Lubrication oils under vacuum

Ionic Liquids (ILs) as Lubrication Oils Under Vacuum... 

Initially, petroleum Is distilled into fractions up to 350 C (650 F) under atmospheric pressure into gas, naphtha, middle distillates, gas oils, and residua. The atmospheric residua can be further distilled up to 350°C under vacuum to produce vacuum gas oils, lubricant oils, and vacuum residua. A modern refinery is no longer just a big distillation column that sells various boiling fractions to different consumer markets. While distillation is usually the first step, it is important to understand that a refinery processes 100,000 to 500,000 barrels of oil a day, and must turn every barrel of that oil into something that can be sold economically in the marketplace. For this reason, many of the crude oil fractions ( streams ) undergo catalytic transformation into more valuable streams and then are blended to produce petroleum products or petrochemicals that provide the highest value to the final end use. 

Considering their heat sensitivity, the separation of fatty acids and rosin with minimal degradation by fractional distillation under vacuum and/or in the presence of steam is surprisingly good (3). Tall oil rosin (TOR) contains about 2% fatty acid and small amounts of neutrals. Tall oil fatty acid (TOFA) contains as litde as 1.2% rosin and 1.7% neutrals. In typical U.S. TOFA, 49% of the fatty acids is oleic, 45% linoleic, and 3% palmitic, stearic, and eicosatrienoic acid. TOR and TOFA are upgraded to resins and chemicals for the manufacture of inks (qv), adhesives (qv), coatings (qv), and lubricants (see Lubrication and lubricants). 

The temperature at which the residue starts to decompose or crack limits the boiling range of the highest boiling fraction obtainable at atmospheric pressure. If the stock is required for the manufacture of lubricating oils further fractionation without cracking may be desirable, and this may be achieved by distillation under vacuum. 

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. 

Refers to any of a wide range of petroleum products produced by distillation, as distinct from bottoms, cracked stock, and natural gas liquids. In fuels, a term referring specifically to those products in the mid-boiling range, which include kerosene, turbo fuel, and heating oil-also called middle distillates and distillate fuels. In lubricating oils, a term applied to the various fractions separated under vacuum in a distillation tower for further processing (lube distillate). 

Part of diesel fuel has to be recovered not in an atmospheric unit but in a vacuum one. This creates a double effect (1) in the feeding of a vacuum column the fraction of light components increases, which, due to their stripping influence, increases recovery of lubricant fractions or gas-oil and (2) the volatilities of components grow under vacuum, which separates diesel fuel from heavier products more sharply and deeply. Figure 8.34 shows the calculation dependence of yield of lubricant fractions in dry vacuum column on the fraction in its feeding of components with bubble temperatures below 360°C. However, increase of vapor flow rate in vacuum column requires application of more productive contact devices. 

The reduced crude is then flashed under vacuum, distilling a clear lubricating oil stock and leaving solid tar. The lubricating oil stock can then be evaluated in the true-boiling apparatus. A true-boiling-point analysis of the crude oil is also necessary if the light stocks are to be evaluated. 

Mechanical Pumps. Perhaps the most common form of vacuum pump is a mechanical pump that operates with some sort of rotary action, with moving parts immersed in oil to seal them against back-streaming of exhaust as well as to provide lubrication. These pumps are used as forepumps for diffusion pumps. Other common laboratory applications are the evacuation of desiccators and transfer lines and distillation under reduced pressure. These pumps have ultimate pressures ranging from 10 to 0.05 Torr, and pumping speeds from 0.16 to 150 L s or more, depending on type and intended application. 

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