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Residence time distribution in spouted bed drying of maltodextrin solutions on a bed of inert particles

Authors

  • Guillermo Osorio-Revilla,

    Corresponding author
    1. Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas del IPN, Prolongación de Carpio y Plan de Ayala, 11340 México, DF, Mexico
    • Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas del IPN, Prolongación de Carpio y Plan de Ayala, 11340 México, DF, Mexico.
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  • Tzayhri Gallardo-Velázquez,

    1. Departamento de Biofísica, Escuela Nacional de Ciencias Biológicas del IPN, Prolongación de Carpio y Plan de Ayala, 11340 México, DF, Mexico
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  • Arturo Ramírez-Torres,

    1. Departamento de Graduados e Investigación en Alimentos, Escuela Nacional de Ciencias Biológicas del IPN, Prolongación de Carpio y Plan de Ayala, 11340 México, DF, Mexico
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  • Yadira Rivera-Espinoza

    1. Departamento de Graduados e Investigación en Alimentos, Escuela Nacional de Ciencias Biológicas del IPN, Prolongación de Carpio y Plan de Ayala, 11340 México, DF, Mexico
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Abstract

Residence time distributions (RTD) for aqueous maltodextrin solutions were determined in two kinds of spouted bed dryers: (1) conventional spouted bed (CSB) 0.305 m diameter with a bed of polypropylene beads and (2) spout-fluid bed 0.143 m diameter with draft tube submerged in a bed of FEP® pellets (S-FBDT). RTD, mean residence time tm, and spread of the distribution σ2, were determined at different drying temperatures, spouting velocities, bed depths, spraying pressures, and feed concentrations. Average values of tm and σ2 were 6.5 min and 26.6 min2 for the CSB and 6.9 min and 36 min2 for the S-FBDT, respectively, for all operating conditions except spraying pressure. RTD curves were well represented by the response of an ideal stirred tank with a superimposed bypass of 15% on average for the CSB and 7% on average for the S-FBDT dryer for all operating conditions. Increase in spraying pressure produced a reduction of tm and an increase in the bypass fraction of the product in both dryers. © 2011 Canadian Society for Chemical Engineering

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