| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 236812 | Powder Technology | 2013 | 10 Pages |
The purpose of this study is to investigate the hydrodynamic characteristics of pulsed fluidized bed experimentally. Three different particles, silica with 196 μm mean diameter, alumina with 95 μm mean diameter and alumina with 10 μm mean diameter were introduced into the fluidized bed. Experiments were performed in 0.11 m ID and 0.5 m height fluidized bed. Pulsed airflow was introduced using square waves at 1 to 10 Hz pulsation frequency, which were generated using a solenoid valve connected to an electronic circuit. A high speed camera recorded the bed behavior to measure the bubble size and velocity. Results indicate that for alumina 95 μm the bed surface oscillation increases with decrease of pulsation frequency. Increasing the pulsation frequency decreases the bed expansion ratio and the bubble's diameter and velocity. In addition, the mean bed pressure drop becomes closer to the continuous airflow by increasing the pulsation frequency. This study indicates that the pulsating airflow decreases the minimum fluidization velocity and enhances fluidization of fine cohesive particles.
Graphical abstractHydrodynamic characteristics of pulsed fluidized bed are studied experimentally. Experiments were performed with a Plexiglas cylinder. Pulsed airflow was generated by using a solenoid valve connected to an electronic circuit. Observations indicate that the pulsed airflow decreases the minimum fluidization velocity and enhances the fluidization quality of fine cohesive particles.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hydrodynamics of gas–solid fluidized bed with pulsed flow is studied experimentally. ► Pulsed airflow is supplied by a solenoid valve at 1 to 10 Hz frequencies. ► Amplitude of bed surface oscillation increases with decrease of pulsation frequency. ► Increasing pulsation frequency decreases the bubble size. ► Pulsed flow at high frequency decreases the minimum fluidization velocity.
