Biodiesel Production from Waste Cooking Oil: Plant-Wide Control System Design Using Integrated Framework Approach

Control system design for a complete plant with overall control perspective, is referred to as plant-wide control (PWC). Methodologies for this are of vital importance for safe, smooth and economical operation of plants. Increasing material recycles, energy integrations, product purity requirements and environmental regulations pose tough challenges to the smooth and stable plant operation. In this article, PWC structure is developed for a complete biodiesel plant using waste cooking oil as the raw material. Firstly, two process alternatives are developed and optimized for two objectives using the elitist nondominated sorting genetic algorithm. Then, the better process is determined based on economic and environmental objectives. Later, PWC system is developed, based on an integrated framework of heuristics and simulation (IF), for the chosen process. This method makes effective use of rigorous process simulators and heuristics to aid in decision making while developing a PWC structure. Also, it is simple to apply with minimal computations other than process simulation. Performance of the developed control system is investigated in terms of settling time and deviation from the production target (DPT). The proposed PWC structure is found to be stable and robust in the presence of several expected disturbances.