Variable Activation Energy Principle to Model Oil Shale Pyrolysis Kinetics

Abstract

The oil shale (OS) sample from Sultani mine, southern Jordan, was subjected to thermogravimetric/differential thermogravimetric (TG/DTG) and differential scanning calorimetry (DSC) analysis. Analysis was used to determine the kinetic parameters in the 300-540 °C temperature range, employing different heating rates (3, 5, 10, 20, 30 °C/min). The first order conversion function was found to best represent the oil shale pyrolysis kinetics. The data in the studied pyrolysis temperature range was divided into three zones according to the behavior of the quantity ln(/ /(1)) dx dT x  vs 1/ () T K. In the first linear zone, the apparent activation energy and frequency factor were found to be in the range of 63.1-94.2 kJ/mol and 9.3E+3-5.03E+6, respectively. In the second zone of analysis, the apparent activation energy was found to be negative and varied between-25.8 and-2.13 kJ/mol and the corresponding frequency factor was in the range of 19.65-0.00098. In the third zone under study, the calculated apparent activation energy and frequency factors were in the range of 186.9-342.1 kJ/mol and 1.87E+12-1.46E+23, respectively.

Kinetic modelling of biomass fast devolatilization using Py-MS: Model-free and model-based approaches

“…11) are obtained at the end of the process (therefore, in the presence of residual solids) and under isothermal conditions (see Supplementary material, section K). The decrease in E α could be explained by a shift of the process-determining step [92] and most probably with exothermic char-forming reactions catalyzed by minerals with biochar and characterized by intrinsic negative activation energy [93,94]. However, further investigation is required to support this suggestion.…”

Cinética de la pirólisis del esquisto bituminoso por el método isoconversional de Kissinger-Akahira-Sunose y gráficos maestros

“…En la Figura 3, se muestran los resultados del análisis isoconversional según el método de KAS y los gráficos maestros para el cálculo de los parámetros cinéticos. Además, muestra la aplicación gráfica del método isoconversional KAS para las etapas (II) y (III), que comprende rangos de conversión de 0.05≤α≤0.35 y 0.35<α≤0.95 respectivamente, donde se obtienen valores promedios de la energía de activación (Ea) por regresión lineal de 81.53 y 163.08 kJ/mol, estos valores son similares al reportado por (Ayed et al, 2017), el cual evaluó la pirólisis del esquisto bituminoso de Jordania obteniendo valores de 82 y 186 kJ/mol.…”

The Chemical Composition and Pyrolysis Characteristics of Thermal Bitumen Derived From Pyrolyzing Huadian Oil Shale, China

“…On the other hand, thermogravimetric analysis (TGA) has been widely used to determine the pyrolysis characteristics of oil shale and kerogen [11][12][13][14][15][16]. Wang et al [11] performed the non-isothermal pyrolysis of Huadian oil shale.…”