10 WOOD TUKPENTINE. 



time for distilling by the destructive process varies from 24 to 30 

 hours. Preliminary experiments conducted in the laboratory several 

 years ago indicated that it is feasible to control the heating of the 

 wood by using an oil jacketed retort, but no work on a commercial 

 scale has been done with such apparatus as far as is known. 



The following diagram shows the products of the destructive dis- 

 tillation of wood and the processes used: 



Charcoal. 



Resinous wood., 

 (distilled) 



fUsed as such. 

 Tar fLightoils. 



Willed Piteh7 ilS ' 



I Acid water. 



Condensable distillate. 



[mpure light rosin spirits. 



Light oils I Destructive wood turpentine. 



(fractionated) ) Pine oils (includes heavier portion of rosin 

 I spirits). 



f Pine oils (includes heavier portion of rosin 

 Heavy oils I spirits) . 



(fractionated) ) Rosin oil. 

 (Pitch. 



(neutXef ^thK? idue < dried and roasted) =acetate of 

 Stilled 1 !) 16 and J D istmate (rectifled)=wood alcohol. 



STEAM DISTILLATION. 



For distilling with steam the procedure and equipment are quite 

 different from those used in destructive distillation. In the first 

 place mill waste, including sawdust, can often be profitably utilized. 

 Other wood must be chipped or cut into small pieces in order that the 

 steam may penetrate it and remove the oils readily. The chipped 

 wood, prepared by what is known as a "hog," is taken directly to 

 the retorts by conveyers, or is placed in one of the many forms of inner 

 containers which have been devised to facilitate the penetration of 

 the chipped wood by the steam, and also the emptying of the retort 

 at the conclusion of the distillation, both of which operations, even 

 under the most favorable conditions, are quite difficult. Live steam 

 is conducted into the retort until no more oils pass over, which requires 

 in most plants from 3 to 24 hours. The distillate, consisting of a 

 mixture of oils and water, is condensed, allowed to separate into two 

 layers, and the crude oil is stored in large storage tanks, from which it 

 is drawn to the refining still. 



The live steam which is turned into the filled retorts may be super- 

 heated or saturated, and used at atmospheric pressure, under ad- 

 ditional pressure, or at diminished pressure, as may be desired. All 

 of these methods of handling the steam are used, but as a matter of 

 fact, it can not be said that under the conditions at present usually 

 obtaining in the industry, higher or better yields are secured by one 

 procedure than by the other. As turpentine distills with steam at 

 from 94 to 98 C., no advantage as to yield can logically be expected 

 from the use of superheated or pressure steam, other than that which 

 may arise from a quicker and more thorough penetration of the wood 



