Mathematical modeling of brown stock washing problems and their numerical solution using MATLAB

The mechanism of the displacement washing of the bed of pulp fibers is mathematically modeled by the basic material balance equation. Non-linear Langmuir type adsorption isotherm is used to describe the relationship between the concentration of the solute in the liquor and concentration of the solute on the fibers. In the present study, the numerical solutions are obtained of the displacement washing model for multistage in counter current manner. For the numerical solution “pdepe” solver in MATLAB is applied on the axial domain of the system of governing partial differential equations. Numerical solutions thus obtained are in good agreement with the results of earlier workers. The technique used in the present investigation is simple, elegant and convenient for solving two point boundary value problems with varying range of parameters.