Facilitating adoption of carbon capture on fcc flue gas (ERTC)
Fluid catalytic cracking (FCC) is a key conversion step in gasoline production.
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A typical FCC unit produces around 20–30% of the total emissions of a petroleum refinery. Most of those emissions, approximately 70–80%, come from the flue gas as a result of coke combustion to satisfy the unit heat balance and regenerate the catalyst. From a carbon footprint reduction perspective, this presents an excellent opportunity for refiners to significantly reduce their footprint by implementing carbon capture on a single-point source. The remaining emissions generated by an FCC unit come from utility requirements, which can be reduced by optimal process and equipment design tailored towards increased energy efficiency, optimised heat integration, and minimised hydraulic requirements.
Cost will be a major factor in facilitating the widespread adoption of carbon capture of FCC flue gas. Financial incentives like the EU Emissions Trading System, 45Q US federal tax credits, and state-level incentives such as California’s Low Carbon Fuel Standard provide motivation for refiners to pursue carbon capture. However, a low-cost technology solution is still required to further increase the profitability of these projects.
To address this challenge, Honeywell UOP, in collaboration with the University of Texas at Austin, is offering Advanced Solvent Carbon Capture (ASCC) technology. ASCC uses a combination of a proprietary solvent, novel heat exchanger system, and high-pressure stripper. The solvent has a high mass transfer rate, enabling the use of a smaller absorber, which typically is one of the largest pieces of capital. And the novel heat exchange system, in combination with the solvent properties, allows for a low regeneration heat duty, commonly between 2.1-2.4 GJ/t of CO₂. Another differentiating factor is the high-pressure stripper, which produces CO₂ at 5-7 bar(g), allowing for the elimination of at least one stage of compression.
These features reduce capital and operating expenditures, which translates into a lower cost of captured CO₂ of up to $8 /m.t. when compared to other second-generation solvents. ASCC is a ready-now technology that has been extensively tested and validated at the US National Carbon Capture Center. ASCC can be integrated with existing FCC units or be included as part of a new FCC unit.
The ~20-30% residual emissions from the FCC can be addressed by improving the energy efficiency of the unit, for example by installing power recovery turbines. A key advantage, apart from the carbon footprint reduction of these solutions, will be improved unit profitability as a result of reduced utility requirements, which will be especially impactful in regions with higher utility costs.
This short article originally appeared in the 2022 ERTC Newspapers, which you can view HERE
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