The production process determines calcium lactate solution with calcium hydroxide, calcium sulfate, calcium carbonate and other impurities. These impurities will cause the increase of boiling point of the calcium lactate solution, increasing steam consumption during evaporation. Meanwhile, the impurities will continue to precipitate in the process of concentration, which causes the wall of the evaporator heating pipe to be fouled, and the production capacity of the evaporator is reduced. Thus, the impurities must be removed before feeding to evaporator.
The solubility of calcium lactate in water varies greatly with the temperature, and the characteristics are as follows:
- 50 centigrade 11.827%
- 60 centigrade 17.0886%
- 70 centigrade 29.228%
- 80 centigrade 50.138%
The evaporation terminal concentration is usually 35%. In order to prevent the product precipitating, the temperature of the final effect evaporation is not less than 75.
As the final effect is negative pressure, the boiling point of the material decreases as the pressure drops. In the application of multi effect evaporation concentration, the temperature of the material (i.e. the boiling point of the material under the final effect pressure) must be higher than the necessary temperature of the material concentration, to prevent calcium lactate solid precipitating. The boiling point of the material under the negative pressure can be calculated by the Dulin rule. It can also be obtained by test.
Selection of calcium lactate evaporator
- Due to the precipitation of solid material during evaporation, the evaporator in the tube is boiling, and the evaporation of solid matter is easy to scale on the tube wall, resulting in the failure. We recommend external tube boiling evaporator for better performance- FC external evaporator. Due to the static pressure, the material reaches the boiling point after leaving the heating tube, and the solid precipitation is mainly outside the heating tube, so it is not easy to scale.
- Forced circulation is applied in the evaporator to increase the flow rate through the heating pipe. It not only increases the heat transfer coefficient but also makes the solid not easy to deposit on the heating pipe, which has been fully confirmed in the phosphoric acid industry.
- In the structure of the evaporator, effective foam removal device must set up before secondary steam leaving the evaporator. The steam phase material will not only cause the loss of material, but more importantly, the secondary steam entering the next effect evaporator and the heating chamber will cause fouling on the outer wall of the heating tube.
- One of our past calcium lactate concentration project:FC external boiling evaporator, the total heating area is 80M2, the evaporation capacity is 4500kg per hour, and the washing cycle is more than 20 days. ?Because of Swirl board foam removal device, the working performance is much better even after two years.