Hydrodynamic characteristics of cyclone reactors

Abstract

Recently, cyclones have been used as chemical reactors for example for coal combustion and gasification. In order to provide information needed for cyclone reactor design, the effects of air inlet velocity (6 ∼ 17 m/s), particle (coal-char and glass beads) size (141 ∼ 211 μm), solid loading (0.0 ∼ 0.189 kg/m 3) and geometric ratio of cylinder to cone height (1.8 ∼ 5.0) on the hydrodynamic characteristics such as pressure drop, collection efficiency and residence time distribution of solid particles have been determined in three different cyclones. Pressure drop increases with gas inlet velocity and decreases with solid loading. Collection efficiency increases with gas inlet velocity up to 1.7 times the saltation velocity, and thereafter decreases with increasing gas inlet velocity. Solid residence time distribution is broadened with increasing gas inlet velocity and the geometry ratio, but narrows with increasing particle size. Average residence time of solids increases with inlet gas velocity but decreases with particle size. Average solid residence time in cyclones is correlated with the relevant dimensionless parameters.