Distillation/clay treatment

Distillation/Clay Treatment Thin-film distillation under high vacuum, such as Luwa evaporators, separates gas oil, lubricant oils and an asphaltic residue containing most of the additives and contaminants from the used lubricant feedstock. The lubricant base oil stream is finished by clay frealmenl. Overall base oil yields are again 70-80% and significant amounts of spent clay must be disposed of. 

The quaHty of the feedstock is important since it affects not only the product quaHty but the rate of hydrogenation. Some of the impurities that affect the rate are sulfur, phosphoms, haHdes, polyethylene, and moisture. Impurities are usually removed by clay treatment or by distillation (30). 

The solvent phase leaving the extractor contains aromatics and small amounts of non aromatics. The latter are removed in the stripper (3) and recycled to the extraction column. The aromatic-enriched solvent is pumped from the stripper to the recovery tower (4) where the aromatics are vacuum distilled from the solvent and sent to downstream clay treatment and distillation. Meanwhile, the solvent is returned to the extractor and the process repeats itself. 

The manufacture of low-cold-test lubricating oils is accomplished by vacuum distillation in the presence of a smidl amount of caustic soda, or soda ash, acid treatment and soda ash neutralization of each of the several lube fractions, and percolation clay treatment. The most viscous oils must be diluted with naphtha, or the lightest lube fraction,before treating. Acid ranges from 10 lb per bbl for the lightest oils to 40 lb for the heaviest (150 to 200 viscosity at 210 F), and the soda ash for neutralization ranges from 1 to 3 lb per bbl. ... 

Materials. Na-Kaolinite A homoionic sample of kaolinite was prepared from a well-crystallized sample purchased from Source Clays, University of Missouri, using a standardized technique (14) which involved repeated washing with distilled water and by treatment with NaCl solutions to remove exchangeable ions such as Ca, and freeze-drying of the final product. Nitrogen specific surface area of this kaolinite was estimated to be 9.4nr/g and X-ray analysis showed the characteristic pattern of kaolinite. 

Solvent deasphalting (Chang and Murphy, 1992 Van Tine and Feintuch, 1997) provides an extension to vacuum distillation and is a later addition to the petroleum refinery. Before its use, many processes capable of removing asphaltic materials from feedstocks were employed in the form of distillation (atmospheric and vacuum), as well as clay and sulfuric acid treatment. 

Used engine oils can be reused. Sometimes, all that is needed is removal of particles by filtration or centrifugation. In others, it may be necessary to remove volatile acids and water by heating, followed by treatment with sulfuric acid, then lime, and, sometimes, bleaching clay. A final distillation under vacuum completes the rerefining.63 Another system uses propane at ambient temperature in a continuous process.64 The additives and impurities precipitate and settle out, after which the propane is flashed off and the... 

In this study a bentonite was modified to a zeolitic material by alkaline treatment in a seawater medium. The structural and textural characteristics of the clays modified in this medium were determined and compared with those of the natural clay and with those of the clays modified under the same conditions but in distilled water. The samples were characterized by XRD, IR, TG and SEM. The modifications observed in the composition of the resulting zeolitic products depend not only on the NaOH concentration and treatment time but also on the nature of the synthesis media. The zeolitic products synthesized in seawater showed higher crystallinity and less heterogeneity. The treatment can be designed according to the characteristics required for the process in which the zeolitic product will be applied. 

Another, similar, application of activated carbons is in the treatment of edible oils and fats to remove undesirable components. Here, they are used in conjunction with certain bleaching clays. Activated carbon are also used in treating wines and spirits to remove any traces of fusel oil. In the production of brandies, they are used to remove undesirable flavours and to reduce the amount of aldehydes in the raw distillate. In the case of beers, activated carbons are used to improve their colour, and to remove flavours attributed to phenol and colouring matter. 

---