| 摘要 |
This invention utilizes a novel method and set of operating conditions to efficiently and economically process a potentially very fouling hydrocarbon feedstock. A multi-stage catalytic process for the upgrading of coal pyrolysis oils is developed. Coal Pyrolysis Oils are highly aromatic, olefinic, unstable, contain objectionable sulfur, nitrogen, and oxygen contaminants, and may contain coal solids which will plug fixed-bed reactors. The pyrolysis oil is fed with hydrogen to a multi-stage ebullated-bed hydrotreater and hydrocracker containing a hydrogenation or hydrocracking catalyst to first stabilize the feed at low temperature and is then fed to downstream reactor(s) at higher temperatures to further treat and hydrocrack the pyrolysis oils to a more valuable syncrude or to finished distillate products. The relatively high heat of reaction is used to provide the energy necessary to increase the temperature of the subsequent stage thus eliminating the need for additional external heat input. A refined heavy oil product stream is recycled to the fresh feed to minimize feedstock fouling of heat exchangers and feed heaters. |
