A new process for the production of ethylene glycol from sorbitol

A new process for the production of ethylene glycol, characterized in that: it includes the preparation of DX value glucose syrup, hydrogenation reaction, refining of sorbitol solution, hydrogenolysis of sorbitol, refining and separation of polyol mixture, the process is as follows:
A). Preparation of DX value glucose syrup: the starch emulsion is separated by the simulated moving bed chromatographic separation system after liquefaction, saccharification, filtration, decolorization and dissociation processes, and DX99~99.7% glucose syrup is obtained; the feed dry matter entering the chromatographic separation system is 50~70%, and the temperature is 60~80 °C;
B). Hydrogenation reaction: evaporate DX value glucose syrup to 50% dry matter, use ruthenium or nickel as catalyst, hydrogenation reaction at 140~160 °C, PH7.5~8.5, pressure 3.5~5.5Mpa, to obtain 96~98% sorbitol solution;
C). Refinement of sorbitol solution: after hydrogenation reaction, sorbitol solution evaporates the dry matter to 50% after cooling, sedimentation, filtration, dissociation, and decolorization;   
D). Hydrogenation of sorbitol: under the condition of PH9~11, temperature 190~250 °C, pressure 2000psig~4000psig, one of Ru/C or Ru-Re/C is used as a catalyst to hydrogenolyze 15min~6hrs to obtain a mixture of ethylene glycol, glycerol and propylene glycol;
E). Refinement and separation of polyol mixture: After cooling, sedimentation, filtration, separation and decolorization of the polyol mixture, ethylene glycol, glycerol and propylene glycol are separated.



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