New investigation of Micro-fluidized bed: The effect of wall roughness and particle size on hydrodynamics regimes

Abstract

This study presents a new design for Micro-fluidized beds (MFBs), together with a new approach to their hydrodynamic analysis. Two 4 mm MFB reactors were manufactured from glass and resin (constructed by stereo-lithographic 3D printing), to assess the influence of wall roughness on the hydrodynamic characteristics. The novel 3D printing scheme ensures air tightness and good transparency of the reactor. Four types of glass, SiC, Al2O3 and TiO2, belonging to groups B, A/C and C from Geldart's classification, were used to investigate the influence of particle size on their fluidization behavior in MFBs. Three grades of MFB wall roughness were tested. Mechanical vibration energy was applied to the MFBs to improve the quality of fluidization, and to overcome wall friction and cohesive forces. Their hydrodynamic properties were obtained by analyzing pressure fluctuations in the time and frequency domains. The results show that only an appropriate increase in wall roughness was helpful for the suppression of slugging fluidization. The use of mechanical vibrations was found to promote the attenuation or destruction of plug phenomena, thus improving the quality of fluidization of Group A/C and C particles. The feasibility of fluidizing group A/C and C particles has thus been verified in a 3D printed MFB reactors.