REQUISITES AND TREATMENT OF KILN FUELS. 



525 



" The use of producer-gas made from wood alone is the most novel 

 feature of the plant. No guiding experience was found for this process; 

 but, with the desire to utilize as far as possible the limited local wood- 

 supply, the gas-producer plant was selected with the object, among 

 other things, of determining the advisability of using, if not wood alone, 

 at least a considerable admixture of wood with bituminous coal. The 

 most obivous difficulty to be feared arose from the large proportion 

 of condensible distillates yielded by wood, and the danger that some 

 portion of these might be imperfectly fixed in passing through the pro- 

 ducer. The trouble from tar deposited in the gas apparatus and pipes 

 would be serious, and even a small quantity of tar in the gas itself is 

 a fertile source of trouble at the engine-valves. Unless a permanent 

 gas could be made from wood, this fuel would be unavailable. 



" The first care, therefore, was to insure that there should be a bed 

 of charcoal on the grate sufficient to form an adequate fixing-zone. To 

 obtain this the producers were filled about 5 feet deep with cordwood 

 sawn in blocks about 6 inches long and the contents blown with a slow 

 fire for four or five hours before the gas was turned into the holder. 

 The gas, as it proved, was turned into the holder too soon. At first 

 it contained some tar, and it was not until after three hours' operation 

 that the charcoal accumulated in sufficient quantity, so that the pro- 

 ducers delivered fixed permanent gases to the holder. 



"The character of the gas produced from different fuels is shown 

 by the following averages from a series of analyses made by A. Sand- 

 berg, of Lund, during the final trials of the gas-making plant, which 

 extended from February 16 to March 20, 1901. 



AVERAGE COMPOSITION OF GAS FROM DIFFERENT FUELS. 



