Detailed kinetic analysis of oil shale pyrolysis TGA data

Abstract

There are significant resources of oil shale in the western United States, which if exploited in an environmentally responsible manner would provide secure access to transportation fuels. Understanding the kinetics of kerogen decomposition to oil is critical to designing a viable process. A dataset of thermogravimetric analysis (TGA) of the Green River oil shale is provided and two distinct data analysis approachesadvanced isoconversional method and parameter fitting are used to analyze the data. Activation energy distributions with conversion calculated using the isoconversional method (along with uncertainties) ranged between 93 and 245 kJ/mol. Root mean square errors between the model and experimental data were the lowest for the isoconversional method, but the distributed reactivity models also produced reasonable results. When using parameter fitting approaches, a number of models produce similar results making model choice difficult. Advanced isoconversional method is better in this regard, but maybe applicable to a limited number of reaction pathways. V

Identifying the reaction mechanism of oil-shale self-heating retorting by thermal analysis techniques

“…1b). The first weight-loss region around $250-500°C is dominated by the desired pyrolysis of kerogen [31]. The second weight-loss region located above 650°C is dominated mainly by the decomposition of carbonates such as calcite in the [31,18].…”

“…Note: the Q Ads value for OS ash is the value for the ash prepared by per gram of raw OS, and thus the unit (J g À1 K À1 ) of the Q Ads for OS ash in the figure is also joules per gram of raw OS per Kelvin. non-isothermal mode, the decomposition of kerogen could be represented by the following reaction [31]:…”

Experimental methods in chemical engineering: Thermogravimetric analysis—TGA

“…Capillary gases may be oxidizing, inert, or reducing. An oxidizing atmosphere, such as air or oxygen, combusts organic materials and oxidizes metals . Changing oxidation states complicates the analysis as the mass increases.…”

Structural characterization of shale oil obtained by Soxhlet extraction

“…Moreover, heating rate is a significant factor and should not be more than 10.0 or 20.0°C/min to get a stable and informative TG plot . On the other hand, the flow rate of nitrogen gas was set at 50 mL/min which is often recommended for oil shale . As indicated in Figure , typical TG plots were reported which confirmed that serious composition of organic matter started at temperatures higher than 400°C at both flow rates.…”