Abstract
Infrared dryers, both gas fired and electrically healed, have become a widespread technology in the paper industry. This work proposes a model for the absorption of thermal radiation in the thickness direction of a paper sheet. The model is based on the multilayer idealization of a paper sheet proposed by Scallan and Porch. In this model, the optical properties of paper are considered as the result of multiple reflections and transmission processes between the layers in the paper sheet. Measurements on a number of commercial paper grades indicate that the basis weight per layer is close to 4 g/m(2). The model parameters, the reflectivity and transmissivity of a single layer; have been fitted to experimental literature data for the reflectivity and transmissivity of paper at different wavelengths, basis weights and moisture contents. In Part II of this work, the model will be used to study the absorption of thermal radiation in the thickness direction of a paper sheet during infrared drying.
Original language | English |
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Pages (from-to) | 349-355 |
Journal | Journal of Pulp and Paper Science |
Volume | 24 |
Issue number | 11 |
Publication status | Published - 1998 |
Subject classification (UKÄ)
- Chemical Engineering
Free keywords
- mathematical models
- equations
- infrared radiation
- absorption
- heat
- transfer
- z direction
- paper sheets
- optical properties
- multiply papers