Urgently follow up on the issue of replenishing catalyst in the regenerator
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Each time the regenerator is filled with a displacing agent, as well as when fresh material is added regularly. Secondary combustion and afterburning problems occur in the regenerator dilute phase, flue header, and flues! I wonder why this problem occurs? And what countermeasures should be taken? (I personally think it’s due to the supplementary catalyst disrupting the coking equilibrium within the regenerator’s bed, as well as the fine division of the newly added catalyst!) I hope to receive guidance from all the teachers!
Personally, I feel that the addition of fresh material increases the amount of raw coke, which in turn leads to changes in the burning load of the regenerator. Moreover, the fine particles present in the fresh material can easily end up in the dilute phase, and a large amount of carbon-containing fresh material entering this dilute phase causes afterburning.
In addition to the reasons mentioned above, it is also related to the temperature of the supplementary fresheners and balancers. If the supplementary amount is too large, it will inevitably disrupt the thermal balance, leading to afterburning. :lol
Fine particles are inevitably introduced into the fresh catalyst. Moreover, as the temperature rises from room temperature to 700°C, thermal degradation of the catalyst can occur, leading to an increase in the amount of fine particles. If a large amount of catalyst is added, it will cause the temperature in the dense phase to drop, resulting in residual combustion in the dilute phase. It is recommended to add catalyst in small amounts multiple times, using an automatic small feeder, removing the catalyst periodically, and then continuously adding fresh catalyst to maintain the microreactivity and specific surface area of the catalyst, thus ensuring good catalytic cracking performance. Activity alone cannot fully reflect a catalyst’s cracking capabilities; after circulating in the system for a certain period, the catalyst loses its ability to crack heavy oil molecules due to damage to its pore structure. Continued removal of the catalyst and addition of fresh catalyst – this is my personal understanding; please correct me if I’m wrong!
I have a different view on your opinion; then why do secondary combustion and afterburning disappear in such a short time after the small-scale fuel addition stops! Has the amount of charring decreased in such a short period of time?
The freshener has high activity; it contains a large amount of carbon during the first reaction, as well as plenty of fine powder. When the addition of new agents is stopped, tail burning will naturally cease. For example, if you use a straw to blow bubbles in a water bottle, the bubbles will disappear once you stop.