Identification, simulation and control for disturbance rejection in industrial boilers

The Cambria cogeneration plant of Air Products and Chemicals, Inc. utilizes a pair of circulating fluidized bed (CFB) boilers to produce steam for export and energy generation. The plant is subjected to disturbances called sootblows which use steam to clear the built-up ash on the heat transfer surfaces of the convection sections of the boilers. Sootblows impart disturbances to the temperature and pressure of the steam in the main header leading to the steam turbine, resulting in increased variance in the power output of the turbine/generator and additional mechanical stresses on the equipment. An effort was undertaken to dynamically model the effects of the sootblow and to devise a control scheme to eliminate its effects on the main steam pressure and temperature