Modelling the Process of Water Penetration into Softwood Chips
Journal of Pulp and Paper Science
||Chips, Computer programs, Mathematical models, Penetration, Saturation, Softwoods, Water permeability, White liquors
Laboratory of Pulping Technology, Helsinki University of Technology, Vuorimiehentie 1, PL 6300 Espoo, Finland
Boreskov Institute of Catalysis, Russian Academy of Science Pr. Ak. Lavrentieva 5, 630090 Novosibirsk, Russia
A mathematical model was developed for the process of water penetration into softwood chips under isothermal conditions. The model takes into account several important phenomena, including capillary rise, air dissolution and outward diffusion, and the decrease in the permeability coefficient of wood as a function of the chip saturation degree. Based on this model, a computer simulation program was written to obtain quantitative information about the penetration of water into different chips under various process conditions. The program was found to predict accurately the course and final level of water penetration into the chips under defined conditions. The suggested model can be used also for predicting the penetration of white liquor into softwood chips. It cannot be used, however as a general model for predicting the penetration of black liquor.