In this study, a program was developed to describe the devolatilization of polymer particles in a mini-plant purge column. The model is based on a material balance around the purge column and utilizes a finite difference method to calculate the devolatilization of spherical particles. A user friendly Excel to FORTRAN interface was programmed, which permits the user to enter all necessary parameters within Excel and to receive the calculation results automatically within Excel. A lock hopper sequencing was successfully incorporated to simulate a moving particle bed. Furthermore, the program calculates the vent gas concentration, which is needed for optimization of the vent gas treatment. Lab scale experiments are conducted to verify the model.