How to handle the catalyst carbon stack?

Personally, in the case of operating under abnormal conditions, there’s no need to rush and worry about how to deal with it. First, we need to understand or become aware of the phenomena and reasons behind these situations. Only by knowing what has happened can we analyze it more effectively and determine how to deal with it. And sometimes, once you understand how it happens, it makes handling it much more efficient.

For carbon piles, understanding the location and phenomena that occur is fundamental; it all comes down to factors such as density, reserve amount, bed temperature, oxygen content, and so on

Increasing the wind speed might be difficult; reducing the feed rate is probably the simplest solution~~~

The last edit to this post was made by hao0080 on 2016-1-2 at 14:16. My understanding is that in the case of carbon piles, there is an excessive amount of carbon, but insufficient burning capacity; then, based on various parameters, it is determined what the problem is and adjustments are made accordingly. For now, I can only learn from books*. After reading some books yesterday, I have a few questions: 1. How can this be handled properly to avoid secondary combustion? With the feed rate reduced, recycling will definitely increase. How should the main air flow be controlled? Should it increase slightly, remain unchanged, or continue to decrease? Or, depending on the high temperature, should fuel be sprayed first to cool things down, and then decide on how to control the main airflow? Is 2 the effect of the temperature difference between the dense and dilute phases? Is it normal for the dilute-phase temperature to be low? Does the secondary combustion increase the dilute-phase temperature? Thank you for the answer.

Thank you for the answer. Is it usually necessary to reduce the feed first? Is the difficulty in increasing the main air flow considered from the perspective of preventing secondary combustion? Are there any other tips for operation?

Light carbon piles can increase air flow, reduce heat absorption and improve coking efficiency; it is possible to reduce the amount used or adjust the raw material composition accordingly； The carbon pile is severe; it is best to stop feeding material, and resume feeding only after the sulfidation and charring are completely resolved.

Thank you. If the carbon pile is in a severe condition and the air flow isn’t adjusted, could it cause secondary combustion?

1. Reduce the processing volume. 2. Increase the main air flow. 3. Add an oxidizer to prevent secondary combustion. As someone mentioned earlier, when dealing with carbon piles, it is necessary to identify the causes behind their formation before taking appropriate action.

After a carbon pile forms, what should be avoided at all costs is adjusting the main air volume and the total feed rate (the amount of fresh material and the amount of recycled material) right away. Changing these two parameters means altering the overall combustion balance and material balance, and the impact is not limited to the reaction unit alone; it also affects the operations in subsequent units. Under normal circumstances, the carbon stack progresses from light to heavy, and during the processing it is necessary to act carefully and quickly to prevent overheating. Methods such as increasing the amount of stripping steam, increasing the amount of atomizing steam, and raising the preheating temperature can be employed. Additionally, the heat extraction load from external sources as well as fluctuations in the pressure difference between two systems can affect the carbon pile process. The above methods are quite effective for dealing with the carbon pile issue; if they do not work, options such as reducing the reprocessing rate, adjusting the feed amount, and modifying the main air supply can be considered

1. This can be achieved by reducing the amount of coking (by increasing the steam used for stripping, reducing the oil slurry, reprocessing oil and feedstock, appropriately increasing the main air flow, and raising the preheating temperature of the feedstock). 2. When carbon accumulation becomes severe, the feed supply should be stopped; after sulfiding and coking occur, the feed supply can be resumed