Derivative proportional integral controller for glycerin heating process

Abstract

Temperature control is crucial because a glycerin heating process depends significantly on the heat requirement. An uncontrolled increase in temperature above the operating temperature and excessive prolonged heating can jeopardize the final glycerine's oxidative stability. A glycerine heating process requires an efficient and simple control system to provide a temperature that is gradually increasing without showing significant overshoot and could settle in a reasonable time. Conventional Proportional Integral Derivative (PID) controllers have significant disadvantages in controlling temperature. They contribute to an increase in extreme temperature and a longer settling time to reach the desired temperature. Therefore, the study aims to build an improved temperature control system that can produce fast control signals without overshooting the process. The study focuses on designing the heating process and temperature control system loop using the Derivative Proportional Integral (DPI) controller structure. The heating system operation uses the principle that the crude glycerine is heated using heat transferred from the electrical heater mounted outside the tank. The study covers the development of process input and output relationships based on the experimental step input tests. The DPI controller is designed using the proposed Nelder-Mead optimization algorithm method based on the Integral Absolute Error (ITAE) performance criteria calculated using Simpson's one-third rule. The DPI is a proposed controller which consists of the Proportional and Derivative control actions that operate on process variables rather than error signals and generate fast control signals to drive the process. The analysis was performed by comparing the achievement of the control system criteria and its robustness to input changes with conventional Ziegler-Nichols PID and the newer PID controllers. The results showed that the optimal parameters were successfully achieved using the proposed optimization algorithm. The DPI controller performs well in tracking the input changes with no overshoot in temperature and achieves the fastest settling time of 3867.2 seconds. The developed glycerine heating process system has a great potential for commercialization of the end-product.