FCC heat balance key to high O/sub 2/ enrichment

For a refinery to benefit from oxygen enrichment, it must be air-blower or regenerator-velocity limiting yet still have sufficient regenerator residence time to facilitate catalyst coke burn-off. The maximum oxygen concentration used in the U.S. is 36%. Technology does exist to go to 100% once there is an economical incentive to do so. It then could become more convenient and more profitable to use pipeline oxygen rather than liquid oxygen as oxygen consumption increases. FCCU regenerators with high levels of oxygen enrichment require heat removal to compensate for the heat that was removed by the nitrogen. Reducing preheat is the most efficient method of achieving heat removal, although increases in regenerator temperature within the limits of catalyst and metallurgy can give some compensation. FCCUs processing residue or operating in full CO combustion require significantly more heat removal.