Feed issues in falling film evaporators
Thread Content
As shown in the figure below, part of the material discharged from the bottom of the falling film evaporator is pumped back to the top of the evaporator; the raw material is also added through this circulation pipeline (at position 1 in the figure), entering the top of the evaporator together with that material. The circulation volume is 45 cubic meters, and the feed volume is 10 cubic meters. My questions are: 1. Why doesn’t the material enter directly from the top of the evaporator? 2. What is the purpose of this pipeline with a circulation volume of 45 cubic meters?
1. Feeding is carried out on the circulating pipeline and at the top of the falling film evaporator; the principle is the same； A circulation volume of 2.45 cubic meters is intended to maintain the membrane thickness and prevent dry walls.
Having a circulation rate may be intended to ensure that there is a liquid film on the wall of the falling film evaporator, thereby preventing the material from overheating. The feed is preheated first, in order to establish a feed temperature and reduce consumption
In the pipes of a falling film evaporator, does the material flow down in a film form along the pipe walls, or does it fill the entire pipe? If it flows downward in a film-like manner along the pipe wall, how is this flow state achieved?
Learned*..........
There is a film distributor installed at the top of the falling film evaporator; this component is key to the quality of the film formation
It is attached in a film-like form; there is a fabric-covered tip at the top, and the liquid phase enters the tube bundles in a spiral pattern