This work aims at studying acid gas removal from natural gas with piperazine (PZ) amine by using Aspen HYSYS V9.0. Design of acid gas removal process is explained using sensitivity analysis. Plant capacity enhancement studies are performed by considering the crucial parameters like sour gas feed rate, amine recirculation rate and regenerator reboiler duty etc. The optimum feed temperature is iden-tified as 31°C. Optimum concentration and flow rate of amine is 30 wt% and 350 m3/hr respectively. Rigorous hydraulic studies are performed for absorber to know the operational issues like flooding and weeping in the column. Arranging the packing in the absorber solved the operational issues and improved the CO2 and H2S removal efficiencies by 58% and 20% respectively. By arranging packing revenue losses are minimized by 2.1%. The techno-economic analysis results of this study are useful for process engineers working in gas plants to take reasonable decisions in operating the gas plant. © Slovnaft VURUP a.s.