The deaerator is not receiving adequate make-up water, resulting in make-up water frequently being forced out through the exhaust port
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During the restart of our plant after major repairs, we found that although the opening degree of the make-up water valve for the deaerator was at 100%, the level in the deaerator continued to drop, meaning no make-up water was reaching the deaerator. A final inspection revealed that the make-up water was escaping through the exhaust port at the top of the deaerator. When the deaeration steam from the deaerator was turned off, the make-up water flow returned to normal, but deaeration was not achieved. At present, the level of the deaerator and the deaeration steam are controlled via manual control valves, with efforts made to ensure that these valves do not open too wide; however, leaks still occur occasionally. Before the production was halted, both the deaerator level control and the deaeration steam control were under automatic operation, and the deaerator head was not repaired during any overhauls. Does anyone know what the problem is?
Our deaerator is a rotary film deaerator; it doesn’t have an overflow port
Did the electrician check the controller? Is there no level feedback?
After all, you are a hands-on instructor; could you take some pictures of what’s going on on site? I’d like to learn from them too. Each design manufacturer has its own set of drawings, which are similar overall but also have some differences. Take the water inlet as an example; some manufacturers do not provide a lower water supply port, instead installing only two types of water connection pipes at the top of the deaeration head. Moreover, the steam input volume needs to be adjusted manually; there seems to be no feedback regarding the pressure at the deaeration head, and no alarm is triggered when the liquid level reaches its minimum. The temperature must also be out of balance. It is recommended to have the instrument checked more frequently.
Before the maintenance, the exhaust vents were also fully open, and there were no problems at all; starting production all of a sudden really caught me off guard
There are also many methods available online for dealing with water in the exhaust gas from deaerators. The teacher achieves this by controlling the amount of air intake. Has the teacher tried increasing the amount of steam supplied for auxiliary heating and reducing the amount of cold water supplied? Such actions are taken on the assumption that the temperature in the deaerator is not at the required level. Someone upstairs also said that trying to reduce the exhaust opening and replacing the packing material (checking when it was last replaced) could be effective solutions. There are various methods, and water entrainment in the exhaust occurs after major repairs; perhaps the actual operating conditions (temperature, pressure, etc.) have changed, and the parameters set previously are no longer suitable for the operation of the deaerator. This leads to an imbalance between steam and water as well as between temperature and pressure, resulting in poor deoxidation performance. The teacher asking questions and helping to solve them is a great opportunity for me to learn*. I hope the teacher will not hesitate to provide guidance after we address the issues.