Using the 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 entrainer is recovered in the distillation column. The concern is the high energy consumption of this process, particularly the distillation column. In this study, a novel method for heat integration of the distillation column of the gas sweetening unit of the Ilam Gas Refinery was used, 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. Preheating the bottom section of feed decreased the reboiler and condenser duties. The results demonstrate that the proposed method decreases the energy consumption by 17%.