Modern Gasworks Practice

120 MODERN GASWORKS PRACTICE turbo blowers, eacli being capable of meeting the requirements of three producers, provide the blast for the plant, and the rotating grates are operated by electric motors—installed in duplicate, one being spare—driving, by belting, the shaft which actuates through eccentrics and rods the ratchet feecL gear of the grates. The steel cylindrical stell of.the producer has the water-cooling jacket so placed as to provide a water-cooled metal surface in that zone of the producer where clinker usually forms. By this provision clinker is prevented from adhering to the walls, and, with the gradual descent of the fuel, the clinker falls to the rotating grate, where it is crushed against the specially prepared grinding surface at bottom of producer, and passes into the luted ash-pan. The rotating grate is formed of a heavy cylindrical casting surmounted by a stepped cone, the whole being mounted eccentrically on the ash-pan. The pan is rotated by power as below described. The pan is provided with sides forming a water lute, into which the bottom extremity of the producer shell dips. When the producer is operating the pan fills up with mixed crushed clinker and ash, which, as the pan revolves, is forced against a stationary adjustable plough blade, and dis-charged on to the ground, or, as is generally arranged, into ash trucks alongside the producer. The water discharged from the cooling jacket pro vides a supply of hot water, which may be used for boiler feed or other purposes. The following test figures obtained by A. E. Broadberry in connection with. the installation are of interest:— Size of Fuel:— Over 1 inch ...... 27-6 per cent. Between J-inch and |-inch . . .33-1 „ „ |-inoh and J-inch. . . . 19-3 „ Below |-inch.........................20-0 Analysis of Fuel. Vertical Retort Breeze:—■ Moisture ....... 14-29 per cent. \ Ash.................................22-33 Volatile matter.....................5-1 lOn dry basis. Total carbon ...... 71-45 Calorific value.......................11,109 B.Th.U. per IbJ Analysis of Producer Gas :— Hydrogen. ..... .14 per cent, by volume. Carbon monoxide . .... 25 „ Carbon dioxide . . . . . 6-4 „ Calorific power (net) . . . .124 B.Th.U. per c’ubic foot. The gas obtained per ton of wet breeze was 110,000 cubic feet, and the temperature at which it left the producer was found to be 197° C. The gas from each producer, after passing through a “ cyclone ” dust extractor into a trunk main, is led through the two other dust extractors into steel, firebrick lined, distributing mains running along each side of the retort house. From tliese, brauch mains are taken between the coke-receiving hoppers under the retort benches and the gas being thereby heated passes to the gas openings in the settings, valves being provided to permit of the necessary regulation of supply. The breeze and very