A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

FUELS. 59 B.T.U. One pound of dry wood, as above, . . . = 6,644 If there is 20 per cent, of moisture, first deduct 20 per cent, of 6,644 ............................= 1,329 5,315 From this must then be deducted 20 per cent, of 966, for the latent heat absorbable by the moisture being converted into steam during the combustion of the wood (20 per cent. of 966 = 193).................................= 193 Heat given from ordinarily dry wood (i.e., with 20 per cent, of moisture)........................= 5,122 9. Petroleum is now coming a good deal into use for boiler work. It is convenient, but furnaces have to be specially constructed for its use—that is, the liquid fuel has to be injected into the furnace. Its heat-giving power is about 30 to 50 per cent, more than the same weight of coal, and may be calculated with the assistance of Table I, on p. 61. 22. In Seaton and Rounthwaite’s Pocket-book of Marine Engineering is given the following classification of various descriptions of coal, and these are further compared with wood and petroleum. The following Table H, based thereon, shows that Welsh coal has the greatest heat- giving power amongst the coals, but that petroleum has about 25 per cent, more heating power than the best Welsh coal. This, it may be added, is the theoretical heat power in B.T.U. per lb. of fuel. In actual practice