Use of high pressure to improve product quality and increase cycle length in catalytic lube dewaxing.

摘要

A process for preparing high quality lube base stock oil from waxy crude oil is provided which comprises separating from the waxy crude a distillate fraction thereof having an initial boiling point of at least 232 DEG C (450 DEG F) and a final boiling point labs than 566 DEG C (1050 DEG F), extracting the distillate fraction with a solvent selective for aromatic hydrocarbons to yield a raffinate from which undesirable compounds have been removed, catalytically dewaxing the raffinate in the presence of hydrogen to a pour point not higher than -1 DEG C (+30 DEG F) by contacting the raffinate at a temperature of 260 DEG C to 385 DEG C (500 DEG to 725 DEG F) at a hydrogen partial pressure of above 10350 kPa (1500 psia) in the absence of hydrotreating catalyst with a dewaxing catalyst comprising an aluminosilicate zeolite having a silica/alumina ratio above 12 and a constraint index of from 1 to 12 thereby forming dewaxed raffinate and lower boiling hydrocarbons, and topping the raffinate subsequent to dewaxing to remove therefrom the lower boiling hydrocarbons; thereby directly recovering substantially all of the remainder of the dewaxed raffinate, the remainder having a pour point not higher than -1 DEG C (+30 DEG F).