Neutralizing oxidation product components in continuous rerefining of used oil stocks

Claim 1

A process for continuously neutralizing oxidation product components in rerefining used oil stock supplies, comprising a process that is carried out on a continuous flow basis and that includes: providing a supply of used oil stock that has been rerefined and that is contaminated with an oxidation product component; injecting a flow of a strong base solution into a flow of said rerefined and contaminated used oil stock, said injected flow of strong base solution is at a flow rate that is not greater than about 1% by volume of the flow volume of said oil stock, in order to form a feed flow of oil composition including said rerefined oil stock and said strong base; flowing said feed flow of rerefined oil composition of oil stock and strong base into a vacuum distilling tower providing low pressure conditions and vaporizing said composition within the vacuum distilling tower to form a vaporized composition that flows upwardly within the vacuum distilling tower; condensing said upwardly flowing vaporized composition and permitting same to fall into a collection means so as to form a treated rerefined used oil flow, said condensing step including impinging the rising vapor composition of oil stock and strong base onto a convoluted surface of an impingement assembly within the vacuum distilling tower and generally downwardly spraying a recycled liquid flow of said treated rerefined used oil stock onto the impingement assembly, contacting said used oil stock and said strong base on the surface of the impingement assembly in order to ensure completion of neutralization of oxidation product component of said used oil stock; and collecting said treated rerefined used oil flow and withdrawing same out of the vacuum distilling tower to provide treated rerefined used oil stock, and said collecting step recovers on the order of approximately 90% or above of the rerefined used oil stock that is said feed flow to the vacuum distilling tower.