Precautions for operating the demineralized water deaerator

The required oxygen content in boiler water is <7ppb. Controlling the operating temperature of the deaerator is mechanical deaeration, while controlling the pH of the effluent water and the amount of chemicals added is chemical deaeration.

1. The water must be heated to its saturated temperature at the operating pressure of the deaerator. During operation, it is necessary to monitor both the water temperature and the pressure; typically, the pressure should be around 0.02 MPa while the water temperature should be between 100–104°C. 2. The amount of steam used for heating must be appropriate, and care must be taken to maintain a balance between the amount of water and steam, so as to ensure that the water in the deaerator remains in a boiling state. Insufficient steam volume leads to a drop in pressure and poor deoxygenation effects, while too much steam volume results in increased pressure, activation of the water seal, and waste of steam – which is neither economical nor safe. 3. It is necessary to ensure that the vent valve at the top of the deoxygenator remains open to a certain degree, so that the gases generated can be discharged properly; however, it should not be opened too much, as this would lead to steam waste. 4. The amount of make-up water supplied must be stable – there should be no interruptions or sudden increases or decreases in supply, to avoid pressure fluctuations and poor deoxygenation effects. 5. For deoxygenated water: oxygen content ≤ 15 μg/L, hardness ≤ 5 μg-equivalents/L