Destructive Distillation of Hardwoods 39 



THE DESTRUCTIVE DISTILLATION OF HARDWOODS 



C. R. TlLLOTSON 



Statistics gathered by the Forest Service show that the 

 amount of wood used for distillation in the year 1906 was nearly 

 1,200,000 cords of which 50,000 cords were pine and the re- 

 mainder hardwoods of an average value of $3.25 per cord. Some 

 of the wood used for distillation consists of the waste incident 

 to logging and lumbering operations while in other cases the 

 wood is cut especially for distillation. The quality of the 

 material necessary in this industry need not be high class. 

 Although a large amount of material, consisting in the hardwood 

 distillation almost exclusively of maple, beech, and birch, is 

 used each year, the industry may, if conducted properly, serve 

 as a means of utilization of crooked, small, defective, and cull 

 body or limb wood, or better still, of the waste always incident 

 to logging and milling operations. Forest Service statistics 

 show that all the hardwood slabs, edgings, and trimmings annually 

 wasted could be made to yield 16,900,000 gallons of wood 

 alcohol and 145,000 tons of acetate of lime or just double*the 

 amount now used each year. 



Wood carbonization or the production of charcoal by means 

 of pits and kilns is by no means a new industry, but the process 

 of destructive distillation of .hardwoods by means of which the 

 secondary products, wood alcohol and acetate of lime, are saved 

 has reached its present state of efficiency in the United States 

 only in the last few years. It is to these secondary products 

 that the hardwoods owe their supremacy over the conifers both 

 in the amount of raw material used and in the finished products 

 resulting therefrom. The principle of this kind of distillation 

 is simply an air-tight retort in which the wood is run on steel 

 cars and heated indirectly. This causes it to carbonize and the 

 volatile substances in part composing it to pass off in the form 

 of gaseous vapor which is later condensed and which gives us the 

 wood alcohol and acetate of lime of commerce. During the 

 winter of 1908-9, it was the writer's privilege to investigate one 

 of these chemical plants situated in Wisconsin and to secure the 

 data contained in the following pages. 



Plant and Equipment 



The plant consisting of four large wooden buildings and con- 

 siderable yard room and covering approximately ten acres of 

 ground is valued at $100,000.00. It has six retorts in operation 

 continuously day and night, uses 48 cords of wood daily, and 



