GB636752A - A process for reactivating a spent refining adsorbent - Google Patents

Abstract

<PICT:0636752/III/1> A spent refining adsorbent such as clay silica gel, or bauxite, used for decolourizing and/or neutralizing mineral oils and fats and containing organic contaminants and a minor amount of water is reactivated by extracting the adsorbent with a partially water miscible polar liquid, e.g. alcohols, aldehydes, ketones, particularly those with 4-7 carbon atoms, ethers and oxygenated organic compounds or mixtures of these with polar and/or non-polar substances such as aromatic hydrocarbons, chloroform or carbon tetrachloride, to form an extract of the organic contaminants and water; separating the extract from the adsorbent; mixing the extract with a non-polar liquid, e.g. aliphatic hydrocarbons preferably having a boiling point 30 DEG C. or more above that of the polar liquid, miscible with the polar liquid to form an extract phase comprising polar and non-polar liquids and a water phase; separating the two phases; and recovering the polar liquid from the extract phase for recycling to further extraction. An oil or naphtha slurry of spent clay is filtered in 2, de-oiled by washing with naphtha (b.pt. 40-100 DEG C.) from tank 5 and dried by blowing with steam or hydrocarbon gas, while the naphtha and oil are separated in still 4 and the naphtha is returned to tank 5 through condenser 10. The clay is transferred to batch or continuous extractor 15 and contacted at normal or superatmospheric temperature and/or pressure with methyl-ethyl ketone from tank 16, and the extract is passed to separator 19. The clay is vacuum distilled and/or steamed to remove remaining ketone which also passes to separator 19 through condenser 21, and the clay is then further steamed to restore its activity. A high boiling naphtha fraction (b.pt. 120-160 DEG C.) is added from tank 25 to the extract in separator 19 causing the separation of a water phase containing little ketone which is discharged at 27, and a ketone-naphtha-organic matter extract phase which is distilled in still 29 to separate organic pitch from the ketone-naphtha mixture which is itself separated in still 33; the ketone is recycled through condenser 35 to tank 16 and the naphtha is recycled to tank 25. The first washing may be omitted and spent clay charged direct to extractor 15. An alternative apparatus is described wherein the de-oiling, extraction, and separation of ketone, naphtha, and water are all carried out in the extractor.