Fuel briquetting

With increasing demand for briquetted fuel, briquetting plants became larger, more sophisticated, and more expensive to operate. These developments eventually resulted in the replacement of briquettes by newly emerging cheaper fuels such as gas and oil. 

Direct Reduction. Direct reduction processes are distinguished from other ironmaking processes in that iron oxide is converted to metallic iron without melting. Because this product, called direct reduced iron (DRI), is soHd, it is most suitable for melting in an electric arc furnace (EAF) as a substitute for scrap (see Furnaces, electric). The briquetted form of DRI, hot briquetted iron (HBI) is used when the product is to be transported. Briquetting increases density and chemical stabiUty. The predominant direct reduction processes (MIDREX and HyL III) are based on natural gas as a fuel and reductant source. They are economically attractive in regions where natural gas is cheap and abundant, especially if iron ore is available nearby (see Iron BY DIRECT reduction). ... 

The moisture content of peat or brown coal that is briquetted for fuel must be reduced to about 15% for satisfactory briquetting. Mechanical or natural means are used because of the cost of thermal drying. Moisture is sometimes desirable. About 8% is necessary for prevention of combustible loss from a chain-grate stoker. 

Although a number of low temperature processes have been studied, only a few have been used commercially. These have been limited in the types of coal that are acceptable, and the by-products are less valuable than those obtained from high temperature processing. The Disco process is used in the United States to supply a limited amount of fuel to meet requirements of smoke ordinances. The British CoaUte and Rexco processes produced substantial amounts of domestic smokeless fuel. Development of fluid-bed methods of carbonizing finer coal at ca 400°C has been studied in the United Kingdom. A reactive char is briquetted without a binder to produce a premium open-fire smokeless fuel. 

Brsnnstoff, m. fuel, combustible Old Chem.) phlogiston, -aufwand, m. fuel consumption, ausnutzung, /. utilization of fuel, -chsmis, /. fuel chemistry, -vsrbrauch, m. fuel consumption. -wsrt, m. fuel value, -wirt-schaft, /. fuel economy, -zisgsl, m. fuel briquet. 

Fines from petroleum coke are too small to use alone for domestic heating. But petroleum coke fines have been briqueted successfully, and the briquets used as domestic fuel (21, 88). In one instance, briquets made with 5 to 10% of refinery acid sludge as the binder were roasted to 1100° F. The resulting briquets were clean, hard, strong, and smokeless and could be stored or shipped in any weather. Uncalcined briquets tend to soften and deform in hot weather (16). 

Other Solid Briquetted Briquetted Small Particulate Any Slurried Fuel... 

Binderless briquetting of lignite, peat, etc. Development of roll and extrusion presses for fuels. 

Improved product appearance, as in the manufacture of fuel briquets. 

J. Martin, Briquetting of peat fuel, Proc. Inst. Briquet. Agglom. Bien. Conf., 14 (1975) 153-171. 

The selection of a binder for a given application remains a matter of experience. In Table 2.4, a rating is given for the effectiveness of a selection of binders and lubricants used in the tableting of different materials. Other reviews of binder systems used in fuel briquetting [43], ceramic [45], pharmaceutical [39,46] and foundry [47] applications are available. 

Staatsmijnen-Otto Also known as the Pieters process, after the inventor, H.A.J. Pieters. A process for removing hydrogen sulfide from coal gas by scrubbing with an aqueous solution containing a suspension of iron cyanide complexes known as iron blue. The product is elemental sulfur, which separates as a froth and is purified by heating with water in an autoclave. Staatsmijnen is a Dutch producer of smokeless fuels, which has also given its name to a briquetting process. 

Briquetting involves a cost of 1 to 2 per ton over that of raw fuel. 

In this analysis, only air-dried wood chips or billets, and pelletized agricultural residues will be considered. The moisture content of these fuels is assumed to be - 20 weight percent. Charcoal briquets are also a highly desirable fuel, but their production requires significant capital investment. The use of charcoal, however, warrants consideration in future studies. (See references 3 and 15 for detailed discussions of biomass fuel use in vehicle engines.)... 

S. Eriksson and M. Prior, The briquetting of agricultural wastes for fuel . Food and Agriculture Organization of the United Nations, Rome, Italy, FAO Environment and Energy Paper 11, 1990. 

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