External circulation evaporator

working principle

The external circulation evaporator is composed of a heating chamber, an evaporation crystallization chamber and upper and lower circulation tubes. The external circulation evaporator circulates and evaporates depending on the density difference of the feed liquid during the heating and evaporation process, so the heating temperature is required to be high and the heating temperature difference is large. It is characterized by simple structure and easy operation. In the structural design, the designer should pay attention to that the position of the evaporative crystallization chamber should be 4-6 m higher than the position of the heating chamber (the distance between the liquid level of the evaporative crystallization chamber and the upper tube plate of the heating chamber), so as to ensure that the upper tube orifice of the heat exchange tube does not boil, there will be no crystallization precipitation in the heat exchange tube, and there will be no tube plugging. Secondly, the flow velocity in the upper circulating pipe shall be less than 1m/s, and the flow velocity in the lower circulating pipe can be designed as 1.3m-1.5m/s. The purpose is that when the heated solution enters the evaporative crystallization chamber, there will be bubbles in the upper circulating pipe due to the influence of vacuum. To prevent sudden boiling, the pipe diameter should be slightly larger than the lower circulating pipe.

      Main features
● Low equipment cost, natural circulation mode and small installed power.
● High efficiency and convenient operation.
● Small floor area and low maintenance rate.
● Low evaporation temperature and fast evaporation speed.