Feasibility Study, Simulation, and Economic Evaluation of Gas Sweetening Process Using MEA/DEA-Methanol Solvent on Refinery Plant of PT Kilang Pertamina Internasional

This study evaluates the effectiveness of using a hybrid solvent, a mixture of Monoethanolamine (MEA) or Dioethanolamine (DEA) with Methanol in the gas sweetening process to remove sour gas content (H 2 S and CO 2 ), but still aiming to meet the sweet gas standards set by PT Kilang Pertamina Internasional–Unit VI Balongan in Indonesia which is H 2 S < 5 ppmv and CO 2 < 5 %vol or < 50,000 ppmv. The research explores the replacement of existing solvent Diisopropanolamine (DIPA) with MEA/DEA-Methanol in water, with concentrations ranging from 1 to 21 wt%, and compared with the use of only MEA, DEA, or Methanol. Additionally, it examines the impact of absorber pressure on the effectiveness of these variations. Using Aspen Hysys V11 with the Acid gas – Chemical Solvent as the fluid Package, the simulation study finds that a 15% MEA-Methanol mixture is the best solvent with 442.6 kPa (at absorber unit HTU) and 1,345 kPa (at absorber unit RCC) as the optimal pressure that can reduce overall costs up to 8.45% per year compared to using existing solvent DIPA, whereas DEA-Methanol that only saved 3.07% per year, while still maintaining H 2 S and CO 2 levels below the desired limits. However, optimal removal using MEA-Methanol solvent is only achieved up to five times the initial sour gas feed for the HTU absorber unit and four times for the RCC absorber unit, with pressures around 342.6 kPa and 1245 kPa for the HTU absorber unit and the RCC absorber unit, respectively.