Experimental evaluation and modeling of condensate effects in dryer cylinders

Online estimation of the condensate load in dryer cylinders during section starting

“…The total inertia of the dryer cylinders and moving gears ˆc yl J reflected to the motor shaft is obtained from the torque developed during an accelerating ramp [4], [5]. The rotational acceleration can be obtained from the speed signal computed from the motor encoder pulses or, more simply, just using the speed ramp reference (as long as the dryer section does not reach the torque limit).…”

“…According to the results reported by different authors [1], [3], [4], the amount of condensate present during the dryer section starting affects the torque and power demand at the different speeds, as well as the transitions speed to the rimming stage. The proposed on-line estimation algorithm of the condensate load uses both conditions to give adequate warning messages.…”

“…In [4] the authors presented a complete set of experimental evaluations of the condensate profiles in the different stages of the condensate during the accelerating ramps, and using the results reported in [3], developed dimensionless correlations for the calculation of power requirements in the cascading and rimming stages, for cylinders without and with spoiler bars.…”

“…Finally in [5] the authors, using the experimental curves reported in [3] as well as the dimensionless correlations reported in [4], evaluated the effect of different condensate loads on one, two, and all cylinders of a 9-cylinder dryer section. The evaluations corroborated Derrick's statement regarding the effect of 1% of condensate load.…”

Expert System for the Detection of Condensate Accumulation Inside Dryer Cylinders During Section Starting

“…In [3], Timm et al extended the previous work to 1800-mm cylinders, using both plain cylinders and cylinders with spoiler bars. Then, Pereira et al reported a set of experimental power/torque curves obtained in a 380-mm experimental cylinder and covering up to 20% of the condensate accumulation in [4]. Finally, the authors in [5] developed an extensive experimental database using two experimental cylinders of 490-and 600-mm diameters, both without and with spoiler bars, reporting sets of condensate power curves ranging from 0.5% up to 40% of the cylinder volumes (equivalent to 55 mm of the rim thickness).…”