IDENTIFICATION OF RESIDENCE TIMES IN CONVENTIONAL CONTINUOUS KRAFT COOKING

Industrial kraft cooking process producing both softwood and hardwood pulp was studied. Residence times of chips in the conventional continuous digester were modelled based on volume fractions of chips. The volume fractions were modelled as a function of a real-time modelled cooking degree profile of chips in the digester. Control of continuous cooking process can be improved by the more accurate information about the residence times.