INTERACTIONS AMONG PRESSURE, ELECTROSTATICS AND PARTICLE ENTRAINMENT IN GAS-SOLID FLUIDIZED BEDS

摘要

The effect of operating pressure on the particle entrainment and electrostatic charges in a fluidized bed of binary mixtures of glass beads was investigated in a column of 150 mm inner diameter and 2 m height.The degree of electrification in the bed is measured by four collision ball probes (stainless steel, 5.3 mm O.D.), at different levels and directly connected to electrometers.The charge density of entrained particles in the freeboard was measured by a freeboard sampler constructed as a Faraday cup.An instrumented stainless pipe (ID=38.1 mm, L=400 mm) coated with Ni is installed in the reactor exit line to measure the electrical current transferred from entrained fine particles to the metal pipe from collisions.The results showed that particle entrainment flux and electrostatic charges increased as the pressure increased from 207 to 517 kPa, probably due to an increase in bubble velocity, frequency and drag forces.