Energy, fuels, and chemicals 



3217 



AIR STACK TO COOL 

 CENTRAL SHAFT 



FEED 

 CONVEYOR 



EMERGENCY 

 BY- PASS STACK 



RABBLE ARM %^ 

 a TEETH 



IN HEARTH 



OUT HEARTH 



CHARCOAL 

 COOLER 



COOLING FAN 



FOR CENTRAL 



SHAFT 



INDUCED- 

 DRAFT FAN 



AIR POLLUTION CONTROLS 



CENTER -SHAFT DRIVE 



Figure 26-32. — Nichols-Herreshoff multiple hearth furnace for the production of wood 

 charcoal. (Drawing from Nichols Engineering and Research Corporation.) 



about 50,000 lb per hour of high pressure steam (Bliss and Blake 1977). Yield of 

 charcoal will vary with moisture content of the feed; about 8 tons of wet wood 

 (50 percent moisture content, wet basis) are required to produce 1 ton of 

 charcoal. 



For an economic analysis of charcoal production with a Herreshoff furnace 

 see section 28-20. 



TECH-AIR SYSTEM 



Knight et al.'^ described a steady-flow pyrolysis system that produces a 

 pyrolytic oil, charcoal, and off gases. The oil, which has a heating value of 



'^J. A. Knight and M. D. Bowen, Pyrolysis — a method for conversion of forestry wastes to useful 

 fuels. 13 p. Paper presented at the Southeast. Tech. Div. of Am. Pulpwood Assoc, fall meeting. 

 (Atlanta, Ga., Nov. 5-6, 1975). 



