Asphaltenes extraction

Table II shows the results obtained by extracting several Uinta Basin, Utah outcrops with successive organic solvents. All outcrop samples are fairly low in sulfur, most are quite high in nitrogen, and all have low ratios of vanadium to nickel. Only the Raven Ridge sample, which was collected in a creek bed, has a very large fraction of organic material that is not soluble in heptane Benzene-methanol (1 1) and pyridine did not extract much material from any of these samples, so analytical data from these materials are not included in the table. The asphaltenes extracted from P. R. Spring and Southeast Asphalt Ridge tar sands are quite rich in nickel (5/jtmol/g), and nickel porphyrins are found in the heptane-soluble fractions of these tar sands as well as is the heptane-soluble fraction of Whiterocks tar sands. Crudes derived from nonmarine sources are usually much higher in nickel content than in vanadium content, and the Uinta Basin tar sands deposits are all of lacrustine origin and are of tertiary age.

PZC/IEP of Asphaltene Extracted from Crude Oil from Swidnik, Poland... 

Fordedal and Sjoblom used dielectric spectroscopy to study several real erode oil emulsions and model systems stabilized with either separated asphaltenes and resins from crude oil or by commercial surfactants (55). Emulsions could be stabilized by the asphaltene fraction alone, but not by the resin fraction alone. A study of a combination of mixtures shows an important interaction between emulsifying components. F0rdedal et al. used dielectric spectroscopy to study model emulsions stabilized by asphaltenes extracted from crude oils (56). Analysis showed that the choice of organic solvent and the amount of asphaltenes, as well as the interaction between these variables, were the most significant parameters for determining the stability of the emulsions. 

Ese et al. found similar results on model emulsions stabilized with resins and asphaltenes extracted from North Sea oil (57). The dielectric spectroscopy results showed that the stability of model emulsions could be eharaeterized. Stability was found to depend mainly on the amount of asphaltenes, the degree of aging of asphaltenes and resins, and the ratio between asphaltenes and resins. 

Figure 4 depicts the main fractions that can be extracted from a solid-free petroleum fluid. The term "solid" here refers to mineral fines, clays, etc. Asphaltenes extracted from bitumen are very likely to contain solids. In this case, solids can be removed by centrifugation of a 5 wt% solution in toluene at 30,000 g for 3 h (Goual et al, 2006) or by filtration using 0.02 im... 

To prepare modified emulsions, first asphaltenes and then solid particles were added to the oil phase, before emulsifying with water When no addition of asphaltenes was required, particles were dispersed in the crude oil. Subsequently, the glass tube was placed on a shaking table for 5 h at 300 min and then in a oven at 40 ° C for 3 6 h to allow the adsorption of crude oil components to proceed. In the case where the total amount of asphaltenes of crude A was increased to 1.65%, asphaltenes extracted from cmde A were added to the oil phase before dispersing the particles. The sample was then placed on a shaking table at 300 min for 5 h, then for 36h in an oven at 60 °C and, finally, cooled to 40 ° C before particle addition and subsequent mixing with water. 

This technique is used to quantify one or more components in a mixture, i.e., extracting them from mixtures to facilitate their final analysis. An example is that for the asphaltenes, already described in the definition of these components in article 1,2.1. 

The complexity of petroleum products raises the question of sample validity is the sample representative of the total flow The problem becomes that much more difficult when dealing with samples of heavy materials or samples coming from separations. The diverse chemical families in a petroleum cut can have very different physical characteristics and the homogeneous nature of the cut is often due to the delicate equilibrium between its components. The equilibrium can be upset by extraction or by addition of certain materials as in the case of the precipitation of asphaltenes by light paraffins. 

Solvent deasphalting. This is an extraction of the heaviest fractions of a vacuum residue or heavy distillate. The extract is used to produce the bitumen. The separation is based on the precipitation of asphaltenes and the dissolution of the oil in an alkane solvent. The solvents employed are butane or propane or a butane-propane mixture. By selecting the proper feedstock and by controlling the deasphalting parameters, notably temperature and pressure, it is possible to obtain different grades of bitumen by this process. 

Fig. 11. Schematic of a residuum oil supercritical extraction (ROSE) process using compressed pentane to separate vacuum resids into asphaltenes (high...

