(51c) Reducing CO2 Emissions In FCC Process

            The FCC process unit has been a major work horse in the petroleum industry since the 1940’s. The attention for improving FCC performance in the past has been on enhancing the reaction conditions and catalysts to deliver value through yield improvements. However, in the current high energy cost environment and forthcoming CO₂ regulations, reducing CO₂ emissions in FCC unit started drawing much more attention. Refineries contribute to ~4% of total CO₂ emissions in the United States. FCC units account for 15-20% of refinery energy consumption and CO₂ emissions. In this project, novel and major improvement opportunities for FCC have been identified which can create a step change in reducing CO₂ emissions in FCC units. 

             In summary, improvement opportunities are identified based on viewing FCC as ISBL (Inside Battery Limit) and integrating FCC with the refinery as whole, i.e. OSBL (Outside Battery Limit). The opportunities include optimization of fractionation/separation flowsheet and conditions, integration of advanced technologies for fractionation/separation, maximizing heat and power recovery within FCC and integration of generated heat and power in ISBL with OSBL balances. Collectively, these improvements could help establish the image of FCC as a utility hub, delivering high value energy utilities to the refinery and lessen the CO₂ emissions from the refinery.

           The new concepts developed as a result of this project include:

-         New flue gas cooler design: Integrating a raw feed preheating system into the flue gas cooler to reduce flue gas cooler discharge temperature and maximize energy recovery.

-         Dividing wall column for naphtha splitting: Using dividing wall columns for naphtha splitting and column sequencing to minimize utility usage and capital costs

-         Main fractionator optimization: Improving the design of FCC Main Fractionator to recover more energy

-         Steam turbine integration: Extraction HP (High Pressure) steam turbine in power recovery section to provide all the MP (Medium Pressure) and LP (Low Pressure) internal steam requirements in FCC unit and maximize power recovery