Mathematical modeling and model-based optimum control of circulating fluidized bed combustors

Abstract

A comprehensive mathematical model of circulating fluidized bed combustors was set up and verified by measurements carried out on a 300 MW industrial boiler. The one-dimensional cell model structure was used, and equations describing the dynamics of coal combustion, gas-gas reactions, fluid dynamics of the suspension and heat transfer were implemented. Partitioning the combustion chamber into only nine cells according to the geometrical characteristics of the technology plus an empirical cyclone temperature model was found to fulfill both requirements regarding accuracy and low computational demand. The later one is a key for its applicability in the area of controller design. Based on the available model, and considering the characteristics of this technology differing definitely from those of conventional combustors, a new optimum control strategy was proposed, modeled and tested successfully.