How to determine as quickly as possible whether carbon buildup has occurred in the catalyst

It’s very simple: once a change is made in the operation, one can immediately use the regenerating agent to observe the degree of coking of the catalyst, and it’s clear at a glance.

The content of regenerated oxygen decreases, and the reaction temperature drops.

If carbon accumulation occurs, the oxygen content in the regenerated material will drop significantly; an increase in temperature will further reduce this level. Additionally, the reaction temperature may decrease, or the color of the sampled regenerated catalyst may turn black. In severe cases, the oxygen content can drop to zero, and there will be an increase in the amount of catalyst present in the flue gases, with a blackish color.

1. The oxygen content in the flue gas decreases, even reaching zero, while the CO content in the flue gas gradually increases； 2. The carbon content of the regenerant increases, and its color darkens ； In severe cases, the regenerated catalyst becomes shiny black and its particles grow larger ； 3. The reaction depth gradually decreases, the amounts of gas and gasoline decrease progressively, the liquid levels in the reprocessing tank and at the bottom of the distillation tower rise, and the amounts of reprocessed oil and slurry increase ；

So, what are the causes of carbon buildup?

Firstly, incomplete regeneration generally results in a higher likelihood of carbon buildup. In complete regeneration, there is initially a phase of overheating in the regenerator, after which it transitions to incomplete regeneration. Judgment: 1: As the oxygen content during regeneration decreases, the temperature in the furnace equipped with a CO combustion system rises sharply. The regeneration temperature decreases. 2: The reaction depth decreases, manifested as an increase in the levels in the reprocessing tank and distillation column (with the same amount of slurry being removed). 3: Significant changes have occurred in product releases. Increase in gas volume, increase in diesel volume ； The amount of gasoline has decreased. 4: If the reaction temperature is kept constant, the opening degree of the regeneration slide valve will increase. 5: The sampled regenerated catalyst turns black. 6: Dry gas analysis may show increased H2 and CH4 levels. The molecular weight of the dry gas decreases. The main reason is likely the increase in coke formation, resulting from inadequate adjustment of the main air supply. Factors that cause an increase in coke formation are all factors that promote carbon buildup. Additionally, a low initial temperature of the coking tank can also lead to carbon buildup, that is, an uneven distribution of the coking load. Overheating of the regenerator can occur easily during the carbon push recovery process, and ignoring this issue can lead to accidents. In principle, incomplete regeneration is no longer required for regenerator regeneration nowadays.

The original poster has covered it quite comprehensively. In fact, there are other phenomena as well: for example, when carbon accumulation is severe, the reserve amount increases, and it becomes difficult to fluidize the catalyst, among other issues.