A correlation for average droplet diameter in rotating packed beds

A rotating packed bed (RPB) is a novel process intensification technology that increases mass transfer rate using a strong centrifugal acceleration. Inside an RPB, the inlet jet of the liquid absorbent is broken into tiny droplets. It is reported that RPBs provide 11 times larger mass transfer area compared to equal-sized packed beds and two to three orders of magnitude higher mass transfer compared to equal-sized stirred tanks. The novelty of the technology and lack of research, however, undermines the adoption of RPBs where a low mass transfer rate is the main bottleneck. In this work, we study the effect of bed size on the average droplet diameter in RPBs and investigate scale-up criteria to preserve the average droplet diameter at a large scale. Furthermore, we develop a correlation for the average droplet diameter using the experimental data and simulation results obtained using a volume of fluid (VOF) method. This correlation is obtained from dimensional analysis. The effects of rotating speed, absorbent flow rate, wire mesh packing diameter, bed diameter, absorbent viscosity, density, and surface tension are included in the dataset. Among these parameters, rotating speed, centrifugal force, and surface tension have the highest correlation coefficients (R-2 = 0.88, 0.83, and 0.42, respectively) with the average droplet diameter.

Automated summary

This study investigates the effect of bed size on the average droplet diameter in a rotating packed bed (RPB) and develops scale-up criteria to maintain the average droplet diameter at a large scale. Experimental data and simulation results are used to determine the correlation between rotating speed, centrifugal force, and surface tension with the average droplet diameter. This research contributes to the wider adoption of RPB technology.