Modeling and Control of the Open Plate Reactor

Sammanfattning: The focus of this thesis is on modeling and control of the Open Plate Reactor (OPR), a new heat exchange reactor being developed by Alfa Laval AB. It combines intensified mixing with enhanced heat transfer capacity into one operation. With the novel concept, highly exothermic reactions can be produced using more concentrated reactants, thus saving time and energy in the subsequent separation stage. To better utilize the reactor, reactants can be injected in multiple injection points and there are internal sensors for process monitoring and control. A flexible process configuration simplifies the adaptation of the reactor to new reactions in terms of residence time, cooling system, actuator and sensor locations. To take full advantage of the flexible configuration and the improved performance, a new process control system is presented. A nonlinear model of the reactor is derived from first principles. After steady-state and dynamic analyses of the OPR, suitable control variables are chosen to allow flexible and accurate control of the reactor temperature and concentration. A Model Predictive Controller (MPC) is designed to maximize the conversion under hard input and temperature constraints. An extended Kalman filter estimates unmeasured concentrations and parameters, to increase the robustness to process variations. The MPC sends reference signals to local feedback controllers within a cascade control structure. To remove the generated heat from the reaction, a cooling system is designed and experimentally verified. For temperature control, a mid-ranging control technique is implemented to increase the operating range of the hydraulic equipment and to increase the robustness to disturbances. Dynamic simulation and optimization show that the designed control system leads to high conversion and ensures that the temperature inside the reactor does not exceed a pre-defined safety limit.