The “coking” problem in catalytic exhaust fans
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This post was last edited by Shuichangshou on 2010-7-20 at 16:52. Recently, I’ve noticed that the smoke extractor is suffering from severe coking. 40% of the catalytic feed is wax oil, with a slag inclusion rate of around 60%. Could experts please analyze what might be the reasons for this and suggest ways to address it? Thank you!
Everyone calls it \"scale,\" and of course there is also black scale. If it’s black, the reason is quite clear; could you show a photo of “coking”? If it weren’t black, it would be a very complex issue that’s hard to explain clearly.
Reply to 1#: I am kind-hearted. Currently, the service life of smoke extractors in local refineries is relatively short. The root cause lies in the modifications made to various units, which result in a mismatch with the original design. I think it’s better to look for the problem within the agent itself; first, check whether there are any issues with the flap valves； It is not clear whether the second centrifuge is produced by a reputable manufacturer; currently, many centrifuges used in oil refining are not of standard quality ； Third, check the three-spin effect ；
It’s scaling, I wonder how coking could occur. Let’s check the content of catalysts in the flue gas and analyze that. Also, is the steam from the rotor normal?
In my opinion, even if it’s not possible to guarantee 100% that the regenerator will not leak, it is essential to ensure the effective performance of the three-spinners. The exhaust fan in my home has been in use since 2003, and aside from regular inspections, there have been no issues whatsoever – it works very well. I believe that for an exhaust fan to function properly, the following factors need to be taken into consideration: 1. The dust content in the exhaust gas is very important. (Renewal centrifugation effect, triple centrifugation effect, etc.) Once a month, generally ranging from 40 to 60. 2. Check whether water, steam is being sprayed into the dilute phase or flue, or whether steam and water are leaking in. 3. The temperature of the flue gas should not be kept too low; it should be at least 695 degrees. Believe me, those cases where the temperature is set at 680 degrees can be considered for further discussion. The smoke temperature from individual units can be controlled to no more than 720 degrees. 4. The temperature of the wheel steam should not be too low nor contain excessive moisture; use 1 instead of 0.5. Steam of 0. Use it as little as possible, but within the control range of the process. 5. It is possible to analyze the issue with the catalysts; some of them have a strong adhesive force, which is also one of the reasons for scaling on the blades of the smoke extractor. Additionally, too much passivator should not be used, as that is not beneficial. Find out the reason yourself. Ha 6: Regularly inspect the three spinning agents to prevent the catalyst from reaching the back route. Just my opinion; hope it helps you
Solutions for scaling: 1. Analyze the particle size of catalyst dust. 2. Stop the cooling water supply. 3. Use high-pressure superheated steam for the disk steam system. 4. Operate smoothly and maintain an appropriate inlet temperature. 5. Install additional four-rotor devices and online dust monitors. 6. Start the backup unit and shut down the smoke generator, carrying out regular maintenance in advance
Understood. Go away. . . . . . . .
Reply to 5# Fluttering Wind001 Thank you
Reply to 6# gaoyd: Okay, thank you
"The temperature of the flue gas should not be kept too low; it should be at least 695 degrees. Believe me, those cases where the temperature is set at 680 degrees can be discussed. Why is that?
The catalytic flue gas extractor in your plant is coking; my first thought is that it’s due to operation under low-oxygen conditions, with carbon accumulating on the catalyst in the regenerator! The reasons can be analyzed from the following aspects: 1. Regarding the equipment, check whether the cyclone separation effects of the first and second stage cyclones are operating within normal conditions, whether the third cyclone is functioning properly, and whether the fourth cyclone is able to discharge fine powder correctly! 2. In terms of operation, the steam volume in the regenerator is high; is there water present? ； Is the regenerator a carbon bed? With a carbon bed, the catalyst becomes lighter and adheres to the turbine disk ； 3. Catalyst issue: the content of fine fresh agent powder is high; a sieve analysis should be conducted, and dust analysis of the flue gas needs to be performed regularly ； Catalyst preparation: Currently, the catalysts used in the MIP process have strong adhesion properties, and tend to adhere to the dust discharge ports of the three-spin cyclone tubes as well as to the rotors! 4. Design issues: Is operation carried out in accordance with the design? Are there deviations from the designed operating conditions, or are there design flaws? Analyzing problems requires a multi-faceted approach; careful operation of the processes and proper equipment maintenance are both very important!