Asphaltenes, resins, and oil

Fractionation. Kett-McGee developed the ROSE process for separating the heavy components of cmde oil, eg, asphaltenes, resins, and oils, in the 1950s. This process was commercialized in the late 1970s, when cmde oil and utility costs were no longer inexpensive. In the ROSE process (Fig. 11), residuum and pentane ate mixed and the soluble resins and oils recovered in the supetctitical phase. By stepwise isobatic temperature increases, which decrease solvent density, the resin and oil fractions ate precipitated sequentially. 

The effect of make-up of roofing asphalts on weathering properties, in terms of the fractions asphaltenes, resins, and oils, has been studied by Thurston (120). Increase of either asphaltenes or oils reduced resistance to weathering, while apparently an optimum content of resins aided permanence under exposure. Weathering properties were dependent not only on the quantities but also on the sources of these fractions, but the effect of source was not sufficiently clarified. 

Table V further shows that vanadium and nickel distributions in fractions closely follow the pattern of Type II nitrogen or Type II sulfur 82%, 17.4%, and 0.6% of the vanadium originally present in the residue are found later in, respectively, asphaltenes, resins, and oils (obtained through C5 precipitation).

One of the most used procedures, an ASTM standard, D4124, was developed by Corbett (61) and separates asphalt into four fractions. Asphaltenes are precipitated by heptane, and the remaining solution is divided into saturates, naphthene aromatics, and polar aromatics by a series of successively more polar solvents on an alumina column. Similar procedures produce fractions variously known as asphaltenes, resins, and oils or saturates, aromatics, resins, and asphaltenes, for example. Although similar, the methods are not identical and produce fractions that overlap those of other methods. 

To mitigate the effects of corrosion resulting from the presence of salts, it is advantageous to reduce the salt concentration to the range of 3 to 5 ppm. Typically, brine droplets in crude oil are stabilized by a mixture of surface-active components such as waxes, asphaltenes, resins, and naphthenic acids that are electrostatically bound to the droplets surface. Such components provide an interfacial film over the brine droplet, resulting in a diminished droplet coalescence. Adding water to the crude oil can decrease the concentration of the surface-active components on the surface of each droplet, because the number of droplets is increased without increasing component concentration. 

Asphalt the nonvolatile product obtained by distillation and treatment of an asphaltic crude oil with liquid propane or liquid butane usually consists of asphaltenes, resins, and gas oil a manufactured product. 

Concentration of Type II Nitrogen or Type II Sulfur in Subfractions. When separating distillation residues of Oficina crude oil into asphaltenes, resins, and deasphalted oils using n-pentane, some drastic changes occur in nitrogen and sulfur distribution, as can be seen in Tables I and II. 

Recently, we have been using electrophoretic mobility measurements in an attempt to support some of our hypotheses. Our experimental plan, however, required the separation of asphaltenes, resins and gas oil as it exists in the crude. To do this we basically used standardized technique //143/57 of the Institute of Petroleum. Electrophoretic mobility measurements were made of the whole crude. Cut 2 and Cut 3 plus asphalt when contacted with the standard... 

The thermal chemistry of heavy oils and bitumen is extremely complicated because of wide variations in chemical compositions. The most refractory components in petroleum feedstocks are asphaltenes, which contribute the most to coke formation dining thermal cracking. Next to asphaltenes, resins and large aromatics also contribute to coke. To investigate the effect of these three heavy oil components on the mesophase induction period, Athabasca bitumen fractions containing varying amounts of asphaltenes (obtained by supercritical fluid extraction) and Venezuelan heavy... 

By contrast, the specific components of crude oil that have been most closely associated with foam behavior reveal radically different chemistry to these simple hydrocarbon chain surfactants. As exemplified by the work of Poindexter et al. [4, 20], those components can be listed as asphaltenes, resins, and waxes. Of these, arguably asphaltenes are the most important. These components are derivatives of polycyclic aromatics, which are distinguished from other crude oil components by insolubility in short-chain n-alkanes such as n-heptane. They are, however, soluble in toluene. Resins are soluble in short-chain alkanes and are therefore usually extracted from crude oil by adsorption onto silica from solution. Both asphaltenes and resins can even each be present in crude oil at concentrations in excess of 15 wt.%. Such extremely high concentrations usually lead to crude oils of high density and high viscosity—so-called heavy crudes (see, e.g., reference [4]). 

Several studies demonstrate the importance of asphaltenes, resins and paraffins existing in crude oil in the promotion and stabilization of emulsions of water-in-oU. 

Interfacial rheology tests are being carried out by varying the concentration of asphaltenes, resins and asphaltenes/resins to better understand the surfadant properties of these species in the oil. 

In crude oil, nitrogen is found mostly in fractions boiling over 250°C and is particularly concentrated in resins and asphaltenes. Nitrogen takes the following forms / to). ... 

Many attempts have been made to characterize the stabiUty of the colloidal state of asphalt at ordinary temperature on the basis of chemical analysis in generic groups. For example, a colloidal instabiUty index has been defined as the ratio of the sum of the amounts in asphaltenes and flocculants (saturated oils) to the sum of the amounts in peptizers (resins) and solvents (aromatic oils) (66) ... 

Petroleum crude oil, gas condensate, and natural gas are generally complex mixtures of various hydrocarbons and nonhydrocarbons with diverse molecular weights. In order to analyze the contents of a petroleum fluid it is a general practice to separate it first into five basic fractions namely, volatiles, saturates, aromatics, resins, and asphaltenes [74, 77]. Volatiles consist of the low-boiling... 

Each oil-dispersant combination shows a unique threshold or onset of dispersion [589]. A statistic analysis showed that the principal factors involved are the oil composition, dispersant formulation, sea surface turbulence, and dispersant quantity [588]. The composition of the oil is very important. The effectiveness of the dispersant formulation correlates strongly with the amount of the saturate components in the oil. The other components of the oil (i.e., asphaltenes, resins, or polar substances and aromatic fractions) show a negative correlation with the dispersant effectiveness. The viscosity of the oil is determined by the composition of the oil. Therefore viscosity and composition are responsible for the effectiveness of a dispersant. The dispersant composition is significant and interacts with the oil composition. Sea turbulence strongly affects dispersant effectiveness. The effectiveness rises with increasing turbulence to a maximal value. The effectiveness for commercial dispersants is a Gaussian distribution around a certain salinity value. 

Certain alkyl-substituted phenol-formaldehyde resins can act as dispersants for asphalts and asphaltenes in crude oils [1681]. The dispersants help keep asphalt and asphaltenes in dispersion and inhibit fouling, precipitation, and buildup in the equipment. 

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