National University of Science & Technology MISIS, Moscow, Russian Federation:

S. A. Epshtein, Head of Laboratory of Physics and Chemistry of Coals, Doctor of Engineering Sciences, apshtein@yandex.ru
D. I. Gavrilova, Engineer, Post-Graduate student
E. L. Kossovich, Senior Researcher, Candidate of Physical and Mathematical Sciences

Moscow State University of Civil Engineering, Moscow, Russian Federation

A. O. Adamtsevich, Senior Researcher, Scientific-research laboratory of Physical and Chemical Analysis, SRI CM & T, Candidate of Engineering Sciences

In the current work various thermal methods are discussed utilized for characterizing the coals oxidation processes. The most commonly used ones are listed and their primary pros and cons are described. Utilization of isothermal calorimeters allows evaluating the coals thermal characteristics in situ. It was demonstrated that the most important condition at such methods application is a maximally fast equilibration of sample and reference heat capacities in order to prevent errors connected with coals oxidation at initial stage of experiment. A method is proposed for thermal characteristics evaluation for low-temperature coal oxidation processes on the basis of TAM Air microcalorimeter. Some issues are discussed regarding reference sample effects on experimental results such as: retention time to the reference line, maximal heat velocity, total heat value, and their metrological characteristics. Utilization of a grinded temperature-stabilized quartz as a reference allowed to reduce the retention time to the reference line. Statistical processing of the results obtained for the parallel experiments revealed high metrological characteristics of the measurements performed with quartz used as a reference. Some measurements were held at a temperature of 40 °C at coals with different composition, properties and rank: lignites, bituminous coals and anthracite It was established that during the processes of low-temperature oxidation of the lignites the maximal heat velocities and total heat are substantially higher in comparison with the corresponding values obtained for bituminous coals and anthracite. The results are in good agreement with the well-known fact that the lignites’ propensity to oxidation is much higher than for bituminous coals and anthracites. But the results analysis for coals of the same type (lignites or bituminous coals) depicts variation of the measures characterizing heat generation at low-temperature oxidation.
The study was supported in the framework of the Federal Targeted Program on R&D in Priority Areas of Science and Technology Advancement in Russia for 2014–2020, Agreement No. 14.575.21.0062, Unique Agreement Identifi er RFMEF157514X0062.

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