development of efficient and scalable carbon capture and utilization (CCU) technologies. This study presents a simulation-based assessment of an integrated catalytic system designed for CO₂ capture and subsequent conversion within industrial flue gas treatment processes. Using Aspen Plus as the primary process modeling environment, a two-stage system is constructed comprising a monoethanolamine (MEA)-based absorption column for CO₂ capture followed by a fixed-bed catalytic reactor for CO₂ hydrogenation to methane (Sabatier reaction) and methanol synthesis. Kinetic parameters for the catalytic conversion reactions are derived from validated literature data, with Ni/Al₂O₃ and Cu/ZnO/Al₂O₃ adopted as reference catalyst systems for methanation and methanol synthesis, respectively. Flue gas compositions representative of natural gas-fired power plants and cement industry stacks are employed as feed conditions. Key performance indicators including CO₂ capture efficiency, single-pass conversion, product selectivity, energy consumption, and heat integration potential are evaluated under varying operating temperatures (200–350^oC), pressures (1–30 bar), and H₂/CO₂ molar ratios (3–5). Sensitivity analyses are conducted to identify critical process parameters governing system efficiency. Preliminary results indicate that integrated heat recovery from the exothermic methanation reaction can offset a significant portion of the reboiler duty in the capture unit, improving the overall energy balance. This computational framework provides a scalable and resource-efficient methodology for evaluating CCU process alternatives prior to experimental validation, offering practical guidance for the design of industrial-scale green process systems.