Solvent de-waxing

SDW [Solvent de-waxing] A general term for processes which remove linear paraffinic hydrocarbons from petroleum fractions by solvent extraction... 

New technology developed continuous operations so that plants became much larger and could make more consistent quality products at lower cost. These new process methods were based on the use of solvents continuous selective solvent extraction for aromatic removal was the process which replaced acid treatment and continuous solvent de-waxing replaced the very labour-intensive cold-pressing technique. Technology has developed further in the last 40 years. Catalytic hydrogenation processes have become the normal method for finishing base oils and a more severe form is used as an alternative to solvent extraction to control aromatics content. 

A catalytic de-waxing plant resembles other hydrotreating plants and operating condition need not be particularly severe. Operating costs can be significantly less than solvent de-waxing, especially for low-pour-point oils where refrigeration costs become prohibitive [7, 8]. 

Scale wax the paraffin derived by removing the greater part of the oil from slack wax by sweating or solvent de-oiling. 

Paraffinic base oils are produced from crude oils of relatively high alkane content typical crudes are from the Middle East, North Sea and US mid-continent. This is not an exclusive list, nor does it follow that all North Sea crudes, for example, are suitable for production of paraffinic base oils. The manufacturing process requires aromatics removal (usually by solvent extraction) and de-waxing. 

Naphthenics are made from a more limited range of crude oils than paraffinics, and in smaller quantities, at a restricted number of refineries. Important characteristics of naphthenic base oils are their naturally low pour points, because they are wax-free, and excellent solvency powers. Their viscosity/temperature characteristics are inferior to paraffinics, i.e. they have low/medium VI, but they are used in a wide range of applications where this is not a problem. Since naphthenic crudes are free of wax, no de-waxing step is needed but solvent extraction or hydrotreatment is often used now to reduce aromatic content and especially to remove polycyclic aromatics which may present a health hazard in untreated oils. The main producers of naphthenics are in North and South America because most of the world s supply of naphthenic lubricant crudes are found there. 

The de-waxed oil/solvent and the crude wax are handled as separate streams for solvent recovery. The wax contains an appreciable amount of oil because filtration... 

In catalytic de-waxing, special shape-selective catalysts are used to selectively hydrocrack only the straight-chain alkanes to low boiling point by-products. Since it is the linear alkanes that comprise the bulk of the waxy components in the lube boiling range, the oil is effectively de-waxed. There are differences in the composition and properties of base oil de-waxed by catalytic solvent processes because of different selectivities. 

Application of wax and various wax resin mixtures was predominantly employed in England until the middle of the last century as a result of misunderstanding of the ancient Roman techniques. The application caused detrimental results. After it was agreed that wax as a consolidant was not appropriate, subsequently techniques of de-waxing had to be devised, which may, however, only reduce the amount of wax in the painting, not remove it completely. Moreover all those removal techniques applied until now involve use of organic solvents, with enormous risks both to paintings and conservators. 

Naxrmac. (Rue eis-Nease] Phosi ate esters emulsifier, lubricant, hydro-trope, wetting agent, stabilizer for heavy duty arid l sehold detergents, emulsion polymerization, solvent de-gieasers, paint and wax strippers, elec-ttolytic Cleaners. 

Staining Sections cut from wax-impregnated blocks must first be de-waxed by immersion in a suitable solvent, traditionally xylene, now often replaced with a less-toxic proprietary substitute. This is generally followed by a succession of increasingly aqueous solutions of ethanol until the specimen is fully hydrated, since most stains are applied in aqueous solution. Once the support of the wax has been removed, the specimen should not be allowed to dry because of damage caused by surface tension. 

Solvent dewaxing removes wax from lubricating oil stocks, promoting crystallization of the wax. Solvents include furfural, phenol, cresylic acid-propane (DuoSol), liquid sulfur dioxide (Eleleanu process), B,B-dichloroethyl ether, methyl ethyl ketone, nitrobenzene, and sulfur-benzene. The process yields de-oiled waxes, wax-free lubricating oils, aromatics, and recovered solvents. 

MEK de-oiling a wax de-oiling process in which the solvent is generally a mixture of methyl ethyl ketone and toluene. 

A similar organized solvent mantle is proposed to be present around the silicate species and a displacement of the hydration mantle around the SDA by the silicate species is the origin of the SDA-silicate interaction. Long-range order is attained in a consecutive layer-by-layer zeolite growth step. This proposed formation mechanism is in agreement with results of an in situ SAXS and WAXS study by de Moor et a//151 of the same system. Their results show the initial formation of colloidal... 

Petroleum ceresins and petrolatum wax are isolated from residues. Paraffin wax, on the other hand, is almost invariably isolated from distillates by solvent extraction or precipitation followed by sweating or emulsion de-oiling. According to Sachanen (77), the wax content of lubricating oil fractions is commonly 10% =b 5%. 

Paraffin wax from a solvent dewaxing operation (Speight, 1999) is commonly known as slack wax, and the processes used for the production of waxes are aimed at de-oiUng the slack wax (petroleum wax concentrate). 

Dianol. [Dai-ichi Kogyo Seiyaku] Fatty acid DE A detergent solubilizer, emulsifier, dispersant for pigments, waxes, solvents. 

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