Heater surface coating effect on fluidized bed heat transfer coefficient

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The effect of different coatings painted on the heat transfer surface of the horizontal heater in a vertical fluidized bed heat transfer unit is studied. Polyurethane and polyurethane based zinc coatings are applied on the horizontal heat transfer surfaces and their effects on the heat transfer coefficient are investigated for different heater heights, different heater heat inputs and for different superficial velocities. It is found that the application of polyurethane coatings has decreased the heat transfer coefficient as compared to the heat transfer coefficient obtained with the bare uncoated heater. It is also found that by applying the polyurethane based zinc coatings the heat transfer coefficient has increased as compared to that obtained with the polyurethane coating. Procedure and the results of the experiments done to study this fluidized bed heat transfer analysis are presented in this paper.