Hydrocracking of Vacuum Residual Oil (Part 1) Thermal Cracking Character of Vacuum Residual Oil under the Influence of High Hydrogen Pressure

摘要

Thermal cracking of Arabian heavy vacuum residue was investigated under influence of a hydrogen pressure of 8 MPa (cold charge), in the temperature range of 410 to 450 deg C, using a micro-autoclave of 140 m/ inner volume. The yield of distillate fraction (C_5-560 deg C, VD) increased with reaction time in 410 and 430 deg C reactions, the increase being quite small after 4 h of reaction time. A maxiumu yield of VD was obtained at 2 h of reaction time in the reactions of 450 deg C attributed to the secondary cracking of VD to gaseous hydrocarbons. Sulfur atoms in HS were transfered into the asphaltene and tetrahydrofuran insoluble fraction (THFI) and the distillates, 20 to 45% of the sulfur atoms in the feed oil was removed as H_2S and nitrogen atoms in HS preferably transfered to asphaltene and THFI. Ninety six percent of HS in the feed oil was cracked in the reaction of 450 deg C, 7 h.The nitrogen content and H/C ratio of the remaining HS was about 4 times and 1/2 of the original value, respectively.