Hydrothermal treatment of C-N-O-H wastes: Model-based reactor effluent control

In this work, we present model-based control and estimation algorithms deve loped to control the effluent composition for a hydrothermal oxidation reac tor. The reactor is used to oxidize the organic compounds present in the hy drolysate solutions obtained from the destruction of HMX-based high explosi ves by base hydrolysis. The objective of the model-based control is to mini mize the total amount of aqueous nitrogen compounds in the effluent of the reactor while maintaining the desired excess oxygen concentration in the re actor to ensure the complete destruction of the organic carbon compounds. A novel aspect of the controller design for this reactor is that the total a queous nitrogen effluent concentration is locally uncontrollable at the des ired optimal operating conditions. The controller uses a plug-flow reactor model with a reduced kinetic model describing the oxidation-reduction react ions in the hydrothermal oxidation reactor. Simulation and reactor implemen tation results are used to verify the closed-loop control algorithm.