Asphaltenes resins

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. 

High Mole weight Asphaltene Resins, precipitate and bind to process equip. 

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. 

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. 

S. D. Dzhanakhmedova, E. I. Pryanikov, S. A. Sulejmanova, K. K. Mamedov, E. G. Dubrovina, N. M. Indyukov, and A. B. Sulejmanov. Composition for preventing asphaltene-resin-paraffin deposits—contains waste from production of synthetic glycerine, in mixture with polyacrylamide. Patent SU 1761772-A, 1992. 

Visbreaking severity is monitored to help minimize cracking and alteration of the nature of asphaltenes within the visbreaker feed. Paraffinic side chain cracking or destruction of the asphaltene-resin complex may occur during visbreaking operations and may result in precipitation of asphaltenes from solution. Asphaltene precipitation has been seen especially when visbroken material is blended with lighter-viscosity paraffinic fuels. 

Fuel asphaltenes, resins, and other heavy compounds can build up as residues on engine components after evaporation and burning away of the more volatile fuel components. These residues can accumulate as deposits which may interfere with heat transfer, lubrication, and efficient fuel combustion. 

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. 

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. 

Residua and heavy oils, like any other petroleum, can be fractionated by a variety of techniques (Speight, 1999) to provide broad general fractions termed asphaltenes, resins, aromatics, and saturates (Figure 6-6). By convention, the asphaltene and resin fractions are often referred to as the asphaltic fraction because of their insolubility in liquid propane and subsequent separation from a liquid propane solution of residua as asphalt. 

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. 

Anti-sludge agents. During acid treatment, sludge, consisting of asphaltenes, resin, paraffin and other high molecular weight hydrocarbons is formed. Addition of oil-soluble surfactants can prevent the formation of insoluble film. 

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. 

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).

Sampling Date Asphaltene, % Resin, % Wax, % Wax Melting Point,°C Viscosity, mPa-s... 

Bitumen is composed of three main fractions (see Fig. 4.12) asphaltenes, resins and hydrocarbons. Asphaltenes and resins are heavy N,S,0-containing molecules (molecular weight >500), whereas the hydrocarbons are usually of lower molecular weights. 

In the compressor oil well, the base of the emulsion formation is the same as at extraction using natural layer pressure. Air sometimes mixes with the gas in an oil well and oxidizes a part of the heavy hydrocarbons to form asphaltenes-resinous materials. These adversely influence emulsion formation negatively. Thus, the presence of salts of organic acids as well as asphaltenes-resinous materials leads to emulsion formation. This type of emulsion has a very high stability. 

Continued attention to this aspect of asphaltene chemistry has led to the postulate that asphaltene-asphaltene clusters form the micelle, although other options such as asphaltene-resin clusters are also possible. 

McMahon studied the effect of waxes on emulsion stability as monitored by the separation of water over time (46). The size of the wax crystals showed an effect in some emulsions but not in others. Interfacial viscosity indicated that the wax crystals form a barrier at the water/oil interface which retards the coalescence of colliding water droplets. Studies with octacosane, a model crude oil wax, show that a limited wax/asphaltene/resin interaction occius. A wax layer, even with absorbed asphaltenes and resins, does not by itself stabilize an emulsion. McMahon concludes that the effect of wax on emulsion stability does not appear to be through action at the interface. Instead, the wax may act in the bulk oil phase by inhibiting film thinning between... 

These data indicate that there are windows of composition and viscosity which result in the forma tion of each of the types of water-in-oil states. The important oil composition factors are the asphaltene and resin contents. While asphaltenes are responsible for the formation of stable emulsions, a high asphal tene content can also result in a high viscosity, one that is above the region where stable emulsions form. The asphaltene/resin ratio is generally... 

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