MODELING OF THE AGE DISTRIBUTION OF FIBER S IN RECYCLING SYSTEMS

One of the most significant prerequisites to the qualitative character ization of waste paper and of paper based on waste paper is the age di stribution of recycled fibres. Since the l970s waste paper modelling h as aimed at a statistical approach for the calculating of the age dist ribution of fibre mixtures affected by several parameters, such as was te paper utilization ratio, number and grade of waste paper components and the share of individual waste paper components. It is common to u tilize more than one waste paper component for the manufacturing of pa per and board. Considering this, the development of a common model is necessary in order to calculate the age distribution of recycled fibre s.The model presented in this paper enables the assessment of the frac tions of waste paper and the number of cycles fibres have passed recyc ling systems. This model takes any number of waste paper components in to account, the filler content of waste paper components as well as th e yield of recycled fibres affected by stock preparation. Furthermore, a new parameter called ''average fibre age'' is discussed, which char acterises the ''state'' of recycling systems.