Green River oil-shale kerogen

Oxygen Functional Groups in Green River Oil-Shale Kerogen and Trona Acids... 

Dr. Fester Brower and Graham reported the presence of one double bond in Green River oil-shale kerogen for each 16-22 carbon atoms, (Ind. Eng. Chem. 50, 1059 (1958)). 

Fester, J. I. and Robinson, W. E. (1966). Oxygen functional groups in Green River oil shale kerogen and trona acids. Coal. Sci. (Adv. Chem. Ser.) 55, 22-24. 

Rajeshwar I52) determined the kinetics of the thermal decomposition of Green River oil shale kerogen by using direct Arrhenius. Freeman and Carroll, and Coats and Redfern methods. The E, A, and values are given in Table 2.7. Rajeshwar concluded that the ability to resolve multiple processes hinges on the efficacy of the particular kinetic analysis employed and is not an inherent difficulty with nonisothermal TG techniques in general. The direct Arrhenius and Coats and Redfern methods clearly indicate the presence of two reactions with distinctly different kinetic parameters. On the olher hand, the Freeman and Carroll method is handicapped at low fractional... 

Table 2.7. Kinetic Parameters for the Nonisothermal Decomposition of Green River Oil Shale Kerogen (152)...

Figure i. X-ray scattering intensities per carbon atom of trona acids and kerogen from Green River oil shale... 

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. 

Oil shales contain large quantities of insoluble organic matter, kerogen, which upon pyrolysis at higher temperatures, yields oil products. Kerogen, which usually represents 80-90% of the total organic matter in Green River oil shales, is neither soluble in aqueous alkaline/acidic solvents nor in the common... 

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. 

Oil shales were characterized using DSC by Rajeshwar et al. (235) a typical DSC curve of a Green River oil shale is shown in Figure 7J4. The endothermic peak in the 250-450°C temperature range corresponds to the thermal decomposition of oil shale kerogen. The area under this peak, the enthalpy value, was found to be directly proportional to the amount of kerogen in the shale in the absence of minerals that are thermally active in this temperature range. A least-squares fit of the AH obtained experimentally follows the equation... 

More recently, Kelemen et al. [154] discussed the pros and cons of XPS, XANES, and N NMR for characterizing and identifying the chemical forms of nitrogen in complex carbonaceous systems. They used both XPS and N NMR quantitatively to study kerogen obtained by demineralization of a Green River oil shale and of a peat sample, as well as chars obtained by pyrolysis and isoquinoline- and quinoline-derived chars. The inherent advantage of using a combination of these methods has thus been demonstrated. 

Structure of Kerogen from Oil Shale of the Green River Formation, In Science and Technology of Oil Shale Ann Arbor Science Publishers, Inc. Ann Arbor, MI, 1976. 

These oil shales represent two trillion barrels of oil in Colorado, Utah, and Wyoming, and an additional one trillion barrels of oil of Devonian shale formation in the eastern United States. Eastern Devonian shale is quite different from western Green River shale. The noticeable differences are in geological age, kerogen structure, oil content, pyrite, and other mineral compositions. In the past, little effort has been focused on Devonian shales. However, the increasing role of eastern shales has now... 

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