LAUSR

Abstract In the process of fluidized bed combustion, the particle-convective component ( h pc ) can evidently affect the overall heat transfer coefficient ( h o ). Therefore, a vigorous mixing of fuel that enhances heat transfer is required. The use of an inclined slotted distributor (IS distributor) is a promising technique to improve the gas-particles contact and particle dispersion. In the present study, experiments were carried out in a fluidized bed equipped with an IS distributor, and the surface-renewal theory was used to investigate the heat transfer between an immersed surface of moving lignite and small particles. The effects of excess gas velocity ( U e ), immersed surface diameter ( d I ), and small particle size ( d p ) on h o were discussed, and a comparison with the conventional fluidized bed was made. The test results confirm that the use of a bed equipped with an IS distributor is effective to enhance the heat transfer performance when compared to a conventional bed. Based on the test results obtained at U mf and different U e , the parameters of the surface-renewal theory were determined, and the correlations were established for predicting h o . A good agreement between the predictions and test results could be achieved when the radiative component ( h r ) is negligible.