An Elementary Treatise on Steam and the Steam-Engine, Stationary and Portable (Being an Extension on the Elementary Treatise on Steam of Mr. J. Sewell) (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1885 Excerpt: ...feet. As, further, the fixed carbon, or the coke which remains after the volatile portions of the fuel are driven off, averages 60 per cent, or 60 lbs. per 100 lbs. of coal, the proportional quantities of air chemically required for the volatile and fixed portions respectively may be simply ascertained. Sixty pounds of carbon require 160 x 60 = 9,600 cubic feet of air--say 10,000 cubic feet, and the proportions are therefore as follows: --Volatile elements 6,000 cubic feet. Fixed element, or coke.... 10,000 Total air per 100 lbs.... 16,000 cubic feet. Or 160 cubic feet of air per pound of coal. Of this supply, three-eighths are consumed by the volatile elements and five-eighths by the fixed element. It is easily conceivable, therefore, in view of so large a demand in behalf of the volatile or smoke-making elements, that the complete combustion of these elements is a matter involving some care to effect the ultimate mixture of the gases and air, which is necessary to effect the complete combustion of the gases. In order to prevent the formation and discharge of smoke, it is necessary to admit a greater quantity of air to the furnace than is chemically consumed, so that each particle of gaseous combustible matter may be supplied with its due equivalent of oxygen. The proportion of such surplus air may, in ordinary furnaces, amount to as much as the air chemically consumed, and thus upwards of 30,000 cubic feet of air may be needed for the combustion of 100 lbs. of coal, or 300 cubic feet for one pound. Temperature of Combustion. The temperature of the products of combustion at the instant of their formation varies, of course, with the quantity of air in dilution. Professor Bankine estimates the temperature to be as follows: --Carbon. TM Fuel, undiluted ...