Effect of gas properties and wall materials on particle charging in gas–solid fluidized beds

The charges acquired by polyethylene and glass particles fluidized by argon, nitrogen, and air at different humidity levels in acrylic and steel columns have been measured. Increased bed expansion at higher fluidization gas velocities lowered the space charge effect, allowing the particles to acquire more charges. The low dielectric strength of argon limits the extent of charging when the particles are fluidized in argon. The effect of the humidity of the air on particle charge differed appreciably between the two columns. The charge densities acquired by the particles in several experiments appear to have been limited by the dielectric strength of the fluidization gas.