The fluidization and drying characteristics of Shengli lignite in a sound-assisted fluidized bed are investigated.
The effects caused by sound frequency and sound pressure level on the minimum fluidization velocity
and drying rate are studied. Experiments indicated that acoustic field can improve the fluidization
quality and drying rate of Shengli lignite. The minimum fluidization velocity decreased with an increase
in sound pressure level and has a minimum value at a sound frequency of 1.5 kHz. The drying rate of
Shengli lignite was especially increased during the initial period of the drying process, while the effect
was minor toward the end of process. Based on the determination of TG, FTIR, and BET, the structure
changes of Shengli lignite were measured to assess the changes in the quality of dried lignite with the assistance
of acoustic field. The weight loss rate of dried lignite decreasedwith the introduction of acoustic
waves. Total pore volume, average pore diameter, and specific surface area were significantly reduced
with introducing acoustic waves. Carbonyl decreased progressively with the assistance of acoustic
field while carboxyl and hydroxyl increased and decreased thereafter. In addition, the energy consumption
of fluidized bed drying system after inducing acoustic field is investigated.