New York Low Pressure Boiler COF Practice

How does an open feedwater heater effectively remove oxygen?

1. Using vacuum pumps

2. Tray and spray deaeration methods

3. Simply by heating the water

4. By adding chemicals

The correct answer is: Tray and spray deaeration methods

An open feedwater heater is designed to effectively remove oxygen from water using tray and spray deaeration methods. In this process, the water is sprayed or distributed over trays in the heater. The combination of heat and the large surface area provided by the trays facilitates the release of dissolved gases, including oxygen, from the water. When the water is heated, the solubility of gases decreases, allowing the trapped oxygen to escape into the atmosphere above the heater. The trays increase the contact area and promote the efficient transfer of heat, further enhancing the removal of dissolved oxygen. This method is particularly effective because it combines thermal and physical techniques to ensure the water entering the boiler is as free from dissolved gases as possible, which is crucial for preventing corrosion and maintaining boiler efficiency. The other methods mentioned, while potentially useful in other contexts, do not specifically capture the mechanism by which an open feedwater heater achieves oxygen removal. For example, vacuum pumps would create a low-pressure environment to draw out gases but are not the primary method used in open feedwater heaters. Heating alone, without a method to enhance gas escape, may not effectively eliminate oxygen. Similarly, adding chemicals can control oxygen levels but doesn’t involve the fundamental process of degassing through the physical mechanisms