Abstract: Through analyzing the properties and compositional structures of atmospheric residue (AR) at different hydrodesulfurization (HDS) depths, the influence of HDS depth on the characteristics of hydrotreated AR and the distribution of sulfur-bearing compound types was investigated. The results indicate that with increasing HDS depth, the aromaticity of hydrotreated AR decreases, while the number of alkyl substituents on aromatic rings in its molecular constituents increases. The predominant sulfur-containing compounds in hydrotreated AR are identified as S1, S2, S1O1, and N1S1-type species. As HDS depth increases, the relative abundances of these major sulfur compounds decline, and sulfur compounds are found to be more readily removed than nitrogen compounds. The most abundant sulfur compound in hydrotreated AR is S1, 90% of which resides in the >500?°C narrow distillation fraction and is primarily composed of benzothiophene- and dibenzothiophene-type structures. Coking test results reveal that with increasing HDS depth, the yields of coking gas, gasoline, diesel, and wax oil fractions from residue coking rise progressively—among which the yield of coking wax oil increases most significantly—while the yield of petroleum coke declines. Concurrently, the sulfur content proportion in coking gas and petroleum coke decreases, whereas the sulfur content proportion in liquid coking products increases.

Key words: residue hydrogenation, delayed coking, petroleum coke, sulfur-containing compound, sulfur transfer, hydrodesulfurization