Plantwide control of a biodiesel production process with variable feedstock

Abstract

Biodiesel can be obtained from a variety of oils and fats rich in triglycerides. Due to this variability, production processes must be flexible enough to handle different raw materials. This work reports the simulation-based design of a biodiesel production process able to obtain the biofuel from different raw materials. This approach avoids dependence on a single kind of raw material by developing a flexible process. The process is designed to ensure that the product accomplishes the international standard EN 14214 for any of the tested raw materials. A plantwide control structure is then developed to handle the potential variations in feed composition. The controllers’ parameters are tuned, and the control scheme is tested to determine its capability to reach a new steady state in an acceptable period. According to the results, the steady state design allows producing biodiesel from three different raw materials in a single process by only adjusting the operational conditions, obtaining the lowest total annual cost when processing microalgae oil. Moreover, the proposed control strategy allows rejecting the perturbations occurring when the change of raw material occurs, stabilizing after a maximum period of 8 h while maintaining a product still accomplishing the international standard EN 14214.