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Title: Mathematical model of steam drying of wood chips and other hygroscopic porous media

Abstract

A model is presented that is focused on the drying kinetics of single wood chips as a function of time and external conditions, such as temperature, pressure and velocity of the superheated steam. A multiphase and 2-D approach was used to model the coupled transport of water, vapor, air and heat in anisotropic hygroscopic porous media. The model was verified by drying experiments where measurements of the average moisture content, center temperature and pressure in a single wood chip could be performed simultaneously. A comparison between the calculations and the measurements showed that the drying behavior was well predicted. The drying can be divided into three stages: a heat-up period when condensation on the surface initially increases the moisture content; a period of constant drying rate when the external heat transfer controls the drying rate; and a period of decreasing drying rate when the drying is controlled by internal mass transfer. Many interesting features of the drying could be assigned to the strong anisotropicity of wood, which makes a 2-D model necessary.

Authors:
;  [1]
  1. Chalmers Univ. of Technology, Gothenburg (Sweden). Dept. of Chemical Engineering Design
Publication Date:
OSTI Identifier:
378000
Resource Type:
Journal Article
Journal Name:
AIChE Journal
Additional Journal Information:
Journal Volume: 42; Journal Issue: 9; Other Information: PBD: Sep 1996
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; WOOD WASTES; DRYING; MATHEMATICAL MODELS; PARAMETRIC ANALYSIS; WATER VAPOR; MASS TRANSFER; HEAT TRANSFER; POROUS MATERIALS; TWO-DIMENSIONAL CALCULATIONS; SOLID FUELS; ENVIRONMENTAL IMPACTS; AIR QUALITY

Citation Formats

Fyhr, C, and Rasmuson, A. Mathematical model of steam drying of wood chips and other hygroscopic porous media. United States: N. p., 1996. Web. doi:10.1002/aic.690420909.
Fyhr, C, & Rasmuson, A. Mathematical model of steam drying of wood chips and other hygroscopic porous media. United States. https://doi.org/10.1002/aic.690420909
Fyhr, C, and Rasmuson, A. 1996. "Mathematical model of steam drying of wood chips and other hygroscopic porous media". United States. https://doi.org/10.1002/aic.690420909.
@article{osti_378000,
title = {Mathematical model of steam drying of wood chips and other hygroscopic porous media},
author = {Fyhr, C and Rasmuson, A},
abstractNote = {A model is presented that is focused on the drying kinetics of single wood chips as a function of time and external conditions, such as temperature, pressure and velocity of the superheated steam. A multiphase and 2-D approach was used to model the coupled transport of water, vapor, air and heat in anisotropic hygroscopic porous media. The model was verified by drying experiments where measurements of the average moisture content, center temperature and pressure in a single wood chip could be performed simultaneously. A comparison between the calculations and the measurements showed that the drying behavior was well predicted. The drying can be divided into three stages: a heat-up period when condensation on the surface initially increases the moisture content; a period of constant drying rate when the external heat transfer controls the drying rate; and a period of decreasing drying rate when the drying is controlled by internal mass transfer. Many interesting features of the drying could be assigned to the strong anisotropicity of wood, which makes a 2-D model necessary.},
doi = {10.1002/aic.690420909},
url = {https://www.osti.gov/biblio/378000}, journal = {AIChE Journal},
number = 9,
volume = 42,
place = {United States},
year = {Sun Sep 01 00:00:00 EDT 1996},
month = {Sun Sep 01 00:00:00 EDT 1996}
}