Complementary Models for Log Grinding

Pulp for making paper is produced in the groundwood (GW) process from logs. In batch-type GW-machines the control of the log loading is a demanding task because of the complicated log group dynamics where also the heterogeneous wood material has a great influence on the batch behaviour. It is essential to achieve better understanding of the regularities occurring in the process in order to improve the loading control and thus the quality and efficiency of pulp production. For this purpose a numerical model of the complete process has been built up and the dynamic system behaviour has been studied by time domain simulation. In this paper the focus is in the description of the log batch behaviour. Three separate approaches have been adopted to model the batch.