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 j acket 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- 



25 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 him self, 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). 



w Jour, of the Soc. of Chem. Ind., 1912, 513. 



