Minimum spouting velocity for conical spouted beds of vegetable waste biomasses

• Spouted beds of different geometry have been used and their hydrodynamic behaviour has been analysed without draft-tube and with nonporous and open sided draft-tubes.
• Five types of biomasses representative of agro-forest exploitation and agro-industrial wastes have been assayed.
• Two fitting strategies have been used, with coefficients being introduced one by one and their significance analysed based on hypothesis testing.
• New correlations have been proposed for the three configurations studied based on existing ones in the literature and modifying the minimum number of coefficients.

Spouted beds are an interesting alternative for the treatment of biomass for energy purposes, given that the insertion of a draft-tube allows large-scale handling of solids with a wide range of sizes and diverse properties. The hydrodynamic correlations proposed in the literature have not been validated with particles of low density and shape factor. Therefore, a detailed experimental study has been conducted using five types of biomasses and different combinations of the contactor geometric factors. The correlations in the literature for plain conical spouted beds and for those provided with nonporous and open-sided draft-tubes have been taken as a starting point and, based on the experimental results, they have been modified in order to account for the properties of the solids. Two strategies have been considered in the methodology for modifying the coefficients in the literature correlations. Both are based on the introduction of coefficients one by one based on a hypothesis test. Accordingly, new correlations based on existing ones have been proposed, with the number of coefficients modified being minimum.

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