Dynamics and Servo Control of Biodiesel Purity from a Reactive Distillation Process

This research work has been carried out to study the dynamics and apply some techniques to perform set-point tracking (servo) control on the purity of biodiesel obtained from a reactive distillation process via the esterification reaction between palmitic acid and methanol reported in the work of Giwa et al. (2015). The model used for the study of the system was developed with the aid of System Identification Toolbox of MATLAB as a first order transfer function. The input variable of the process model was the reboiler duty of the column while its output variable was the mole fraction of biodiesel obtained from the bottom section of the reactive distillation column of the process. The open loop simulation of the developed model revealed that the system was a stable one because its response could attain a steady state when simulated. Furthermore, the closed loop responses obtained from the simulations of the process using proportional (P) , proportional-integral (PI) and proportional-integral-derivative (PID) controllers tuned with Cohen-Coon and Ziegler-Nichols techniques showed that the best controller for the system was PID controller tuned with Ziegler-Nichols method because, apart from the graphical comparisons made among the various controllers and techniques, the integral absolute error (IAE) and the integral squared error (ISE) of that combination (PID controller tuned with Ziegler Nichols technique) were found to be the lowest, implying that that was the best for the process considere