Applicability of Static Supercritical Carbon Dioxide Extraction in Biogeochemical Characterization of Oil Shales

Abstract

This study aimed at the assessment of applicability of static supercritical carbon dioxide extraction method (SFE) in biogeochemical characterization of oil shales as an alternative to the standard Soxhlet extration. A comparative investigation on yields and compositions of the solvent soluble bitumoids and their constituents extracted from Estonian Kukersite and Dictyonema oil shales by using Soxhlet extraction method (SEM) and static CO 2 supercritical fluid extraction in an autoclave at varied subpyrolysis temperatures was carried out. Resulting from TLC-and GC-MS-analyses, aliphatic and aromatic hydrocarbons and neutral oxygen compounds were separated and identified. For the first time, in the composition of the Kukersite bitumoid, homologous series of n-alkanones-3 to n-alkanones-7 were detected. The extracts obtained were similar in both group and individual composition, and geochemical parametres calculated on the basis of aliphatic hydrocarbons including that made static SFE applicable to geochemical investigation of oil shales.