Abstract :
[en] Global warming is nowadays one of the most urgent environmental and scientific challenges which is caused by the increased CO2 emissions in the last decades. To reduce these CO2 emissions, a reduction of energy consumption, the use of renewable energy as well as CO2 capture strategies must be implemented. One of the most mature strategies involves post-combustion capture, which focuses on the CO2 in flue gases emitted from industrial point sources. The CO2 capturing can be performed either via an absorption, cryogenic, membrane or adsorption approach. Absorption technology, relying on CO2 capturing in liquid amine solvents, is the more advanced method. However, the process shows some major drawbacks such as degradation and evaporation of the solvent as well as the requirement for high energy consumption during regeneration [1]. Adsorption, on the other hand, makes use of solid porous materials that adhere the CO2 gas onto their surface by significantly weaker interactions than with amino solvents. As a result, the energy for regeneration is lower, making it a promising and possibly more efficient approach [2]. However, the commercial implementation of these materials remains an unsolved challenge due to the unwanted competition with other gaseous components present in the post-combustion flue gas. Although many adsorbents show high selectivity to CO2 over other gases, the high affinity for moisture in flue gas remains one of the biggest issues. Since CO2 tends to interact more weakly to the adsorption sites than the dipole moment of water, a drastic decrease in the CO2 adsorption capacity is often observed [3].
The most studied adsorbent for CO2 capture on an industrial scale is the zeolite 13X due to its wide availability, knowledge, price and its steep increase in CO2 capacity at lower pressures, which is desired for the flue gases emitted at ambient pressure [4]. However, zeolite 13X loses a significant amount of adsorption capacity, ranging from 20-90 % depending on the relative humidity [3]. As a result, the use of zeolite 13X necessitates a pretreatment of flue gases to remove most of the moisture content in a dryer, increasing the overall operation cost. To overcome this additional drying step and increase the overall efficiency of the process, several innovative strategies in material design are being evaluated, including the modification of existing adsorbents and the use of newly developed materials [4].
The developed materials will be evaluated on adsorption performance in terms of capacity, kinetics and selectivity in dry and humid conditions. In a first instance, characterization will be performed on powdered samples. However, to increase their applicability, the powdered samples will be structured onto honeycombs by a vacuum wash-coating procedure. Different modification strategies to obtain moisture-insensitive adsorbents will be evaluated, either performed on the powder prior to shaping (pre-modification) or via a post-modification strategy after the shaping process.
References
[1] Asif, M.; Suleman, M.; Haq, I.; Jamal, S. A. Greenhouse Gases Science and Technology 2018, 8 (6), 998–1031.
[2] Raganati, F.; Ammendola, P. Energy & Fuels 2024, 38 (15), 13858–13905.
[3] Kolle, J. M.; Fayaz, M.; Sayari, A. Chemical Reviews 2021, 121 (13), 7280–7345.
[4] Ray, B.; Churipard, S. R.; Peter, S. C. Journal of Materials Chemistry A 2021, 9 (47), 26498–26527.
