Crude oil distillation fraction

Lee, M. K. Prince, R. C. Pickering, I. J., et al., Microbial Desulfurization of Crude Oil Distillate Fractions Analysis of the Extent of Sulfur Removal and the Effect on Remaining Sulfur. Abstracts of Papers of the American Chemical Society, 1997. 213 p. 11-FUEL. 

Lewis, S.C., R.W. King, S.T. Cragg, and D.W. Hillman. 1984. Skin carcinogenic potential of petroleum hydrocarbons Crude oil, distillate fractions and chemical class subfractions. Pp 139-150 in Advances inModern Environmental Toxicology, Vol. 6. Applied Toxicology of Petroleum Hydrocarbons, H.N. MacFarland, C.E. Holdworth, J.A. MacGregor, R.W. Call, and M.L. Lane, eds. Princeton, NJ Princeton Scientific Publishers. 

FIGURE 1.10 GCxGC chromatogram of a crude oil distillation fraction. (Source Phillips, J. B. and J. Beens. 1999. J. Chromatogr. A 856 331-347. With permission.)... 

The primary process for separating the hydrocarbon components of crude oil is fractional distillation i.e. separation according to the boiling points of the components. These separated fractions are processed further by catalytic reformers, cracking units, alkylation units, or cokers which have there own fractional distillation towers for its products. 

Natural gas and crude oils are the main sources for hydrocarbon intermediates or secondary raw materials for the production of petrochemicals. From natural gas, ethane and LPG are recovered for use as intermediates in the production of olefins and diolefms. Important chemicals such as methanol and ammonia are also based on methane via synthesis gas. On the other hand, refinery gases from different crude oil processing schemes are important sources for olefins and LPG. Crude oil distillates and residues are precursors for olefins and aromatics via cracking and reforming processes. This chapter reviews the properties of the different hydrocarbon intermediates—paraffins, olefins, diolefms, and aromatics. Petroleum fractions and residues as mixtures of different hydrocarbon classes and hydrocarbon derivatives are discussed separately at the end of the chapter. 

Their bulk properties as well as their chemical composition can characterize crude oils. Distillation of cmde oil provides fraction profiles over a certain boiling range. The crude oil as well as the distillation fractions can be described in terms of density, viscosity, refractive index, sulfur content, and other bulk parameters. 

Air emissions from a petroleum distillation unit include emissions from the combustion of fuels in process heaters and boilers, fugitive emissions of volatile constituents in the crude oil and fractions, and emissions from process vents. The primary source of emissions is combustion of fuels in the crude preheat furnace and in boilers that produce steam for process heat and stripping. When operating in an optimum condition and burning cleaner fuels (e.g., natural gas, refinery gas), these heating units create relatively low emissions of sulfur oxides, (SO c), nitrogen oxides (NO c), carbon monoxide (CO), hydrogen sulfide (H2S), particulate... 

The terms residual fuel or sometimes resid are used to describe high boiling fractions obtained from crude oil distillation and processing. The following petroleum fractions are often described as residual oils ... 

In a surprisingly large number of industrially important processes reactions are involved that require the simultaneous contacting of a gas, a liquid and solid particles 28 . Very often the solid is a catalyst and it is on the surface of the solid that the chemical reaction occurs. The need for three-phase contacting can be appreciated by considering, as an example, the hydro-desulphurisation of a residual petroleum fraction, i.e. of the liquid taken from the base of a crude oil distillation column. 

Distillation was the first method by which petroleum was refined, but this was not so much a refining method as a method for separation of the crude oil into fractions, such as kerosene, for which there was a demand and hence a ready market. Nevertheless, as petroleum refineries have evolved into present-day complexes, distillation units may still find a place, depending upon the characteristics of the crude oil feedstock, in a refinery sequence. A multitude of separations is accomplished by distillation, but its most important and primary function in the refinery is its use for the separation of crude oil into component fractions (Table 7-2) (Speight, 1999). 

Crude oil distillation separates the desalted crude oil into fractions of different boiling ranges. Instead of trying to match final product boiling ranges, the fractions are defined by the number and type of downstream processes. 

Single or multiple distillation columns are used to separate the crude oil into fractions determined by their boiling range. Common identification of these fractions was discussed using Fig. 18.12, but should only be considered as a guide. Many refining schemes can... 

Alkanes, that are generally extracted from crude oil by fractional distillation, can also be produced in the laboratory. 

Crude oil enters the refinery and is stored and excess salt removed prior to distillation. Often several different crude oils are co-mingled before distillation in the atmospheric distillation tower. This has the duty to separate the crude oil into fractions according to distillation range. 

Several of the commercial simulation programs offer preconfigured complex column rigorous models for petroleum fractionation. These models include charge heaters, several side strippers, and one or two pump-around loops. These fractionation column models can be used to model refinery distillation operations such as crude oil distillation, vacuum distillation of atmospheric residue oil, fluidized catalytic cracking (FCC) process main columns, and hydrocracker or coker main columns. Aspen Plus also has a shortcut fractionation model, SCFrac, which can be used to configure fractionation columns in the same way that shortcut distillation models are used to initialize multicomponent rigorous distillation models. 

Thus, water, with specific gravity of 1.00 has an "API of 10, crude oils run the range from about 5 to about 65, lubricating oils run about 26-35, and gasolines run about 60. The less dense the crude or distillate fraction, the higher the "API. 

FIGURE 18.2 Partial cut-away view of continuous crude oil distillation via a pipe still and fractionating column. Frequently the heat content of the distillate fractions is employed to preheat the incoming crude oil (not shown here). 

TABLE 18.2 Atmospheric Pressure Boiling Point Ranges, Trends in Properties, and Approximate Composition of Representative Fractions from Crude Oil Distillation"... 

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