Woranee Paengjuntuek

Neural network-based optimal control of a batch crystallizer

In batch crystallization, the control of size and shape distributions of crystal product is known to be a difficult and challenging task. Although various model-based control strategies have been widely implemented, the effectiveness of such the control strategies depends heavily on the exact knowledge of crystallization of which the dynamic behavior is complicated and highly nonlinear. In this study, a neural network-based optimal control was proposed to regulate the batch crystallization of potassium sulfate chosen as a case study. A neural network model of the batch crystallizer was first developed to capture the nonlinear dynamics of crystallization in terms of the solution concentration within the batch crystallizer and the moment variables that relate to a crystal product quality over a prediction horizon. Then, the developed neural network model was incorporated in an optimal control framework to find an optimal operating temperature profile for improving the quality of the crystal product. The simulation results showed that the neural network can predict the final product properties and the optimal control integrated with the developed neural network gives a better control performance compared to a conventional linear cooling control technique.

Heat-integrated reactive distillation for biodiesel production from Jatropha oil

Abstract Minimizing the biodiesel production cost by using inexpensive and inedible feedstock like Jatropha oil is more practical as it is readily available and also not competes with edible oils. However, Jatropha oil contains high free fatty acid content, which causes operational problems in biodiesel production via alkaline-based transesterification reaction. This study aims to design a biodiesel production process from Jatropha oil. A hydrolysis reactor is applied to convert triglyceride in Jatropha oil to fatty acid. The fatty acid obtained then reacts with methanol to produce methyl ester (biodiesel product) using an esterification process. A reactive distillation is employed to intensify reaction and separation tasks for the esterification process. In order to minimize energy consumption, the heat integration of a reactive distillation process is considered. The simulation result using a flowsheet simulator indicates that the heat-integrated reactive distillation can improve the biodiesel production by minimizing the energy requirements, compared with a conventional process.