SEPARATION OF H2S AND CO2 WITH IONIC LIQUIDS ON LOW RATIO OF H2S/CO2

• Main Author: Imanuela, Patricia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48241
• Institution: Institut Teknologi Bandung

In the production of oil and natural gas, along with hydrocarbons, there are numerous impurities including CO2 and H2S that are co-produced. The removal of H2S and CO2 needs to be done in Acid Gas Removal Unit (AGRU) before further processing. H2S removed in the AGRU process is sent to the Sulfur Recovery Unit (SRU) as acid gas to convert H2S to valuable elemental sulfur and to minimize the amount of sulfur compounds released to the atmosphere. Natural gas in Indonesia’s gas wells contains about 0-4%-v/v of H2S and 20-70%-v/v of CO2. The CO2 content in Indonesia is much higher than the average content of CO2 globally, which is at 0-8%-v/v. The high content of CO2 leads to a lower ratio of H2S/CO2 which resulted in the need of a very selective solvent in the sulphur recovery process. One of the promising solvent that can achieve this separation is ionic liquid or Room Temperature Ionic Liquids (RTIL). RTIL or salts that melt below 100°C have unique characteristics that are caused by the interaction between the anion and cation contained. The interaction between H2S and RTIL is expected to be strong which makes the gas absorption is easier. The main purpose of this experimental research is to analyze the selective absorption performance of H2S with CO2 using [BMIM][Br] as the ionic liquids. The solubility of gas in [BMIM][Br] is measured using the gravimetry analysis that will resulted in the value of H2S/CO2 selectivity. The experimental work procedure in this study is divided into two main parts, which are the synthesis of ionic liquids and gas absorption using ionic liquids. The reaction of bromobutane and methyl imidazolium is done in a triple neck flask to obtain ionic liquids, later on it will be characterized by using NMR spectrometer. Gas absorption will be carried out by flowing each 6 mL/min of H2S (1%-v) and CO2 (100%-v) into vials that contain 5 mL of [BMIM][Br] at room pressure and temperature. The results show that when water is added to [BMIM][Br], the absorption ability of the solvent will be degraded. Pure [BMIM][Br] has higher H2S/CO2 selectivity than MDEA solvent, which is 2,417 for [BMIM][Br] and 0,038 for MDEA. Lastly, the mixture of [BMIM][Br] and MDEA with weight ratio of 1:3 has the highest H2S/CO2 selectivity among all the solvents, which is 6,222.