22 DISTILLATION OF RESINOUS WOOD BY SATURATED STEAM. 



CHIPS LARGER THAN 1 INCH X INCH X \ INCH. 



At the maximum pressure used, 70 pounds, chips larger than 1 

 inch X i inch X % inch can not be completely distilled, but as the 

 size of chips is increased there is no sudden drop in the yields obtain- 

 able at this pressure until sizes larger than 2 inches with the grain 

 (runs 27 and 28) 1 and 4 by 4 inches across the grain are used (runs 14 

 and 24). It is probable that from 80 to 85 per cent of the oil could 

 be removed from chips 2 inches X 4 inches X 4 inches by distillation 

 at 70 pounds pressure. 



EFFECT OF PRESSURE ON COMPOSITION OF OIL. 



Analyses were made by the method described in Bulletin 105 2 of 

 part or all of the oil from each of the runs, but there was so little differ- 

 ence between the various samples that all of the analyses need not 

 be given, and only a few distillation curves, which show the main 

 points of interest, are presented. 



PINE OIL. 



The proportion of pine oil in the crude turpentine did not vary, 

 except in cases which could be explained by variation in other factors 

 besides pressure, and therefore, so far as the results show, the pressure 

 has no influence on the proportion of pine oil except the influence due 

 to increasing the total yields. That is, the pine oil has a higher boil- 

 ing point, and therefore would be removed last, giving a higher pro- 

 portion of pine oil in those cases in which the yield is greater. In ah 1 

 cases where the total oil obtained was analyzed and where the oil was 

 nearly completely removed from the wood the percentage of pine oil 

 by weight varied only between 48 per cent and 52 per cent. 3 In cases 

 where only part of the oil was removed by the distillation, as in run 4, 

 the proportion of pine oil was less. 



1 In determining the percentage of total oil obtained in the runs of Group VI it must be remembered that 

 the sawdust of run 25 was not exactly a representative sample of the material of that group, but that it was 

 mixed with the sawdust obtained in cutting the slabs from the blocks. (See Table 1.) In several cases 

 similar samples of sawdust obtained in cutting the slabs had been distilled and found to contain more volatile 

 oil than the sawdust obtained in cutting the blocks. It is probable, therefore, that the proportion of volatile 

 oil in the mixed sample of sawdust was somewhat greater than in the rest of the material in this group. 

 This point is further indicated by a comparison of the yields obtained from the sawdust runs in the different 

 groups. With the exception of Group VI (run 25) the yields from the sawdust decrease, as might be 

 expected, for the reason that the material for the groups was cut from the same log in order of the group 

 number, beginning at the butt end, and the content of volatile oil in the butt end was higher than in the 

 upper portions of the log. It is probable, therefore , that a value of from 24 to 25 c. c. of oil per pound of wood 

 would more nearly represent the volatile oil content of the group. 



2 Bulletin 105, Forest Service, U. S. Department of Agriculture, "Wood Turpentines, Their Analysis, 

 Distillation, and Composition." 



3 Exceptions were found to this in the oils from Group II,which contained about 28 per cent pine oil, but" 

 the material for this group did not represent a complete cross section of the log, being composed instead only 

 of the outside pieces, the slabs. The outer layers of this log evidently contained a smaller proportion of pine 

 oil than the rjest of the wood. 







