Asphaltene Syncrude

The stability of the products from coal-derived syncrudes must be examined carefully. Many unique compounds are present in these syncrudes peri-condensed aromatics and naphthenes, oxygen compounds, and asphaltene-like hydrocabons. Traces of these compounds may remain in the hydrotreated product and their effect on jet, thermal, and oxidation stabilities cannot be predicted from the behavior of petroleum products. 

This sample has been discussed elsewhere [78,79,92]. Table 33.1 shows the elemental analyses of the sample and the fractions, while Table 33.2 shows the proportions of the maltene and asphaltene fractions. Figure 33.7 shows LD-MS of a distillation residue of Syncrude sweet blend from the Athabasca tar sands, at different LPs and different HMA voltages (9 and 10 kV). At 30% LP, the spectra (1 and 2) were very weak and close to the ionization threshold at 40% LP, the maximum ion intensity shifted slightly to higher mass (m/z 300-400) and the upper mass limit moved to about m/z 5000 at 50% LP, the maximum ion intensity remained between 300 and 400 though off-scale, while the upper mass limit moved to m/z 20,000-30,000 with evidence of cluster ion formation. Figure 33.8 shows the Syncrude mass... 

Figure 33.9 shows the LD mass spectrum of the NMP-insoluble fraction of the sample, with maximum ion intensity at m/z 3000 and an upper mass limit of m/z 10,000. Table 33.3 lists the maximum intensity masses (m/z) and upper mass limits of the mass spectra of the whole sample, the maltene and asphaltene fractions, and several TLC fractions from each of them. It is clear that the Syncrude contains some material of relatively high mass that can only be defined by fractionation to isolate it from low-mass components. 

FIGURE 33.9 Syncrude asphaltene, NMP-insoluble fraction. Data from Alvarez et al. [78,79]. 

FIGURE 33.10 LD-MS spectra of the Syncrude residue (1) and its three solubility fractions Syncrude maltene (2), Syncrude asphaltene (3), and a toluene insoluble fraction (4), obtained in linear mode with no delay and HMA of 30%-40%. Data from Alvarez et al. [78,79]. 

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