Modeling And Control Of A Batch Sugar Boiling Process

Crystallization is one of the key steps in the cane sugar processing. And sugar cryatallization with strongly nonlinearity and nonstationarity is a complicated physicochemical process. It is the step that produces the final product which must be monitored very closely as the quality of the final product determines profit. Crystallization occurs by boiling a sugar solution until it becomes oversaturated and crystals grow. Care must be taken not to exceed a critical oversaturation to prevent nucleation of new cyrystals, as these greatly affect the quality of the final product. So oversaturation must be controlled well.Since the crystallization process is complex , a model is required to understand the effect of operating conditions on parameters such as growth rate and crystal size. What's more, the first and maybe the most important step in designing a perfect controller is to develop a model as accurate as possible, which is valid under a wide range of operating conditions.In this paper, a working model for the batch is developed and discussed. And the matlab coding for the working dynamic model of batch vacuum pan has been completed and tested. According to the control characteristic of sugar crystal process, a kind of nonlinear PID controller is designed. From the effect of a series of simulations, the nonlinear PID controller can efficiently achieve to control the oversaturation and help to design the actual auto-control system of sugar crystal process. From the results, we can see the model presented in this paper is validated.