Surge tank control in a cane raw sugar factory

The control problem that is addressed in this paper is the minimisation of the rate of change of the secondary mixed juice flow in a cane raw sugar factory. This is a particularly important problem since the clarifier´s efficiency is reduced by rapid flow rate variations with the ultimate result being a reduction in raw sugar quality. Previous techniques, which did not result in sufficiently high levels of performance, involved some form of feedback level control on each of the two surge tanks that precede the clarifier. The new solution that we present in this paper involves using feedforward techniques to control the existing surge tanks so that the available capacity is used in an efficient way. The new control scheme was implemented on existing hardware and achieved the desired level of performance