Using neoteric solvents in oil shale studies

Abstract

Abstract:The liquefaction, gasification, and other chemical modifications of oil shale are challenging goals of chemistry and chemical engineering. The use of new solvent systems, such as supercritical fluids and ionic liquids, represents new avenues in the search of environmentally benign technologies. Supercritical fluid extraction (SFE) with carbon dioxide is particularly effective for the isolation of substances of medium molecular weight and relatively low polarity. At elevated temperatures it is possible to unite the breaking chemical bonds in the kerogen organic matter and convert the former into oil with extraction using supercritical fluids. Quantitative and qualitative information obtained at different temperatures during SFE is providing some insight into the speciation of hydrocarbons in geological samples. Ionic liquids were studied as potential solvents for kerogen extraction. However, these chemical processes are favored at elevated temperatures up to the thermal degradation temperature of kerogen, ≈400 ºC. There were observed significant differences in the chemical composition of extracted oil and from the oil from the classical semicoking process of oil shale. An additional application would be a combination of the two methods-the use of supercritical carbon dioxide to recover nonvolatile organic compounds from room-temperature ionic liquid without using organic solvents.

Processing of Fuel Materials with Hydrothermal and Supercritical Water

“…The extraction yield and composition from Kukersite oil shale at T ¼ 200 C with water is quite similar to that obtained with methanol-modified carbon dioxide [30]. At supercritical conditions, water can be used for degradation of kerogen, and thus can be used to produce oil from shale.…”

“…At these conditions, the presence of minerals can lead to the formation of additional products. Also, using modifiers to carbon dioxide having a hydrogen-donor capability, like alcohols, lead to hydrogenation reactions [30].…”

Naphthenic acid extraction and speciation from Doba crude oil using carbonate-based ionic liquids

“…This is consistent with work by Shi et al [18] which showed that 4.7 wt% of the crude oil was extracted by ethanol. Koel et al also showed that addition of methanol to supercritical CO 2 also led to an increase in the extraction of more polar hydrocarbon-based compounds [32].…”

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

“…Rather little effects than essential advantages were observed. In [8], solvents of different polarities as methanol, acetonitrile, acetone, methylene chloride, tetrahydrofuran, toluene and hexane were used, and the authors became convinced that the yields of extractables from different oil shales at room temperature were in time lower compared with SEM depending differently on the nature of the solvent. In the same work, dynamic SFE was demonstrated as effective for the isolation of substances of medium molecular weight and relatively low polarity.…”

“…It has been reported that, in oil shales, dynamic extractions with pure supercritical carbon dioxide in a flow reactor, mainly n-alkanes, were extracted while addition of modifiers as methanol or ionic liquids slightly increased extract yield and enriched its composition with other compounds [8,12].…”