The purpose of the air distribution system in a fluidised bed combustor is to provide a reasonably uniform spread of combustion air over the entire horizontal cross-sectional area of the bed. One of the simplest, and hence cheapest, forms of air distributor is the sparge pipe design, in which an array of horizontal pipes is fitted at the base of the bed. Combustion air is then supplied to one end of each pipe and is subsequently distributed to the bed through a series of downward facing holes. The paper describes the development of an improved sparge pipe system for a large coal fired fluidised bed producing hot combustion gases for drying of pressed sugar beet pulp. The air flow out of the holes varied by a factor of three along the length of the pipes with the existing system and in addition the overall flow and hence the thermal output of the bed was unduly restricted. Excessive erosion of the pipe walls near some of the holes was also a problem. A computational fluid dynamics (CFD...
D. R. Garwood, J. Ward, D. R. Bowen, M. Fisher, D.