Exergy-based analysis is a useful method to analyze, evaluate and improve refining processes.
Advanced exergy analysis can identify the improvement potential of each component and the interaction among the different components in the whole system. The analysis is made here to evaluate the performance of the conventional and new gasoline absorption-stabilization processes.
Gasoline absorption-stabilization processes (GASPs) are core parts of crude oil refining and are widely applied. A new GASP is proposed for better energy utilization considering the absorption process intensification. The new process is proposed to reduce the repeated cooling and heating which results in the exergy destruction.
A novel and energy-saving flowsheet is proposed in which a side draw stream in the absorber is mixed with rich gas and stripper gas. The side draw stream is cooled into the flash tank, and the bottom stream flows into the stabilizer directly. Advanced exergy analysis is performed for the conventional and new GASPs, including their exergy efficiency, the total exergy destruction.
It is identified that the air cooler for rich gas has the largest potential for reducing exergy destruction in the both processes. Furthermore, sensitivity analysis of the new gasoline absorption-stabilization process is performed to study the effects of key operation and design parameters on the exergy destruction of the absorber.