Bitumen Simulated Distillation

Sulfur compounds in the gas oil fractions from two bitumens (Athabasca oil sand and Cold Lake deposit)> a heavy oil (Lloydminster) from Cretaceous reservoirs along the western Canada sedimentary basin, and a Cretaceous oil from a deep reservoir that may be mature (Medicine River) are investigated. The gas oil distillates were separated to concentrates of different hydrocarbon types on a liquid adsorption chromatographic column. The aromatic hydrocarbon types with their associated sulfur compounds were resolved by gas chromatographic simulated distillation and then by gas solid chromatography. Some sulfur compounds were further characterized by mass spectrometry. The predominant sulfur compounds in these fractions are alkyl-substituted benzo- and dibenzothiophenes with short side chains which have few dominant isomers. 

Simulated Distillation of Bitumen Sample. The boiling-range distribution of the recovered bitumen was determined by simulated distillation gas-liquid chromatography using the procedure of Poulson et al. (15). Boiling points are determined by calibration with a mixture of n-paraffins ranging from Cn to C42. The upper limit for boiling point determination in this analysis is about 540°C (1000°F). 

To test these hypotheses, a tar sand bitumen containing 20 wt % pentane asphaltenes was characterized and processed by hydropyrolysis before and after removal of asphaltenes. Product yields and structure were determined and the influence of asphaltenes on results was determined by inferrence. Feedstocks and products were characterized according to elemental analysis, physical properties, simulated distillation, and carbon-type analysis. Inferences made in this study are discussed in the context of the reported literature. 

Simulated Distillation Results. Important insight concerning the molecular-size distribution of asphaltenes vs. maltenes is gained by the simulated distillation data. The boiling point distribution curves are shown in Figure 3. These curves were drawn as follows. Quantitative simulated distillation data was obtained on the virgin bitumen and the maltenes. Direct information is obtained up to a nominal boiling point of 535°C shown by the vertical dashed line. The area under the curve for the nonvolatile portion is... 

Figure 3. Simulated distillation boiling point curves for virgin bitumen, mal-tenes, and asphaltenes...

The separation scheme for deasphaltened bitumen on silica [WOELM, activated at 140°C (4 hr)] is shown in Figure 1. The fractions obtained were loosely termed hydrocarbons. Polar I, II, and III. The IR spectra of these fractions, as shown in Figure 2, suggested that Polar I was very similar to the polyaromatic/neutral polar fraction from the API 60-based separation after removal of additional material from alumina with pure benzene. Also, simulated distillation curves for this fraction from either procedure are very similar (Figure 3). The IR spectra of the Polar II and III fractions show the presence of all the functional groups which can be distinguished in these complex mixtures and which... 

The end point for the Hempel distillation is equivalent to 425°C. Data for bitumen and heavy oils were obtained by simulated distillation, and data for light oils were obtained by Hempel distillation. 

Fig. 4-18 Simulated Distillation of Bitumen B45 by TG 750 Sample No. 2 Safaniya Crude Sample No. 4 Venezuela Cmde...

Fig. 4-20 Simulated Distillation of Bitumen B200 by TG 750 Sample No. 9 North Sea + Arabian Light Crudes Sample No. 10 Arabian Heavy Crude...

The Conradson coke residue in the simulated vacuum residue ((CCR/SVR) 100) for the vacuum residues and bitumens has a mean value x2l.6%( y= 7.01% relative). For the atmospheric residues the mean amounts to x = 13.8 % ( + y = 8.7 % relative). The products from conversion processes (samples 19, 20, and 22) have extremely high values demonstrating that they have been distilled exhaustively, whereas the distillate of the residue of a cat-cracker, sample 25, exhibits the extremely low value of 4.4 %. 

The behavior of a vacuum residue from a Venezuelan crude was simulated by a distillation bitumen B80 (according to DIN 1995). Further, a vacuum residue of a Middle East crude (VR Kuwait) and its colloid components, i.e. dispersion medium, petroleum resins, and asphaltenes were investigated. Those substances were characterized by element analysis and average relative particle weight (molecular weight) (Table 4-200) and by analysis of their colloid composition according to Neumann [4-10] (Table 4-201). 

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