Influence of dispersed particles in ultrasonic field on mass transfer in bubble column

The influence of activated carbon dispersed particles on the variation of bubble diameter and volumetric mass transfer coefficient of the system of CO2-water absorption in ultrasonic field of a single frequency and multi-frequency was investigated in real time in a bubble column with a bubble feature measuring system called duplex conductivity probe.The results showed that multi-frequency ultrasonic field was superior to single-frequency ultrasonic field in enhancing volumetric mass transfer coefficient without dispersed activated carbon particles.Volumetric mass transfer coefficient increased by 40%—64% in the ultrasonic field of multi-frequency of 20-50-100 kHz and input power of 100 W.As activated carbon particles of 38 μm were added to the system,volumetric mass transfer coefficient firstly increased and then gradually decreased.However,the trend of variation in bubble diameter was on the contrary.Enhancement of mass transfer was most significant when solids content was 1.0 kg·m-3.When solids concentration was at a specific value,volumetric mass transfer coefficient decreased with the increase in activated carbon particle diameter.Compared with the system without activated carbon particles,when solids content was 1.0 kg·m-3,volumetric mass transfer coefficient was enhanced about by 1.58 times,and volumetric mass transfer coefficient further increased by 2.02 times under combined action of particles and reverberating ultrasonic field of multi-frequency of 20-50-100 kHz and input power 100 W,which suggested that multi-frequency ultrasonic field and dispersed particles had a significant synergistic effect on enhancement of mass transfer in CO2-water absorption system.