
220 Refining Used Lubricating Oils
effectiveness of three methods of mixing the propane with the used oil that had not
been exposed to a pretreatment bubbling the propane through the oil, mixing the
propane with the oil by owing through a venturi, and by mixing the components in
a globe valve. The globe valve mixing was presented as the best option for reducing
the level of all of the impurities considered.
Data was also provided to show that treating used oil by the preferred methods pre-
sented in this patent could reduce the level of lead in the used oil by 52% w/w, sodium
by 88% w/w, magnesium by 98% w/w, calcium by 88% w/w, phosphorus by 73 ...