Vertical gas—solid transition flow with electrostatics

Effects of an electrostatic field in pneumatic conveying of granular materials through inclined and vertical pipes

“…The occurrence of unexpected flow patterns of the granular material within the conveying pipes as described above is an example of the significance of such electrostatic effects. Joseph and Klinzing (1983) mentioned that electrostatic effects should be minimized in the design of pneumatic conveying systems as these have an adverse effect on the optimal operating conditions. In particular, they showed that the pressure drop at choking conditions and the required gas velocity at minimum pressure drop in vertical pneumatic conveying were higher in the presence of electrostatic forces.…”

On the electrostatic equilibrium of granular flow in pneumatic conveying systems

“…Al-Adel et al 16 investigated the effect of static electrification on gas-solid flows in vertical risers and captured qualitative features of riser flows: core-annular particle distribution, annular particle downflow at low riser gas velocities, and annular upflow at high gas velocities. Joseph and Klinzing 17 demonstrated that the choking of granular flow is caused by electrostatic effect in vertical pneumatic transport. On the other hand, electrostatic effects are dependent on a variety of factors such as the physical, chemical, and electrical characteristics of the material used and ambient conditions.…”

Modeling the electrostatic effect on the hydrodynamic behavior in FCC risers: From understanding to application

“…4, the pressure drop predicted by the coupled model in the presence of the electrostatic effect is higher than the simulation in the absence of the electrostatic effect. The excess pressure gradient, which can be attributed to the presence of charges on the particles, is often called the "electrostatic pressure gradient" (Ally & Klinzing, 1985;Joseph & Klinzing, 2000;Plasynski, Klinzing, & Mathur, 1994;Smeltzer, Weaver, & Klinzing, 1982;Zaltash, Myler, & Klinzing, 1988). Furthermore, the simulation result is similar to the experimental results shown by Knowlton et al (1995), which further demonstrates that the model in the present work has a qualitative prediction capability for simulating an FCC riser.…”