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Gravitational drainage of compressible organic materials

Authors

  • Morten Lykkegaard Christensen,

    Corresponding author
    1. Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmvej 49 and 57, 9000 Aalborg, Denmark
    • Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmvej 49 and 57, 9000 Aalborg, Denmark
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  • Dominik Marek Dominiak,

    1. Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmvej 49 and 57, 9000 Aalborg, Denmark
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  • Per Halkjær Nielsen,

    1. Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmvej 49 and 57, 9000 Aalborg, Denmark
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  • Kristian Keiding,

    1. Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmvej 49 and 57, 9000 Aalborg, Denmark
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  • Maria Sedin

    1. Dept. of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden
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Abstract

A model was developed to simulate drainage of compressible particle suspensions, and study how cake compression and volumetric load influence the process. The input parameters were settling velocity, cake resistance and compressibility. These parameters were found using a new experimental method. Dextran-MnO2 particle suspensions were drained as these resemble organic waste slurries with respect to settling and compressibility. It was demonstrated that cake compressibility must be taken into account to obtain adequate simulations. This implies that pressurized filtration resistances cannot be used for drainage simulations. In the filtration step, a distinct increase of dry matter from top to bottom of the cake was observed. During the subsequent consolidation, the cake compressed and a uniform dry matter profile was found. The final dry matter content of the cake increased with feed concentration and volumetric load. The drainage time increased proportionally with feed concentration and, more importantly, proportionally with squared volumetric load. © 2010 American Institute of Chemical Engineers AIChE J, 2010

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