The approach for reducing of slagging and corrosion properties of fuels with a high content of alkali and alkaline earth metals

In order to involve coal with a high content of alkaline and alkaline earth metals (so-called salty coal) in the fuel base of the Ukrainian energy sector and to solve problems in its use (formation of ash deposits and development of corrosion processes), studies were performed on the co-combustion of salty coal with traditional steam coal. The phase composition of the ash of the studied samples of salty coal and its blends with traditional steam coal was analyzed using X-ray diffraction (XRD). It was found that significant changes in the phase composition of the ash blends occur, namely the formation of new mineral phases such as Nepheline ( NaAlSiO 4 ), Jadeite ( NaAlSi 2 O 6 ), Albite ( NaAlSi 3 O 8 ), and ultramarines such as Hauyne ( Na 6 Ca 2 (Al 6 Si 6 O 24 )(SO 4 ) 2 ) and Nosean ( Na 8 Al 6 Si 6 O 24 SO 4 ), which have high melting points. In addition, using the optical and gravimetric methods, a significant decrease in corrosion activity during the combustion of composite fuel with the participation of salty coal was determined. It was found that the composite fuel involving the studied salty coal at its content of 20 to 50 % in the blend significantly reduces the effects of slagging (due to an increase in the melting point) and the corrosion activity of the fuel.