Abstract: The dehydration column of furfural refining unit generally adopts single-column stripping process. Because of the low temperature and pressure at the top of the dehydration column, the heat of the gas overhead can not be recovered well by conventional technology. Based on the NRTL thermodynamic model, Aspen Plus software was used to simulate the dehydration column system, and the feasibility of adopting the thermal-coupling variable pressure swing stripping process was determined according to the change of azeotropic temperature. Comparing and analyzing the conventional steam stripping process and the thermal-coupled pressure swing steam stripping process, taking the annual total cost (CTA) as the evaluation index, and considering the reduction of the initial investment, the parameters such as the number of trays and the operating pressure of the low-pressure column and high-pressure column were optimized. The theoretical trays of the low-pressure column were recommended to be set to 4, the theoretical trays the high-pressure column were set to 8, and the operating pressure of the high-pressure column should be between 230 and 305 kPa. Compared with the conventional single-column stripping process, the total cost of equipment in the thermal coupling pressure swing stripping process is increased by 32.1%, the annual operating cost is decreased by 28.1%, and the CTA is decreased by 22.9%. The thermal coupling pressure swing stripping process has significant economic advantages.

Key words: furfural refining, variable pressure steam stripping, thermal coupling, simulation optimization, energy saving, dehydration column