Extract from the book “Recent Analytical Developments in the Petroleum Industry” edited by D.R. Hodges of Essochemical Ltd., Fawley, Hunts, U.K..
R.A. Cummins (Department of Supply, Australia House): If my calculations are correct Mr Hooks has stated that the dispersed base in the additive is less than 50A (5nm) diameter. However, usually this base is dispersed in the oil in micelles that are usually very much bigger than this and moreover the size of these micelles is dependent on base oil, additive and concentration. How sure can he be that the filtration technique on used oil does not remove still “active material”? Would he state what were the additive and base oil?
These base additives used in the work, described in the paper, are highly basic dispersions of carbonate/hydroxide which are suspended in conventional HVI oils by means of a metal alkyl substituted phenol carboxylate. Electron micrographs show that the most frequent particle size for unused oil is 0.005 micron (50A, 5nm) with most of the particles below 0.008 micron (80A, 8nm). No micelle formation was evident in unused oils.