What factors determine the pressure level inside the deaerator?
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What is the relationship between the pressure inside the deaerator and the pressure of the four-stage extraction steam? Are these two values equal? It is still the sum of the four stages of extraction steam pressure and the pressure of non-condensable gases that equals the deaerator pressure
It’s best to start with the principles; once you understand them, you’ll know how to control it. For reference.
There is a pressure reducing valve in front of the steam inlet of the deaerator; since the solubility of oxygen in water varies with its saturation temperature, this valve is used to achieve the desired effect； To prevent changes in the saturation temperature within the water tank caused by pressure fluctuations, as well as fluctuations in the deoxygenation effect resulting from oxygen re-dissolving into the water, operation is generally carried out at a constant pressure; therefore, it is usually operated at the equipment’s rated working pressure. The operating pressure of the deaerator is maintained by adjusting the air intake volume. The operating pressure is basically the rated operating pressure specified in the design.
Now, don’t most deaerators use variable pressure operation in order to overcome throttling losses?
However, the inlet steam flow rate cannot be measured. Is the pressure inside the deaerator the same as the pressure of the steam being injected?
There is a pressure gauge on the deaerator; inside the deaerator, a steam condensation process takes place. The supply pressure is higher than the pressure inside the deaerator. Under normal operating conditions, the pressure inside the deaerator is maintained through natural balance, with this pressure being lower than the rated operating pressure. Increasing the steam supply raises the pressure above the rated value, while reducing the steam supply lowers it. The pressure in the deaerator can be stabilized by controlling the feed steam cut-off valve.