Surge tank control in a cane raw sugar factory

The perfonnance of the juice circuit in a cane raw sugar factory is critical to the production of high quality sugar, and hence its saleability on the international market. In this paper, we present a control project that deals with this aspect of the raw sugar production process. The problem that is addressed is to control surge tanks within the juice circuit in order to steady the flow (minimisation of the rate of change) into a settling vessel known as the clarifier. This is a particularly important problem since the clarifierʹs efficiency is reduced by rapid flow rate variations with the ultimate result being a reduction in raw sugar quality due to increased extraneous matter in the sugar. The new solution involves using gain-scheduled 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 perfonnance.