Evaporators are an essential component in the chemical industry for separating solvents and concentrated solutions. Rising film evaporators are a popular choice for the chemical industry due to their efficiency in processing heat-sensitive and viscous liquids. In this blog, we will explore the different types of evaporators, the benefits of using rising film evaporator in the chemical industry, and how to use rising film-evaporators for chemical processing.
Types of Evaporators:
Various types of evaporators, such as rising film evaporators and falling film evaporators, are used in the chemical industry. Falling film evaporators are similar to rising film-evaporators, but they operate in reverse. Instead of liquid flowing down the inside of the tube, the liquid is fed at the top of the tube and flows down due to gravity. So, this allows for efficient and gentle evaporation of heat-sensitive liquids.
Other types of evaporators include flash evaporators, forced circulation evaporators, and natural circulation evaporators. So, each type of evaporator has its advantages and disadvantages, and the choice of evaporator depends on the specific properties of the solution being processed.
Benefits of Rising Film Evaporators:
Rising film evaporator have several advantages over other types of evaporators, making them a popular choice for chemical processing. One of the main benefits, is their efficiency in processing heat-sensitive and viscous liquids. The tube gently and efficiently evaporates the liquid without causing any damage, thanks to the thin film that forms on its inside.
Another advantage of rising film-evaporators is their scalability. Depending on the production requirements, one can easily scale up or down the rising film evaporator. So, this makes them a flexible option for chemical processing operations.
Using Rising Film-Evaporators in the Chemical Industry
The chemical industry commonly employs rising film-evaporators to concentrate various chemical solutions, including acids, solvents, and resins.
Here are some of the steps for using rising film-evaporators for chemical processing:
Pre-treatment of the feed solution-
It is necessary to pre-treat the feed solution to get rid of any solid contaminants or particles, that might clog the evaporation tubes. To achieve this, one can use centrifugation or filtration.
Preheating of the feed solution-
To ensure efficient evaporation, preheat the feed solution to the appropriate temperature.
Feed the solution to the evaporator-
The feed solution is then fed into the evaporator and distributed evenly among the evaporator tubes.
Evaporation-
Gravity pulls the solution down to the inner surface of the evaporator tubes, where the steam outside the tubes heats it. So, this creates a thin film of the solution that evaporates, as it moves down the tubes. The evaporator collects the generated vapor at its top.
Concentration-
As the solution moves down the tubes, the concentration of the solute increases due to the removal of water vapor. While, the evaporator collects the concentrated solution at the bottom.
Post-treatment of the concentrated solution-
The concentrated solution may need to undergo post-treatment to remove any remaining impurities or to adjust the concentration.
Collection of the distillate-
If necessary, condense and collect the distillate (vapor) that accumulates at the top of the evaporator separately.
Conclusion:
Rising-film evaporators are a popular choice for chemical processing because of their efficiency in processing heat-sensitive and viscous liquids. They offer several advantages over other types of evaporators, including scalability and gentle evaporation. By following the steps outlined above, rising film-evaporators can be used effectively for chemical processing in the chemical industry.
