Deaeration

Deaeration is the process of removing dissolved gases, primarily oxygen and carbon dioxide, from water or other liquids. It is a critical procedure in various industrial processes, particularly in boiler feed water treatment, to prevent corrosion damage in steam systems. Deaeration relies on the principle that the solubility of a gas in a liquid decreases as the liquid's temperature increases and as the gas's partial pressure above the liquid decreases.

Principles of Deaeration

Deaeration operates on two fundamental principles: Henry's law and the physical relationship between gas solubility and temperature. According to Henry's law, the amount of dissolved gas in a liquid is directly proportional to its partial pressure in the gas phase. Therefore, reducing the partial pressure of the gas or increasing the liquid's temperature will decrease the gas's solubility in the liquid.

Methods of Deaeration

There are several methods of deaeration, including mechanical, chemical, and vacuum deaeration, each suitable for different applications.

Mechanical Deaeration

Mechanical deaeration involves the physical removal of gases by spraying the liquid in a tank or vessel and subjecting it to a vacuum. This method often uses a deaerator, a specialized device that combines both physical and thermal processes. The two main types of mechanical deaerators are the spray type and the tray type.

Chemical Deaeration

Chemical deaeration involves adding chemicals to the water to remove dissolved gases. For example, oxygen scavengers are added to bind with dissolved oxygen and remove it from the solution. This method is often used in conjunction with mechanical deaeration.

Vacuum Deaeration

Vacuum deaeration involves reducing the pressure around a liquid to below the vapor pressure of the dissolved gases, causing them to come out of solution. This method is particularly useful for temperature-sensitive liquids.

Applications of Deaeration

Deaeration is essential in many industries, including:

• Boiler feed water treatment: Removing oxygen and carbon dioxide prevents corrosion in steam boilers and steam systems.
• Food and beverage industry: Deaeration can prevent oxidation and spoilage in food and beverages.
• Pharmaceutical industry: Deaeration of water used in pharmaceutical processes can prevent oxidation of sensitive ingredients.

Challenges and Considerations

While deaeration is effective in removing dissolved gases, it requires careful control and monitoring. The efficiency of deaeration can be affected by factors such as the temperature and pressure of the operation, the type of deaerator used, and the specific characteristics of the liquid being treated.

Conclusion

Deaeration is a vital process in many industrial applications, crucial for preventing corrosion, spoilage, and oxidation. By understanding the principles and methods of deaeration, industries can effectively protect their equipment and products from damage caused by dissolved gases.

Deaeration Resources
Latest articles Most recent articles Ongoing trials	Wikipedia