Abstract: Aiming at the problem that the catalyst activity of a company's liquid-phase diesel hydrogenation unit is difficult to meetthe long-term operation goal of "third-year maintenance", this paper analyzes the feasibility of changing coking diesel oil to aresidue hydrogenation unit. After it is hydrorefined in the residue hydrogenation unit and fractionated, the diesel oil is sent back tothe liquid-phase diesel hydrogenation unit for further ultra-deep desulfurization, and the feasibility of producing diesel productsthat meet the national VI emission standards. The operation of the residue hydrogenation unit after blending coking diesel oil hasbeen tracked and monitored for a long time. After more than two years of operation practice, it shows that the practice of the cokingdiesel residue hydrogenation unit is successful. It effectively alleviates the problem of long-term operation of the company'scontinuous liquid-phase diesel hydrogenation unit, which can ensure that the device achieves the goal of a four-year majoroverhaul. At the same time, it also solves Due to the long cycle of the diesel hydrogenation device, part of the coking diesel fuelenters the wax oil hydrogenation device, resulting in the economic loss caused by the forced takeaway of part of the catalytic dieselfuel, and the effect is obvious.