Abstract: The 2.6Mt/a gas oil full-liquid phase hydrogenation unit of the second phase of the CNOOC Huizhou Petrochemical Co. Ltd. project was completed and put into operation in 2017. The unit is the first gas oil hydrogenation unit adopting DuPont's full-liquid hydrogenation technology in China. During 2 years operation， the device experienced many start-ups and shutdowns, but it still showed good operation convenience and economy. After more than two years of operation, the calibration results showed that for Saudi Arabia vacuum gas oil raw materials with sulfur mass fraction greater than 2.7% and nitrogen mass fraction greater than 500 μg/g, the sulfur mass fraction and nitrogen mass fraction of hydrogenated gas oil products was less than 1 000 μg/g and 100 μg/g, respectively, which could meet the feed requirements of catalytic cracking unit. The comprehensive energy consumption was 274.63 MJ/t，lower than those in traditional trickle-bed unit and superior to the device design.

Key words: full liquid phase, VGO, hydrotreating, IsoTherming, circulating oil pump, comprehensive energy consumption