{delta}{sup 13}C GC-IRMS characterisation of extractable and covalently-bound aliphatic hydrocarbons in petroleum source rocks to reveal compositional fractionation effects
- Univ. of Strathclyde, Glasgow (United Kingdom)
- Scottish Universities Research & Reactor Centre (SURRC), Glasgow (United Kingdom)
The structural elucidation of sedimentary fossil organic matter at a molecular level remains a challenging task, on account of its heterogeneous, largely insoluble nature. An elaborate sequential extraction/degradation scheme to differentiate between molecular alkanes (both easily extractable, and those physically-trapped or clathrated within the macromolecular structure) and alkyl moieties covalently bound within the kerogen network, was recently devised by the Strathclyde group. Briefly, the scheme incorporates exhaustive solvent extraction with dichloromethane (DCM) Followed by pyridine to remove physically trapped material and then a mild batch hydrogenation step is performed to cleave weak heteroatomic bonds (principally ester, thioether and possibly ether linkages). The key and final stage in this procedure to release strongly-bound hydrocarbons is pyrolysis at high hydrogen pressures (up to 15 MPa, about 150 atmospheres) which is known as hydropyrolysis. Thermolysis in a high hydrogen pressure (reducing) environment eliminates the problem of low yields often associated with the use of sterically-bulky chemical reagents and limits the extent of retogressive, char-forming chemistry. Hydropyrolysis gives rise to overall carbon conversions approaching 100% for Type I and Type II kerogens (these have higher H/C ratios than coals, which are classified as Type III kerogens on the basis of elemental composition) with low hydrocarbon gas yields.
- OSTI ID:
- 420579
- Report Number(s):
- CONF-950801-; ISSN 0569-3772; TRN: 97:000005-0013
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Vol. 40, Issue 3; Conference: 210. national meeting of the American Chemical Society (ACS), Chicago, IL (United States), 20-25 Aug 1995; Other Information: PBD: 1995
- Country of Publication:
- United States
- Language:
- English
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