Integration of the FCC unit with amine base post-combustion capture

• CCS integration is a viable technology for emissions reduction for the FCC unit, and therefore the refinery operation. • 60–85% of emissions can be avoided with amine-based CCS depending on the heat integration adopted, based on 90% capture rate. • CO 2 avoidance is comparable when CCS runs standalone with external heat or uses only FCC flue gas waste heat for regeneration. • Using electric fired boiler sourced steam offers the worst CO 2 avoidance due to relatively high carbon footprint. Despite the drive towards the use of renewable sources of energy, it is expected that fossil fuels will continue to be used for energy supply for the foreseeable future. Given the role that the Fluid catalytic cracking (FCC) unit plays in the refinery, it is necessary to decarbonise these units if the goals to low carbon energy systems are to be realised. With carbon capture and storage (CCS) emerging as a promising technology towards decarbonising industrial processes, it is applied to the FCC regenerator in this study. We present detailed models of the major process units involved in an integrated FCC-CCS plant. The models are validated using various pilot and commercial plant data available in the literature, and are subsequently linked in the gPROMS platform to analyse three different scenarios for FCC-CCS integration. The capture plant in this analysis was designed to operate at 93 % capture rate. A key finding of this study was that the carbon dioxide (CO 2 ) avoidance rate of the integrated plant is greatly affected by the emissions from the steam boiler which provides the reboiler duty for solvent regeneration. We observed that if the CCS and heat recovery steam generator (HRSG) are retrofitted as standalone units downstream of the FCC regenerator, then the avoided CO 2 of the integrated plant drops from 93 % to 67 %. If, however, steam is extracted from the steam turbine exhaust of the HRSG cycle, it lowers the steam demand from the boiler by 37 % and improves the CO 2 avoidance rate from 67 % to 82 %.