Xylitol Production Process

Production Process

Neutralization and deacidification

Neutralization and deacidification process is used in the purification of hydrolyzate neutralization method. The sixties of last century, China's xylitol in Baoding began trial production, is to use this method, such as Baoding plant on the 1st production line. The route of this method is as follows:

Raw materials → hydrolysis → neutralization → concentration → decolorization → ion exchange → concentration → hydrogenation → concentration → crystallization → separation → packaging

This is a typical xylitol production process, in the process of purification of the hydrolyzate, to take a neutralization and ion exchange process, in this process on the basis of a hydrogenated liquid ion exchange, it becomes a neutral Deacidification secondary exchange process, are both in the deacidification process. We know that in the process of xylitol production, corn cob first to hydrolyze the production of hydrolyzate, hydrolysis to add catalyst - sulfuric acid, and hydrolysis, sulfuric acid exists in the hydrolysis solution, but in the production process, this part of the sulfuric acid must Remove, as the name implies and deacidification process is to neutralize the method to remove the acid, neutralizer is usually used calcium carbonate. Sulfuric acid is neutralized with calcium carbonate into gypsum - calcium sulfate, calcium sulfate in water solubility is very small, most of the gypsum have become precipitated by filtration to remove.

Neutralization and deacidification process advantages and disadvantages: neutralization and deacidification process is relatively simple, low consumption of acid and alkali, can reduce costs, equipment is relatively simple, easy to operate, less investment. But because it is the initial process, there must be shortcomings, its shortcomings mainly to the process itself, we all know, although the solubility of gypsum in the water is small, it is not absolutely insoluble, into the next enrichment process, with the hydrolyzate Thickened, the concentration of gypsum in the hydrolyzate is also large, was supersaturated state, then there is part of the gypsum and precipitated out, deposited in the evaporator wall, the formation of insulation, reduce the evaporation efficiency, waste steam, Equipment utilization. Because this layer of scaling is difficult to remove, especially difficult to remove with chemical methods, had to use mechanical removal of fouling, not only trouble, and labor intensity is great, the equipment has different degrees of damage, reduce equipment life.

Ion exchange

In order to solve the confusion caused by deacidification, scientific and technological workers and manufacturers of scientific and technological personnel through unremitting efforts to research and development of ion exchange deacidification of new technology, such as Baoding plant on the 2nd production line. Ion exchange deacidification process is

The ion exchange resin was used to remove the sulfate by ion exchange. This process also has two exchanges and three exchange points, but whether it is two exchanges or three exchanges have belong to the scope of ion exchange. The route of this process is as follows:

Raw materials → hydrolysis → decolorization → ion exchange → concentration → ion exchange → hydrogenation → ion exchange → concentration → crystallization → separation → packaging

The exchange is different, so the use of ion exchange resin is also different, the first exchange is mainly to remove the sulfate in the hydrolyzate, so the use of anion exchange, the second exchange using cation exchange resin, the third exchange Yang, yin two kinds of resin, there are single use of cationic resin. Ion exchange deacidification process, the process is more complex, more resin dosage, more equipment, large investment. Increase the consumption of acid and alkali, increased costs. But the ion exchange deacidification process has its irreplaceable advantages, it solves the neutralization and deacidification process equipment fouling the shortcomings of the equipment to improve the utilization and service life, reducing the hydrolysis of ash and acid Content, improve the quality of the hydrolyzate, the corresponding increase in product quality. As the ion exchange deacidification process has many advantages, new plants have adopted this process.

Whether it is neutralization and deacidification process or ion exchange deacidification process, their last exchange, are the hydrogenation liquid and then a exchange, to improve the quality of the liquid, and then improve product quality. And deacidification process and ion exchange process, have their own advantages and disadvantages, to take that kind of technology must be long and short, the maximum development advantages and improve economic efficiency.