Heat Transfer Coefficients in Air-Solid Fluidized Bed Using Vertical Heating Element

Abstract

In various chemical industrial applications such as hydrocracking, drying, and Fischer-Tropsch, the utilization of fluidized bed systems is prevalent. Efficient heat transfer is crucial for maintaining stable temperatures and ensuring product quality in industrial processes. Gas-solid fluidized beds, which involve gas circulation through a bed of solid particles, offer a means to achieve efficient heat exchange. However, factors such as particle size, gas velocity, and heating methods can influence the effectiveness of these systems. To investigate the impact of internal heating on heat transfer in gas-solid fluidized beds, an experimental study was conducted using glass beads of 200 and 600 μm. A Perspex fluidization column with an inner diameter of 10 cm and a total height of 2 m was packed with these beads. The experiments were performed under superficial gas velocities ranging from 0.1 to 0.5 m/s. Highly responsive sensors were employed to measure temperatures and calculate the heat transfer coefficient. Additionally, the position of the heating element and local heat transfer coefficients at different gas velocities were examined. The experimental results were compared to a mathematical model developed to simulate laboratory findings. The total heat transfer coefficient was evaluated in a gas-solid fluidized bed at different bed temperatures. Furthermore, a comparison was made between the experimental results and the model to validate the practical application, while the practical results were also compared with previous studies.

Keywords

• fluidized bed
• heat transfer coefficient model glass beads
• minimum fluidized bed
• vertical heating element