LOW-CARBON CEMENT PRODUCTION VIA EMERGING ELECTRIFIED TECHNOLOGIES

The cement industry accounts for 6-7% of global anthropogenic CO2 emissions, with clinker production being the most carbon-intensive stage. About 60% of clinker emissions are process-related, generated from limestone calcination, while the rest arises from fossil fuel combustion in the calciner and rotary kiln, and electricity use. Owing to the substantial share of unavoidable process emissions, the deployment of carbon capture is indispensable, while electrification of heat demand offers a complementary strategy by reducing fuel-related emissions and enabling the production of high-purity CO2 streams. Despite significant efforts advancing mature carbon capture options, several promising alternatives are still underexplored from a techno-economic standpoint. Among these, calciner electrification represents a near-term solution capable of mitigating both process- and fuel-related emissions from the calciner. In parallel, wet carbonation of recycled concrete fines (RCF) offers the potential to combine CO2 abatement with material circularity through clinker substitution. Finally, cryogenic CO2 capture (CCC) represents a fully electrified post-combustion option with the potential for high capture efficiency and competitive energy performance. This Thesis explores the techno-economic potential of these emerging strategies by leveraging detailed process modelling, steady-state simulation, techno-economic assessment, and sensitivity analysis. Different cement plant configurations combining calciner electrification with MEA-based capture are evaluated to enhance decarbonisation by exploiting waste heat. Configurations differ in calciner design (entrainment vs. drop-tube) and CO2-rich stream heat recovery. While CO2 avoidance is similar among the alternatives, economic performance varies due to capital costs. The entrainment calciner with direct raw meal preheating emerges as the most favourable option, achieving a CO2 avoidance cost of 217 €/tCO2, compared with 231-234 €/tCO2 for the alternatives. However, the high electricity demand limits emission reductions and economic attractiveness in the current EU context. The integration of wet carbonation of industrial RCF within an electrified-calciner plant is evaluated as an alternative. The carbonation unit captures rotary kiln emissions while producing supplementary cementitious material, increasing cement throughput. The carbonation process is highly energy-intensive and delivers limited additional decarbonisation compared to MEA-based capture. Although coupling RCF carbonation with calciner electrification slightly improves economic performance relative to the MEA-based alternative, the incremental emission reductions achieved over the direct use of non-carbonated RCF in the cement blend are modest and economically unfavourable. CCC is comprehensively assessed for cement applications, including process design, optimisation, techno-economic analysis, and benchmarking. CCC shows high energy efficiency (1.2 MJel/kgCO2) compared with MEA-based capture across a range of flue-gas CO2 concentrations. Increasing capture rates beyond 90% is particularly attractive as it enables higher CO2 avoidance with minimal additional energy and cost penalties. With a CO2 avoidance cost of 127 €/tCO2, CCC proves more cost-effective than electrified-calciner plants combined with MEA capture and conventional MEA-based systems. While remaining slightly less competitive than oxyfuel and calcium looping under the current EU energy mix, CCC emerges as a credible alternative to established carbon capture options. Overall, economic viability is primarily driven by energy supply, as electricity costs dominate production and CO2 abatement costs. Sensitivity analyses show that competitiveness improves under low-carbon electricity (<50 kgCO2/MWhel) and electricity prices below 50 €/MWhel for electrified-calciner plants and 65 €/MWhel for CCC, conditions aligned with renewable-dominated energy systems.