Experimental development of approaches to reduce the slagging and corrosive activity of salty coal

Abstract

The problems of reducing the slagging ability and corrosiveness of coal with a high content of low-melting salts (the so-called salty coal (SC) in the processes of its combustion) are considered. Salty coal is considered to be the coal, the ash of which contains Na2O>2 %. The object of study is the salty coal of Donbass and ways of solving the problems of its use. The influence of low-melting salts on the formation of ash deposits and the development of corrosion of the metal surface during the combustion of salty coal from different fields was determined.A noticeable decrease in the slagging ability and corrosiveness of the test coal was noted during the removal of salts by water extraction. The composition of corrosive compounds (oxides Fe2O3, Fe3O4 and iron sulfide FeS) has been determined, formed during the combustion of native coal, and their absence in the case of desalinated coal.Artificial fuel mixtures produced from more reactive salty and conventional low reactive coal have been studied. To create a mixed fuel, long-flame salty coal (low stage of metamorphism) from the Northern Donbas and unsalty lean coal (high stage of metamorphism) from Kuzbas were used. A significant deviation (to 9 %) was noted for the release of ash during the combustion of mixtures from the additivity, indicating a chemical interaction between the mineral components of the mixture. The formation of new refractory mineral phases of ash (nepheline, ultramarine, combeite) during the combustion of composite fuel from coals of different metamorphism and salinity was established.The obtained results will be useful in the development of recommendations for the preparation of model fuel mixtures and their accident-free combustion in industrial boiler units. Experimental data on the determination of new mineral compounds in the case of composite fuels can be used to create a general theory of slagging in the combustion of salty coal of different origins