Techno-economic assessment of high temperature heat pumps integrated in MEA-based post-combustion CO2 capture for cement plant

• Energetic, economic and CO₂ balance of electrified MEA-based CO₂ capture in cement • Assessed LVC, High Temperature Heat Pumps and Mechanical Vapor Recompression • Waste heat recovery from cement and capture plant for thermal integration with HTHP • Lowest cost of CO 2 avoidance case uses HTHP coupled with MVR and LVC • Best case: 125.9 €/tCO₂, 42.5 €/tclk; 16% and 32% less than NG boiler optimal case This study presents a techno-economic assessment of solvent-based (MEA) post-combustion CO₂ capture integration within cement production process, exploring both conventional natural gas (NG) boiler configurations and innovative high-temperature heat pump (HTHP) solutions for thermal duty supply. Heat Pumps exploit the low-temperature waste heat from the cement plant and the capture unit as thermal source in the evaporator. The following options are assessed, separately or in combination, for the replacement of the boiler for the supply of steam for solvent regeneration: (i) a lean vapor compression (LVC) system within the capture process itself; (ii) a closed Reverse Rankine heat pump; (ii) a cascade of a closed Reverse Rankine heat pump bottoming a mechanical vapor recompression (MVR) system. Process simulations and sizing are performed with a validated rate-based model of the absorption process in Aspen Plus and the economic analysis is carried out with a referenced bottom-up methodology. The cost-effectiveness of each technology is provided in terms of cost of CO 2 avoidance (CCA), clinker cost increment (∆CC) and cost of CO 2 capture (COC). In the case of conventional steam supply with NG boiler, two different positions for the capture plant are evaluated: tail end (Case #1 - Tail end) and integrated upstream the raw mill (Case #2 - Integrated). The best configuration with steam generation via NG boiler is case #2 with LVC at a flash pressure of 0.8 bar, featuring an incremental cost of clinker of 62.1 €/t clk and a CCA of 149.6 €/t CO2 . The integration of HTHPs has been found to bring significant benefits in terms of energy performance and cost competitiveness. The comparative evaluation of multiple HTHP configurations, including reverse Rankine cycle heat pumps and mechanical vapor recompression (MVR) systems, demonstrates that the most viable solution is an MVR-based HTHP combined with LVC.Fuel consumption for solvent regeneration of around 100 MW th is replaced by an additional electricity demand of 26.9 MW el in the best case. The CO 2 avoidance rate of the overall cement plant is reduced from almost 91 % to 89 % due to the increased Scope 2 emissions, with the assumed electricity carbon intensity of 100 kg CO2 /MWh. With baseline NG and electricity prices of 40 €/MWh and 100 €/MWh respectively, the cost of CO 2 avoidance and incremental clinker cost are 125.9 €/t CO2 and 42.1 €/t clk , respectively. These findings provide insights into the techno-economic trade-offs of integrating carbon capture in cement plants and highlight the potential role of HTHPs in helping the decarbonization of this sector. Sensitivity analyses on the main factors impacting the energy performance and costs are included to highlight how the competitiveness and costs of the different solutions change under different assumptions or market conditions.