Temperature difference between dense and dilute phases in catalytic cracking regenerator
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Under normal conditions (without carbon buildup or secondary combustion), is the temperature of the dilute phase in a catalytic cracking regenerator always higher than that of the dense phase? Why?
You mean the case of complete regeneration; if it is incomplete regeneration, under normal conditions, the temperature in the dilute phase must be lower than that in the dense phase.
Under normal conditions, there should be a negative temperature difference, that is, the temperature of the dilute phase is lower than that of the dense phase~~~~~~~~~
Modern catalytic cracking units generally employ two-stage regeneration, which helps to protect the catalyst, remove excess heat, and increase the unit’s processing capacity. The first regeneration is an oxygen-deficient regeneration, with the dense-phase temperature being slightly higher than that of the dilute phase. The second regeneration is oxygen-enriched regeneration, with the dense-phase temperature being lower than that of the dilute phase.
My unit is designed for coker regeneration, with the lean phase being about 20 units higher than the rich phase.
Even under oxygen-poor regeneration, the dilute-phase temperature may exceed the dense-phase temperature. However, the temperature difference between the dilute phase and the dense phase should not be too large
If the dilute-phase temperature exceeds the dense-phase temperature by too much, it can easily cause thermal bouncing of the catalyst
Upon observation, if it is complete regeneration, the density of the dilute phase is higher than that of the dense phase; whereas in the case of incomplete regeneration, the temperature difference between the dilute and dense phases is negative.