MECHANISM AND KINETICS OF COAL COMBUSTION IN OXYGEN ENHANCED CONDITIONS

摘要

The study of the coal combustion process carried out in an oxygen enhanced conditions is presented. Thepresented paper is focused on the analysis of the kinetics and the mechanism of coal combustion processes. This analysisis based on both the data acquired during an experimental investigation and a mathematical model. The combustionprocess was considered to be carried out in gas The investigation covers coal which was represented by hard coal andlignite. From this work a mathematical model that describes the combustion process was developed. This model wasvalidated against experimental data, which took into account the varying oxygen concentration. The model wasdeveloped through the analysis of the rate of mass loss of the fuel sample in the test facility. The test facility setup wasallowed to predefine the given oxygen concentration and the temperature of the gas mixture in range of 500 °C to 850 °C.It was observed that the combustion mechanism of this type of coal depended on the oxygen concentration as well as thekinetics of the combustion process of such a fuel type. A strong response to oxygen concentration was also shown. Ahigher concentration of oxygen in the gas mixtures caused higher concentration of carbon monoxide as a primaryproduct of the carbon oxidation process. Increasing the contribution of the oxidiser in the gas mixture raises the rate ofoxygen diffusion toward the surface of the fuel grain. Similarly, the rate of chemical reactions during the combustionprocess rises for gas mixtures enriched with oxygen. Both of those trends significantly reduce the total time of thecombustion process. The kinetics of the combustion process of such a type of fuel, has shown a strong response tooxygen concentration.