Key words: brown and bituminous coals, anthracite, ignition, combustion, water-oxygen fluid
The results of a study on the oxidation of coals with varying degrees of coalification in an oxygen atmosphere and a water-oxygen fluid (oxygen excess coefficient 1.22—1.43) are presented. The experiments were carried out in the reactor heated at a constant rate (1 °C/min) to 550 °C. The temporal dependences of the temperature and pressure of the reaction mixtures indicate that the addition of water vapor to oxygen reduces the temperature of ignition of the coals and intensifies their combustion. This effect is most pronounced for coals with a high degree of coalification. At certain values of total heat release, coal oxidation in both O2 and H2O/O2 fluids proceeds via a thermal explosion mechanism. The influence of the composition of organic and mineral components of coals on their ability to ignite is discussed.