Evaporators are widely used in food, pharmacy, biology, environmental protection, petrochemical and other fields. In recent years, as the number of companies manufacturing evaporation equipment in my country has increased, the concepts of high efficiency, energy saving, and environmental protection have become the trend of our country's economic development.
Then choose the evaporator to clarify the following precautions before you can correctly choose the relevant evaporation process, evaporator equipment form, material, etc.
1.Determine what the purpose of evaporation is
a. Increase the concentration of the solution;
b. Concentrate the solution and recover the solvent;
c. Prepare pure solvent.
2.Determine evaporation parameters
a. Feeding temperature and concentration;
b. Discharge temperature concentration;
c. Total feed volume;
d. Total evaporation.
3.Determine the characteristics of the evaporated solution
a. The heat sensitivity of the solution and the highest temperature it can withstand;
b. The corrosiveness of the solution;
c. The boiling point of the solution rises at each concentration;
d. The viscosity of the solution;
e. The saturation concentration of the solution;
f. The density of the solution.
a. Power supply; b. Steam pressure; c. Cooling water inlet and allowable return water temperature.
a. Recompression design of secondary steam: steam jet heat pump (TVR), mechanical compression heat pump (MVR);
b. In a reasonable range, try to increase the number of effects;
c. Recover the condensed water and discharge the sensible heat of the evaporator material;
d. Correctly select the feed pump and circulating pump;
e. Feed the solution at the boiling point;
6. How to make the evaporator investment more economical?
Optimal design of the process flow is the key to investment savings. For example, optimizing the static pressure of the liquid column so that the condensate does not flow back or flow backwards. In this way, there are usually multiple condensate tanks that only need to be designed.
As far as the evaporation form is concerned, the falling film evaporator should be selected first, because the falling film has no liquid column static pressure, and the pure heat temperature difference is significantly higher than other forms. If other forms of evaporator are selected for reasons of material characteristics, then it should be strengthened The setting of the circulating flow rate in the tube, experiments have proved that increasing the flow rate can significantly reduce the required evaporation area;
In addition, the number of effects of the evaporator should be strictly controlled. Experiments have shown that the single-effect to double-effect steam can save 50%, while the four-effect to five-effect steam saves only 10%. Saving investment is also very meaningful. In fact, an excessively large evaporation area will not only increase investment but also cause unplanned fouling, and crystallization will reduce the heat transfer coefficient and reduce the overall operating economy of the equipment.
