How can a smoke extractor remove scale online?
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The average service life of our company’s smoke extractors is around 1 year; during this period, the blades of the extractors need to be cleaned of dirt at least three times. During the most recent maintenance session, after removing the flue gas turbine, it was unexpectedly found that there was only a small amount of catalyst scale on the blades. The downtime this time was longer than in previous instances; the turbine had to be fully cooled down before it could be disassembled. In previous maintenance operations, disassembly and cleaning of the scale were carried out while the turbine was still hot, at 300°C. In normal production, if the vibration level of the smoke extractor increases or the opening degree of the double-acting slide valve grows, it is possible to manually close the smoke shutters and dishes, allowing the main fan to be driven solely by the motor. This helps to cool down the smoke extractor, enabling the catalyst deposits on the blades to fall off due to thermal expansion and contraction. It avoids the need for repeated startups and shutdowns of the equipment, as well as frequent adjustments in production processes, thereby ensuring relative stability in production, saving energy consumption, and creating value. But if this is done while the unit is still running at high speed, could it be that the catalyst deposits on each blade fall off at different rates, leading to excessive vibration and malfunctions in the unit? Please, experts, share your thoughts or introduce your own experiences! ! !
This question is worth studying!* Waiting for the experienced master to provide an answer!
To address this bottleneck issue, a passive defensive approach will not suffice; it is necessary to take action at the source. Reducing the dust content of catalysts in the flue gas coming from the regenerator is key to ensuring the prolonged normal operation of the flue gas treatment equipment. :P
Is it possible to manually shut down the smoke valves and ash trays, so that the main fan is driven solely by the motor in order to cool down the smoke extractor? This would allow the catalyst deposits on the blades to fall off due to the principle of thermal expansion and contraction. However, this approach does not yield significant results; the effect is minimal. I have a question: why is scaling so severe on your smoke extractors? They need to be cleaned three times a year
Have you used them? How effective are they? I heard that there’s a cleaning agent from the United States that works quite well
1. What are the reasons for such rapid scaling of the flue gas extractor? Is it due to poor centrifugation efficiency, the properties of the catalyst, steam from the rotor, or something else? 2. Online descaling primarily targets the catalyst; a thorough plan needs to be developed in advance. 3. The process must progress steadily, with equipment safety being of utmost importance
It is still necessary to address the root cause of scaling in the flue gas engines, manage properly the issue of leakage, and conduct regular disassembly and inspection of these engines. This is beneficial for the engines themselves, as it allows one to monitor their operation and restore their efficiency. When removing scale online, surge can occur if the scale is not evenly distributed.
It sounds a bit mysterious – can the power grid handle it? The cooling and descaling process is uncontrollable, vibration changes are difficult to predict, and the possibility of surge is significant. There’s also a possibility that nothing major will happen; it all depends on luck!
It can be cleaned online; I’ve done it several times, and it’s very safe. Reduce the load to that required for motor drive, close the high-temperature gate valve, switch the steam used for cooling the wheel disc to saturated steam, activate the warm-up circuit, and use the inlet butterfly valve to control the speed. After starting up, open the steam bypass line for the wheel disc; keep the speed around 3,000 revolutions per minute, and normal operation will be achieved after 3–4 hours. This is only a temporary solution that can address the apparent problem. In the end, it is still necessary to thoroughly analyze the causes of scaling. Take the time to check the stability of your wheel steam inlet before the smoke extractor; if the temperature is below 200 degrees, it can easily lead to catalyst dust accumulating on the impeller.
Thank you, I’ve learned it! But as you said, when using a motor for drive, the speed of the motor is fixed, so the speed of the smoke extractor is also fixed. How can then the speed be adjusted using a smoke butterfly valve? Don’t understand? Furthermore, during online cleaning, if the dirt on the fan blades is not removed evenly, could this affect the excessive vibration of the fan? At what temperature should the inlet temperature of the smoke extractor be reduced to in order for it to operate, and for how long? Is the main unit always used to supply air for the reaction during online descaling? I have quite a few questions{:1_90:}, please feel free to give me some advice! ! !