Advancements in Acid Gas Removal: A Novel Approach Using Minisorb, Custom-built Laboratory Simulators for Enhanced Efficiency and Cost Savings In Natural Gas Processing

Abstract Amine solvent Methyldiethanolamine (MDEA) absorption method remains the most effective approach for removing acid gases: Hydrogen Sulfide (H2S) and Carbon Dioxide (CO2) from sour natural gas. Unfortunately, due to the process relying on chemical reactions, operational parameters become crucial for maintaining its effectiveness. Inaccuracies in these parameters and dynamic changes in chemical and process fluids can disrupt the process, leading to off-specification sales gas and ultimately revenue loss. Donggi Matindok Field produces gas from a carbonate reservoir with a high content of CO2 impurities. Despite optimizing parameters from the plant's base design to accommodate dynamic changes caused by various factors during the carbon dioxide absorption process at the Acid Gas Removal Unit (AGRU), Donggi Matindok still experienced off-specification sales gas due to CO2 levels exceeding acceptable limits. To address this issue, the authors have developed "MiniSorb," a custom-built laboratory tool for simulating the actual acid gas absorption process in AGRU. By replicating the real-time absorption process of amine solvent with the actual feed gas in a lab-scale ratio, the authors could analyze the current state of the absorption process and assess the effectiveness of the operating parameters in removing CO2 from the gas. Through iterations and adjustments, the optimal parameters for amine strength and temperature were determined to generate the most effective absorption reaction, subsequently implementing these findings in the actual plant process. As a result of implementing this method, Pertamina EP Cepu achieved a cost saving of USD 236k annually by avoiding off-specification sales gas and reducing fresh amine solvent usage. This publication introduces a cost-effective, low-risk, and real-time tool for analyzing the effectiveness of acid gas absorption in the process. It also highlights its success in eliminating potential losses in gas sales due to CO2 off-specification in Donggi Matindok Field. The authors hope that this invention can be replicated for other gas processing plants facing similar conditions and problems.