Exploring Opportunities for Capacity Enhancement in Sour Gas Treatment Unit

Abstract

Methyl Di-ethanol Amine (MDEA) based Gas Sweetening Process is an established process for treatment of sour gases to meet pipeline specifications with regards to H2S contents. One of the Gas Sweeting Unit (GSU) has been designed with generic MDEA solvent to selectively remove H2S along with 32% Co-absorption of CO2. It was observed that because of higher receipt of sour gas, all GSU trains were operating with higher feed gas throughput resulting in higher H2S content in sweet gas & higher quantity of acid gas generation. A detailed study was carried out to explore the possibilities for maintaining sweet gas quality with increased sour gas throughput. Detailed simulation studies on "HYSYS" process simulator revealed, that using generic MDEA it was difficult to increase the operating capacity of the GSU while maintaining H2S content in sweet gas & acid gas quantity generation within acceptable limits. Hence opportunities for speciality amines were explored. Case studies revealed successful use of specialty amines for capacity enhancement and improved performance in the existing system. With the targeted sweet gas quality, the capacity can be enhanced up to 30% with minor modifications in the existing set up. This also resulted in significant reduction in consumption of utilities like steam, power and cooling water.