Kerogens concentrations

In all of the functional group tests of kerogen, the inorganic material removed from the oil shale by attrition grinding was used as a mineral blank. Because pyrite was concentrated with the kerogen and was not separated with the mineral, pyrite equivalent to that present in the kerogen concentrate was added to the mineral blank. 

Figure 2. Infrared spectra of trona acids and kerogen concentrate...

Figure 3. Infrared spectra in the 5.5-6.5 micron region of trona acids and kerogen concentrates and derivatives of these materials...

The complete disintegration and dissolution of the mineral material. This method frees the largely intact kerogen. Concentrated hydrofluoric acid is the most widely used reagent in this class (6,7) since it is still the only reagent that can effectively solubilize the silicate mineral (clay and quartz) that is resistant to most chemical treatments. 

Table II. Activation Energy for Thermal Decomposition of Raw Shale and Kerogen Concentrate from Green River Oil Shale and Devonian Shale °...

Figure 2. DSC thermal analysis for (A) Green River oil shale and (B) Devonian shale (No. 43). (Both raw shale and kerogen concentrate.) (--) Raw shale, (----) kerogen concentrate, (— —) baseline.

The thermal properties of Devonian shale are quite different from those of Green River oil shale. The associated pyrite in kerogen concentrate may contribute greatly to the effect on thermal degradation of Devonian gas-bearing shale. For the first time DSC was applied to determining thermal properties of Devonian shale as well as Green River oil shale. 

Figure 4. Thermogravimetric analysis of treated Green River oil shales. Key A, water-washed 184 L/1 B, bitumen free C, bitumen- and carbonate-free D, kerogen concentrate E, kerogen concentrate float fraction and F, kerogen concentrate sink fashion.

This proposed silicate mineral catalytic effect is further demonstrated by TG measurements of the kerogen concentrate, Sample D, which show a decrease in the net pyrolysis yield from 68.8 wt% for the bitumen-, carbonate-free Sample C to 57.6 wt% for the now silicate-free sample. These results suggest that the optimum pyrolysis oil yield is achieved for Green River oil shales which are carbonate-free, but still retain their original silicate mineral concentration or, possibly, an increased silicate concentration. 

The last step outlined in Figure 1 is the separation of the kerogen concentrate, Sample D, into sink-float fractions, samples E and F, respectively, by heavy media techniques (13,14) at a density of 1.145 g/mL. As seen in Figure 4, both fractions showed the typical organic matter decomposition at 460-470°C. As with the kerogen concentrate, Sample D, neither Sample E nor F exhibited the 520°C peak associated with silicate catalytic activity. 

Fig. 20. cramps spectra of (a) kerogen concentrate of Colorado oil shale, (b) Colorado oil shale. (Reprinted with permission from Maciel 1993, Anurkan... 

With oil shales, the application of the CRAMPS technique is virtually nonexistent. To the author s knowledge, the only published CRAMPS spectra of an oU shale and its kerogen concentrate are shown in Fig. 20. Hie H spectra of the kerogen concentrate exhibit a narrower line width than the raw oil shale, analogous to that observed in the C spectra (Fig. 16). 

Figure 11. Plot of oil yields of shales vs. aliphatic carbon content determined by C CP/MAS NMR spectra. Key O, kerogen concentrate and , raw oil shale. (Reproduced, with permission, from Ref. 18a. Copyright 1979, IPC Bus Press.)...

Table 2. Analytical results for the kerogen concentrates from the unheated and heated samples...

Fig. 10. (a) Plot of organic carbon versus stable carbon isotope composition for the kerogen concentrates of the composited unheated and pyrolyzed samples, (b) Plot of the stable carbon isotope composition versus pyrolysis temperature for the kerogen concentrates (sample numbers cf. Tables 1 and 2, samples 1 and 8 are the unheated composites). 

Fig. 11. Plot of the vitrinite reflectance data (logf o) versus pyrolysis temperature for the kerogen concentrates.

Fig. 12. Plot of atomic H/C versus hydrogen index for the two kerogen concentrate sets (square data points are starting composites 1 and 8 other sample numbers refer to kerogens heated from 250 to 500°C as given in Table 2).

Fig. 4-111 Thermogravimetry of Kerogen Concentrate from Oil Shale Goyniik Heating Rate 10 K/min Gas Flow Rate 25 cm /min Curve 1 Argon Curve 2 Air...

Fig. 4-112 Thennogravimetry of Pyrolysates from Oil Shale Goyniik Residue at 600 °C R600 versus Pyrolysis Temperature X Oil Shale o Kerogen Concentrate...

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