| 摘要 |
This invention relates to the refining of petroleum products, and more particularly to an integrated hydroprocessing scheme involving a hydrocracking stage and subsequent dewaxing stage. Materials boiling in the middle distillate or lube oil range may be dewaxed. The bottoms streams (and optionally, other streams) of each stage are maintained separately from one another, during processing. Dewaxing may occur using either hydroisomerization catalysts or shape-selective catalysts or both in series. One embodiment employs a baffle in the flash zone of a fractionator to separate bottoms streams from each other. Alternatively, the effluent from the hydrocracking stage may be processed separately from the effluent from the dewaxing stage. The bottoms fraction from the dewaxing stage may be recycled back to the hydrocracking stage for further processing or used as lube base stock.
|
