Model Based Control of the Circulating Fluidized Bed Boiler

The paper describes Advanced Combustion Control (ACC) system for the circulating fluidized bed (CFB) boilers. ACC is based on the model-based predictive control technology. The CFB boiler dynamics is represented by a non-linear low order model which captures the key CFB boiler behavior. The model exhibits strong cross-interactions between the process variables, therefore the control based on single input single output PID loops is difficult; however, it is shown the CFB boiler can be successfully controlled using the multiple-inputs multiple-outputs (MIMO) model. The bed temperature, boiler power and the oxygen concentration in the flue gas can be controlled simultaneously and independently via the primary and secondary air flows and the fuel supply rate.