Optimizing the performance of rotary sugar driers through modelling and control.

摘要

A steady-state mathematical model of a rotary sugar drier was developed. The model comprises 2 parts: a mass/energy model; and a model for bulk sugar transport through the drum. The model was expanded and incorporated into a control strategy trialled at 2 sugar factories using a feed forward system. The approach took into account changing moisture content of sugar in the drier and inlet air flow conditions in order to achieve correct moisture and temp. specification for dry sugar based on a series of drier model predictions while operating in real time in the background. Model-based control was satisfactorily applied to control of sugar moisture and temp. while minimizing formation of sugar dust. Evening out of short- and long-term term fluctuations in sugar flow was necessary in order to achieve acceptable control and comply with quality parameters for dry sugar. A drier information system was also developed as part of the control package to assist factory personnel (supervisors and operators) to define appropriate operating conditions for the drier station. [This paper is based on a communication initially presented at the XXVI Congress of the International Society of Sugar Cane Technologies held in Durban, South Africa on 29 Jul.-2 Aug. 2007.]