Steam Deaerator Control

Make up water with temperature 30 deg C is fed to boiler deaerator to heat up to 105 deg of C (water saturation temperature at 0.2 BarG/1.2 bara). Saturated steam pressure at 14 bar is fed to deaerator to keep water temperature at 105 deg of C. Pressure control valve is used to maintain deaerator temperature 105 deg of C

The deaerator has the function to reduce the concentration of the corrosive gases oxygen and carbondioxide dissolved in the feeding water of the boiler. The solubility of the gases in the water reduces when the temperature increases; the problem’s solution is to increase the feeding water temperature

water according to the pressure and the temperature. It can be noticed that at the boiling temperature of 105°C for an absolute working pressure of 1.2 bar we are in a zone where the oxygen content in the water is practically void. Pressure Fluctuations, sudden increases in free or “flash” steam can cause a spike in deaerator vessel pressure, resulting in re-oxygenation of the feedwater. A dedicated pressure-regulating valve should be provided to maintain the deaerator at a constant pressure