PULVERISED FUEL

Evening Post, Volume XCVIII, Issue 32, 7 August 1919, Page 7

PULVERISED FUEL

AN ECONOMIC SYSTEM,

The subject of pulverised fuel attract increasing attention In America the amount of coal now pulverised is said tobel^OOOjOOOtons^nd the attention of -engineers and metallurgists in Britain is,, being increasingly directed to this improved method of combustion of coal and other fuels. Foremost among the advantages claimed for this system are (1) complete combustion, each particle ot fuel oeing surrounded by air and undergoing almost instantaneous combustion;, (2) the use' of a minimum amount of air owing to the approximation of tie fuel to the form of gas-. Thus a 20 per cent, excess air becomes possible, as compared 50 to 200 per cent, in the case of solid fuel furnaces; (3) the consequent higher temperature of combustion; (4) reduction of loss of heat through tho diminished volume of waste gas; (5) minimum amount, of unbornt carbon down to one-half of 1 per cent.,' as against 4 to 5 per cent, in many furraces fed with ordinary solid fuels; (6) the decreased labour attaching to ash removal; (7) the maintenance of a less oxidising atmosphere; ajid (8| tho utilisation of lowrgrado fuels r.ot otherwise serviceable in modern types of furnaces, leading to economy of fuels of higher calorific value. It may be urged that, sooner or later, the direct combusition of coal, and consequent loss of by-products, must cease in Britain, this being, however, largely dependent upon the report of tho Fuel Research Board's experiments now in progress, and that the changes necessitated by the of the neW system would hardly be justified. Assuming that such prohibition eventuates, it is still urged that pulverised fuel should be the last example of direct combustion to go. Further, the fact that, the system is applicable to coals of low grade unsuited to preseut furnaces, and that such utilisation is a direct step towards coal conservation, justifies tho hope that what has presumably been an undue delay in this development by reason of war conditions may now give place to the introduction of the method. Even if coal carbonisation on the large scale obtains in the near future, it u> still claimed that pulverisation will be applicable to a coko containing 10 per cent, of volatilo matter, such as results from low temperature carbonisation with recovery of fuel oil. The extension of the method in America may be judged front its application to steam boilers, locomotives, open-hearth puddling, and reheating furnaces, in soaking pits, for annealing, brass melt--1 ing, and other purposes. The production and maintenance of a nearly' ncUr' tral atmosphere at once loads to a reduction of scale formation in billet heating, and to a considerably increased life of annealing boxes. More recently pulverised fu»l has beon used in admixture with fuel oil, a suitable mixture containing 70 per cent, of oil and 30 per cent, of powoered coal," tho mixture being applied without any change of burners or _, combustion areas.