INVESTIGATION OF THE EFFECT OF SAWDUST-COAL COMPOSITE FORMATION ON THE PROCESSES OF IGNITION, COMBUSTION, AND THERMAL DECOMPOSITION OF THE OBTAINED FUEL SAMPLES

Abstract

The paper presents a comprehensive study of the ignition of composite fuel from pine sawdust and brown coal. Using the method of synchronous thermal analysis, it was shown that the combustion of the samples occurs in two main stages. At the first stage, the release and combustion of gaseous products occurs; at the second stage, the product of the first stage, carbon, is oxidized. An increase in the carbon content in the composite leads to a shift in the maximum decomposition rates in the first stage to higher temperatures, a decrease in the decomposition value in the first stage, and an increase in the second. Experiments in a vertical tube furnace showed that the value of the ignition delay time for the composite is less than for other samples (mixture, coal, sawdust). An experimental study of ignition, gasification, and flare combustion of selected samples was carried out in a setup with a thermal power of up to 50 kW. It was found that the combustion temperatures of the mixture and composite fuel are higher than those of sawdust. The composite burns better than the mixture-combustion begins earlier; the combustion zone is shifted to the center, which contributes to an increase in the completeness of fuel combustion. The electron paramagnetic resonance shows the formation of paramagnetic centers on the surface of particles during mechanical activation grinding of samples, the concentration of which is related to the ignition time of the fuel.