Abstract: Using the unit that produces pentane foaming agent from light naphtha and produces liquefied petroleum gas (LPG) as a byproduct as the research object, the conventional double column (DC) process, upper dividing wall column (DWC-U) process, middle dividing wall column (DWC-M) process, and feed preheated middle dividing wall column (FP-DWC-M) process were designed. Using total annual cost (TAC), CO₂ emissions (E_CO2), and thermodynamic efficiency (η) as objectives, the second-generation non-dominated sorting genetic algorithm (NSGA-II) was employed for multi-objective optimization of process parameters to obtain Pareto front solutions. The results indicate that the application of DWC and feed preheating can improve economic and environmental benefits and reduce component remixing within the distillation column. The FP-DWC-M process offers the best economic and environmental benefits, with TAC and E_CO2 reductions by 14.3% and 23.8%, respectively, compared to the DC process.

Key words: pentane foaming agent, dividing wall column, distillation, multi-objective optimization, energy saving