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 evaporators in the chemical industry, and how to use rising film evaporators for chemical processing.
Types of Evaporators:
There are several types of evaporators used in the chemical industry, including rising film evaporators and falling film evaporators. 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. 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. 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 evaporators 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 thin film of liquid that forms on the inside of the tube allows it for gentle and efficient evaporation, without causing any damage to the liquid being processed.
Another advantage of rising film evaporators is their scalability. Rising film evaporators can be easily scaled up and down, depending on the production requirements. This makes them a flexible option for chemical processing operations.
Using Rising Film Evaporators in the Chemical Industry
Rising film evaporators are commonly used in the chemical industry to concentrate various chemical solutions, such as 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. Centrifugation or filtration can be used to achieve this.
Preheating of the feed solution-
The feed solution is preheated to the appropriate temperature to ensure efficient evaporation.
Feed the solution to the evaporator-
The feed solution is then fed into the evaporator and distributed evenly among the evaporator tubes.
The solution flows down to the inner surface of the evaporator tubes due to gravity and is heated by the steam outside the tubes. This creates a thin film of the solution that evaporates, as it moves down the tubes. The vapor generated is then collected at the top of the evaporator.
As the solution moves down the tubes, the concentration of the solute increases due to the removal of water vapor. The concentrated solution is collected at the bottom of the evaporator.
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-
The distillate (vapor) collected at the top of the evaporator, may be condensed and collected separately if required.
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.