Crude fractions, composition

Crude fraction Boiling point, °F (melting point) Approximate chemical composition Uses... 

Thin-layer chromatography (75) and sodium dodecylsulfate-(poly)acrylamide gel electrophoresis (SDS-PAGE) are helpful for analyses of the lipid and protein composition, respectively. Size-exclusion chromatography allows estimation of the size distribution of the (proteo)liposomes and crude fractionation of the material as reviewed in Ref. 76. Accurate determinations of size distributions require analyses by static or dynamic... 

In aLkaline flooding, the injected aUcali reacts with the saponifiable components in the reservoir crude oil. These saponifiable components are described as petroleum acids (naphthenic acids). Naphthenic acid is the name for an unspecific mixture of several cyclopentyl and cyclohexyl carboxylic acids with molecular weight of 120 to well over 700. The main fractions are carboxylic acids (Shuler et al., 1989). Other fractions conld be carboxyphenols (Seifert, 1975), porphyrins (Dnnning et al., 1953), and asphaltene (Pasquarelli and Wasan, 1979). The naphtha fraction of the crnde oil raffination is oxidized and yields naphthenic acid. The composition differs with the crude oil composition and the conditions dnring raffination and oxidation (Rndzinski et al., 2002). 

Not all petroleum reservoirs can be exploited successfully by the in situ combustion method. The applicability of this method depends on such factors as depth to the oil reservoir, thickness of the oil-bearing bed, amount of oil in place within the reservoir, degree of water saturation of the petroliferous formation, specific gravity of the crude and its fractional composition, reservoir pressure, geological type of the oil trap, physical characteristics of reservoir rocks, and the initial oil recovery factor prior to fire flooding. All of these factors must be thoroughly studied before it is decided to apply the in situ combustion method. 

The composition of the crude fraction A (Table IV) was very similar to that calculated from the sequence of residues 1-16 in porcine pepsinogen it made little difference to the results whether the activation was above (inter) or below (intramolecular) pH 3. The compositions show alanine and valine from the excess of pepstatin added, since this compound is not retarded by polylysine-Sepharose. 

HCN/lb coal. The crude product composition was 11 percent HCN. However, the data reported were obtained under a partial helium atmosphere, and performance under realistic conditions may be difficult. The process is of possible interest in coal mining states where the cost of carbon from coal is a fraction of that from methane. More work is required to commercialize the technology. 

Crude oil is a mixture of enormous variety of hydrocarbons derived from multiple sources and it contains hundreds of thousands of different molecules. As a result, we generally do not deal with crude in terms of molecular composition, especially in the case of the crude fractionation. We indicate the composition of crude (and refined hydrocarbon products) in terms of bulk properties and distillation-based properties. 

An important industrial example of W/O emulsions arises in water-in-crude-oil emulsions that form during production. These emulsions must be broken to aid transportation and refining [43]. These suspensions have been extensively studied by Sjoblom and co-workers [10, 13, 14] and Wasan and co-workers [44]. Stabilization arises from combinations of surface-active components, asphaltenes, polymers, and particles the composition depends on the source of the crude oil. Certain copolymers can mimic the emulsion stabilizing fractions of crude oil and have been studied in terms of their pressure-area behavior [45]. 

Crude oils are refined to separate the mixture into simpler fractions that can be used as fuels, lubricants, or as intermediate feedstock to the petrochemical industries. A general knowledge of this composite mixture is essential for establishing a processing strategy. 

As a starting point, the book reviews the general properties of the raw materials. This is followed by the different techniques used to convert these raw materials to the intermediates, which are further reacted to produce the petrochemicals. The first chapter deals with the composition and the treatment techniques of natural gas. It also reviews the properties, composition, and classification of various crude oils. Properties of some naturally occurring carbonaceous substances such as coal and tar sand are briefly noted at the end of the chapter. These materials are targeted as future energy and chemical sources when oil and natural gas are depleted. Chapter 2 summarizes the important properties of hydrocarbon intermediates and petroleum fractions obtained from natural gas and crude oils. 

For crude oils C and D, some lighter hydrocarbons are formed during the cracking reactions but the composition of the 210 fraction is hardly modified. In particular, it can be noticed that the asphaltene contents of both of the recovered oils remain high. 

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. 

Hirose and Kushiro (1993) have determined the composition of basaltic melts segregated from peridotite at 10-30 kbars. Some of the data are listed as molar fractions in Table 5.4. Making the rather crude assumption that the clinopyroxene Kcpx solubility product can be formed as... 

---