[Zurück]

A. Schuster, M. Kozek, B. Voglauer, A. Voigt:
"Grey-Box Modelling of a Viscose-Fibre Drying Process";
Mathematical and Computer Modelling of Dynamical Systems (eingeladen), 18 (2012), 3; S. 307 - 325.

A dynamic model of a Through-Air-Drying process for viscose staple fibres is presented. In
this process fibres formed to a porous web are transported through a convective dryer which
consists of numerous rotating drum sieves. Finally, the fibres pass through two remoistening
drums. The structure of the model is modular and scalable. Applying spatial discretisation
the originally partial differential system equations (conservation of mass and energy) turn
into a system of ordinary differential equations. Drying rates and heat transfer rates are
calculated using phenomenological equations for heat and mass transfer. Kinetics of drying
are separated into three stages, where viscose fibres are hygroscopic. The process model is
able to simulate transient behaviour of the dryer like changes of the incoming fibre moisture,
changes of the drying air temperature and humidity, and changes of the thickness of the
fibre layer on the drums. Stationary validation of the longitudinal fibre moisture distribution
along the dryer show good accordance with measurement data at different operating points
e.g. different temperature profiles. Dynamic data like temperature transients are utilised for
both model fitting and validation of the dynamic model. For the remoistening process and
disturbance behaviour concerning the thickness of the fibre web, black box models have been
identified. Results of a successful application of the model in a predictive control algorithm
are shown.

through-air drying; drying kinetics; cellulosic fibres; physical modelling; dynamic model; model validation

http://dx.doi.org/10.1080/13873954.2012.662777