Energy-optimised cryogenic CO2 capture for cement production decarbonisation: process design and techno-economic analysis

Achieving net-zero emissions in the cement sector requires the development of effective carbon capture technologies to address process-related emissions from limestone calcination. While much of the current research and applications focus on more conventional methods such as chemical absorption and oxyfuel, cryogenic CO2 capture offers potential advantages in energy efficiency, capture rate, and product purity, though it remains underexplored at an industrial scale. This study presents a comprehensive assessment of cryogenic CO2 capture for cement applications in the EU, including thermodynamic modelling, process design and optimisation, and techno-economic analysis. Two process configurations targeting 90% and 95% capture at 99.9%mass CO2 purity are benchmarked. The 90% capture design achieves an energy penalty of 1.19 MJel/kgCO2, corresponding to a threefold increase in electricity consumption compared to an unabated cement plant. Sensitivity analysis demonstrates consistent energy performance across a 17-28%mol range of flue gas compositions. Increasing the capture rate from 90% to 95% maintains the energy penalty nearly constant (1.19-1.21 MJel/kgCO2), with only marginal economic impact. At 95% capture, the incremental cost of clinker production rises by 5% compared to 90% capture, while the higher CO2 avoidance yields a similar cost of avoided CO2 (127-128 €/tCO2). From an economic perspective, cryogenic capture significantly outperforms conventional MEA-based capture, while remaining slightly less competitive than oxyfuel and calcium looping under current EU energy mix conditions. Overall, cryogenic capture emerges as an energy-efficient and economically viable post-combustion option for cement industry decarbonisation, with the added benefit of delivering a high-purity CO2 stream suitable for storage or utilisation.