Vacuum deaeration Methods- RH and DH Vacuum
Deaeration
Vacuum deaeration is a method used to remove dissolved gases from water or other solutions. There are two main types of vacuum deaeration: RH (recirculation and headspace) and DH (direct headspace) vacuum deaeration. These methods can be used to greatly reduce the amount of dissolved oxygen in the water, which can be beneficial for certain processes. In this article, we will discuss the principles behind both RH and DH vacuum deaeration and the advantages and disadvantages of each.
RH Vacuum Deaeration
The RH (recirculation and headspace) method of deaeration involves drawing a vacuum over the surface of an enclosed tank of water which has been heated. The vacuum reduces the pressure of the system and lowers the boiling point of the water. As the system reaches the boiling point, bubbles of dissolved gases escape from the water, and the vacuum draws these gases away from the solution. The process is repeated until the desired amount of gas has been removed.
The main advantage of the RH method is that it allows for higher levels of deaeration than other methods. The RH process can remove up to 99.9% of the dissolved oxygen, which is more effective than the 99.25% removal rate of the DH method. Additionally, this method is quite efficient and cost effective, making it a popular choice.
The main disadvantage of the RH method is that it is not able to remove trace amounts of dissolved gases, such as carbon dioxide and nitrogen. This can be an issue if there is a need to remove these gases from the solution. Additionally, RH deaeration requires the use of a specialized container, which can add to the cost of the process.
DH Vacuum Deaeration
The DH (direct headspace) method of deaeration is similar to the RH method but does not require the use of a container. In this method, a vacuum is drawn over the surface of the water in an open system, and bubbles of gases escape as the boiling point is reached. The gas is then drawn away and removed from the solution.
The main advantage of the DH method is that it does not require the use of a container and is thus less expensive than the RH method. Additionally, this method is able to remove both dissolved oxygen and trace amounts of gases, such as carbon dioxide and nitrogen, which the RH method cannot do.
The main disadvantage of this method is that it is not as efficient as the RH method, and the removal rate of dissolved oxygen is only 99.25%, not 99.9%. In addition, the open system can become contaminated more easily, which can reduce the effectiveness of the process.
Conclusion
Vacuum deaeration is an effective method of removing dissolved gases from water and other solutions. There are two main types of vacuum deaeration, RH (recirculation and headspace) and DH (direct headspace). The RH method is more effective and efficient than the DH method, but it requires the use of a container, which can add to the cost. The DH method does not require the use of a container and can remove both dissolved oxygen and trace amounts of gases, but it is not as effective as the RH method. Ultimately, each method of vacuum deaeration has both advantages and disadvantages, so it is important to consider all factors before choosing the method that is best for your application.
