Abstract: To address the prominent issues of high environmental pressure, excessive energy consumption, and low hydrogen purity in the recontacting system of a 0.6 Mt/a continuous catalytic reforming unit in a refinery, a process revamping was carried out on the recontacting system: a new recontacting absorber was constructed, the original pre-cooler, chiller and ammonia refrigeration system were decommissioned, and the original recontacting drum was repurposed as a knockout drum for the exported hydrogen. The results show that after the revamping, the hydrogen volume fraction in the reformer hydrogen product increased from 92.88% to 95.49%, with significant improvement in light hydrocarbon recovery. To address the operational issues encountered after the revamping, namely difficulty in liquid level establishment in the absorber and liquid entrainment at the top of the column, comprehensive analysis and Aspen simulation of the absorber operating conditions were conducted, and the optimal number of trays for the new absorber was determined to be 20―40. Through strategies such as optimizing tray and downcomer structures, replacing with high-efficiency demisters, reducing the absorber column diameter, and adopting staged absorption, the operational problems after the revamping were effectively resolved, ensuring stable and efficient operation of the continuous catalytic reforming unit.

Key words: continuous catalytic reforming, recontacting absorber, hydrogen purity, liquid level establishment, liquid entrainment