Model-based control of a partial burn fluid catalytic cracking unit

A dynamic matrix controller (DMC) has been successfully installed on the fluid catalytic cracking reactor/regenerator section at RVI´s Vohburg Refinery in Germany. A very short payback time was achieved based on increased feed processing and more stable regenerator operations (reduced catalyst addition rates). The controller has 6 inputs (manipulated variables) and 13 outputs (controlled variables). The application provides an excellent example of the importance of controlling processes at constraint limits. From the initial day of commissioning, the controller has stayed online and sustained a service factor of between 95% and 98% over an 11 month operating period. The limiting factor at the moment is the performance of the CO analyser. The controller has proved to be robust and operated well with constraints; it has handled disturbances effectively.<>