384 



FUEL, GASEOUS. 



and combustion simultaneously, but a surpris- 

 ing calorific power is also gained by the com- 

 bustion of gases at extremely high tempera- 

 tures accumulated in the retorts where they 

 are generated. Two instances of such practice 

 may here be given. The first is an instance of 

 the use of oil and water at a high temperature 

 of their vapors in the moment of contact, and 

 at a much higher temperature in the moment 

 of their contact with air. 



Reaction in Superheated Oil and Steam. Many 

 devices have been tried for burning oil as fuel, 

 and many of these devices have sought to em- 

 ploy the decomposing power of hot carbon 

 upon steam. None of them attained any de- 

 cided economic progress until the burning of 

 the oil-vapor was postponed to the decomposi- 

 tion of the water- vapor, and the freed gases 

 were burned all together, in an enormous accu- 

 mulated heat, on which a dividend, as it were, 

 of surplus heat could be declared without im- 

 pairing the capital stock of heat on which the 

 continued production of such a surplus de- 



Eends. In the water-gas locomotive u 0. Hol- 

 ind," this principle was in a measure realized. 

 Oil and steam were admitted by gauge into 

 highly heated retorts placed in the fire-cham- 

 ber of the boiler, and the carbon of the oil was 

 allowed to take up the oxygen of the steam 

 alone, in the absence of atmospheric oxygen. 

 The temperature at which this reaction takes 

 place between carbon and water-oxygen has 

 been determined, by the Swedish chemist Dah- 

 lerus, to be about 400 or 450 centigrade. 

 Theoretically, it has been assumed that the 

 heat evolved by the recombustion of the sep- 

 arated elements of water must be balanced 

 by the heat absorbed in separating them. 

 But practically, from some cause or other, it 

 has been found, even under ordinary condi- 

 tions (not of such extreme heat as was em- 

 ployed in the after-combustion of the separated 

 elements in the Holland-engine furnace), that 

 the exchange of carbon for water-hydrogen 

 resulted in a considerable gain of heat. It is 

 still more significant that, as determined by 

 Grassi, the number of pounds of water raised 

 one degree by the union of one pound of oxy- 

 gen with its full combining equivalents of car- 

 bon and hydrogen respectively, were 2,893 and 

 4,333. The direct gain by exchange, therefore, 

 would be almost exactly 50 per cent. But the 

 practical economy of using oil and steam in this 

 way proved to be much greater (computing 

 commercial cost) than the scientific determina- 

 tions seemed to account for. Out of many 

 tests of the locomotive " 0. Holland " on dif- 

 ferent railroads, it is sufficient to quote from 

 the report of its work on the Eastern Kailroad, 

 which corresponds with all others: 



Comparative statement of the performance of en- 

 gine " C. Holland," known as the l <water-gas engine," 

 and engine No. 31, of our own road, for six days, Dec. 

 31 to Jan. 5, inclusive, both running in the same 

 service (regular schedule passenger-trains) : Engine 

 " C. Holland," cylinders 15 x 24 inches, run 216 miles, 

 consumed 796 gallons of naphtha, at cost of $15.92. 



Engine No. 31, cylinders 15 x 22 inches, run 216 miles, 

 consumed 12,960 pounds of coal, at a cost of $27.77. 



The carbon of oil is consumed by combina- 

 tion with the pure oxygen of steam, no atmos- 

 pheric air having access to it in the retorts, 

 and thus the large amount of heat always lost 

 by absorption in the nitrogen of an air-blast is 

 here saved, so far as the carbon is concerned. 

 Then the combustion of both tfie direct and 

 the produced fuel is perfect, as against a semi- 

 combustion of coal. Besides, the hydrogen- 

 flame is the most advantageous of heating 

 agents, from its unequaled intensity and rapid- 

 ity of action, and from the energy with which 

 it is diffused and thrown upon every avail- 

 able point of heating surface. The rapidity 

 with which heat is imparted increases in a 

 geometrical ratio to the increase of its in- 

 tensity, and since the hydrogen-flame is so 

 many times hotter than carbon in combus- 

 tion, its concentrated heat must have a vastly 

 greater effect, unit for unit, in any given time 

 of passage through the flues. But it remains 

 to be added that the already intensely hot 

 gases issue at the burners in contact with dis- 

 tinct jets of heated air, with the effect of a 

 blow-pipe. 



Anthracite-Gas Furnace. This furnace is ap- 

 plied to a stationary steam-boiler. The first 

 maxim in its construction is to get the fire away 

 from the water the direct opposite of the first 

 object with boiler-makers hitherto. This is in 

 order to secure the grand condition of the be-t 

 combustion, which is the highest initial heat ; 

 and also to provide for the volatilization of the 

 coal, by a temperature that could not be at- 

 tained in a furnace surrounded by water. Sub- 

 sidiary to these purposes, extreme measures are 

 taken to confine the heat both from radiation 

 and from escape in the gases. The products of 

 combustion, after imparting to the hot water in 

 the boiler all the heat it can take from them, 

 are cooled in the air-blast down to about 150, 

 before being allowed to escape. The ^exhaust 

 steam is also condensed into the feed- water. 

 The hot-air blast is gauged into the furnace in 

 the exactest possible proportion to the volume 

 of fuel-gases with which its oxygen is to unite, 

 and is driven with sufficient force to insure the 

 utmost activity of circulation throughout the 

 labyrinths of the combustion-chamber and of 

 the boiler. The combustion-chamber is in two 

 distinct parts, one above the other ; although 

 the proper operation in the lower chamber 

 where the coal is put is volatilization without 

 combustion, or nearly so, after the initial firing- 

 up. Both chambers are strictly air-tight, down 

 even to the feed-door and the ash-pit. The 

 upper or gas-combustion chamber is a laby- 

 rinth of perforated fire-brick, containing thou- 

 sands of minute passages and returns for the 

 gases to be driven through, superheated, and 

 atomized together into the finest mixture ; the 

 fuel-gas and air-blast meeting in these passages 

 from opposite directions, and not until both 

 have been heated to the highest practicable 



