using the modified feed splitting technique in optimizing the energy for the natural gas sweetening unit of the ilam gas refinery

The sweetening unit of the ilam gas refinery plays a major role in providing olefin feed, and at the present time, the provinces of ilam, kermanshah, hamedan, kurdistan, and lorestan in iran are the consumers of the gas produced by this refinery. the gas sweetening unit of the ilam gas refinery has an absorption and distillation column. h2s and co2 are removed by diethanolamine in the absorption column, and the solvent used is also recovered in the distillation column. the concern is the high energy consumption of this process, particularly the distillation column. in this paper, a novel technique was used for heat integration of the distillation column of the gas sweetening unit of the ilam gas refinery, so that the feed entering the distillation column was splitted into two sections prior to feeding. afterwards, the bottom section was preheated by the bottom product of column and the top section was precooled by the distillate product of column. preheating the bottom section of feed reduced the heat duty of reboiler and precooling the top section of feed reduced the heat duty of condenser. the results demonstrate that the proposed method decreases the energy consumption by 18%.