TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 CONT

Hydrolysis with Hydrogen Chloride Gas .... A variation of the use of concentrated hydrochloric acid combined with hydrogen chloride is the process of Hereng. Here, wood chips are impregnated with 30% hydrochloric acid in a mixer and then transferred by a conveyor into the reactor. Because the chips are not predried, the acid concentration in them is reduced to 20%. The reactor consists of a hexagonal upright vessel equipped with numerous inclined trays. The impregnated wood is moved from the top toward the bottom by means of a vibrator and thus the prehydrolysis is completed after 45 minutes. The acid, containing chiefly pentoses, is filtered off and part of it is returned to the mixer. In this way, the sugar concentration in the prehydrolyzate is increased to about 20% to 25%. In a second step, the material, which has again been mixed with 30% hydrochloric acid, is passed through the reactor and hydrogen chloride gas is injected at the bottom in a countercurrent. In this way, the acid concentration is increased to 40% to 41% or more. The hydrolyzed material is conveyed from the bottom of the reactor to a drying chamber and is dried there with anhydrous hydrogen chloride gas which has previously been passed through a calcium chloride solution. The hydrolyzed material, consisting of lignin and sugar, is extracted with water and the sugar solution is subjected to a posthydrolysis.  1, fiche 1, Anglais, - Hereng%20process

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 CONT

Plusieurs pays continuent à faire des recherches pour améliorer l'hydrolyse chimique. Le procédé Hereng utilisant l'acide chlorhydrique gazeux permet d'atteindre un meilleur rendement en sucre et de récupérer l'acide.  1, fiche 1, Français, - proc%C3%A9d%C3%A9%20Hereng

Fiche 1,  Justifications,  Espagnol