Destructive Distillation of Hardwoods 41 



box. This box is supported by five U bolts li inches in diameter 

 which are fastened to eyebeams. These eyebeams together 

 with lap tiling 4 inches thick form the cover of the retort. Be- 

 tween the steel and the brick walls, a space of 4 inches is allowed 

 for expansion. The average life of one of these retorts is about 

 ten years. Heat is applied from beneath by means of a firebox 

 which is constructed of brick surrounded by steel bands f inches 

 thick and 18 inches apart and which extends four feet outside 

 of the retort, the purpose being to heat uniformly the whole 

 retort. The firebox is roofed by an arch of fire-clay which ap- 

 proaches to within 32 inches of the base of the retort and whose 

 object is to prevent the direct application of the flame to the base 

 of the retort and thus cause it to warp. Slits about 1 inch wide 

 by 12 inches long are cut through the side of the arch to allow 

 the heat to come in contact with the retort. The draught is 

 regulated by a flue with dampers. As fuel, about six cords of 

 waste material from a sawmill is used each day. After the 

 wood in the retort has been subjected to heat for about twelve 

 hours, gas begins to come off. The portion of this which does 

 not condense is fed into the furnace and burned. The tar which 

 is formed in the process of distillation is also burned. 



Chief Product 



The chief product obtained from this wood distillation is 

 charcoal. To char the wood thoroughly, it is left in the retort 

 for 24 hours at a temperature of about 750 degrees F. At the 

 expiration of this time, the cars of charcoal are run into gal- 

 vanized iron coolers which are just slightly larger than the cars 

 themselves. In these, the cars are left for two days and are 

 then run into the yards for one day. From here, they are 

 switched to a shed whose floor is 22 feet above a railroad track 

 on which standard cars are set. The charcoal is screened and 

 by means of a chute run into these cars whose capacity is about 

 13 to 15 of the charcoal cars. 



Secondary Products 



ALCOHOL 



As the wood is charred, the volatile substances in part 

 composing it are driven off in the form of a gas which passes 

 through condensers of which there are two to each retort. These 

 condensers are hollow cylinders 4 feet in diameter by 8 feet tall 

 with a steel jacket J inch thick, and contain 70 copper flues. 

 Water comes into these condensers from below and is discharged 

 through an overflow pipe above. The gas from the retort comes 

 in at the top and passes into the flues where part of it, the so- 

 called pyroligneous acid composed of wood alcohol and many 



