ETHYL ALCOHOL FROM WOOD WASTE. 11 
same size and shape as those used in the French plant, the idea being 
to save steam by means of indirect heating. Sawdust and enough 
water were added through a manhole into the space between the 
tubes to raise the moisture content to about 45 per cent. Anhydrous 
sulphur dioxide was then added, and the mixture was cooked at 75 
to 100 pounds pressure. The cost of conversion was excessively 
high, because the corrosion of the digesters was very rapid; the time 
necessary to heat them by indirect heat was very long; and it was 
necessary to replace the low-pressure steam with high-pressure steam 
in the outside jacket in order to prevent the sulphurous-acid gas from 
leaking out of the digester into the jacket. The extraction equip- 
ment was very inefficient, as the modern type of diffusion battery was 
not used. The plant was very well built, and much of the equipment 
was imported from France at a high cost. The extracted sawdust 
was mixed with Hawaiian molasses and was put on the market as a 
cattle food. 25 It was necessary to dry the extracted material to about 
12 per cent moisture, in order to prevent decay, and this gave great 
difficulty because of explosions of dust in the driers. In addition, 
the plant was located 80 miles from a railroad, and this distance 
greatly increased all transportation charges both to and from the 
plant. This and the very poor design of the digester and extraction 
equipment were, no doubt, the chief reasons for the failure of the 
plant. 
In the process covered by United States Patents Nos. 985725 and 
985728, granted to W. P. Cohoe, of Toronto, Canada, hydrochloric 
acid is used and preferred as a catalytic agent because of its vola- 
tility. A yield of 25 to 28 per cent of fermentable sugars is claimed. 
It is also stated that the acid can be completely removed from the 
wood by blowing it out with steam. If this is true, the cost of neu- 
tralization is removed. It is also claimed that 1 to 2 per cent of 
acetic acid can be obtained from the preliminary steaming of hard- 
wood sawdust. In addition, the preliminary steaming is claimed to 
be of value, because, after the blowing off, the sawdust is of a con- 
stant moisture content, irrespective of its initial moisture content. 
In a later paper Cohoe 26 further describes his work in which hydro- 
chloric acid is used. The following quotations are of particular inter- 
K The production of cattle food from sawdust has been attempted at another plant in this country, 
situated at Marinette, Wis. This plant, however, was unsuccessful in marketing the product obtained, 
since the chief value of hydrolyzed sawdust as a cattle food lies in the carbohydrates that it contains. 
Carbohydrate foods, as a rule, are the cheapest that the farmer can grow for himself, and usually the only 
foods purchased are nitrogenous concentrates. The Marinette company was finally forced to add oil cake 
and similar materials to its product. In addition, the Port Hadlock plant had a great deal of difficulty 
from spoilage due to the absorption of water and the consequent growth of mold in their product. The 
material was put on the market under the trade name of " Bastol." A similar material has recently been 
produced in London by Zimmermann (see article in Jour. Soc. of Arts, 1912, p. 68). 
26 Jour, of the Soc. of Chem. Ind., 1912, 513. 
