322
A. Strobel et al.
Fig. 8 a Particle size x 50,3 in the milling chamber, b x 50,3 of the discharged product, c product mass
flow rate, d fines residue inside the milling chamber. Data for fed-batch experiments with varying
initial holdups. Adapted from Köninger et al. [29], with kind permission of Elsevier
residence time was calculated by dividing the product mass flow rate by the initial
holdup. From the product mass leaving the mill during 40 min of processing, residence times between ~75 min (100 g) and ~110 min (700 g) can be calculated for
holdups of 100 g and 700 g, respectively. Since the number of impacts strongly correlates with the holdup, the number of impacts increases with increasing residence
time.
Within the first 10 min, coarser product particles leave the mill until the steadystate is reached (Fig. 8b). This time was found for all different holdups. A similar
observation was made for the corresponding mass flow rates. Independent of the continuously changing fluid mechanical behaviour, which is caused by the decreasing
A. Strobel et al.
Fig. 8 a Particle size x 50,3 in the milling chamber, b x 50,3 of the discharged product, c product mass
flow rate, d fines residue inside the milling chamber. Data for fed-batch experiments with varying
initial holdups. Adapted from Köninger et al. [29], with kind permission of Elsevier
residence time was calculated by dividing the product mass flow rate by the initial
holdup. From the product mass leaving the mill during 40 min of processing, residence times between ~75 min (100 g) and ~110 min (700 g) can be calculated for
holdups of 100 g and 700 g, respectively. Since the number of impacts strongly correlates with the holdup, the number of impacts increases with increasing residence
time.
Within the first 10 min, coarser product particles leave the mill until the steadystate is reached (Fig. 8b). This time was found for all different holdups. A similar
observation was made for the corresponding mass flow rates. Independent of the continuously changing fluid mechanical behaviour, which is caused by the decreasing