Fluid dynamic analysis for pyrolysis of macadamia shell in a conical spouted bed

• Fluid dynamics of a mixture of sand and macadamia shell in a spouted bed was studied.
• Different mass fractions and static bed heights were investigated.
• The axial profile of particle segregation was assessed.
• Correlations for the predictions of the minimum spouting conditions were proposed.
• It was found acceptable levels of segregation for pyrolysis of biomass.

The pyrolysis is an important technology for generating energy from agro-industrial wastes. The processing of macadamia nut generates a lot of shell residues. In literature, the conical spouted bed has been pointed out as a promising air-solid contact system for pyrolysis process. Due to low density of biomass and their poor flowability, sand is added to improve the fluid-dynamic stability of the spouted bed. This research aims to experimentally investigate the fluid dynamics of a mixture of sand and macadamia shell in a conical spouted bed, with different mass fractions and static bed heights. The particles exhibited good circulation in the bed for mass fractions of 25 to 75%, with acceptable levels of segregation for pyrolysis process. Moreover, correlations have been proposed for the calculation of the minimum spouting air velocity and pressure drop in conical spouted beds made up of mixtures of macadamia shell and sand.

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