Abstract: To address the problem of high-sulfur petroleum coke in domestic refining and chemical enterprises, SINOPEC Research Institute of Petroleum Processing Co., Ltd. has developed the S-COKE technology, which is a combined process of residue hydrotreating and delayed coking. This technology utilizes inferior high-sulfur, high-vanadium residue as feedstock, aiming to produce low-sulfur, low-vanadium petroleum coke with a sulfur mass fraction of less than 3.0% and a vanadium mass fraction of less than 300 μg/g at low cost, while increasing the yield of liquid products. Fundamental research shows that by moderately increasing the reaction temperature and significantly raising the volume space velocity, hydrogen consumption can be reduced at the same desulfurization rate; the type and proportion of diluent oil have a significant effect on demetallization performance. This technology achieved its first commercial application in China on a 2.60 Mt/a residue hydrotreating unit and its supporting delayed coking unit at a company. The results show that the actual feedstock processed in the unit had a metal (nickel+vanadium) mass fraction as high as about 200 μg/g. By optimizing the catalyst grading (increasing the proportion of demetallization catalyst) and the reaction temperature operation mode (raising temperature in the front reactors and controlling temperature in the rear reactors), the hydrogen consumption in the second cycle was significantly reduced, and the operating cycle was extended to about one year. After the delayed coking unit processed only the hydrotreated residue, the sulfur mass fraction of the petroleum coke dropped to 1.84% and the vanadium mass fraction to 250 μg/g, meeting the low-sulfur, low-vanadium standard; the yield of liquid products increased by 13.04 percentage points, while the coke yield decreased by 11.43 percentage points.

Key words: residue hydrotreating, delayed coking, petroleum coke, sulfur, vanadium