Carbon content of the regenerant
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This post was last edited by keinudao on 2011-6-12 15:46. What is the typical carbon content range of catalyst cracking regenerants? Is 0.09% too high? If it is too high or too low, how should the operating conditions of the device be improved?
0.09% is on the high side; the normal range is 0.04–0.06%. Increase the main air volume to reduce coking amount.
Reply to 2# Refining Operator: One more question – for catalytic cracking calculations, the dense-phase linear velocities in the first and second regenerators are 0.71 and 1.45 respectively. Is the normal range generally around 0.6 to 1.2? What issue does the high dense-phase linear velocity in the second regenerator indicate, and how should it be improved? Thank you
The carbon content of 0.09% in the cracking regenerator is not high; a value below 0.1 is considered normal
Reply to 4# Sanlian and Workshop: I think it’s too high. You mentioned 0.1; that figure comes from the documents I’ve seen, as mentioned in \"Calculation and Analysis of Catalytic Cracking Processes\" as well. But those documents were compiled in the 1970s, and the values have changed since then.
After the modifications here, the regenerated carbon content often exceeds 0.1%, and the flue gas analysis shows normal results. After a week of continuous observation, it was found that if the regeneration pressure was below 215 KPa about 10 minutes before sampling, the carbon content would generally be high; whereas if the regeneration pressure was above 225 KPa, the carbon content would generally be on par with previous levels. This is mainly due to the low coking formation in the modified unit; to ensure that the oxygen content in the flue gas does not exceed the specified values and to save energy, the main air flow rate was reduced. Meanwhile, the double-acting spool remains positioned according to its previous positioning relationship, making it difficult to maintain a high regeneration pressure.