Modeling of a fluidized bed combustor with immersed tubes. Quarterly report, December 1977--February 1978

Abstract

A mathematical model of a fluidized-bed combustor will be developed which will include coal combustion phenomena and incorporate basic mass transport relationships, bubble mechanics, heat transfer and configuration effects. A cold model test bed will be designed, constructed and operated to generate data in support of the effort in developing the mathematical model. In particular, experiments will provide data concerning heat transfer effects of tubes and tube bundles in fluidized beds, bubble formation, dispersion etc. In work to date, the analytical expressions for conversion-time relationship have been developed for multiple gas-solid reactions taking place on a single particle using results derived earlier for a single gas-solid reaction. The formulation has been developed for independent, parallel and consecutive reactions. The effect of changing particle size on conversion-time characteristics as the reaction proceeds has been emphasized. The fabrication and assembly of the fluidized bed reactor has been completed. An experimental arrangement to determine the bed-to-tube overall heat transfer coefficient has been installed. A preliminary experiment to investigate the temperature distribution in the axial and circumferential directions of the horizontal tube has been performed. A review of the literature dealing with heat transfer in fluidized bed equipped with horizontal tubes has been initiated.more » (auth)« less