When I take my used oil to the auto parts store what happens to it after that? What is used oil good for? How is it recycled? Do they get money for the old oil or do they have to pay to have it taken away?
Much used oil is processed to remove the water (basically just heated), then blended with heavy fuel oil to lower the specific gravity and viscosity to meet the specs of the buyerof the fuel oil. Diesel fuel, especially contaminated fuel, is also used as this sort of cutter stock...basically anything light, thin, and cheap that burns. Sometimes flammable toxic waste finds it way into cutter stock....
Re-refined motor oil is made from some used oil. If I had to guess, it'd think that they used oil from a large consumer (railroads, etc.) so they knew that the used oil was the same type of oil, but that's just my guess.
I'd be interesting to see analysis of re-refined oil. It's said to be as good as new. Who knows?
In the Bahamas and other Caribbean islands futher south, I'll change the oil in my diesel boat engine or genset and place it next to a dumpster ashore. In most cases it would be gone within minutes. The locals reuse the old oil in their cars, trucks, etc. "One man's junk is another man's treasure."
I know that some places have heaters that run on used engine oil. I have also seen recycled engine oil for sale in the parts stores too, they re-refine it or something (not sure what that process involves though)
Those were interesting posts on the re-refined oil. It doesn't seem like the process would work very well because used motor oil is burned (oxidized). How could you unburn oil by re-refining it? Another thing -- if you are using the oil to make CV boots or something similar, how do synthetic basestocks affect that?
I always wondered about that. How does introducing PAO or esters affect the way used oil burns in a furnace?
I'll bet they make up such a small volume of all the oil being burned, they go unnoticed.
--- Bror Jace
Truely re-refined oil is more expensive than virgin oil. the correct process is too expensive. In Puerto Rico there is a fee charged on the sale of new oil that goes towards the recovery. The recovery pays back part of this fee on picking up the old oil. Then they filter out all of the impurities, sometimes as much as 55%, sample it for contaminates, and when the EPA approves the batch, it is blended into bunker fuel for the ships. The sludge (45% or so) can be blended into asphalt.
In Bolivia, the "recylclers" just filter it and resell it. It destroys engines, but it is cheap, so taxi drivers and bus drivers who are responsible for oil changes out of pocket but not repairs buy it. They also deliver by night and fill any partial drums the find in oil change places that the manager wants some quick change. The manager comes in the next morning and see that the oil level is the same as the day before, so assumes there were no sales.
Since a good bypass filter can make the oil last much longer, I guess all those rerefine just filter out the bad stuff and add in new additives. This makes sense for those quick lube place since they don't want their oil to last too long so their customer will return.
Regarding to the CV boot making, they don't even worry about the PAO, sludges or additives since CV boot is not a very high precision item. As long as most of the stock is what they needed, the result will be just a matter of quality. Hint: they OEM one of the big three American car company.