Coal use and fuel utilization in the industrial, commercial, and residential sectors

The reduction of premium fuel use through the introduction of coal and improved fuel utilization techniques in boilers, furnaces, and process heaters in the industrial, commercial, and residential sectors is the goal of many current research and development efforts. For refit applications the first consideration for coal utilization is in the direct substitution of powdered coal for premium fuel. In steam-raising boilers this is possible with substantial derating of the unit. Direct substitution in process heaters raises almost insurmountable problems of process control, product contamination, corrosion, and safety. An obvious answer to the problems of direct coal substitution is to change the coal into a form more compatible with the existing equipment. Coal gasification and liquefaction are two technologies available at this time. Potential near-term premium fuel substitutes are coal slurries, in the form of either coal-oil mixtures (COM) or coal-water slurry. Important opportunities exist for natural gas and fuel oil conservation within the commercial and residential sectors. About one third of the energy used in the United States is consumed in the combined commercial/residential sector. Combustion equipment within these sectors are major consumers of energy, with natural gas and fuel oil being the primary fuels. Central warm air furnacesmore » and hot water (or steam) boilers are commonly used, and the annual efficiency and fuel consumption of residential equipment varies with many operating parameters, but an average efficiency of about 60% is expected. Similarly, small commercial combustion devices, which account for about half the commercial fuel use, are expected to operate with comparable efficiency. Considerable performance improvement is possible, and fuel use can be reduced by 15 to 60% through modification or replacement of existing heating systems.« less