Catalysis — Regarding the reprocessing ratio
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In the technical Q&A section, there is a statement regarding the reprocessing ratio that goes something like this: \"As the reprocessing ratio increases, the temperature required for the reaction rises, while the heat recovered decreases.\" Why is it said that an increase in the reprocessing ratio leads to a decrease in the regeneration temperature?
There is indeed such a sentence in the book: we know that the recycle ratio equals the total amount of recycled material divided by the amount of fresh raw material fed in. When the amount of fresh feed remains constant, an increase in the recycle ratio means that a portion of heavier materials is added to the total reaction feed, which increases the heat required for the reaction. Since the heat needed for the reaction comes from the regenerator, more heat flows from the regenerator into the reactor to maintain the reaction temperature. So the regenerated heat is reduced. But this statement does widen the scope, because what we usually say when the reprocessing ratio increases is that the amount of reprocessed oil or reprocessed oil slurry increases, while the amount of fresh feed remains unchanged. It would be incorrect to assume that if the total amount of reprocessing stays the same but the amount of fresh feed decreases. If we take into account the increase in reprocessing volume leading to an increase in coke yield, then it becomes even harder to determine whether the amount of heat generated from regeneration decreases or increases. Personal opinion, for reference only!
I’m not sure what the title of the book you’re referring to is. Could you recommend it? I’d like to give it a read
Questions and answers on catalytic cracking technology, regarding the reprocessing ratio
I support the moderator’s theory; I think the same way. If there’s too much coke produced, how can the regenerator’s temperature drop? It’s probably because of the increase in the instantaneous temperature of the reprocessing ratio
In normal production, when the total feed volume remains constant and the recycle ratio increases, the composition of the feed becomes heavier; it becomes difficult to carry out secondary catalytic cracking on the recycled oil or recycled slurry, and most of it ends up as coke. This increases the carbon content in the raw catalyst. Even with sufficient air supply in the regenerator, the heat generated will increase rather than decrease!
The original poster’s explanation is extremely insightful. . Support
The catalytic cracking reaction has a self-balancing function. A change caused by a certain condition will eventually return to its initial state (an approximate position, not an absolutely constant one)