Fundamental characteristics of combined impingement and through air drying of paper

Authors

  • G. Chen,

    Corresponding author
    1. Department of Chemical Engineering and Pulp and Paper Research Centre, McGill University, Montreal, QC H3A 2A7, Canada
    • Department of Chemical Engineering and Pulp and Paper Research Centre, McGill University, Montreal, QC H3A 2A7, Canada
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    • Department of Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong

  • R. H. Crotogino,

    1. Department of Chemical Engineering and Pulp and Paper Research Centre, McGill University, Montreal, QC H3A 2A7, Canada
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  • W. J. M. Douglas

    1. Department of Chemical Engineering and Pulp and Paper Research Centre, McGill University, Montreal, QC H3A 2A7, Canada
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Abstract

An experimental facility was developed to determine fundamental characteristics of combined impingement and through air drying of paper. Removal of impingement boundary layer humidity by through flow makes both components of the combined process nonadiabatic, complicating the analysis. Water removal rate curves for both the impingement exhaust and the through flow exhaust are strikingly different from pure impingement and pure through drying rate curves, with the through flow water removal rate curve having at times a unique, secondary increasing rate period. Total drying rate is enhanced substantially by removal of a small fraction of the drying air as through flow exhaust.

Abstract

On a mis au point un systèrme expérimental afin de déterminer les caractéristiques fondamentales du séchage du papier combiné par contact et à air traversant. Le retrait de l'humiditee de la couche limite de contact par le débit traversant rend les deux composantes du procédé combiné non adiabatique, ce qui complique l'analyse. Les courbes de vitesse de retrait de I'eau pour le séchage par contact et le séchage par air traversant sont étonnement différentes des courbes de vitesse de chacun des mecanismes pris isolement; la courbe de vitesse de retrait de l'eau posédant parfois une période de croissance secondaire unique. Le taux de séchage total est substantiellement renforcé par une légerè diminution de l'air de séchage dans le débit traversant.

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