Integrated process energy optimization and heat recovery analysis of amine-based CO₂ removal from natural gas streams using aspen HYSYS simulation

The high thermal energy requirement associated with solvent regeneration remains one of the greatest obstacles to improving the efficiency and economic viability of amine-based carbon dioxide (CO₂) removal in natural gas processing facilities. Although chemical absorption using aqueous alkanolamines is the dominant industrial technology for natural gas sweetening, opportunities for systematic process energy optimization and integrated heat recovery remain insufficiently explored, particularly under operating conditions representative of emerging hydrocarbon-producing regions. This study presents a comprehensive process simulation and energy optimization analysis of amine-based CO₂ removal systems using Aspen HYSYS under conditions representative of Niger Delta natural gas streams. A steady-state absorber–stripper process model was developed employing the Electrolyte Non-Random Two-Liquid (e-NRTL) thermodynamic framework to evaluate the performance of monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA) solvents. Process performance was assessed using key thermal and operational indicators, including reboiler duty, condenser duty, lean–rich heat exchanger effectiveness, specific regeneration energy, and overall process energy efficiency. Parametric sensitivity analyses were performed by varying absorber operating pressure, temperature, solvent circulation rate, and feed CO₂ concentration to identify their influence on energy demand and CO₂ removal performance. Advanced heat integration strategies, incorporating optimized lean–rich heat exchange and thermal energy recovery, were subsequently evaluated to minimize regeneration energy consumption. The simulation results demonstrated that regeneration energy requirements followed the sequence MEA > DEA > MDEA, reflecting differences in solvent reaction mechanisms and thermodynamic behavior. Implementation of optimized heat recovery reduced total process energy consumption by approximately 25–35%, with MDEA exhibiting the greatest improvement in thermal efficiency owing to its lower regeneration energy requirement and superior heat recovery potential. Sensitivity analysis further identified absorber temperature and solvent circulation rate as the dominant operational variables governing energy consumption, while optimized heat integration substantially enhanced thermal utilization throughout the process. Nevertheless, the analysis revealed inherent trade-offs between maximizing CO₂ removal efficiency and minimizing energy demand, highlighting the importance of multi-objective process optimization. Overall, the study demonstrates that strategic integration of process optimization with advanced heat recovery can significantly reduce the energy penalty associated with industrial amine-based CO₂ removal. These findings provide practical design guidance for improving thermal efficiency, reducing operating costs, and supporting more sustainable natural gas processing operations in carbon-constrained energy systems.Carbon Dioxide Removal; Amine Absorption; Process Energy Optimization; Heat Integration; Solvent Regeneration; Aspen HYSYS Simulation; Natural Gas Processing; Thermal Energy Recovery