Thermal and Kinetic Characteristics of some Oil Shale Samples

2015 ◽  
Vol 1126 ◽  
pp. 67-74
Author(s):  
Tiit Kaljuvee ◽  
Rein Kuusik ◽  
Vilma Petkova
Keyword(s):  
Oil Shale ◽  
Isoconversional Method ◽  
Heating Rates ◽  
Low Temperature Oxidation ◽  
Gaseous Species ◽  
Temperature Oxidation ◽  
Model Free ◽  
Thermooxidative Decomposition ◽  
Volatile Organic ◽  
Ftir Spectrometer

The thermal behaviour of different oil shale samples (Estonia, Jordan, Israel, Morocco) were studied using a Setaram Setsys 1750 thermoanalyzers coupled to a Nicolet 380 FTIR Spectrometer. The experiments were carried out under non-isothermal heating conditions up to 1000 °C at different heating rates in an oxidizing atmosphere. A model-free kinetic analysis approach based on the differential isoconversional method of Friedman was used to calculate the kinetic parameters. The thermooxidative decomposition of oil shale samples proceeded in three steps. Firstly, thermooxidation of volatile organic compounds occurred – depending on the heating rate, up to 460 °C. Secondly, thermooxidation of heavier part of organic matter (kerogen) and fixed carbon as well as thermooxidation of pyrite proceeded up to 580 °C. Finally, carbonates contained in oil shale samples decomposed up to 870 °C. The combined TG-FTIR study of thermooxidative decomposition of samples made it possible to identify in addition to CO2 and H2O as major gases evolved a number of gaseous species like CO, SO2, COS, methane, ethylene, etc. formed and evolved at that. The value of activation energy E in the low-temperature oxidation region was for Estonian and Jordanian oil shale samples lower than that in the high-temperature region which was contrary for Israeli and Moroccan oil shale samples. Therefore, the results obtained indicated the complex multi-step character of the thermooxidative decomposition of the oil shale samples studied.

scholarly journals Study on the Low-Temperature Oxidation Law in the Co-Mining Face of Coal and Oil Shale in a Goaf—A Case Study in the Liangjia Coal Mine, China

Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 174 ◽  
Author(s):  
Gang Wang ◽  
Yue Wang ◽  
Lulu Sun ◽  
Xiang Song ◽  
Qiqi Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Coal Mine ◽  
Oil Shale ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Mining Face

Determination of activation energy during the thermal degradation of Polyamide 66/glass fiber composites

2019 ◽  
Vol 33 (7) ◽  
pp. 956-966
Author(s):  
Hamidreza Azimi ◽  
Pardis Abedifard
Keyword(s):  
Activation Energy ◽  
Glass Fiber ◽  
Degradation Kinetics ◽  
Isoconversional Method ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Polyamide 66 ◽  
Isokinetic Relationship ◽  
Exponential Factor ◽  
Model Free

The objective of this study was to clarify the mechanical properties and the non-isothermal degradation kinetics of Polyamide 66 (PA 66)/glass fiber (GF) composites. The non-isothermal degradation behavior of the samples was studied by thermal gravimetric analysis under nitrogen purge. The perfect compatibility of GFs with polymer matrix in composites was studied by scanning electron microscopy. It was found that with increasing content of GFs in samples due to good distribution of fibers in PA 66, the degradation temperature and calculated activation energy in composites increased in all heating rates. The activation energy was calculated by the Flynn–Wall–Ozawa method (isoconversional method). It was concluded that the model-free methods can be a reliable way to determine the kinetic parameters. Furthermore, the isokinetic relationship was used to estimate a model-independent pre-exponential factor (ln A) corresponding to a given degree of conversion.

scholarly journals Study on Low Temperature Oxidation Characteristics of Oil Shale Based on Temperature Programmed System

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2594 ◽  
Author(s):  
Wenzhou Du ◽  
Yue Wang ◽  
Xuelin Liu ◽  
Lulu Sun
Keyword(s):  
Low Temperature ◽  
Oil Shale ◽  
Steady Increase ◽  
Low Temperature Oxidation ◽  
Combustion Heat ◽  
Temperature Oxidation ◽  
Air Supply ◽  
Oxidation Stage ◽  
Oxidation Characteristics ◽  
Temperature Programmed

Oil shale is a kind of high-combustion heat mineral, and its oxidation in mining and storage are worth studying. To investigate the low-temperature oxidation characteristics of oil shale, the temperature, CO, alkane and alkene gases were analyzed using a temperature-programmed device. The results showed that the temperature of oil shale underwent three oxidation stages, namely a slow low-temperature oxidation stage, a rapid temperature-increasing oxidation stage, and a steady temperature-increasing stage. The higher the air supply rate is, the higher the crossing point temperature is. Similar to coal, CO also underwent three stages, namely a slow low-temperature oxidation stage, a rapid oxidation stage, and a steady increase stage. However, unlike coal, alkane and alkene gases produced by oil shale underwent four stages. They all had a concentration reduction stage with the maximum drop of 24.20%. Statistical classification of inflection temperature of various gases as their concentrations change showed that the temperature of 140 °C is the key temperature for group reactions, and above the temperature of 140 °C, all alkane and alkene gases underwent the rapid concentration increase stage.

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