Technoeconomic feasibility of integrating carbon capture technology with primary aluminum production using an advanced cogeneration waste heat recovery system

Integrating carbon capture with primary aluminum production remains challenging due to high energy demands and low CO₂ concentrations. Here, this study proposes an innovative system incorporating carbon capture technology into primary aluminum production through an advanced Cogeneration Waste Heat Recovery (CGWHR) system. The process is simulated in ASPEN Plus, including key subsystems such the Parallel Two-Stage Organic Rankine Cycle (PTORC) and Waste Heat Steam Generator (WHSG) for waste heat recovery, Wet Flue Gas Desulfurization (WFGD) for SO₂ removal, and Monoethanolamine Carbon Capture System (MEA-CCS) for CO₂ capture. Key performance indicators evaluate energy, economic, and environmental efficacy. The CGWHR system recovers 31% of sidewall heat, producing 10.86 t/h of steam and decreasing the demand for carbon capture steam. The optimal working fluids for PTORC balance efficiency and cost, with R1233zd achieving the highest efficiency and R601 offering the best trade-off between energy performance and cost. The WFGD system attains complete SO₂ removal with a gypsum purity of 96.8%, whereas the MEA-CCS system realizes a 90% CO₂ capture efficiency with an optimized solvent regeneration requirement of 5.00 MJ/kg CO₂. The CGWHR-CCS configuration achieves the lowest specific primary energy consumption for CO₂ avoidance (1.87 MJ/kg CO₂) and reduces carbon capture costs to 54.94 $/ton CO₂, surpassing competing scenarios. The results indicate that the CGWHR-CCS system has the capacity to improve sustainability in aluminum production by substantially decreasing energy penalties, emissions, and costs. Future research should examine absorbent qualities and evaluate the system's dynamic performance under varied industrial conditions.