45 



Such methods appear illogical and unscientific, as the uncondensed 

 vapors leaving the retorts contain sufficient heat to separate them into 

 their three chief constituents tar, acetate liquor, and dilute alcohol. 

 The process may be greatly simplified in this way, as is shown in the fol- 

 lowing comparative statement of present methods and the suggested 

 method. The present process involves the following independent 

 successive steps: 



(1) Cooling and condensing the tar, acids, alcohols, etc. 



(2) Storing, settling, and separating tar from aqueous distillate. 



(3) Redistilling tar from (2); cooling, condensing, and storing aqueous distillate, 

 and storing tar. 



(4) Redistilling aqueous distillate from (2); cooling, condensing, and storing dis- 

 tillate, and storing tar. 



(5) Neutralizing, distilling, cooling, condensing, and storing distillate from (3) and 

 (4). 



(6) Fractionating distillate from (5). 



(7) Evaporating, drying, and roasting residue from (5). 



The operations under 3, 4, 5, 6, and 7 require a great amount of heat, 

 which is entirely lost in 1, and which is obtained for these operations 

 from additional fuel. The operations under 2, 3, 4, and 5 require 

 apparatus and storage room, part of which is not needed with the 

 modified system. 



Under the modified system the heat lost at (1) in the present 

 system is utilized to separate the constituents of the distillate without 

 expense for fuel. Thus 



(1) Receive the tar, alcohol, and acid distillate in a closed still, from which the acid 

 and alcohol will be distilled by their own heat. 



(2) Pass the uncondensed vapors through mire of lime; the acids will combine with 

 the lime and remain in the mixing vat while the alcohol distils by its own heat. 



(3) Pass the uncondensed vapors of alcohol-water from (2) to a column still, and 

 rectify as usual. 



(4) Evaporate, dry, and roast residue from (2), as usual. 



Such a procedure as this is perfectly feasible, can be made continu- 

 ous, and will result in the saving of fuel, boiler capacity, apparatus, 

 and storage room. Further, it .will prevent any losses now due to 

 incomplete condensation of vapors, which certainly occur at several 

 points in the present system. The process can also be made largely 

 automatic, resulting in more regular production, reduction of operat- 

 ing expenses, and in general economy and efficiency of the plant. 

 Where resinous woods are distilled the distillate from the tar must be 

 condensed in order to separate the turpentine and pine oils from the 

 alcohol and acids. 



[CIr. 361 



