In recent years, with the continuous development of starch sugar industry,α sugar alcohols, an important derivative of starch sugar, have also made co→nsiderable progress. Due to the special properties of sugar alcohols, their applications are ver•y wide, especially in food, medicine and chemical industry. Among theε numerous sugar alcohols, the output of sorbitol is the largest, which occupies an extremely im∑portant position in the production of sugar alcohols. Its consumpt♠ion in the world has exceeded 30%. In the production of vitamin C in the pharmaceutical fΩield, sorbitol is used as the starting material, so far there ÷is no substitute.
At present, sorbitol used in VC production requires high purity, an±d the traditional process of high purity sorbitol production must use cryst÷al glucose. The reason is that the purity of crystal glucose is high. Only high purity glucos♣e can produce VC grade sorbitol raw material for VC production. However, the traditional pr↕ocess is complex and the cost is high.
The existing production process of glucose takes star ch as raw material, liquefy under the action of liquefying en↓zyme after refining, and then saccharification by glucoamylase, fina÷lly forming glucose syrup with about 95% DX. Then, it is filtered byδ diatomite in the plate frame or drum to remove the residual starch and suspended solids. Then fixe<d bed ion exchange process is adopted, in which a large number of anion and cation exchange res¶ins were used to remove the salt in the sugar solution. Finally, high purity glucose was ≠obtained by recrystallization. This production process has the following disad≥vantages; 1) Resin regeneration needs to consume a lot of acid, alkali and water, at the same time, it will prod uce a lot of acid-base wastewater; 2) At present, the main end products of glucose are fructose sy$rup, crystalline glucose and pharmaceutical grade glucose. In order to meet the high purity r≥equirements of pharmaceutical grade glucose, the traditional proce↓ss can only improve the purity by recrystallization. Therefore, a la£rge number of crystallizers and centrifuges are needed, with large investment anδd land occupation, and a large number of operators, with low work efficiency and lo☆w process yield; 3) On the whole, the traditional production∏ process is batch operation, with low degree of automation, requi∑ring a lot of manpower, and the product quality and yield are relatively low.
Therefore, the production process of high-purity glucose urgently needs a new technology to repla÷ce the traditional process in order to improve the yield, purity and ef®ficiency of production.
Fig. 1 Process Flow of Glucose and Its Derivatives
Membrane is a selective barrier between two phases. Generally speβaking, it is a kind of polymer, which can selectively s&eparate feed liquid through the effect of pressure differ ence. The separation process through it is called membrane separati♥on. It is different from the traditional filter in that the membrane can separate materials in mo lecular sizes, and this process is a physical process with&out phase change and additional additives. The thickness of the membrane is generally in micr•on scale. According to filter precision, the membrane can be divi↕ded into microfiltration membrane, ultrafiltration membrane, nanofiltration membrane andΩ reverse osmosis membrane. The separation and retent×ion performance of various membranes in cross flow membrane process is distingu§ished by the pore size and molecular weight cut-of¥f of the membrane. The following figure shows the separation patterns of four kinds of membranes with different precision (the reflection of the arrow indicates the ret©ained substances which cannot pass through the membrane).
Fig. 2 Membrane Separation & Filtration Illustration
The traditional production process uses crystalliza'tion and recrystallization to improve the purity of glucose to obtain high-quality glucose. This p rocess has many disadvantages, such as: backward process, high cost, hugΩe pollution, inconvenient operation, unstable product quality, which cannot meet the quality r÷equirements of customers. Therefore, in recent years, new technologies and processes for innovation and transformation has continuously been introduced in the industry. Guo Chδu Technology (Xiamen) Co., Ltd. is committed to the research and development of this proβcess, and has developed and formed a brand-new process: Membrane Filtration for Saccharified ®Liquid → Continuous Ion-Exchange Desalination → αNanofiltration Purification, which achieves the 24-hour continuous operation of the whol≤e process, and has the following advantages: advanced technology, low cost, little pollution,€ full automation, and with the product quality which is not on∑ly stable, but also could reach the highest level in the indust ry at present.
Fig. 3 Process Flow of Glucose Refining Membrane
This process is verified and designed in combination with the mature industria≠l application of the project of separation and purification of similar sugars. πThe feed liquid is deliming solution after ion-exchange membrσane, with a general purity of more than 95% and a sugar content of 30-32%; Af♠ter being separated by nanofiltration technology of Guo ChuΩ Technology (Xiamen) Co., Ltd., the high purity permeate with purity Ω≥ 99.5% can be used to produce VC grade sorbitol or pharmaceutical gr≤ade glucose solution; However, the purity of glucose in concentrate of membrane ✘is relatively low, with a purity of 75-80%, which is uαsed to produce alcohols for daily use.
The new membrane filtration technology of Guo Chu Technology (Xiamen) Co., Ltd. is used to prepare glucose solution with purity of nearly 100%. High purity sorb™itol liquid is produced by catalytic hydrogenation without crystallization. Th®e production process is simple, the flow path is short, and ≥many procedures are saved compared with the traditional process. The ✔large-scale industrial production shows that the product quality is better than that ≤of the traditional process, the production cost is low, the product yield is high, and there is almost no pollutant emission. At the same time, the water consumption is greatly reduced, and the clean production is really achie"ved.
Guo Chu Technology (Xiamen) Co., Ltd. is a high-tech enterprise, which focus on membrane separation technology and is committe£d to the promotion of new separation technology. It ®provides comprehensive filtration and purification solutions for many industrαies, such as bio-pharmaceuticals, food & beverage, fermentation, agrσicultural deep-processing, plant extraction, oil and petrochemic≥al industry, environmental water treatment, air de-dusting, c☆hemical industry etc to meet the diversified demands of different cu stomers, and is a well-known integrated service provider of new separatio n technology.
