Patent ID: 6287454
Filing Date: 2001-09-11
Classification: C10G

Abstract:
A process for making a lubricant oil of low pour point and improved oxidation stability, employing a hydrocarbon feedstock which boils in the lube range, containing aromatic compounds, sulfur-containing compounds and nitrogen-containing compounds, the method comprising the following steps:(a) passing the hydrocarbon feedstock to a solvent extraction zone for the improvement of viscosity index, wherein a solvent is used to extract a portion of the aromatic compounds contained in the hydrocarbon feedstock, thereby forming an extraction zone raffinate;(b) passing the extraction zone raffinate to a catalytic dewaxing zone wherein hydrogen is contacted with extraction zone raffinate at catalytic dewaxing conditions at a dewaxing temperature between 500.degree. F. and 700.degree. F. in the presence of a first catalyst composition comprising an intermediate pore size zeolite, and which does not contain a metal hydrogen component, in the hydrogen or decationized form, to form a catalytically dewaxed product, the dewaxing being carried out in a dewaxing cycle in which the dewaxing temperature is progressively increased to maintain a substantially constant product target pour point;(c) passing the catalytically dewaxed product to a hydrotreating zone wherein the catalytically dewaxed product is hydrotreated under hydrotreating conditions, at hydrotreating temperatures in the range from about 400.degree. to 600.degree. F. in the presence of a second catalyst compositions comprising a Group VIII metal hydrogenation component selected from the group consisting of Co, Ni, Pd, and Pt and a non-acidic material which is amorphous or crystalline oxide, which is selected from the group consisting of alumina, silica, and silica-alumina; and(d) at the end of the dewaxing cycle, reactivating the catalyst by contact with hydrogen at elevated temperature, after which the catalyst is subjected to a dewaxing cycle which is of a duration at least equal to that of the previous dewaxing cycle.