Liquid ring vacuum pump system in vacuum concentration
Liquid ring vacuum pump system is widely used in vacuum concentration, especially in sugar industry. In this paper, the specific application of liquid ring vacuum pump system in sugar industry is analyzed.
Sugar mills can get about 125 kilograms of sugar juice for every 1000 kilograms of beet processed. The sugar content is generally more than 10%. The juice is then heated in an evaporator and condensed into a syrup containing 35% water. Because the water content is still too much, sugar can not crystallize. At this time, syrup should be put in a vacuum tank and concentrated into an extract containing 7-8% water. Sugar gradually crystallizes from the saturated solution of the paste.
Because the concentration of syrup is very high, the boiling point of syrup is increased by 20 degrees, so the boiling point of syrup is 100 + 20 = 120 degrees. Boiling sugar at such a high temperature (the process of concentration is boiling sugar) will cause carbonization of sugar and increase its loss. If the sugar is boiled at a certain vacuum, the boiling point will be greatly reduced. Therefore, the syrup condensed into enamel must be carried out in a certain vacuum.
At first, the syrup is far from saturated due to the large amount of water. Therefore, the water evaporation should be carried out under the maximum vacuum. The required vacuum is - 620 - 640 mm mercury column, and its boiling point is 68 - 70 C. The boiling point will increase with the increase of the concentration of the solution. With the continuous concentration of syrup at the same vacuum, the temperature of syrup will gradually rise to 74 ~ 77 C. The second stage of vacuum boiling sugar can be carried out at low vacuum. The required vacuum is - 420 - 460 mm Hg column with boiling point of about 93 - 94 C.
What does vacuum concentration mean?
Vacuum concentration refers to the entrance of the condensed material and secondary steam into the separator at a relatively fast speed along the tangent direction under the induction of secondary steam and the high vacuum attraction of the separator. Vacuum technology preserves the nutrients and aroma of raw materials.
Purpose of Liquid Ring Vacuum Pump System for Vacuum Concentration
1. Remove a large amount of water from food, reduce weight, reduce volume, save packaging, storage and transportation costs.
2. The purpose of food storage is achieved by increasing the concentration of food.
3. To meet the requirements of follow-up processing.
The application of liquid ring vacuum pump system in vacuum concentration has many advantages. In the boiling state, the evaporation of solvents is very fast. The boiling point of liquids varies with the pressure. The pressure increases, the boiling point rises, the pressure decreases, and the boiling point decreases. For example, milk boiling point at 101 kPa is 100 C, while at vacuum 82.7-90.6 KPa, boiling point is only 45-55 C. Because of evaporation at lower temperatures. At the same time, because the material is not affected by high temperature, the damage and loss of thermal unstable components are avoided, and the nutritional components and aroma of the material are better preserved. Especially some amino acids, flavonoids, phenols, vitamins and other substances can prevent heat damage. Low temperature evaporation can prevent coking of some materials with high viscosity, such as carbohydrates, proteins, pectin and mucus.