Request for help regarding abnormal drop in the temperature of the smoke extractor wheel
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The temperature of the smoke extractor wheel in this device is normally kept between 300–330°C. However, recently it has been observed that the wheel’s temperature drops slowly and inexplicably to 250°C. Sometimes it drops to 250°C and then returns to 310°C on its own after half an hour, while other times it remains at 250°C for several hours. We conducted checks: there were no fluctuations in the inlet temperature and pressure of the smoke extractor, nor in its outlet temperature and pressure. The temperature and pressure of the steam supplied to the wheel also remained stable. The flow rate of steam to the wheel increased from 850 kg/H, the normal value, to 920 kg/H every 7 minutes, before returning to 850 kg/H, and this pattern of regular fluctuations continued. It was observed that each time the wheel temperature dropped to its lowest level, the vibration on the exhaust side of the smoke extractor would increase suddenly by 2-3 micrometers; this led to the conclusion that the temperature of the smoke extractor’s wheel represented the true value. Our flue gas turbine disk steam control valve adjusts the flow rate manually by controlling the valve position; therefore, significant fluctuations in the steam pressure at 1.0 MPa can indeed affect the steam flow rate to the flue gas turbine disk. However, the repetitive, regular fluctuations in the disk’s steam flow rate every 7 minutes are difficult to explain. Moreover, the drop in the temperature of the smoke extractor wheel cannot be addressed either. At first, we saw the disk temperature drop and assumed that too much steam flow was responsible for this, so we reduced the steam flow. As a result, the disk temperature rose a bit, but since it was just a tentative adjustment, we did not dare to reduce the steam flow to the disk by too much. That’s about it for the questions. Today I plan to go to the site to check whether the rotary steam control valve is working properly. I would appreciate it if the experts could share their insights. Thank you!
It’s better to invest in automation; if it doesn’t work, then a technician needs to be called in to handle it. For reference.
Yes, our rotary steam temperature control valve combines temperature control with steam flow regulation; it can be set to automatic mode to maintain a specific rotary temperature value. But I’ve never thrown it before
Is the control valve unstable? Leave a message – stay tuned for the correct result
This post was last edited by lupg on 2022-1-9 at 12:31. 1. Since the specific details regarding the steam cooling mechanism of the fan’s rotor are not clear, no definitive conclusions can be drawn; the following information is provided for reference only. 2. The rotor spins at high speeds, making it impossible to measure its temperature. The temperature closest to that of the rotor is found in the steam chamber at the high-pressure end of the rotor; the poster should verify whether this is indeed the case. 3. Fluctuations in the steam flow and temperature associated with the rotor generally do not show up in the parameters at the fan’s inlet, but they can be observed at the outlet. By expanding the time scale to seconds, some patterns can be detected. 4. Fluctuations in the steam supply to the rotor can also affect shaft displacement; this should be monitored as well. 5. In most cases, the steam supplied to fans comes from the end of the steam distribution network, with a low flow rate and poor quality. Based on our experience, it is advisable to superheat this steam to 250–300°C in order to obtain a stable supply of steam of lower quality that can be used for cooling the rotor. 6. We have dealt with cases where water was present in the cooling steam circulating in the rotor; mild levels of water presence caused changes in temperature and vibration, while severe cases led to shaft displacement issues and even damage to the internal components. 7. Regarding the trend chart provided by the original poster, it is recommended to zoom in for a more detailed analysis, and to combine relevant parameters on the same diagram to examine their mutual influences. 8. The integrity of the measurement, display, and control circuits is a prerequisite for obtaining reliable analysis results. 9. The attached figure shows an example of observing trends; by zooming in on the time axis, it is possible to clearly see the changes that occur
1 Question: The inlet pressure of the smoke extractor is 200 KPa, and the value of PI1104 for the steam cooling process in the flow diagram shows 68.1 KPa. At which point does the steam enter the wheel? 2 If steam enters the high-pressure side steam chamber of the wheel, can this steam pressure get in? Figure 3 is a schematic diagram showing the pressure relationships at various points of the wheel cooling steam