Abstract: Simulations of absorption-stabilization systems were conducted to study the methods for decreasing the content of C3 and C4 in dry gas. Taking a typical absorption-stabilization system of a domestic delayed coking unit as case study, the simulation strategies including the selection of unit model, the determination of thermodynamic methods and etc. were discussed. The main factors affecting the separation effect were analyzed and finally, an operation scheme to improve the separation efficiency of absorption-stabilization process was proposed. Results showed that RKS equation is a suitable thermodynamic model for absorption-stabilization system, its simulation results are in good agreement with the data from commercial performance test. With the increase of inlet feed temperature of desorption tower, and decreasing the flow rate of absorbent for stabilized gasoline, the energy consumption of the system could be reduced, yet the absorption effect might be reduced as well. Attention should be paid to the bottom temperature of the desorption tower since it might effect the compositions and flow rate of LPG, as well as the C3 and C4 content in dry gas. There is an idea LPG reflux ratio for stabilizer, in order to obtain improved absorption effect the operating reflux ratio should be less than the idea value.

Key words: absorption, stabilization, process simulation, delayed coking, catalytic cracking