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Abstract  

Thermal analysis is increasingly being used to obtain kinetic data relating to sample decomposition. In this research differential scanning calorimeter (DSC) was used to determine the combustion kinetics of three (an, Himmetoglu and Mengen) oil shale samples by ASTM and Roger & Morris methods. On DSC curves two reaction regions were observed on oil shale sample studied except an oil shale. In DSC experiments higher heating rates resulted in higher reaction temperatures and higher heat of reactions. Distinguishing peaks shifted to higher temperatures with an increase in heating rate. Three different kinetic models (ASTM I-II and Rogers & Morris) were used to determine the kinetic parameters of the oil shale samples studied. Activation energies were in the range of 131.8-185.3 kJ mol-1 for ASTM methods and 18.5-48.8 kJ mol-1 for Rogers & Morris method.

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Introduction Oil shales (OS) are fine-grade sedimentary rocks containing relatively large amounts of combustible organic matter (kerogen) in mineral matrix. The amount and composition of organic matter as well as the

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References M. Abu Ajamieh 1980 An assessment of the El-Lajjun Oil Shale Deposit Natural Resources

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Abstract  

In this research, pyrolysis and combustion behavior of three different oil shale samples from Turkey were characterized using thermal analysis techniques (TG/DTG). In pyrolysis experiments, two different mechanisms causing mass loss were observed as distillation and cracking. In combustion experiments, two distinct exothermic peaks were identified known low and high temperature oxidation. On the other hand, determination of activation energies are required for the estimation of oil extraction conditions from the oil shales. Differential methods are used to determine the activation energies of the samples where various f(α) models are applied from the literature. It was observed that the activation energies of the all oil shale samples are varied between 13.1–215.4 kJ mol−1 in pyrolysis and 13.1–408.4 kJ mol−1 in combustion experiments which are consistent with other kinetic results.

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Abstract  

Combustion and pyrolysis experiments of Huadian oil shale have been conducted using a STA409 thermogravimetric analyzer. The effect of various factors on combustion of oil shale is studied. Particle size has little effect on combustion process of oil shale; starting temperature of combustion mass loss and ignition temperature of oil shale decrease with increasing O2 concentration of ambient gas; increase of heating rate can result in ignition temperature, burn-out temperature and maximum rate of combustion mass loss increasing. Homogeneous ignition mechanism of oil shale is ascertained using a hot state microscope. Activation energy was determined using Arrhenius model that is solved by Freeman–Carroll method. Calculation results show activation energy will increase with heating rate.

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Abstract  

The combustion kinetics of Göynük oil shale, polystyrene and several polystyrene-oil shale blends were investigated by thermogravimetric analysis in the present study. Experiments were conducted at non-isothermal conditions with a heating rate of 5, 10 and 20 K min−1 in the 298–1173 K temperature interval under an air atmosphere. Differential thermogravimetric data were analyzed by two different models. Effects of blending ratio of oil shale and polystyrene and heating rate on the combustion kinetics were investigated. Kinetic parameters were determined and the results were discussed.

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Abstract  

This research was aimed to investigate the combustion and kinetics of oil shale samples (Mengen and Himmetoğlu) by differential scanning calorimetry (DSC). Experiments were performed in air atmosphere up to 600�C at five different heating rates. The DSC curves clearly demonstrate distinct reaction regions in the oil shale samples studied. Reaction intervals, peak and burn-out temperatures of the oil shale samples are also determined. Arrhenius kinetic method was used to analyze the DSC data and it was observed that the activation energies of the samples are varied in the range of 22.4–127.3 kJ mol−1 depending on the oil shale type and heating rate.

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Abstract  

Pressurised differential scanning calorimeter (PDSC) has been used to obtain information on the pyrolysis and combustion characteristics of oil shales. Two distinct exothermic peaks were identified in combustion experiments known as low temperature oxidation (LTO) and high temperature oxidation (HTO) reaction regions. The pyrolysis process of all studied oil shale samples showed one exothermic effect at each total pressure studied. Kinetic data were analysed by Roger & Morris and Arrhenius methods and the results are discussed.

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Abstract  

In this paper, pyrolysis characteristics of oil shale obtained from Huadian, China, are investigated by thermogravimetry method. The effect of operating conditions, such as particle size, heating rate on the pyrolysis process is analyzed, and kinetic parameters of pyrolysis at different heating rates are calculated using a two-stage Arrhenius model that is solved by the Freeman-Carroll method. On the basis of these experimental results and theoretical analysis, a mathematical model, fully suitable for the pyrolysis characteristics of oil shale, is developed: mass loss rate is described by a two-stage intrinsic kinetics equation for reducing the calculation error; pyrolytic heat value of volatile is contained in energy equation, and density equation is considered as well, due to the release of a large amount of volatiles in pyrolysis process. Thermogravimetric experimental data are used to validate the described models.

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Abstract  

The pyrolysis and combustion kinetics of Gynk oil shale were investigated by thermogravimetric analysis in the present study. All experiments were conducted at non-isothermal conditions with a heating rate of 10–60 K min–1 in the 298–1173 K temperature interval under argon and air atmospheres for pyrolysis and combustion, respectively. Differential thermogravimetric data were analyzed by a reaction rate model assuming first order kinetics.

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