Mixing characteristics of binary mixtures using promoters and secondary fluidizing medium

In the present investigation, a new technique for augmenting mixing of particles, expressed through the mixing index (IM), has been found. Correlations for the mixing index have been developed with system parameters such as static bed heights, average particle densities, average particle sizes and gas mass velocities under four different experimental conditions, viz., only primary air, simultaneous primary and secondary air, disc promoter and rod promoter using the factorial design approach. The values of the mixing index obtained through the developed model are found to agree well with their experimental counterparts. Furthermore, it has been observed that the best mixing performance is achieved (IM ≈ 1) under conditions of simultaneous primary and secondary air supply.

Graphical abstractInvestigations have been carried out in a cylindrical gas-solid fluidized bed to find a new technique for augmenting mixing of a binary mixture of varying densities, which is expressed in terms of mixing index (IM). Based on factorial design approach, correlations for the mixing index have been developed with system parameters such as static bed heights, average particle densities, average particle sizes and gas mass velocities under four different experimental conditions, viz., only primary air, simultaneous primary and secondary air, disc promoter and rod promoter. During fluidization, samples have been collected through the side ports on diametrically opposite sides at different heights of the fluidizer (intervals of 4 cm from the distributor plate, which is diametrically opposite to the secondary air inlet) for all the four experimental conditions as shown in Fig 1. It has been found from these investigations that under simultaneous primary and secondary air supply conditions the best mixing performance is achieved, i.e., IM ≈ 1.0 as compared to rod promoter, disc promoter and only primary air supply.Figure optionsDownload full-size imageDownload as PowerPoint slide