Authors: N.I. Fedorova, I.Yu. Zykov

Title of the article: Thermogravimetric study in an oxidizing atmosphere of anthracite coals

Year: 2025, Issue: 5, Pages: 83-90

Branch of knowledge: 2.6.12. Chemical technology of fuel and high-energy substances

Index UDK: 662.749

DOI: 10.26730/1999-4125-2025-5-83-90

Abstract: The relevance of the work is determined by the need to establish the relationship between the structure and chemical and technological properties of coal raw materials in order to determine the rational ways of its technological processing into products of the required quality. The purpose of the study was to identify the structural features of the organic matter of anthracite coals by NMR spectroscopy and to determine their reactivity to atmospheric oxygen by thermogravimetric analysis. Three samples taken from commercial anthracite samples extracted from the Bungursky, Krasnogorsky and Listvyansky sections were used as research objects. The test samples belong to the group of highly metamorphosed coals (Cdaf > 95%), have low ash content (about 4%), volatile matter yield (less than 8%) and low total sulfur content (Std no more than 0.3%), as well as vitrinite reflection index of 2.6%, 2.8% and 5.3%, respectively. NMR spectroscopy data showed that the composition of the organic mass of the studied samples is mainly represented by aromatic fragments. The sample of the "Listvyansky" section has the highest degree of aromaticity (fa = 0.98). The reactivity to oxygen in the air of the test samples was determined by thermogravimetric analysis. The following indicators were used as criteria: TВ - is the ignition temperature, determined by the beginning of the bend in the DTA curve; T1 - is the temperature of the beginning of mass loss, determined by the beginning of the bend in the TG curve; Tmax -is the temperature at which the maximum oxidation rate is reached; T2 -is the final temperature at which the coke residue burns out. Taking into account the time parameters, the ignition and gorenje indices are calculated. It was revealed that the structural features of their organic mass determine the parameters of oxidative degradation of the studied anthracite samples. With an increase in the degree of aromaticity (fa), the ignition temperature (TВ), the temperature of the maximum mass loss rate (Tmax) and the final temperature of thermal oxidative degradation (T2) increase. It has been established that anthracite samples from the Bungur and Krasnogorsk sections, having a relatively large number of aliphatic structures and oxygen functional groups in their organic mass, are characterized by increased reactivity to atmospheric oxygen.: They are characterized by lower temperatures and, as a result, higher values of the ignition and flammability indices. It is advisable to use samples from these sections as high-calorie fuel, as well as as raw materials for the production of microporous adsorbents according to a combined scheme, which includes low-temperature oxidation at 270-300oC at the first stage.

Key words: anthracite NMR spectroscopy degree of aromaticity thermogravimetric analysis ignition index gorenje index reactivity

Receiving date: 25.02.2025

Approval date: 22.09.2025

Publication date: 23.10.2025

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