Step 1 — Pretreatment
The oil sample is tested and analyzed. The specific pretreatment various bases on the quality difference of the feedstock.
Step 2 — Dehydration
The oil is stored to allow water and solids to separate out from the oil, then the oil is heated in a closed vessel to boil off any emulsified water and some of the fuel diluents.
Step 3 — Vacuum Distillation
The dehydrated oil is then fed continuously into a vacuum distillation plant for fractionation. Lighter oils boil off first and are removed, followed by the lubricating oil itself. Other heavier components do not boil in the conditions used.
The dehydrated oil is then fed continuously into a vacuum distillation plant for fractionation in exactly the same fashion as crude petroleum. The fractions obtained are as follows:
- Light fuel and diesel. Dominion Oil produces enough diesel from the used oil feedstock to run all the burners and boilers, giving total self-sufficiency in fuel.
- Lubricating oil. The bulk of the feedstock will distill off in the plant to produce a lubricating oil fraction.
- Residue. The non-distillable part of the feedstock contains all the carbon, wear metals, degraded additives and most of the lead and oxidation products. This residue can be used as bitumen for road paving.