A technical evaluation of CO2 capture technologies when retrofitted to a cement plant is performed. The investigated technologies are the oxyfuel process, the chilled ammonia process, membrane-assisted CO2 liquefaction, and the calcium looping process with tail-end and integrated configurations. For comparison, absorption with monoethanolamine (MEA) is used as reference technology. The focus of the evaluation is on emission abatement, energy performance, and retrofitability. All the investigated technologies perform better than the reference both in terms of emission abatement and energy consumption. The equivalent CO2 avoided are 73–90%, while it is 64% for MEA, considering the average EU-28 electricity mix. The specific primary energy consumption for CO2 avoided is 1.63–4.07 MJ/kg CO2, compared to 7.08 MJ/kg CO2 for MEA. The calcium looping technologies have the highest emission abatement potential, while the oxyfuel process has the best energy performance. When it comes to retrofitability, the post-combustion technologies show significant advantages compared to the oxyfuel and to the integrated calcium looping technologies. Furthermore, the performance of the individual technologies shows strong dependencies on site-specific and plant-specific factors. Therefore, rather than identifying one single best technology, it is emphasized that CO2 capture in the cement industry should be performed with a portfolio of capture technologies, where the preferred choice for each specific plant depends on local factors.

This paper presents an assessment of the cost performance of CO2 capture technologies when retrofitted to a cement plant: MEA-based absorption, oxyfuel, chilled ammonia-based absorption (Chilled Ammonia Process), membrane-assisted CO2 liquefaction, and calcium looping. While the technical basis for this study is presented in Part 1 of this paper series, this work presents a comprehensive techno-economic analysis of these CO2 capture technologies based on a capital and operating costs evaluation for retrofit in a cement plant. The cost of the cement plant product, clinker, is shown to increase with 49 to 92% compared to the cost of clinker without capture. The cost of CO2 avoided is between 42 €/tCO2 (for the oxyfuel-based capture process) and 84 €/tCO2 (for the membrane-based assisted liquefaction capture process), while the reference MEA-based absorption capture technology has a cost of 80 €/tCO2. Notably, the cost figures depend strongly on factors such as steam source, electricity mix, electricity price, fuel price and plant-specific characteristics. Hence, this confirms the conclusion of the technical evaluation in Part 1 that for final selection of CO2 capture technology at a specific plant, a plant-specific techno-economic evaluation should be performed, also considering more practical considerations.

The envisioned role of hydrogen in the energy transition – or the concept of hydrogen economy – has varied through the years. While in the past hydrogen was mainly considered...

A new ammonia-based process for CO capture from flue gas has been developed, which utilizes the formation of solid ammonium bicarbonate to increase the CO concentration in the regeneration section of the process. Precipitation, separation, and dissolution of the solid phase are realized in a dedicated process section, while the packed absorption and desorption columns remain free of solids. Additionally, the CO wash section applies solid formation to enable a reduction of the wash water consumption. A rigorous performance assessment employing the SPECCA index (Specific Primary Energy Consumption for CO Avoided) has been implemented to allow for a comparison of the overall energy penalty between the new process and a standard ammonia-based capture process without solid formation. A thorough understanding of the relevant solid-solid-liquid-vapor phase equilibria and an accurate modeling of them have enabled the synthesis of the process, and have inspired the development of the optimization algorithm used to screen a wide range of operating conditions in equilibrium-based process simulations. Under the assumptions on which the analysis is based, the new process with controlled solid formation achieved a SPECCA of 2.43 MJ kg, corresponding to a reduction of 17% compared to the process without solid formation (with a SPECCA of 2.93 MJ kg). Ways forward to confirm this significant improvement, and to increase the accuracy of the optimization are also discussed.

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