Relative contributions from particle conduction and gas convection to the heat transfer coefficient between dense gas-solid fluidized beds and surfaces

Abstract

Abstract Relative contributions from particle conduction and gas convection to the heat transfer coefficient between gas-solid fluidized beds and surfaces are studied using experimentally measured values. The measurements were made over a wide range of fluidization conditions ( d av = 56–1789 μ m, U = 0.02–2.6 m/s). This includes 18 different systems, i.e. five different materials (glass, sand, aluminum, polypropylene, FCC), twelve different particle sizes, and two different distributor plates. Twelve of these systems were measured using a sintered distributor plate and six using a perforated distributor plate. The study was conducted in a 5 cm × 30 cm fluidized bed. At about a particle size of 650 μm or at the onset of Geldart D type powders the primary mode of heat transfer charges from particle conduction to gas convection.