| 摘要 |
PROCESS FOR PRODUCING A PRODUCT HYDROCARBON HAVING A REDUCED CONTENT OF NORMAL PARAFFINS A waxy hydrocarbon feedstock is converted into a product hydrocarbon of reduced normal paraffin content by either dewaxing or hydrodewaxing the feedstock in the presence a dewaxing or hydrodewaxing catalyst under conditions such that the normal paraffin content of the feedstock is reduced by selectively converting waxy paraffins into lower molecular weight hydrocarbons. At least a portion of the effluent from the dewaxing or hydrodewaxing zone is then passed to a hydrocracking zone where it is contacted with a hydrocracking catalyst in the presence of hydrogen under conditions such that a further reduction in the normal paraffin content is effected. When the desired product is a lube oil base stock, the overall conversion of components in the feed boiling above about 650.degree. F. to components boiling at or below about 650.degree. F. that takes place in the dewaxing or hydrodewaxing step and the hydrocracking step combined is no more than about 20 volume percent, preferably no more than about 10 volume percent. When the desired product is a middle distillate, the overall conversion of feedstock constituents in the dewaxing or hydrodewaxing step and the hydrocracking step combined to components boiling below about 300.degree. F. is no more than about 25 volume percent, preferably no more than about 15 volume percent. |
