Effect of Wax Content in Hydrocracker Unconverted Oil on Viscosity Index and Yield of Lubricant Base Oil ۱۵۰N

Hydroprocessing has become the main technology for the production of API Group II and III base oils. One of the key properties is viscosity index for Group II and III base oils. The effect of wax content in hydrocracker unconverted oil on viscosity index and yield was studied in a ۴۰۰ kton/year hydroisomerization dewaxing plant at a total pressure of ۱۵ MPa, a feed rate of ۳۸ ton/hour, and a gas to oil ratio of ۷۱۰ Nm۳(H۲)/m۳(feed). The contribution of wax hydroisomerization to the viscosity index of the main product ۱۵۰N base oil increases with the wax content in the ۱۱-۱۹% range and reaches a constant value of ۶ VI units rather than continuously rising with the wax content. The ۱۵۰N yield decreases about ۱.۳%, when the wax content increases by ۱%. This is related to a higher dewaxing temperature required at increased wax contents in order to keep the low pour point of ۱۵۰N, which results in more multi-branched compounds with a low viscosity index in the base oils and more light hydrocracking products.

Keywords:

Mineral Base Stock Refining , Hydroisomerization Dewaxing , Base Oil , Viscosity Index