How to recycle old-engine oil @KenyanTraffic

Oil is never changed in its native composition even after long usage in a combustion engine. It only acquires impurities and can easily be purified to regain the original state. However, additives included by different manufactures as value addition will be lost.

This is how oil is made in the first place, you take crude oil and refine it to make a lubricant. This is called base lube stock. Then you have to take that base lube stock and blend it with additives in order to put it into a passenger car. That’s what gives it color actually. You’re adding an anti-foaming additive, a dispersant and a detergent.

When you put the oil into the engine, it is essentially degraded by heating it, and is also oxidized. As all these additives start to break down, the engine starts to wear more. That puts some heavy metals into the oil. The anti-foaming additive breaks down and you start to get water mixing with the oil and making sludge. The same breakdown happens with the dispersant and the detergent. That’s the reason they recommend to change it every X number of miles because of the thermal degradation and oxidation. Because of this Oil only has a certain life span.

We can clean that used oil by using pretty conventional refinery technologies. One of them is vacuum distillation, which dewaters the oil. Used motor oil comes with somewhere between 5 and 7 percent water in it. The first thing you have to do is get the water out of it.

Then we do wiped-film evaporation. This essentially separates out all the contaminants and additives that are put into passenger car motor oils. Then after that, we go through a hydrotreating process that gets up to 400 degrees celsius and 500 [Kilograms per square inch]. That infuses hydrogen back into the hydrocarbon molecules and makes it a very high quality re-refined oil.

If you’re thinking of it in a very simple way, we’re filtering the used oil with very sophisticated technologies and processes.