Ecologically hazardous elements in coals of the Donets Basin

Abstract

The coals from the Donets Basin are widely used in electric power plants (EPP). These, together with air pollutants generated by other industrial enterprises create a hazardous situation in the densely populated region of the Basin. Together with sulfur oxides, nitrogen oxides and solid particulates the emissions contain very toxic, noxious trace elements such as Be, F, V, Cr, As, Se, Cd, Hg, Mn, heavy metals and natural radionuclides. To establish potentially ecologically hazardous concentrations of elements-admixtures in coals it is necessary to have the following information: (1) Their concentration in feed coal used and (2) their ability to transfer into the gaseous phase when burned. The data for item 1 are the result of geological exploration; data for item 2 may be obtained during laboratory experiments or by monitoring EPP utilizing coals. National standards for air quality give the highest allowable concentrations of trace elements in coals. Calculation of hazardous concentrations is performed in accordance with the mathematical model for emissions in the air by the Main Geophysical Observatory (Russia, St. Petersburg). Ecologically hazardous trace elements in coals of the Donets Basin are the following: (g/t): Be—0.7–0.8, Se—1.9, As—2, V—33, Mn—38, Cr—44, Cd—58, Pb—186, Th—373.3 and S—1.2%. Emissions of hazardous trace elements have also been determined for steam-boilers with a circulating boiling layer (fluidized bed combustion—FBC). Determining ecologically hazardous concentrations of trace elements in coal and coal combustion products gives the required initial data for planning nature-conservation measures in designing and construction of coal-burning EPP.