Lubricating oils, petroleum refining process

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. 

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. 

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. 

In a trickle bed reactor the gas and liquid flow (trickle) concurrently downward over a packed bed of catalyst particles. Industrial trickle beds are typically 3 to 6 m deep and up to 3 m in diameter and are filled with catalyst particles ranging irom to in. in diameter. The pores of the catalyst are filled with liquid. In petroleum refining, pressures of 34 to 100 atm and temperatures of 350 to 425°C are not uncommon. A pilot-plant trickle bed reactor might be about 1 m deep and 4 cm in diameter. Trickle beds are used in such processes as the hydrodesulfurization of heavy oil stocks, the hydrotreating of lubricating oils, and reactions such as the production of butynediol from acetylene and aqueous formaldehyde over a copper acetylide catalyst. It is on this latter type of reaction,... 

Crude petroleum can be converted by physical and chemical processes into a wide range of refined products including gasoline, kerosene, heating oils, diesel oils, lubricating oils, waxes, and asphalts. 

FIGURE 7.3 Effect of feed type on the distribution of VI after bulk hydrocracking. Source M. C. Bryson, W. A. Home, and H. C. Stauffer, Gulf s Lubricating Oil Hydrotreating Process, Proceedings of the Division of Refining of the American Petroleum Institute 49 439 153 (1969). With permission. 

G. L. Everett and A. Suchanek, Lubricant Oil Production The Proper Marriage of Process and Catalyst Technologies, Paper AM-96-37, presented at the annual meeting of the National Petroleum Refiners Association, San Antonio, Texas, March 17-19, 1996. 

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