Solvent Deasphalting This is the solvent extraction of virgin residuum to remove asphaltenes or other tarry constituents. The deasphalted oil may be further processed into lubricating oils and greases, or used as cat cracking feed. 

Solvent extraction may also be used to reduce asphaltenes and metals from heavy fractions and residues before using them in catalytic cracking. The organic solvent separates the resids into demetallized oil with lower metal and asphaltene content than the feed, and asphalt with high metal content. Figure 3-2 shows the IFP deasphalting process and Table 3-2 shows the analysis of feed before and after solvent treatment. Solvent extraction is used extensively in the petroleum refining industry. Each process uses its selective solvent, but, the basic principle is the same as above. 

Temperature-Controlled Residuiun Oil Supercritical Extraction (ROSE) The Kerr-McCee ROSE process has been used worldwide for over two decades to remove asphaltenes from oil. The extraction step uses a hquid solvent that is recovered at supercritical conditions to save energy as shown in Fig. 20-21. The residuum is contacted with butane or pentane to precipitate the heavy asphaltene fraction. The extract is then passed through a series of heaters, where it goes from the liquid state to a lower-density SCF state. Because the entire process is carried out at conditions near the critical point, a relatively small temperature change is required to produce a fairly large density change. After the light oils have been removed, the solvent is cooled back to the liquid state and recycled. 

In this zone, the quantity of extracted oil is generally sufficient to obtain the distribution of the different structural groups (SARA analysis) except for oil A (Fig. 6 to 9) For oil B (Fig. 6), for the first two samples, the amount of extracted products is too low and the analysis is uncertain. It can only be noticed that the asphaltene content is null. On the contrary, just beyond the coke zone (samples III-IV), the asphaltene content respectively reaches 12.9 and 5 4 whereas the asphaltene content of the initial oil is only 0.3. This effect is also observed for oil C (10 versus 6.3%) (Fig. 7), D 24% versus 13.8 ) (Fig. 8), E (24 4 versus 8.1 ) (Fig. 9) For all the oils, the amount of resins+asphaltenes generally remains constant and the amount of saturates increases... 

In the case of the hot-rod reactor experiments, the toluene solutions were combined and the toluene removed under reduced pressure. n-Hexane (250 ml) was added to the extract and it was allowed to stand for 24 hours with occasional shaking. The solution was filtered to leave a residue (asphaltene) and the hexane was removed from the filtrate under reduced pressure to give the oil. 

The present authors studied the solvolytic liquefaction process ( ,7) from chemical viewpoints on the solvents and the coals in previous paper ( 5). The basic idea of this process is that coals can be liquefied under atmospheric pressure when a suitable solvent of high boiling point assures the ability of coal extraction or solvolytic reactivity. The solvent may be hopefully derived from the petroleum asphaltene because of its effective utilization. Fig. 1 of a previous paper (8) may indicate an essential nature of this process. The liquefaction activity of a solvent was revealed to depend not only on its dissolving ability but also on its reactivity for the liquefying reaction according to the nature of the coal. Fusible coals were liquefied at high yield by the aid of aromatic solvents. However, coals which are non-fusible at liquefaction temperature are scarcely... 

ROSE (1) [Residuum Oil Supercritical Extraction] A process for extracting asphaltenes and resins from petroleum residues, using supercritical propane or isobutane as the extractant. Developed by Kerr-McGee Corporation in 1979 and sold to the MW Kellog Company in 1995, at which time 25 units had been licensed. 

Quantitative FT-IR Analysis. Selected samples of the liquefaction products, total product, the chloroform extracts, the asphaltenes, and the solid residues were analyzed as KBr pellets by FT-IR. The methods employed for quantitative analysis have been described previously (14-17). Measured amounts of sample are mixed with measured amounts of KBr, so that spectra are reported in absorbance units/mg of sample in a 1.33 cm pellet. A spectral thesis routine was used to obtain peak areas for individual functional groups and previously determined absorbtivities (17) were employed to obtain the reported percentages of each functional group. 

Quantitative FT-IR functional group analysis was performed on the starting coals, preliquefaction residua, chloroform extracts, oils, and asphaltenes. 

Figure 4. Comparison of FT-IR Spectra of THF Extracts of the Residue (Asphaltene) Formed at 350 C in the Presence of Catalyst and the Presence of Hydrogen.

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