The selective removal of hydrogen sulfide (H₂S) in the presence of carbon dioxide using Methyldiethanolamine (MDEA) solutions is a significant process in the petroleum and natural gas industries. An industrial plant with an energy consumption of 3.36 GJ/mol CO₂ was simulated and validated using rigorous kinetic and equilibrium models for H₂S-CO₂-MDEA-H₂O system that are incorporated into the Amine Package in Aspen HYSYS^®. A modified Murphee-type vapor tray efficiency of 15% for CO₂ and 100% for H₂S was utilized to account for the non-ideal behavior of the stages. Sensitivity analyses were performed on circulation rate (L/G = 0.6–2 kg/kg), stripper pressure (50–220 kPa), lean amine temperature (45–65 °C), number of absorber stages (8–14), and concentration of MDEA (15–50 wt%). These process variables were evaluated with respect to percentage recovery of sour gaseous components and normalized reboiler duty. The sensitivity analyses results showed that the circulation rate and the MDEA concentration are the two main factors improving process performance. The optimized scenarios exhibited better selective H₂S absorption and higher energy savings.