Modeling and countermeasures of combustion characteristics of char particles in CFBC

A mathematical model of single char particle combustion in circulating fluidized bed combustor (CFBC) is developed in this paper. Its numerical solution in operating conditions of CFBC verifies the nature of a phenomenon that the distribution of carbon content of char particles has a peak value versus their diameters. The results show that the temperature of smaller char particle is close to the bed temperature, and there also exits a peak value for the burn-out time of char particles versus their diameters. The countermeasures are presented to improve combustion of fine particles, such as use of the fly-ash recirculation, the hot cyclone, and so on.