Lubricating oils, petroleum refining

The products obtained by vacuum distillation include fuel oils and asphalts. From them the refiner extracts lubricating oils, petroleum and paraffin. 

The presence of these acids in crude oils and petroleum cuts causes problems for the refiner because they form stable emulsions with caustic solutions during desalting or in lubricating oil production very corrosive at high temperatures (350-400°C), they attack ordinary carbon steel, which necessitates the use of alloy piping materials. 

Urea has the remarkable property of forming crystalline complexes or adducts with straight-chain organic compounds. These crystalline complexes consist of a hoUow channel, formed by the crystallized urea molecules, in which the hydrocarbon is completely occluded. Such compounds are known as clathrates. The type of hydrocarbon occluded, on the basis of its chain length, is determined by the temperature at which the clathrate is formed. This property of urea clathrates is widely used in the petroleum-refining industry for the production of jet aviation fuels (see Aviation and other gas-TURBINE fuels) and for dewaxing of lubricant oils (see also Petroleum, refinery processes). The clathrates are broken down by simply dissolving urea in water or in alcohol. 

Low temperature filtration (qv) is a common final refining step to remove paraffin wax in order to lower the pour point of the oil (14). As an alternative to traditional filtration aided by a propane or methyl ethyl ketone solvent, catalytic hydrodewaxing cracks the wax molecules which are then removed as lower boiling products. Finished lubricating oils are then made by blending these refined stocks to the desired viscosity, followed by introducing additives needed to provide the required performance. Table 3 Usts properties of typical commercial petroleum oils. Methods for measuring these properties are available from the ASTM (10). 

Based on the evidence that acceptable recycled petroleum products can be produced, there is a considerable legislative record encouraging the recycling of used oil. Starting with the Resource Conservation and Recovery Act in 1976 (20), used oil was held apart from the normal hazardous waste system because the oil was viewed as a valuable commodity. This was followed by the Used Oil Recycling Act in 1980 (33), which removed any federal requirement that lubricants containing re-refined base oil carry special labeling. 

NPRA. 1992. 1991 Report on U.S. lubricating oil sales. National Petroleum Refiners Association, Washington, DC. 

The wax content of crude petroleum in itself is of no immediate concern to the refiner, although it may be a major problem to the producer because of waxing up of well casing and sucker rods. It may cause difficulty in transportation of the raw crude oil, and wax settling out in tanks may also become troublesome. The refiner, however, is concerned with wax occurring in the oils to be processed and in the finished oils. The major portion of waxes present in crude petroleum boil in the same range as the lubricating oils produced from the crude oil, so that the wax and oil cannot be separated by distillation. Waxes are... 

The most outstanding development resulting from these investigations is the use of liquid propane for the selective precipitation of resins and asphalts. The development of the propane deasphalting process is a very important contribution to petroleum technology in the refining of residual oils and provides a method for substantially complete separation of lubricating oils from the asphaltic materials contained in the residua derived from any crude source. 

Solvent extraction is used extensively in the petroleum industry to refine lubricating oils, kerosene, and specialty oils for medicinal and agricultural purposes. It is a process that separates hydrocarbons into two phases—a raffinate which contains substances of high hydrogen to carbon ratio and an extract which contains substances of low hydrogen to carbon ratio. 

Early refiners utilized simple batch distillation to prepare kerosenes and lubricating oils. As the demand for these materials expanded and new crude oils were found, certain desirable and undesirable characteristics became apparent. Crude oils were selected from which products possessing desirable characteristics could be distilled—for example, oxidation stability, low smoke tendency, low carbon-forming tendency, small viscosity change with change in temperature (high viscosity index), light color, and attractive appearance were more likely to be found in petroleum of the paraffinic or Pennsylvania type. 

Furby (12) has developed a method for evaluating stocks in the lubricating oil range that results in a breakdown of components into asphaltenes, resins, wax, and dewaxed oil and provides a yield-viscosity index relationship for the dewaxed oil. The author has found such analyses very useful and inexpensive for evaluating a large number of potential lubricating oil stocks. Furby s method utilizes petroleum ether to precipitate asphaltenes, a fuller s earth-petroleum ether fractionation to isolate resins, methyl ethyl ketone-benzene dewaxing on the deasphalted-deresinified material to separate wax, and an adsorption fractionation to provide cuts from which the yield-viscosity index relationship for dewaxed, solvent-refined oil is obtained. 

As discussed above, hydrocarbons (oil and gas) are used primarily as fuels to generate energy and for space heating. Refined petroleum products provide gasoline, diesel fuel, heating oil, lubricating oil, waxes, and asphalt. A relatively small (4%) portion of oil is used as raw material to produce chemical products essential to our everyday life ranging from plastics to textiles to pharmaceuticals, and so on. 

Petroleum refining establishments produce gasoline, fuel oils, lubricants and other products from crude petroleum. Related industries include production of asphalt and tar mixtures for paving and roofing applications coke, fuel briquette, powdered and packaged fuel production, and scrubbing and distribution of natural gas. 

AMERICAN PETROLEUM INSTITUTE (API). Founded in 1919. It has 5500 members. The members are the producers, refiners, marketers, and transporters of petroleum and allied products such as crude oil, lubricating oil, gasoline, and natural gas. The address is 1220 L Street, NW. Washington, DC 20005-4070. http //wvzw.api.org... 

Gas Oil—A fraction derived in refining petroleum with a boiling range between kerosene and lubricating oil. 

Lube Stock—Refiner term for fraction of crude petroleum suitable in terms of boiling range and viscosity to yield lubricating oils when further processed and treated. 

Medicinal oil highly refined, colorless, tasteless, and odorless petroleum oil used as a medicine in the nature of an internal lubricant sometimes called liquid paraffin. 

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