HEAT CONSUMPTION AND HEAT UTILIZATION. 



509 



TABLE 193. 

 TESTS AND ESTIMATES OF HEAT DISTRIUBTION, B.T.U. PER BBL. 



* Roughly equivalent to the heat necessary to bring the mix up to the clinkering point. 



t By difference. 



j By calculation. 



Does not check, owing in part to temperature allowances. 



Heat Utilization and Economics. 



Much of the heat carried out by the clinker and the stack-gases is 

 recoverable with some ease, while that lost by radiation from the kiln 

 is not so readily utilized. Helbig and Carpenter have described methods 

 of waste-heat utilization in the papers cited on p. 511, to which refer- 

 ence should be made for further details. 



Carpenter, in discussing his Cayuga tests, notes that "at the time 

 of the test that portion of the air not supplied by the coal-feeding appa- 

 ratus was forced by a special blower through the hot clinker and thence 

 into the kiln. By this regenerative action about 80 per cent of the enter- 

 ing air was heated to 480 F., restoring to the two kilns about 2,000,000 

 B. T. U. per hour, or about 7 per cent of the heat produced by the com- 

 bustion of the coal. The regenerator, while distinctly economical, made 

 the clinker elevators difficult to keep in order and tended to deliver 

 dust into the kiln-room; it also took up valuable room and after a 

 few months of use was abandoned. The test shows, however, the 



