GB448009A - Process for reclaiming used lubricating oils - Google Patents

Abstract

<PICT:0448009/III/1> Used lubricating-oil is treated with acid, and after recovering the sludge, the oil is neutralized, mixed during or after neutralization with fuller's earth, and the mixture is heated in a closed chamber to distil off moisture and eventually one or more of the light components, sufficient pressure being developed to prevent cracking. As shown, used oil in a vessel 1 is first treated with sulphuric acid, the mixture being agitated by air admitted through a pipe 5. After settling and removal of sludge through a valve 2, lime and fuller's earth are added and the mixture again agitated. The mixture is then run off through a valve 58 and pipe 28, adapted to be coupled through a union 30 to a valve 25, into a rotary still described in Specification 450,822, comprising a drum 8, adapted to be oscillated by segmental gearing 10, 50 and heated by a burner 18. When charged, the valves 58, 25 are closed, the union 30 disconnected and the drum set into oscillation, and heating continued up to 350 DEG F. A cam 37 is then adjusted to contact with the head of a spring-actuated valve 33 so as periodically to release the pressure and permit escape of steam through vents 22, 21 to a condenser 24. The cam 37 is then retracted and the temperature raised to about 550 DEG F., to drive off light oil vapours which are similarly released through the vents 22, 21. Preferably a light cut of lubricating oil is removed by raising the temperature further to 700--750 DEG F. After removing the desired number of components, the mixture is run off into a cooler 27 from which it is removed by a pump 54 and forced through a bag filter 55, the reclaimed oil passing off through a conduit 57.