The heat-transfer performance of gas—solid trickle flow over a regularly stacked packing

The heat-transfer behaviour of a countercurrent gas—solid trickle flow contactor is studied, using coarse sand particles as the solids phase. Experimental data on the overall heat-transfer rate constant between the gas flow and the solid particle flow were obtained in a 0.15 m square cross-section column packed with regularly stacked packing elements specially developed for dilute countercurrent gas—solid contactors. Pressure drop over these packings is low, while countercurrent heat-transfer properties are remarkable; for 0.5 m of packing, the number of transfer units may amount to about 2 to 4, depending on the gas and solids mass flow rates and the packing construction used. Therefore, the present contactor might be attractive for application as a heat exchanger. The pressure drop caused by the solids flow and the heat-transfer rate constant show very similar behaviour and at low solids mass fluxes their values agree with the data obtained from the single-particle flow model described in a previous paper [1]. Heat-transfer behaviour is described reasonably well by a model based on single-particle flow and by incorporating the effect of particle agglomeration at higher solids fluxes