Sorbitol
1. Preparation
The starch milk is fed into liquefaction PH regulation tank measurably, add Na2CO3
the solution continuously according to the starch milk flow rate to regulate the PH value and add a part of α-amylase at the same time.
2. Liquefaction
Pump the regulated starch milk to 1st. jet cooker to have the first liquefaction done with steam, the gelatinized starch enters into the first hold tank and pumped into 2nd. Jet cooker to have the 2nd. Liquefaction done with steam, the hydrolysate enters into 2nd. hold tank, add another part of α-amylase to the discharge line of the tank, after the solution is pumped to the continuous plug flow reactor to finish the liquefaction, cooling it to be 60℃ for saccharification unit.
3. Saccharification
Add HCl to regulate the PH value according to the hydrolysate flow rate, and has the saccharification done with enzyme, during the process, stir it to make the saccharification goes evenly, after reach the required DE value, the solution is sent to the next unit
4. Vacuum Rotary Drum Filtration
The saccharified material contains lots of protein and insoluble impurities that difficult for filtration. It adopts a diatomite precoating vacuum drum filter to remove the impurities since the filter cake on the surface of diatomite is being removed continuously to be always new which makes the filtration fast and in-depth.
5. 1st. Decolorization and Filtration
Add activated carbon to the saccharified material to absorb the organic impurities
(mainly the soluble colored impurities),then filter the activated carbon together with the impurities by pressure filtration.
6. Ion Exchange
After the filtration of insoluble and organic impurities, there are still some soluble inorganic impurities in the saccharified material, they exist in the form of cation and anion, ion exchange aims to remove them, the cation inside the saccharified material is exchanged with the H+ of cation resin, while the anion is exchanged with the OH- of anion resin, then the exchanged H+ and OH- inside the saccharified material is combined to water, the inorganic impurities came to corresponding wastewater. Certainly, to keep the exchangeability of exchange resin, it usually uses acid and alkali to regenerate the cation and anion resin respectively when the exchangeability weakened.
7. Vacuum Concentration
The syrup after ion exchange go through a multi-effect vacuum falling film evaporator to remove part of the water, then the concentration will be increased from about 31% to 50%
8. PH Regulation
Add analytical grade solid NaOH (caustic soda flakes) to regulate the PH of glucose solution to be 7.5~7.8
9. Hydrogenation
Sent the glucose solution into an autoclave, it reacts with hydrogen under the effect of catalyst to get sorbitol. Hydrogen adding adopts intermittent low pressure( 4.5MPa) inter autoclave sedimentation mode
10. Decolorization
The hydrogenated solution contains color impurities since the high temperature during the hydrogenation, add activated carbon powder to the hydrogenated solution, the colored impurities are absorbed by the surface of carbon and be get rid of by press filtration
11. Pressure filtration
Filter the activated carbon with the colored impurities absorbed inside the hydrogenated solution by plate-and-frame press filter, the hydrogenated solution becomes clear and transparent, a part of catalyst remaining inside the hydrogenated solution is also filtered
12. Ion Exchange
The hydrogenated solution after decolorization goes through cation exchange column, anion exchange column, mixed bed, cation and anion inside the solution is separated, and inorganic impurities(including the residue catalyst)is also basically removed out
13. Vacuum Concentration
The hydrogenated solution after ion exchange goes through the multi-effect vacuum falling film evaporator to remove a part of water, the concentration then increase from about 48% to 70%
14. Filling
Filling the sorbitol liquid after concentration to vessels which are easy for transportation and storage, seal and label well to get finished product liquid sorbitol
G-Luckey an engineering consulting firm, offer fermentation process, corn wet milling service in starch sugar manufacturing industry. We have many cases for fructose, glucose, erythritol, allulose, xylitol, sorbitol production line.