CO2 Capture by Adsorption on Fine Activated Carbon in a Sound Assisted Fluidized Bed

Among all the carbon capture and storage strategies, post-combustion capture can provide a near-term solution for stationary fossil fuel-fired power plants, eliminating the need for extensive modifications to existing combustion processes and facilities. In this respect, adsorption using solid sorbents has the potential, in terms of energy saving, to complement or replace the current absorption technology. Therefore, the design of highly selective CO2 adsorbents materials is needed. In this framework, great interest is focused on nanomaterials, whose chemico-physical properties can be tuned at the molecular level. As regards the handling of such materials, sound-assisted fluidization is one of the best technological options to improve the gas-solid contact by promoting a smooth fluidization regime. The present work is focused on the assessment of sound-assisted fluidization in the CO2 capture on fine activated carbon. Tests have been performed in a laboratory scale experimental set-up at ambient temperature and pressure, pointing out the effect of sound intensity and frequency. The experimental results show that the acoustic field positively affects the fluidization quality and adsorption efficiency of the powder in terms of remarkably longer breakthrough time, adsorption capacity, fraction of bed utilized until breakthrough and adsorption rate. In particular, sound intensities higher or equal to 125 dB are enough to obtain a good fluidization quality. Whereas, sound frequency has a not monotone effect on the fluidization quality and adsorption efficiency, actually, it is possible to find an optimum range of frequency (50-120 Hz) providing the best performance.