- The situation of glycerin production in China
At present, there are 4 ways of producing glycerol in China. The production of glycerol by saponification has been reduced dramatically. The chlorination of propylene only stays in the intermediate process of producing epoxy chloropropylene mirrors (which can not be put into long-term operation due to corrosion etc.). Fermentation and chemical synthesis (which refers to the heating synthesis method developed in China) remain in the middle and small-scale production stage. More advanced technology is still blank in China.
Although the domestic chemical synthesis technology is not as advanced as that of foreign countries, but the product quality is better than that of fermentation method, the product number is more, and the application is wide. Medium-sized production plants can be properly built according to local advantages.
If we produce large tonnage and high quality glycerin, we should adopt the following methods:
① Propylene oxidation. The unit consumption is low, and the combined production market is tight;
② Propylene over acetic acid. The process is simple and the yield is high.
③ Modified propylene chlorination (direct hydrolysis method). No corrosion, high conversion rate.
These methods all take propylene as raw material, and their resources are abundant, which is the preferred development direction.
- Application
Glycerol is widely used. Only over 2000 kinds of products in the United States require glycerol in production.
From the consumption structure of glycerol, the United States and Japan are mainly used to synthesize alkyd resin, medicine and food beverages and other domestic refined glycerol (mainly saponified glycerol or chemically synthesized high-quality glycerol) is mainly used for coatings, toothpaste, etc., composite glycerol is mainly used for paint and paper.
The application fields of glycerol can be divided into two broad categories:
Direct contact with skin (including entry) and non-contact skin.The former includes food (including beverages), hair glue, toothpaste, cosmetics, medicine, tobacco, textiles and so on, as well as papermaking, latex, defense industry, paint, leather, shoe polish, ink, ink, synthetic resin, paint, dyes and printing industry. Refined glycerol has a wide range of applications, both of which can be used, and is very popular with users, but the price is high and the supply is small. Compound glycerin is widely used in non skin and purity demanding applications. The shortage of glycerol has seriously affected the development of related industries. People are looking for glycerine substitutes.
- Domestic market
As early as in the 1980s, China introduced the synthesis method of using epoxy chloropropylene as raw material to produce sweet sleeve. At present, the production capacity of 50,000 t/a has been formed.However, due to the high price of epoxy chloropropylene firing, the production capacity is difficult to play, and the current output is only about 20,000 T / A. In recent years, China’s synthetic detergent industry has developed rapidly, occupying a large part of the soap market, a large number of imported soap has also robbed China’s soap market, coupled with the rising price of oil, making China’s soap industry suffered a greater impact, oil hydrolysis glycerol production has been greatly affected, the annual output is only 37,000 tons; Compound glycerol from distiller’s grains developed by our country, although the method is simple and low cost, plays a certain role in easing glycerol in our country, but because of the low content of glycerol, the use is limited, resulting in poor sales; Since 1994, starch fermentation has been favored in the production of glycerol. It has developed rapidly in our country. There are many factories in different parts of the country. It is helpful to alleviate the tension of glycerol in our country in a certain period of time.
At present, the demand for glycerine is about 6.5 T in China, and its annual output is about 5T Since 90s, glycerol has been imported more than 1 T per year. In recent years, a variety of glycerol substitutes, such as pentaerythritol, ethylene glycol, propylene glycol and other used in the coating industry; propylene glycol, sorbitol, ethanol, xylitol and other used in toothpaste production. This has eased the market demand for glycerine, but most of the substitutes are not as effective as glycerin.
With the development of China’s economy, the demand for glycerol will continue to grow, making the contradiction between supply and demand of glycerol market increasingly acute. It is estimated that by 2000, China’s glycerol demand will reach 120,000 tons, natural glycerol production will reach 50,000 tons (including fermented glycerol about 20,000 tons), synthetic glycerol production will reach 20,000 tons, the shortage of about 50,000 tons. In the future, the glycerol market will continue to be tight, especially more than 98% of saponified or medicinal grade sleeves, domestic production is very small, mainly by imports.
In the future, efforts should be made to reduce the production, quality and cost of domestic glycerol production to ease the contradiction between domestic glycerol production and demand.
