Gas Interchange between a Bubble and Continuous Phase in Gas-Soild Fluidised Bed

Abstract

The mechanism of gas interchange between a bubble and the continuous phase was investigated by blowing a bubble of visible brown NO₂ gas into two dimensional fluidised bed. From this investigation, it was found that the gas interchange occurred by the diffusion and by the flow out of gas from the cloud which was caused by variations of velocity and diameter of bubble. Based on the above transfer mechanism, a model for gas interchange was suggested and the gas interchange coefficient was calculated. Furthermore, gas interchange coefficients were obtained by measuring the change of the concentration of a CO₂ gas bubble at two different heights in the bed. The gas interchange coefficients calculated from the model coincided well with that obtained from experiments.