Hydrodynamic of mixed-feed in circulating fluidized bed

Abstract

The research was conducted in a circulating fluidized bed having diameter and height of riser of 5 and 200 cm., respectively, at ambient temperature and pressure. The objective was to study hydrodynamics of mixed-feed between sand and various biomasses including rice husk, sawdust, and bagasse at 50% by volume. The air flow rate was in the range of 4.2-5.7 m/s. The velocity of sand in the riser was obtained by using a high speed camera and an image processing software. The results showed that at the lowest gas velocity the velocities of sand in the mixture were higher than those in the single system. Howerver at the highest gas velocity it was found that the sand velocity in the mixture of sand and sawdust was the highest among all mixtures. Next the experiment was conducted by means of mixture of glass beads and rice husk. It was found that in the bottom part of the riser the velocities of glass beads in the mixing system were lower than those in the single system. Nevertheless, the velocities of glass beads in both systems reached similar values at the top of the riser.