Master of Science in Chemical Engineering (MSChE)
Crystallization is an old unit operation in the industry which is widely used as a separation process due to its ability to produce highly valued chemical with high purity. Despite the long history of batch crystallization, industry still relies on rule of- thumb techniques for their crystallization processes. Thus, any method to improve the products characteristics such as size and morphology will be highly valued. Advances in robustness and accuracy of automated in situ sensors give the possibility to move towards an engineering based approach by implementing the real-time monitoring and control of the process. The research undertaken here investigates the development of an advanced framework for the operation of crystallization processes. This project builds upon the synergy among the research teams at LSU and at the University of Cagliari. The proposed methodology comprises of exploiting an advanced model to simulate the process, On-line implementation of the image-based approach within a feedback loop in a completely automated feedback fashion and implementation of model-free control technology. In situ measurement of crystals’ size distribution by using image-based technique and wavelet-fractal algorithm is implemented in a real-time environment for inferring the particles characteristics captured at different time of the experiment. This technique is becoming increasingly more attractive due to availability of high speed imaging devices and powerful computers at reasonable costs and the adaptability to real time application. The process is modelled by means of a stochastic approach. This is an alternative method to the traditional population balance which leads to a more straightforward model that can be solved analytically and obtain the CSD over time. The simplicity of the model gives the possibility to properly implement an automatic control strategy.
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Ghadipasha, Navid, "A Model-based Framework to Control the Crystal Size Distribution" (2015). LSU Master's Theses. 4237.