GB681345A - Improvements in or relating to a method for the hydrolysis of cellulose materials - Google Patents

Abstract

681,345. Hydrolysis of cellulose. SOC. DU GLUCOL, and BONCIENNY, P. July 27, 1948, No. 20066/48. Class 127. A method for the hydrolysis of cellulose material comprises introducing into a continuously operated rotating hydrolyser 4 steam heated from a high pressure supply system 5, the cellulose material 1, hydrolysis acid from a container 2 and dilution water from a supply line 3, removing the now vaporized hydrolysis product at 6 into a mixer 8 where it is neutralized with an alkaline solution from the reservoir 9, diluted with water, homogenized by an agitator and discharged into fermentation vats 11, 12 for fermentation by a pump 10 which recirculates part of it to the mixture. After the fermentation, the worts are again homogenized by agitation and are then pumped by a pump 13 through one half of a first heat exchanger 14, one part being thereafter recirculated back into the vat 12 whilst the other part is passed into a first concentration column 15. The alcoholic vapours at the head of the column 15 pass through the other half of the heater 14 and then pass partly to the second concentration column 16 and are partly recirculated back into the column 15. The alcohols of high concentration emerging as vapour products at the exit of the column 16 are condensed and cooled in the first condenser 17 and cooling means 18 and stored at 18a. The liquid products from the base of the column 15 are withdrawn by a pump 19 one part being recirculated in the base of the column 15 and the remainder passed into a first decantation installation 20 from which the solid layer 21 is carried to a store 22. The liquid portion is taken by the pump 23 and carried either as diluting water to the mixer 8 or to the hydrolyser 4, or again is drained off at the pipe 25. The liquid products from the second column 16 are recirculated by the pump 26 back into the column 15. The vaporised products formed in the course of the hydrolysis in the hydrolyser 4 are carried by the steam throughout the course of the operation, and when they are at the working pressure of the evaporator the steam charged with these products is carried from the hydrolyser and through a valve 27 to the evaporator 24, then after condensation, evacuated by a blow off valve 38 through a cooler 29 and then stored in a container 30. As soon as the pressure of the vapours coming from the hydrolyser 4 falls below the working pressure of the evaporator 24, the vapours are carried through a valve 31 to the second condenser 32 and the condensate after passing through a cooler 33 is stored in the container 30. The condensates are neutralised in the container 30 by the addition of an alkaline solution coming from the reservoir 9 and this neutralized condensate is carried by means of a pump 34 successively through one half of a second heat exchanger 35 and one half of a heater 36, then to a third concentration column 37. The vaporised products coming from the head of the third column 37 pass through the other half of the heater 36, and then partially through one half of a third condenser 38 and partially recirculated back into the concentration column 37. From the condenser 38 the condensate passes to a second decanter 39. From the decanter 39, the lower layer, consisting of furfurol is withdrawn and eventually, after appropriate dehydration, passes to storage means 40. The upper layer from the second decanter 39, after passage through half of a third heat exchanger 41 is carried to a fourth fractionating column 42. The vapours coming from the upper part thereof pass through a fourth condenser 43 and the condensate, a light solvent called methylene is partially stored at 44 and partially recirculated back into the column 42. The liquid products from the lower part of the fourth column 42 are passed by the pump 45 into the other half of the heat exchanger 41 and are recirculated into the third column 37. The liquid products from the lower part of the column 37 are taken through the other half of the heat exchanger 35 by a pump 46 and pass through half of a fourth heat exchanger 47 to feed the evaporator 24. The concentrated liquids at the exit of the evaporator 24 pass through the other half of the fourth heat exchanger 47 and are stored in the container 48 which feeds the dryer 49, the dried product, therefrom, consisting of a mixture of various formates and acetates being stored at 50. The steam produced by the evaporator 24 is used for the thermal needs of the installation, passing through the circuit 51.