Discussion on the use of carbon monoxide as an oxidizer in the oxygen-deficient regeneration process of heavy oil catalytic units
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The heavy oil catalytic cracking unit features a single-riser coaxial configuration. The regenerator operates under oxygen-deficient conditions. A carbon monoxide incinerator is installed prior to the waste heat boiler to recover carbon monoxide from the flue gas. Online flue gas monitoring is conducted after the third cyclone; the oxygen content remains at zero, while the carbon dioxide content fluctuates frequently around 8%. The carbon monoxide content stays relatively stable at approximately 0.024%. Two kilograms of carbon monoxide combustion promoter are added every eight hours. The temperature of the dense phase bed is 680°C, whereas that of the dilute phase bed fluctuates between 650°C and 664°C. Under these operating conditions, I would like to ask: Is it possible to reduce the amount of carbon monoxide combustion promoter added? What is the purpose of adding this promoter? Why do the process parameters remain unchanged even when the promoter is not added as per regulations? In fact, there have been days when no promoter was added at all, yet no overheating in the dilute phase bed occurred. The catalyst coking removal process is performing well
The purpose of adding it is to prevent tail burning, but based on the data you provided, although oxygen deficiency conditions are present there, charring seems to be under control; the oxygen supply is sufficient to meet the requirements for preventing charring, and not much carbon monoxide is generated. The frequency of addition or the amount added can be reduced according to the operations, but it cannot be omitted!