Transactions . he fire-tube, the precaution shouldbe taken of providing the first sectionâsay from 1 to m.âof thelatter with a refractory lining, to avoid injury to the boiler from im-pinging jets of flame. GENERATION OF STEAM BY WASTE HEAT FROM FURNACES. 289 Experiments covering more than a month with a furnace of thiskind, built for a rolling-mill, gave, according to the above-namedfurnace-building company, the following results: Heating-value of the coal-mixture in its original condition 6,192 h. u. Heating-value of the coal-mixture in air-dried condition 6,763 h. u. Heating-surface of
Transactions . he fire-tube, the precaution shouldbe taken of providing the first sectionâsay from 1 to m.âof thelatter with a refractory lining, to avoid injury to the boiler from im-pinging jets of flame. GENERATION OF STEAM BY WASTE HEAT FROM FURNACES. 289 Experiments covering more than a month with a furnace of thiskind, built for a rolling-mill, gave, according to the above-namedfurnace-building company, the following results: Heating-value of the coal-mixture in its original condition 6,192 h. u. Heating-value of the coal-mixture in air-dried condition 6,763 h. u. Heating-surface of the boiler 80 sq. m. Water evaporated by 1 kg. of coal burned on the grate kg. Average evaporation of the boiler per hour for 1 sq. m. surface 12 kg. Coal-consumption for 100 kg. of pieces, charged cold kg. Total weight of pieces charged per shift 42,000 kg. In order to determine separately the parts played by furnace andboiler in utilizing the heat from the coal, each must be considered Fig. 1.âSbctiox Through Furnace and Overhead Flame-TubeBoiler of the German Furnace-Building Co., ;seldorf. On the assumption of a complete combustion, there were generatedabout 68,000 h. u.,of which, in round numbers, 100 X X 1,100= 18,000 h. u. were transmitted to the pieces heated. The utiliza-tion of heat in the furnace was therefore about 26 per cent., whileabout 17,000 h. u., or 25 per cent., were consumed in the productionâ¢of steam. The total heat-utilization was therefore about 51 per figures have approximate value only, since the temperature ofthe material as charged and as withdrawn was merely estimated. If the calculation be pursued further, and 10 per cent, of C09 beassumed in the gas at the end of the boiler (after complete combus-tion), it is found that there is a loss of about 19 per cent, in the gasesescaping at about 300° C. from the boiler. Hence the loss byradiation, conduction, and uuburned residues is 100 â 51 â 19 = 30
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
