ETHYL ALCOHOL FROM WOOD WASTE. 
39 
would probably have reduced these variations, but they were not 
deemed necessary to establish the principle involved. 
Although 100 per cent of water gave results practically as good as 
did larger amounts, the operating conditions chosen for future work 
was 125 per cent of water. This was done for two reasons: First, 
to insure a better mixture of the acid in the wood, which, of course, 
is easier to accomplish with larger amounts of water, and, second, 
to use the maximum amount of water possible and still obtain a 
digested sawdust that has no drip. The advantages from the use 
of 125 per cent of water were felt to outweigh the small increase in 
steam consumption and to justify its adoption for future work. 
From calculations that have been made to determine the steam 
load on a commercial digester it was found that it takes 1,816,000 
B. t. u. to a cook for heating the wood and acid solution, and 1,183,000 
B. t. u. to heat the digester — a total of 2,999,000 B. t. u. to a cook. 
Decreasing the ratio of water to wood from 125 per cent to 100 per 
cent would decrease the total steam load to 2,709,000 B. t. u., a 
difference of 290,000, or about 10 per cent. The digester load, 
however, is only 25 to 30 per cent of the total steam load of the 
plant; consequently, the above would make a difference of only 
2 or 2.5 per cent of the total steam load of the plant. 
RATIO OF ACID TO WOOD. 
The above ratio of water to wood (125 per cent) and a 0-minute 
cooking period were the constants used in the next series, in which 
the ratio of acid to wood was the variable. Sulphuric acid was used 
as the catalytic agent and in amounts varying from 0.5 per cent to 
4 per cent of the dry weight of the wood. The results are given in 
the following table : 
Series V. 
125 per cent of H 2 0; 7.5 atmospheres; minute. 
Per cent 
H 2 S0 4 . 
Per cent of 
total sugars. 
Per cent of 
total sugars 
ferment- 
able. 
Alcohol yields. 
Cook No. 
Per cent of 
dry wood. 
Gallons 
absolute 
per ton. 
38 
0.5 
.75 
1.00 
1.40 
1.40 
1.40 
17.42 
21.83 
21.68 
23.17 
23.74 
22.37 
43.13 
56.03 
56.43 
54.20 
53.67 
53.92 
4.172 
6.085 
6.506 
6.972 
6.319 
6.214 
12.62 
37 
18.41 
35 
19.68 
33 
21.09 
40 
19.11 
391 
18.80 
Average 
1.40 
23. 455 
53. 935 
6. 6455 20. 10 
34 
1.80 
1.80 
2.50 
2.50 
21.96 
21.09 
21.45 
22.77 
59.29 
60.68 
63.66 
62.65 
6.805 
6.440 
6.859 
6.994 
20.58 
30 2 
31 
45 
19.48 
19.75 
21.15 
2.50 
22.11 
63. 155 
6.9265 20.95 
36 
4.00 
21.10 
66.63 
7.000 21.17 
Blow-off open, not averaged. 2 30 to 100 per cent H2O, not averaged. 
