Technologies of coatings employment for coals oxidation resistance improvement

The paper is dedicated to studying of the efficiency of application of the dust control agents not only for their original aims, but also for increasing of oxidation resistance of the solid fossil fuels. The complex investigation included: studying of coals quality alteration after treatment by the selected solution, scanning electron microscopy for investigation of their surface topology changes and, finally, ozonating treatment at low ozone concentrations with kinetic modeling for evaluation of oxidation resistivity. As it was expected, application of the selected solution allows no quality loss for coals. Scanning electron microscopy allowed to visualize the mechanism of working of the dust control agent. It revealed that the studied solution forms a thin smooth film around coal particles. This film tightly binds all the fine particles that were already formed and stored at the coal surface. Also, the solution tends to cover the surface thus decreasing the accessibility of the surface to active oxygen. The latter was proved by treated and untreated coals ozonating processing at low concentrations of ozone. The applied kinetic model allowed evaluation of the total coals activity to ozone decomposition. It was found that the treated coals have twice as low total activity to ozone decomposition as compared with the untreated ones. The latter parameter is closely related to coals oxidation resistivity (the lower the coals activity, the higher the coals oxidation resistivity). Therefore, it was finally concluded that application of the studied dust control agent allows for significant increase of sought-for quality indicator.