HEAT CONSUMPTION AND HEAT UTILIZATION. 



501 



Assuming that the above data are substantially correct, and that 

 the specific heat of the mix is about 0.22, the heat required for the simple 

 heating of the mix to the clinkering point can be calculated as follows: 



Per Barrel 

 B.T.U. 



600 Ibs. mix heated 60 to 1300, spec, heat 0.22 = 1260X0.22X600 = 166,320 

 380 " " " 1300 to 2600, " " 0.22 = 1300X0.22X380 = 108,680 



Total heat required, B.T.U 275,000 



This estimate is probably above what is actually required, for the 

 temperatures, weights and specific heat have all been taken on the 

 safe side. The actual heat requirements are probably close to 250,000 

 B.T.U. for this part of the operation. 



In running an actual test of a kiln this quantity could be checked 

 roughly by the amount of heat contained in the clinker as it leaves 

 the kiln. In other words, a barrel of clinker carries out with it almost 

 as much heat as was required to clinker the raw mix for that barrel. 



As pointed out on a previous page (p. 497), the heat required for 

 bringing the mix up to the clinkering point is not utilized in causing 

 chemical changes, and can therefore be utilized again. In this respect 

 it differs from the heat required for dissociating the carbonates and 

 sulphates, decomposing the clay, etc. for in these cases the heat 

 is absorbed in doing chemical work and cannot be regained. For 

 this reason it will be convenient to omit, from the total thermal re- 

 quirements, the heat used in heating the mix up to the clinkering point; 

 and to consider it rather in its outgoing form as heat carried out by the 

 clinker. 



Total heat requirements. The data given in preceding paragraphs 

 may now be conveniently summed up as in the table below. The basis 

 for the various figures may be seen by referring back to the upper pages. 



TABLE 189. 

 THEORETICAL HEAT REQUIREMENTS IN B.T.U. PER BARREL. 



