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Indiana University Studies 



have been given up if the combustion had been complete and the 

 entire product had passed off as carbon dioxide. This represents 

 70 per cent of the heating value of the coal and with dry-air 

 blast the other 30 per cent is dissipated in the producer. When 

 this is done the temperature of the fuel bed is raised accordingly, 

 so that when steam is introduced into the bed the steam is de- 

 composed into oxygen, which combines with the carbon of 

 the coal, and hydrogen, which passes in this form to the engine. 

 Here it is again burned into steam. Thus much of the 30 per 

 cent which remained behind in the fuel bed when the air blast 

 was running is saved by the steam blast. The steam also re- 

 duces the temperature of the fuel bed and lessens the amount of 

 clinkering. 



The successful gas producer should have the following features: 



1. A deep fuel bed carried on top of a deep bed of ashes; 

 the first to make good gas, and the second to prevent waste of 

 fuel. 



2. Blast carried by conduits thru the ashes to the incandescent 

 fuel. 



3. Accessibility of the ash bed and proper arrangements for 

 the removal of the ashes. 



4. Level, grateless support for the burden, insuring uniform 

 depth of fuel at all points, and consequent uniformity in the 

 production of gas. 



The following table showing the distribution of the heat of the 

 coal w^hen used in producer-gas power plants and steam plants is 

 of interest. The coal used was of 13,000 B.T.U. thermal effi- 

 ciency. 





Steam Plant 



Gas Plant 



Heat lost in ashes 



2.00 



1.10 



In radiation and cooling 



4.60 



18.60 



Heat lost in smoke 



24.60 



none 



Heat lost in engine radiation 



3.30 



4.30 



Heat lost in exhaust 



53.50 



23.70 



Heat lost in water jacket 



none 



33.50 





7.30 



none 



Total heat losses 



95.30 



81.20 





4.70 



18.80 



