Causes of vaporization in feed water pumps and solutions

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We are all aware, from operational experience, that boilers and turbines have strict requirements regarding water and steam; in particular, the feed water is of utmost importance as it constitutes the key component for supplying water to the boiler. It transports deionized water to the high-temperature, high-pressure boiler drum, providing the source of water needed to generate steam continuously. It is a critical device that must not fail under any circumstances, as a lack of water can lead to shutdowns of the boiler and other equipment, and may even cause pipe ruptures, severely affecting the economic efficiency of the power plant. Typically, a redundant configuration of one operating unit and one standby unit, or two operating units and one standby unit, is used to ensure a steady supply of water to the boiler. As for how to handle abnormalities in the feed water pump, I will briefly discuss the issue of vaporization in such pumps. First, let’s look at the reasons behind vaporization of the feed water pump: 1. Sudden drops in pressure in the deaerator, caused by the turbine losing load or other factors. 2. The flow rate of the feed water pump is less than 30% of the rated flow rate, and the recirculation valve is not open. 3. The inlet filter of the feed water pump is clogged. 4. Low deaerator water level or no water in the water tank. 5. The feed water pump is operating under overload. So what phenomena occur during the vaporization process? 1. The current of the feed water pump fluctuates and decreases, while the inlet and outlet pressures also fluctuate and decrease. 2、There is obvious noise and steam/liquid impact sounds inside the pump, along with increased vibration. What should we do if vaporization occurs? 1. Try to increase the pressure in the deaerator. 2. If the recirculation valve is not open, it should be opened immediately; if the problem persists, stop the pump. 3. If it is confirmed that the pump inlet filter is clogged, the pump should be reversed; the shift supervisor should be informed, and maintenance personnel should be called to handle the issue. 4. Check whether the water pump is operating under overload; if so, activate the backup pump. 5. If vaporization occurs in the feed water pump, the cause must be identified promptly and removed; if it cannot be eliminated, the pump should be switched off immediately to prevent damage to the feed water pump. In cases of severe vaporization, the pump should be stopped right away. 6. The vaporization pump may be put back into operation only after relevant technical personnel confirm that it is ready for use and the shift leader gives approval. During operation, we must not only pay attention to the parameters of the main equipment; we also need to give sufficient attention to these important auxiliary devices in order to ensure the safe and stable operation of our unit.