1, the choice of efficiency: the main consideration of the size of the amount of evaporation, the boiling point of the material to be boiled, and the number of equipment. Large capacity should be used to operate with more efficiency; the more efficient, the smaller the steam consumption, the higher equipment investment; Boiling point is large, the effective temperature difference is small, the use of the number should be reduced.
2, lack of steam condenser choice: lack of steam (ineffective secondary steam) should be used when the indirect condenser should be recycled, such as tube type, spiral plate heat exchanger; lack of recovery of steam should be used when the direct condenser, such as Direct air condenser, water jet pump condensation and so on. Final effect for atmospheric evaporation can also be directly empty steam exhaust, no condenser.
3, the process of choice: downstream operation, after the effect of evaporation chamber pressure is lower than the previous efficiency, the transfer of solution in the pump required power is small. In addition, the post-effect evaporation temperature is less effective, so after the former solution into effect, it will flash out part of the steam, so raw steam consumption less. However, the concentration of aftereffect in the downstream process is high, the temperature is low, the viscosity is increased, and the heat transfer rate is small. Reverse operation and downstream operation contrary, the pre-effective temperature, high concentration, low afterglow temperature, low concentration, so that the heat transfer rate close to each effect, but the required efficiency of the pump power over steam consumption and more. Not suitable for handling heat-sensitive materials, is not suitable as the temperature and concentration increases, the media corrosive enhancement of the material. Here you can also advection and mixed flow according to the specific circumstances of the material.
4, the heating area: evaporator heating area determined by the material balance, heat balance, heat transfer calculation and the use of the form of processes and other factors considered after the decision.
Multi-effect evaporator to use points, can be divided into ordinary multi-effect evaporation system and forced circulation multi-effect evaporator, forced circulation evaporator is the use of more than one outside the loop evaporator and then add the outer circulation pump. In general, the double-effect evaporation system with heat pump has the same energy consumption as the three-effect evaporation system, which can increase the flow rate of the material in the evaporation tube, increase the heat transfer effect and increase the evaporation intensity. Forced circulation evaporator can be used in the evaporation process of crystallization, and is non-heat-sensitive materials.