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Reply To: Propylene production

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Paul R Orlowski

Michael Edwards says:
The CO2 does not come from the reactor itself. The regen catalyst is bathed in flue gas components as it enters the regen standpipe, and even full combustion regen operation generates more CO2 (AND CO) in the few seconds the catalyst flows to the riser. Note, most regenerators fluidize the catalyst with air next to the standpipe, so flue gas and air enter the pipe with the regen catalyst. You will see both O2 and CO in reactor fuel gas, though there should be no CO in full regen, and O2 in fuel gas, though there should be no O2 in partial combustion. Some few units do fluidise the regen cat near the standpipe entry or in separate steam stripped withdrawal well next to regen. There, you would increase the stripping steam. More stripping steam in reactor does not affect amount of CO2 (essentially all flue gas components are already stripped), but can increase amount of LPG recovered, so reduce % flue gas in LPG and fuel gas.

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