48 



BULLETIN 983, U. S. DEPARTMENT OF AGRICULTURE. 



Commercially, the subject of extraction, covering the questions of 

 size, design, and number of cells in a diffusion battery, is one that 

 has received a great deal of attention in the beet-sugar industry. In 

 the light of data obtained in units of commercial size in the ethyl- 

 alcohol industry, it may be said that at least a 5-cell draw — that is, 

 passing the extracting medium through 5 cells in rotation — is neces- 

 sary, and that a 6 or 7 cell draw is more desirable. The amount of 

 water to be used and the proper end point or time of drawing must 

 be determined for each particular battery, and with proper care and 

 supervision the efficiency of the entire operation can be maintained 

 at a 92 per cent extraction with a 10° to 11° Brix acid juice corrected 

 for temperature. 



VOLATILE ACID YIELDS. 



In addition to the sugars obtained as hydrolytic products, acetic 

 and formic acids were also obtained in varying amounts. The yields 

 are given on the acid-yield sheet in the Appendix, in addition to the 

 following tables, in which the cooks have been outlined in the differ- 

 ent series as given before under pressure, time, water to wood and 

 acid to wood ratios : 



Series 16. 

 PRESSURE VARIABLE. 

 1.80 per cent of HcS0 4 ; 400 per cent of H»0 (water); minute. 



Cook No. 



Pressure. 



Yield of volatile acid (per cent of dry 

 weight of wood). 





Acetic. 



Formic. 



Both. 



20 



6.5 

 7.5 

 7.5 

 9.0 



1.25 

 1.22 

 1.62 

 1.60 



0.105 

 .185 

 .220 

 .443 



1.355 



15... 



1.405 



16 



1.840 



19 



2.043 







Series III. 



TIME VARIABLE. 



2.5 per cent of H2SO4; 125 per cent of H2O; 7.5 atmospheres. 



Cook No. 



Time of 



cook 



(minutes). 



Yield of volatile acid (per cent of dry 

 weight of wood). 





Acetic. 



Formic. 



Both. 



31 





 

 10 

 10 

 20 

 45 

 90 



1.755 



1.670 



1.67 



2.62 



2.360 



2.915 



2.140 



0.572 

 .790 



1.090 

 .340 



1.450 



1.492 

 .440 



2.827 



45... 



2.460 



32 



2.760 



47 



2.96 



46 



3.81 



56 



4.407 



55 



2.580 







