TY - JOUR
T1 - Ultrasound-assisted regeneration of activated alumina/water adsorption pair for drying and dehumidification processes
AU - Daghooghi-Mobarakeh, Hooman
AU - Miner, Mark
AU - Wang, Liping
AU - Wang, Robert
AU - Phelan, Patrick E.
N1 - Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/8
Y1 - 2022/8
N2 - Desorption processes are important part of all processes which involve utilization of solid adsorbents and are inherently energy-intensive. Here we investigate how those energy requirements can be reduced through the application of ultrasound for the activated alumina/water adsorption pair. To analyze the energy-saving characteristics of ultrasound, the ultrasonic-power-to-total power ratios of 0.2, 0.25, 0.4 and 0.5 were investigated and the results compared with those of no ultrasound at the same total input power. Duplicate experiments were performed at three nominal frequencies of 28, 40 and 80 kHz to observe the influence of frequency on regeneration dynamics. Regarding moisture removal, the highest desorption was achieved at the lowest ultrasonic-to-total power ratio corresponding to about 27% reduction in energy consumption. A nonlinear inverse proportionality was observed between the effectiveness of ultrasound and the frequency at which it is applied. Regarding regeneration temperature, application of ultrasound at higher ultrasonic-to-total power ratios of 0.4 and 0.5 reduces the regeneration temperature without taking a toll on desorption. Based on the variation of desorption dynamics with ultrasonic power and frequency, a novel ultrasound-enhanced desorption mechanism involving adsorbate surface energy is proposed and a relationship between acoustically induced strain and adsorbate surface energy is introduced. An analytical model that describes the desorption process is developed based on the experimental data. From this a novel efficiency metric is proposed, which can be employed to justify incorporating ultrasound in regeneration and drying processes.
AB - Desorption processes are important part of all processes which involve utilization of solid adsorbents and are inherently energy-intensive. Here we investigate how those energy requirements can be reduced through the application of ultrasound for the activated alumina/water adsorption pair. To analyze the energy-saving characteristics of ultrasound, the ultrasonic-power-to-total power ratios of 0.2, 0.25, 0.4 and 0.5 were investigated and the results compared with those of no ultrasound at the same total input power. Duplicate experiments were performed at three nominal frequencies of 28, 40 and 80 kHz to observe the influence of frequency on regeneration dynamics. Regarding moisture removal, the highest desorption was achieved at the lowest ultrasonic-to-total power ratio corresponding to about 27% reduction in energy consumption. A nonlinear inverse proportionality was observed between the effectiveness of ultrasound and the frequency at which it is applied. Regarding regeneration temperature, application of ultrasound at higher ultrasonic-to-total power ratios of 0.4 and 0.5 reduces the regeneration temperature without taking a toll on desorption. Based on the variation of desorption dynamics with ultrasonic power and frequency, a novel ultrasound-enhanced desorption mechanism involving adsorbate surface energy is proposed and a relationship between acoustically induced strain and adsorbate surface energy is introduced. An analytical model that describes the desorption process is developed based on the experimental data. From this a novel efficiency metric is proposed, which can be employed to justify incorporating ultrasound in regeneration and drying processes.
KW - Activated alumina
KW - Adsorption potential
KW - Desorption
KW - Drying
KW - Surface energy
KW - Ultrasound
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U2 - 10.1016/j.ultras.2022.106769
DO - 10.1016/j.ultras.2022.106769
M3 - Article
C2 - 35644098
AN - SCOPUS:85131094647
SN - 0041-624X
VL - 124
JO - Ultrasonics
JF - Ultrasonics
M1 - 106769
ER -