The Oil Refinery designs are Gravity-Feed devices. Some manufacturers add one or two components to their filter media and label the multi-function devices as oil refineries. Marketing a bypass device as an oil refinery overstates the devices abilities, as one can see by examining the process in an actual oil re-refinery facility. How does an Actual Oil Refinery Facility Operate? An oil re-refinery plant is a large processing facility. Re-refining oil is a sophisticated process involving chemical pre-treatment, dehydration, vacuum distillation, hydro treating, fractionation, and hydro finishing. This process creates the lubricating base oil, which makes up approximately 80% of the lubricating oil. Next, the re-refined base oil must receive the other 20%, which consists of a mixture of chemical additives designed for the various oil specifications. These additives can not simply be poured into the base oil. Another process, called a blender operation, is required to produce the final pro