Energy from coal: a state-of-the-art review. [State-of-the-art survey]

Coal as a solid fuel can be currently applied to only a limited portion of the total national energy demand. The primary user of coal is the electric utilities industry, where coal is mechanically cleaned, pulverized, and then burned in solid form in boilers; the transportation sector depends nearly exclusively on liquid fuels; the household and commercial sectors depend almost entirely on liquid and gaseous fuels; and three-quarters of the energy used by industry is provided by liquid and gaseous fuels. Therefore, the development of coal conversion processes by the Energy Research and Development Administration is oriented towards accelerating and stimulating a synthetic fuel industry. Research, development and demonstration strategy is to sponsor a wide variety of technical options so that promising processes will eventually be commercialized and provide a long-term payoff. Coal's immediate future is closely tied to its consumption by the electric utilities. The use of low ash and low sulfur products from the liquefaction and gasification of coal by the industrial transportation and heating sectors of the economy, as well as by the electric utilities, should be possible by the 1990's. Advanced methods of generating electricity from coal, using fluidized-bed boilers and combustors, MHD generators, solid electrolyte fuel cells and topping cycles are currently in fundamental research stages. These concepts theoretically offer a means of increasing the efficiency of coal's utilization in the production of energy. The long-term expansion of the coal market will depend upon the eventual commercial availability of clean synthetic fuel products and advanced power systems now under development by ERDA.