Temperature requirements for deionized water entering the deaerator
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Are there any requirements regarding the temperature of the deionized water entering the deaerator? Is it better to have a higher temperature, or must it not exceed a certain level?
Between 70~90°C, I guess; if it’s too high, the deaerator doesn’t need to heat the steam.
Today I heard a concept: when the temperature rises, the oxygen in the desalinated water causes corrosion of the pipelines! ! Is that the reason?
Both too low and too high inlet water temperatures in the deaerator affect its operation and deoxidization efficiency. For most deaerators, it is appropriate to raise the temperature of the deoxygenated water to 40–70°C; within this temperature range, the operation of the deaerator is simple and cost-effective.
There are no specific requirements regarding the temperature of the water entering the deaerator; by heating the water, dissolved oxygen is removed from it – so how can this cause corrosion of the pipelines? ;P
The dissolved oxygen and other gases that precipitate from the water are continuously carried out of the deaerator through the steam exhaust pipe at its top, along with the remaining steam. Deoxygenation must be carried out at a certain saturation pressure and temperature.
1. The purpose of deoxidizing the boiler feed water is to prevent oxygen corrosion in the boiler. When the water temperature is above 95°C, dissolved oxygen in the water causes severe corrosion. 2. Thermal deaeration involves heating the boiler feedwater to its boiling point, which reduces the solubility of oxygen; as a result, oxygen in the water escapes continuously, thereby removing various gases from the water (including dissolved CO2 and N2). Therefore, the higher the feedwater temperature, the lower the steam consumption of the deaerator, and the lower the energy consumption. However, when the water inlet temperature is high, the corrosion of the inlet pipeline must be taken into account.
That’s the principle, but it’s not oxygen that’s involved; rather, it’s the increased temperature that leads to intensified corrosion caused by dissolved oxygen in water.
Is it appropriate to raise the temperature of deoxygenated water to 40–70°C?