PRODUCTS FROM DISTILLATION OF RESINOUS WOODS. 17 



YIELDS OF VARIOUS PRODUCTS FROM THE DISTILLATION OF 

 RESINOUS WOODS. 



The yield of crude oil obtained is governed by two factors the 

 quantity of oil in the wood and the completeness with which this is 

 removed by the method used. Thus, by steam processes from 2 to 

 15 gallons per cord are recovered from sawdust and slabs, from 8 to 

 20 gallons from lightwood, and as high as 30 gallons from very rich 

 lightwood. By destructive processes from 10 to 20 gallons are recov- 

 ered from ordinary lightwood, and larger quantities from exception- 

 ally rich lightwood. By extracting with soda it is claimed that some- 

 what better results are obtained. 



The operators claim that when using fixed retorts and the steam 

 process a good yield from lightwood, under usual conditions, is ap- 

 proximately 15 gallons of crude oils per cord; with rotary retorts the 

 production is increased to about 18 gallons, and experiments have 

 shown that at least 3 gallons of crude oil, containing about 25 per 

 cent of actual turpentine, are often left in the wood. The crude oil 

 yields about 80 per cent of refined oil a result which is only obtained 

 by distilling much of the heavy oil with the turpentine. By the 

 destructive process the yield of wood turpentine is several gallons per 

 cord greater than by the steam process. 



The data on yields of various products as summarized in the fol- 

 lowing tables were obtained from many sources, mostly from wood 

 distillers, some from the literature, and some based on the experi- 

 mental work of the bureau. The whole is harmonized as far as pos- 

 sible in accordance with the experience and judgment of the author. 

 The data on yields of crude oils, refined wood turpentine, charcoal, 

 methyl alcohol, acetate of lime, and unbleached wood pulp may 

 safely be regarded as quite accurate. In fact, all the data on the 

 steam and volatile solvent processes may be so regarded. The other 

 data on pine oils, rosin spirits, rosin oils, and creosote, by the destruc- 

 tive and alkali extraction processes, are not exact and in general are 

 to be regarded as careful estimates rather than as known results. 

 This is due to the fact that less attention has been paid to the separa- 

 tion and utilization of these products, and what one producer terms 

 "creosote" may in reality embrace all oils heavier than pine oil, or, 

 in some cases, those heavier than turpentine. In other plants all oils 

 heavier than pine oils may be combined with the tars and disposed of 

 under this term. Further work will be necessary before more defi- 

 nite information can be given as to the quality and nature of the 

 products variously termed "rosin spirits," "rosin oils," "creosote/' 

 "wood oils," "tars," etc., obtained in the destructive distillation of 

 pine wood. 



7085 Bull. 14411 2 



