Characterization of Macromolecular Structure Elements from a Green River Oil Shale, I. Extracts

Abstract

This paper is the first of two associated papers describing the structural details of three sections of an oil shale core taken at the Skyline 16 mine in the Utah Uinta Basin. Bitumen was extracted from the shale using methanol/dichloromethane. Kerogen was isolated from the shale, using a nine-step extraction procedure using HCl and HF. Bitumen samples from the three cores were analyzed using high-resolution 13C NMR liquid-state spectroscopy, showing carbon aromaticities of 7%–11%. Aliphatic carbons were dominated by methylene structures, with average aliphatic chain lengths of 24 carbons. The three parent shales and the demineralized kerogens were each analyzed with solid-state 13C NMR spectroscopy. Analysis of the carbon structure in the shale was hindered by the large amount of carbonates and ferri/ferro magnetic material present, but the organic structure of the shale was shown to be almost identical to the structure of the demineralized kerogen. Carbon aromaticity of the kerogen was 23%–24%, with 10–12 aromatic carbons per cluster and estimated molecular weights of 776–946, side chain molecular weights of 131–148, and side chain lengths of 11–13 carbons.

Characterization of Macromolecular Structure Elements from a Green River Oil Shale, II. Characterization of Pyrolysis Products by 13C NMR, GC/MS, and FTIR

“…These peaks were never observed in the bitumen spectra. 27 However, these two peaks in the aromatic region are consistent with the presence of terminal alkene functional groups. These two functional groups are also consistent with the alkane/alkene pairs that are found in the GC/MS data.…”

“…This paper is related to a companion paper that describes the solid-state NMR characteristics of the unreacted Green River oil shale from this core, together with the corresponding demineralized oil shale kerogen and bitumen. 27 The detailed NMR data presented here at different stages of pyrolysis for a well-characterized oil shale sample are unique and add to the understanding of the thermal decomposition of oil shale.…”

“…The 9-step demineralization procedure is outlined in Figure 1 of Solum et al 27 The three demineralized kerogen samples are referred to as GR1.9, GR2.9, and GR3.9. Ash tests were performed on the three kerogen concentrate samples to determine the residual mineral matter not removed by the demineralization procedure.…”

Modeling Light Gas and Tar Yields from Pyrolysis of Green River Oil Shale Demineralized Kerogen Using the Chemical Percolation Devolatilization Model

“…Miknis et al then postulated that the oil yield could be correlated with the aliphatic content of the kerogen. More detailed chemical structure characterization with advanced NMR techniques were obtained by Solum et al 16 and Fletcher et al, 18 which have been used to develop the model reported here for three samples of a Utah Green River oil shale. This model is only applicable to the Green River kerogen samples referenced herein.…”

Dynamic imaging of oil shale pyrolysis using synchrotron X‐ray microtomography

“…The largest known deposit is the Eocene Green River Formation in Western Colorado, Eastern Utah, and Southern Wyoming [Dyni, 2003;Johnson et al, 2009]. Kerogen, which constitutes most of oil shale's organic matter, is a highly cross-linked, macromolecular material distributed in a heterogeneous inorganic matrix [Fletcher et al, 2014;Solum et al, 2013]. Pyrolysis of oil shale breaks down the complex kerogen network structure to produce shale oil and natural gas [Hillier et al, 2013;Sun et al, 2014].…”