Effect of particle size on gas holdup in three-phase reactors

Gas holdups were measured in a batch three-phase cocurrent column in which glass beads ranging from 17 to 5000µm were suspended up to 20 vol %. The effect of particle size on gas holdup was found to be different in three types of reactors such as the gas-sparged slurry reactors, three-phase bubble columns and three-phase fluidized beds. An increase of particle size reduced gas holdup in three-phase bubble columns, while raising it in gas-sparged slurry reactors and three-phase fluidized beds. The maximum and minimum gas holdup were observed respectively for particle size of about 88–250µm and 500µm, but the values of particle size were dependent on solid content and gas velocity.