Controls Strategy and Implementation for Supercritical Water Oxidation Reaction

Due to the complexity of the reaction, waste sanitation using supercritical water oxidation controls requires a high level of strategy and design. A programmable logic controller was constructed using an Allen-Bradley 1756 ControlLogix controller and other industrial control components. This controller was chosen for its robustness and ease of integration with a multifaceted process. The supercritical water oxidation reaction has nearly fifty inputs and multiple outputs that are used to monitor and control the entire process. The responsibility of the control system ranges from process security and safety to adjusting mass flows of critical reaction components in order to reach a stoichiometric reaction balance. The controls system uses a sophisticated series of proportional integral derivative (PID) controllers to adjust the various control parameters such as reactor temperatures and reactant mass flows. Using a PID tuning method known as the Ziegler-Nichols method, the supercritical water oxidation reaction can be tuned and controlled to run as a self-sustaining waste sanitation unit.