CONCLUSIONS
In order to intensify the mass transfer for gas-liquid-solid reaction in
fixed bed, CMGD was applied to disperse gas into a large quantity of
multi-scale bubbles in liquid phase, increasing the gas-liquid
interfacial area to improve the mass transfer efficiency. The effects of
gas-liquid flow rate and rising height on bubble size were investigated.
The results show that the d av is ranging from 330
to 345 μm and the quantity of bubbles is 500 under the optimal
conditions of 10 cm ceramic membrane, gas flow rate of 10 ml/min, liquid
flow rate of 1 ml/min. A large number of bubbles will coalesce in
ceramic membrane channel and rising process, which is contrary to the
strategy of increasing the two-phase boundary area. The ceramic membrane
channel was divided into several channels by installing baffle-type
internals, consequently reducing the radial migration between bubbles
and significantly inhibiting the coalescence of bubbles. This work
revealed the influence of operating conditions and internals on bubble
size in CMGD, and discussed the deformation, coalescence, trajectory and
velocity of multi scale bubbles, contributing to gas-liquid dispersion,
enhancement of mass transfer efficiency and improvement of heterogeneous
catalytic reaction performance.