GB717939A - Improvements in or relating to the recovery of glycerol and other high boiling substances from fermentation liquors - Google Patents

Abstract

High boiling components such as glycerol and 2 : 3 butandiol are volatilized from fermentation liquors by feeding the concentrated liquor into contact with a continuously renewed bed of granular solid material, e.g. sand, maintained in a fluidized condition by passing superheated steam through the bed. The vapours leaving the fluidized bed may be washed with water, whereby there is obtained an aqueous solution of the high boiling components, which may then be recovered by distillation. Steam withdrawn from the water-washing zone may be compressed, re-superheated, and recycled to the fluidized bed. The spent granular material, <PICT:0717939/III/1> withdrawn from the fluidized bed, is transferred to another fluidized bed wherein the carbonaceous residue, deposited on the material, is burned off with air or oxygen; the re-vivified material is then returned to the main fluidized bed. In the Figure, air is introduced through pipe 1, and carries sand from pipe 2 to the separating vessel 3, where the air leaves by pipe 4. Concentrated fermentation liquor is introduced through pipe 5. The granular mixture of sand and liquor passes through pipe 7 into vessel 9 where it is maintained as a fluidized bed 8 by passing superheated steam from pipe 10 through perforated base 11. The spent mixture, after removal of glycerol, passes over weir 12 and through pipe 13 into vessel 15. The vapours from vessel 9 are introduced into tower 17, where they are washed by a stream of water entering the top of the tower from pipe 18. Aqueous glycerol is taken off from the base of the tower by pipe 19, and is passed to a rectifying still. Steam leaves the head of the tower through pipe 20; some of it is bled off through pipe 22 and the remainder is passed to compressor 21. The compressed steam is superheated in heat exchanger 24, and is then recycled to vessel 9 through pipe 10. The fluidized bed 14 in vessel 15 is maintained in a fluidized state by passing air from pipe 25 through perforated base 26. The combustion gases leave vessel 15 via cyclone 27, and are passed through pipe 29 to heat exchanger 24, and thence to a stack. Ash is withdrawn through pipe 28. The sand from bed 14 passes continuously over weir 31 into pipe 2, from which it is recycled to vessel 9.