Thermogravimetric Analysis of Coal Activated by Various Means

The organization of thermal analysis using a differential scanning calorimeter to investigate the combustion of fuel mixtures based on coal prepared by different methods is considered. The results of thermogravimetric analysis are presented for coal prepared in a mill and a disintegrator. Stages in the combustion process are distinguished. The idea that thermal analysis is an objective means of assessing the properties of materials at different temperatures is briefly discussed. An organizing procedure is proposed for experiments on the ignition of lignite, coal, and anthracite using a test bench that simulates a vertical tubular furnace. According to the experiments, the peak of energy liberation in combustion is at 580°C; active mass loss begins at 520°C. For coal samples crushed in a hammer mill, this peak is at 480°C; for samples from a disintegrator, it is at 420°C. The ignition time of mechanically activated coal depends on the presence of chemical processes with the liberation of volatiles, which readily ignite. Deep crushing also shortens the ignition time. An alternative method of determining the ignition temperature is outlined; in this method, the temperature is decreased to the ignition temperature. Results obtained by this method are presented.