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The use of an axial dual-zone vortex chamber for spray drying applications is experimentally studied, focusing on water spray evaporation. In the hot zone of the vortex chamber, hot air (maximum 30...

The intensification of interfacial mass, heat, and momentum transfer makes vortex chambers potentially interesting for the efficient drying of paddy, allowing shorter drying times and/or more compact equipment. The presence of a shell introduces particular challenges. Intraparticle diffusion limitations are strong and may reduce the advantage from intensified interfacial mass and heat transfer and the efficiency of air usage. Furthermore, high shear and normal stresses in the fast rotating particle bed may cause damage to the paddy shell, posing problems for transport and storage. With these specific aspects in mind, the use of vortex chambers for paddy drying is experimentally evaluated.

The performance of a conventional fluidized bed and a rotating fluidized bed in a static geometry (RFB-SG) for the drying of woody biomass is experimentally studied. The performance with respect to the specific biomass drying rate, product uniformity, and air utilization is evaluated. RFB-SGs are shown to intensify the drying process by easily one order of magnitude, due to a combination of increased gas–solid slip velocities and improved particle bed density and uniformity. The cost in terms of increased and less efficient air utilization can be minimized by optimizing the RFB-SG drying chamber design.