The acetylene hydrogenation reactor in the 220 kt/a ethylene plant of PetroChina Dushanzi Petrochemical Company has two parallel reaction beds and adopts the mode of "one in operation and one standby". The R-401A/B reactor continued to use the catalyst A from the original manufacturer, and the operation cycle was less than 10 months, failing to meet the 12 months required. After replacing the catalysts in R-401C/D with new catalysts, it was found that the green oil production increased significantly during operation, and the initial operation cycle was only 3 months, failing to meet the 6 months required. The short operation cycle of the reactor affects the ethylene increment. Also, when the reactor is switched at the end of operation, the materials need to be discharged to the flare system, resulting in material loss. Therefore, long operation cycle of reactor is significant for improving the quality and efficiency of the unit and reducing energy consumption.