Upgrading waxy distillates and raffinates by the process of hydrotreating and hydroisomerization

摘要

Waxy distillates, or raffinates containing from as little as 10% wax but more typically about 30% wax or more are upgraded by a process comprising the steps of hydrotreating the waxy oil under conditions which convert less than 20% of the feed into products boiling lower than the feed to reduce the sulfur and nitrogen content of the oil followed by hydroisomerizing the hydrotreated waxy oil to reduce the wax content and increase the viscosity index. This oil having a waxy content of less than 30%, preferably less than 25%, can now be more easily dewaxed using conventional solvent dewaxing procedures. The advantage of the present process resides in the increased yield and/or stability of oil as compared to other upgrading, dewaxing processes which convert wax to light products. The isomerization catalyst is preferably a low fluorine content catalyst, more preferably a noble metal on 0.1 to less than 2 wt % fluorine on alumina catalyst, most preferably a noble Group VIII metal (e.g. Pt or Pd) on low fluorine content (less than 2 wt % fluorine) on small particle size alumina (less than 1/16 inch diameter) catalyst. The most preferred alumina support is a 1/20 inch trilobe.