Construction of an Analytical Model of Paper Drying

A theoretical model developed is presented to simulate the paper drying process on a production paper machine. The paper sheet is represented as a matrix of pulpfibres which contains free and bound water, water vapour and air. The model is heavily dependent upon a wide range of physical data including pore size distribution, permeability, sorptive characteristics, thermal conductivity, specific heat capacity, density, diffusion coefficients and shrinkage characteristics as well as heat and mass transfer behaviour at the interfaces. Theoretical relationships to describe these parameters in terms of the physical pore structure are developed and compared with published data. The model was compared against actual measurements on the Australian Newsprint Mills Boyer PM3 newsprint machine. The comparison with actual machine moisture content values showed the model prediction of moisture change during drying to cylinder No. 38 on PM3 to be 2% less than actual and 0.1% more than actual by the exit from the drying cylinder. In terms of predicting thermal energy consumption of the paper machine a 91% correlation was obtained. | A theoretical model developed is presented to simulate the paper drying process on a production paper machine. The paper sheet is represented as a matrix of pulpfibres which contains free and bound water, water vapour and air. The model is heavily dependent upon a wide range of physical data including pore size distribution, permeability, sorptive characteristics, thermal conductivity, specific heat capacity, density, diffusion coefficients and shrinkage characteristics as well as heat and mass transfer behaviour at the interfaces. Theoretical relationships to describe these parameters in terms of the physical pore structure are developed and compared with published data. The model was compared against actual measurements on the Australian Newsprint Mills Boyer PM3 newsprint machine. The comparison with actual machine moisture content values showed the model prediction of moisture change during drying to cylinder No. 38 on PM3 to be 2% less than actual and 0.1% more than actual by the exit from the drying cylinder. In terms of predicting thermal energy consumption of the paper machine a 91% correlation was obtained.