Q656. My fluidized catalytic cracking unit (FCCU) is monitored by a CEMs. How should those emissions be reported?

A656. EPA has prepared a general table of reporting instructions for FCC units with CEMs as presented in the table below. In addition EPA has provided guidance on how to report regenerator and process gas and explained how to avoid double counting of emissions in the following common situations:

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1. I have a CEMS that monitors the CO₂ emissions from a catalytic cracking unit with a complete combustion regenerator (no CO boiler) that burns off petroleum coke which has deposited on the catalyst.  Should I report this as a “process-only” configuration or as a “shared process/combustion stack” configuration?

You should report this as a “process-only” configuration.  The emissions from the combustion of petroleum coke deposited on the catalyst are considered to be process emissions, not combustion emissions. The only time a complete combustion catalytic cracking unit would report as a “shared process/combustion stack” configuration is if the unit had auxiliary fuel fired by the catalytic cracking unit during start-up or idling of the unit and these emissions were measured by the CEMS.

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You would typically report only the CH₄ and N₂O emissions due to combustion of fuel gas and other Table C-2 fuels used in the CO boiler. If you have a separate stationary combustion source that shares a common stack with the process emissions, also include and report the CH4 and N2O emissions due to combustion of fuels used in the stationary combustion unit following the requirements of subpart C. The CH₄ and N₂O emissions generated from the combustion of catalyst petroleum coke are reported under the subject process unit’s e-GGRT data entry forms and should not be included in the CML’s reporting section “CEMS Equation C-10 Summary and Results.”