Choose multi effect evaporator need to pay attention to three points.
The main consideration is the size of the processing capacity, the increase of the boiling point of the evaporating material and the number of equipment.
2.Selection of the steam condenser.
When the steam must be recycled, it is best to use indirect condenser, such as tube type and spiral plate heat exchanger.
It doesn't have to be recycled,it is better to use direct condenser, such as direct atmospheric condenser, water jet pump condensation, etc.
When the flow is in operation, the pressure of the after-effect evaporation chamber is lower than that of the former, and the power of the pump needed for the delivery of the solution is small.
In addition,Because the aftereffect evaporates the hair temperature is low, so the former effect solution enters after effect, can flash evaporate part of the steam, so the raw steam consumption is less
However, in the downstream process, the concentration of the back effect is high, the temperature is low, the viscosity increases, and the heat transfer rate is small.
The inverse operation and the downstream operation is on the contrary, when high temperature, high concentration, before after effect, low temperature, low concentration, make the effect of the heat transfer rate is close to, but the effect between the feed pump power is big, steam consumption.
It is not suitable for heat sensitive materials, and it is not suitable for materials with higher temperature and concentration.
In addition, it can adopt the flow and mixed flow according to the specific situation of the material.
4. Heating area
The heating area of the evaporator is determined by the factors such as material balance, heat balance, heat transfer calculation and the process form adopted.
Multi-effect evaporator can be divided into common multi-effect evaporation system and forced circulation multi-effect evaporator.
The forced circulation evaporator is based on the multi - stage evaporator and the external circulation pump is added.
The forced circulation evaporator can be used in the case of crystallization during evaporation and it is non-thermal sensitive material.