SELECTIVE ABSORPTION OF H2S USING KOH AS A SOLVENT

• Main Author: Daffa Yezaldy, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/55638
• Institution: Institut Teknologi Bandung

Natural gas is the third primary energy resources that’s still developed to this day in Indonesia. Natural gas that’s received from the separation of natural gas and oil still contains impurities, such as CO2 and H2S otherwise called acid gas. The acid gas needs to be removed in the AGRU before being processed further. After the acid gas has been separated from the natural gas, it can’t be released directly to the environment, due to the regulation regarding the sulphur content requirement according to Regulation of the State Minister for the Environment No. 13 Tahun 2009. Thus, further research regarding the H2S separation from acid gas in AGEU unit is needed. There are a few methods that can be used in AGEU, one of those methods is selective H2S absorption in KOH solvent. This research was conducted to evaluate the effect of adding a buffer to increase the selectivity of H2S absorption with KOH and its comparison to the NaOH system. Experiments were carried out with ASPEN PLUS V10 with rate based method under ambient pressure and temperature condition. The simulated L/G range is 0.001-0.03. Inlet gas composition is similar with natural gas industry data (66.67% -mol CO2; 0.03% -mol H2S; 33.3% -mol CH4). KOH concentration variations are in the range of 1% - 5%-mass. Bicarbonate buffers are added in the range 0:1 - 3:1 to KOH and carbonate buffers are added in a fixed ratio of 1.38:1 to bicarbonate. This study shows that the addition of a buffer has no effect on increasing the selectivity of H2S in KOH solvent. Buffer actually acts as a solvent that actively absorbs H2S at small L/G (0.001), but there will be a significant effect when L/G is quite large (0.3). The performance of KOH compared to NaOH is indistinguishable (maximum efficiency of KOH: NaOH; 91.29%: 90.72%). NaHCO3 solvent was able to achieve a very high selectivity (156.3), whereas in KHCO3 solvent, CO2 was not absorbed at all. However, bicarbonate solvents require a much larger amount of caustic solvent (approximately 25:1), so the use of NaOH-based solvents is still more economical in terms of solvent requirements.