Characteristics of coals and boiler design

The coal-fired boiler presents more difficult problems than the oil- or gas-fired unit. Apart from the special design consideration required for transportation, the characteristics of coal, such as high levels of ash, sulfur, and nitrogen impose many limitations on the boiler design. Also, coals now contemplated as boiler fuel are almost without exception of foreign origins, and wide variations in their properties make the design problem even more complicated. The increasingly rigid regulations for environmental protection require advanced technical expertise to reduce NOx, SOx, and dust emissions. This paper discusses the effects of characteristics of coal on boiler design and also reviews experience with the operation of the modern boilers installed in the Electric Power Development Company, Matsushima Thermal Power Station, which started its commercial operation in January 1981.