PAPERS OX CHEMISTRY AND PHYSICS 355 



Fortunately for our purpose tliis fact of exother- 

 micity and of carbonization are not only compatible with 

 each other, but we believe are essential to the successful 

 accomplishment of the prime purpose we seek, namely, 

 the carbonization of high oxygen coals. 



In attempting to maintain low temperature condi- 

 tions, the first problem with which one is confronted is 

 the physical impossibility of conveying heat into the 

 center of a non-conducting mass without maintaining at 

 the exterior a high heat head for the purpose of driving 

 the heat forward through the insulating layers of coke 

 that are continually in the process of fonnation. Some 

 idea of the actual conditions involved may be seen from 

 Fig. 12 here presented. The diagram at the right is a 

 cross-section of a by-product oven with points indicated 

 where temperatures within the coking mass were taken. 

 It will be seen that in an extended 35-hr. coking period, 

 the temperatures at the center of the mass did not reach 

 the stage of decomposition, say 250 deg. C. (482 deg. F.) 

 until after 20 hr. The obtaining of heat transmission, 

 therefore, by simple process of conductivity is at once 

 seen to be impracticable if low temperature conditions 

 throughout the mass are to be maintained. It is at this 

 point that we have attempted to use the exothermic 

 reactions involved in the carbonization process. These 

 exotheimic reactions are directly due to the oxygen com- 

 pounds of the raw coal. By reference again to the chart. 

 Fig. 6, showing the makeup of an Illinois coal, we can 

 at once see the possibility of a very considerable amount 

 of heat available from this source. The high oxygen 

 content therefore becomes an asset instead of evidence 

 of a nullifying influence in the process of carbonization. 

 The direct measurement of this exothermic heat has been 

 one of the most interesting as well as one of the most 

 elusive features of the problems involved. If time per- 

 mitted it would be worth while to illustrate the methods 

 of measurement employed. It will doubtless be better 

 at this point to follow out the sequence of the process 

 wherein use is made of the exothermic heat and how it 

 is made available. 



