The Use of By-product Coal as Fuel on Boiler Plants of Small and Medium Power

Abstract

A significant environmental problem for the coal regions of Russia is the presence of large volumes of finedispersed coal sludges formed during the operation of coal mines and coal-preparation plants. In addition to direct environmental damage, storage of these sludges in sedimentation tanks, hydro-dumps or on sludge sites requires significant economic costs. Thus, the solution of the utilization problem of coal-enrichment wastes, especially finely-dispersed, represented by filter cakes of filtration compartments, containing practically all chemical reagents used in coal washing (flocculants, coagulants, etc.) is topical. The paper presents the results of research on the use of fine coalenrichment wastes as a fuel in boiler plants. It is shown that on the basis of these wastes it is possible to prepare a suspension water-coal fuel with a solid phase content of 56-60%, with the required structural-rheological characteristics and a net calorific value of up to 13 MJ / kg. A boiler with a thermal capacity of 0.63 MW with a vortex combustion system efficiently operating on fuel from coal waste was designed, manufactured and tested. The composition and effect of plasticizing additives on the rheological characteristics of the fuel is defined; the dependence of fuel consumption on its ash content is established. The results of the boiler operation on this fuel showed its high efficiency (the efficiency is 83-85%) with the level of harmful emissions in the flue gas significantly below the permissible values. Keywordsutilization of coal prepared waste, filter-cake, preparing, combustion of suspension coal-water fuel, structural and rheological characteristicsThe 9th Russian-Chinese Symposium. Coal in the 21st Century: Mining, Intelligent Equipment and Environmental Protection