Abstract
Among all the carbon capture and storage technologies, adsorption is considered one of the most promising alternative due to its low energy requirements, thus stimulating intense research to find suitable and highly specific adsorbents for removing CO2 from flue gas. Much attention has been focused on metal-organic frameworks (MOF), a new class of crystalline microporous materials that has potential applications in separation processes. Therefore, a major point to be addressed is the development of a process which can handle such fine materials. In this respect, sound-assisted fluidization has been indicated as one of the best technological option to improve the gas–solid contact by promoting a smooth fluidization regime. The present work is focused on the CO2 capture by sound assisted fluidized bed of a copper based, water stable MOF, namely HKUST-1. Tests have been performed in a laboratory scale experimental set-up at ambient temperature and pressure. The results show the capability of the sound in promoting and enhancing the adsorption process in terms of larger values of amount of CO2 adsorbed, breakthrough time, adsorption rate and fraction of bed utilized at breakpoint. Experimental tests have also been carried out to find a suitable regeneration strategy of the sorbent, in order to study its stability to cyclic adsorption/desorption operations. An extra-situ regeneration strategy has been adopted, 150 °C under a 50 mbar vacuum. A thorough chemico- physical characterizations on a sample of HKUST-1 subjected to 10 CO2 adsorption/desorption cycles confirms the effectiveness of this regeneration strategy and the remarkable stability of the material.
