GB679179A - Improvements in or relating to the distillation of ethyl alcohol - Google Patents

Abstract

<PICT:0679179/III/1> Aqueous ethyl alcohol, particularly that obtained by the fermentation of sugar solutions, is purified and concentrated by feeding the aqueous solution into the upper section of an analyzing column, withdrawing a minor quantity of vapours from the top of the column and a major quantity from the side, introducing the side-stream vapours into the base of a rectification column wherein the heat of the vapours serves to effect the rectification, and withdrawing purified and concentrated alcohol as a liquid side-stream from an upper section of the rectification column. The vapours leaving the head of the rectification column are condensed, part of the condensate is passed to the top of the rectification column and part to a heads column; and dilute alcohol from the base of the rectification column is introduced into the analyzing column just below the level at which side-stream vapours are withdrawn therefrom. The vapours from the head of the analyzing column are introduced into the heads column, which is heated solely by the vapours entering it and the vapours from the head of this third column are passed to a condenser via a valve which is used to control the relative quantities of the two vapour streams withdrawn from the analyzing column. The aqueous solution in the analyzing column preferably contains less than 12 per cent by weight of ethyl alcohol. Light-bodied rum from fermented cane molasses wash, containing 6.5 per cent ethyl alcohol is fed at 840 gallons per hour through heat-exchanger 1 where it is heated to approximately 80 DEG C by the alcohol-free effluent withdrawn through line 3 from the base of analyzing column 2. The preheated feed then enters part A1 of column 2 which is supplied at the base with 1,400 pounds of live steam per hour. The dissolved gases, very volatile components and some ethyl alcohol are passed in vapour form from the head of column 2 into column 5 and the passage of vapours from the head of column 5 to condensed 6 is controlled by needle-valve 7. A portion of the condensate from condenser 6, which contains the major portion of the impurities in the feed and 6 to 15 per cent of the alcohol, is withdrawn from the system through line 8 while the remainder is returned to column 5 as reflux. The non-condensible gases are passed through line 10 to water-scrubber 11. A major portion of the vapours issuing from part A of column 2 is passed through pipe 15 to the base of rectifying column 16 and light-bodied rum containing 92 per cent alcohol is withdrawn through one of pipes 17. The major part of the distillate from column 16 is returned as reflux to the column through line 20, but a small portion is passed to column 5 via line 21. Fusel oils and light oils are withdrawn from column 16 via pipes 22 and 23 respectively, while dilute alcohol is withdrawn at the base and pumped to column 2 via line 24 together with the effluent from the base of water-scrubber 11. Specifications 224,921, [Class 32], 419,170 and 462,433 are referred to.