Optimization and Exergy Analysis of Natural Gas Liquid Recovery Processes for the Maximization of Plant Profits

Maximizing the profits of natural gas liquid recovery plants is a challenge. To improve the performance of an existing plant, three process schemes were compared and analyzed with Aspen HYSYS. A high-pressure absorber (HPA) performed better owing to the added compressor and more reasonable cold energy utilization. The HPA was further optimized by establishing an objective function and identifying and adjusting the main variables on the basis of a new optimization algorithm. The propane recovery of the optimized HPA was 98.8 %, and the plant profitability increased by 3352 million $ a(-1). Exergy analysis of the optimum process indicated that the column and air cooler contributed the most to the total exergy destruction. Suggestions for decreasing the exergy destruction of the process are also given.