Optimization analysis of the absorption-stabilization process for fluid catalytic cracking unit

The absorption-stabilization process (ASP), an important part of petroleum refinery used in the end-use products of petroleum (such as stable gasoline, liquid petroleum gas, and dry gas), is energy-intensive and has low product quality. Aspen Plus process simulator was used for the development of the ASP process model. The developed process model was validated with the actual plant data. The validated model was used to optimize to minimize the cost of the ASP. This work shows that the optimization analysis of the ASP can further improve the product quality and reduce thermal energy consumption. In the new process, changing feeding parameters of supplementary absorption oil, stripping tower intermediate reboiler, and feeding position of stabilization tower reduced the C₃ contents of dry gas considerably and lowered the C₂ and lighter contents of LPG. Additionally, the new process saved 1.32 MW of thermal energy consumption compared with the existing process. The operating cost has been reduced from 10.921 million USD annually to 9.830 million USD per year. Furthermore, the cost-saving effect of this optimization is about 9.99% (1.091 million USD per year).