86 ILLINOIS ACADEMY OF SCIENCE 



heating value of perhaps 155 B. t. u. per cubic feet with 

 coal fuel, clue to the ijresence of carbon monoxide and 

 hydrocarbons. It was concluded that a certain amount of 

 this gas was worth saving and as the carburetor and super- 

 heater had usually attained a suitable temperature of 1350 

 to 1400 degrees F., by this time, the stack valve was closed 

 and the blast continued for 15 to 30 seconds, no secondary 

 air being admitted during this time. The term "blow-run" 

 was coined for this part of the operation since it was a run 

 with blast instead of steam. This additional blasting time 

 improved the generator condition and since the gas was 

 not burned in the carburetor and superheater, these cham- 

 bers were not overheated by this additional blast. A vol- 

 ume of gas equal to 20 to 30 per cent of the usual volume 

 was added to the production and while the amount of oil 

 required to enrich this relatively i^oorer gas was somewhat 

 greater, it did not equal that usually required with coke. 

 The amount of generator fuel consumed per unit of gas 

 volume materially decreased. 



While this method is not claimed to be a panacea for all 

 the troubles experienced in using bituminous coal in 

 water-gas making, it worked successfully at Streator and 

 has been applied with more or less success at other plants 

 according to the extent to which the particular conditions 

 are favorable to it. It is hoped that the investigation of its 

 application may be continued farther. 



The choice of a generator fuel for gas making is an 

 economic matter depending upon the cost of the fuel and 

 the efficiency with which it can be used. Assuming that a 

 given fuel is usable and will produce the amount of gas 

 required, the question which must always be answered is, 

 what will be the relative cost of making 1000 cubic feet of 

 gas with various fuels. Not only cost per ton and the 

 actual amount of fuel consumed enter into the problem 

 but also the effect on the amount of oil required to enrich 

 the gas and the cost of other materials and of labor occa- 

 sioned by its use. These costs will not be the same for a 

 particular fuel in different plants, even if the actual cost 

 of generator fuel is the same. To take a particular case 

 and assume certain costs for materials and labor is always 

 likely to lead to erroneous or misleading conclusions for 

 there ai-e always those who are sure to take assumed 



