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Measurement of coke porosity by image analysis methods
Ščučka, Jiří ; Kožušníková, Alena
An effective method for visualization and quantitative analysis of coke porosity is presented in the paper. The method is based on image processing and analysis combined with fluorescence microscopy of impregnated coloured preparations and enables the determination of percentage portion of pores in the coke, mean pore-size, mean cell-wall thickness and their distribution.
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Study of the coal oxidation temperature dynamics
Taraba, B. ; Peter, R. ; Slovák, V. ; Janek, Jiří ; Dušková, Anežka
Temperature dependence of coal oxidation rate was investigated between 30°C and 160°C using air flow reactor and/or methods of inverse gas chromatography, pulse flow calorimetry and thermogravimetry. As a parameter quantifying the temperature dynamics of coal oxidation, values of activation energy E were calculated from Arrhenius plots (Ln (oxidation rate) versus Reciprocal temperature). These E values were found to vary between 28 and 57 kJ/mol. Moreover, non-linear course of the Arrhenius plots was confirmed with breaks at temperatures between 45°C and 120°C. The break was denoted as threshold temperature Tth and its value indicates a temperature beyond which the coal oxidation gains more intense disposition. Based on the experimental results, reason of the change in coal oxidation process at the Tth temperature was revealed to be chemical in character.
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