| 摘要 |
A method and apparatus for hydrocracking an oil feedstock to produce a light oil stream without build-up of heavy polynuclear aromatic (HPNA) hydrocarbons in the recycle stream is provided. The method includes the steps of (1) hydrocracking the oil feedstock with a hydrotreating catalyst in a first reactor to produce an effluent stream; (2) fractionating the effluent stream into first, second and third product streams, wherein the first product stream includes C1-C4, naphtha and diesel boiling in the range of 36-370 °C, the second product stream includes hydrocarbon components with an initial nominal boiling point of 370 °C and a final boiling point ranging from 420-480 °C, and the third product stream that includes HPNA hydrocarbons and other hydrocarbons boiling above about 4200C to about 4800C, depending upon the final boiling point of the second product stream; (3) cracking the second product stream in a second reactor; and (4) cracking the third product stream in a third reactor at a higher operational pressure than the second reactor. |
