Trennung der Einflüsse von Material und Maschine bei der Prallzerkleinerung: Modellierung mit Populationsbilanzen

A systematic approach to the simulation of comminution in rotor impact mills is described. The subprocesses comminution, classification and transport that take place in the mill are modelled separately. Attention is focussed on making a clear distinction between material and operating parameters in order to investigate their influence on the comminution performance separately. The increase in fineness is described by the breakage probability and breakage function, which are determined in single-particle tests independent of mill-specific boundary conditions. Classification is implemented by the separation efficiency, which is variable in respect of cut-point and separation sharpness. The hold-up in the mill is regarded as ideally intermixed. For verification of the simulation results, tests were performed with two mills (an air classifier and a sieve hammer mill) on plant scale. Very good agreement between the test and the simulation results was achieved while a clear distinction between material- and mill-specific parameters was maintained. The free model parameter demonstrates systematic trends with the operating parameters and can be interpreted as the stress frequency.