Dispersion model for level control of bubbling fluidized beds with particle cross-flow

Abstract

A fluidized bed with a large, continuous horizontal flow of particles (cross-flow) can lead to a sloped bed level, leaving a heat exchanger immersed in the fluidized bed covered by different amounts of particles. This facilitates particles bypassing the heat exchanger, thereby reducing its efficiency. Pressurized zones can be utilized to control the bed level along the particles' horizontal path, achieving a more even distribution of particles across the heat exchanger. Designing this level control system requires a physical model of the particle flow that accounts for the impact of pressurized zones, for which a new particle dispersion model was developed in this study. Dynamic simulations and experiments on a test rig were used to calibrate and validate the new particle dispersion model. The model was able to correctly predict the dynamic behavior of bed levels influenced by pressurized zones within a few millimeters. This model can be used to design and analyze a fluidized bed level control system. Further research on additional influencing factors of particle dispersion, in particular the heat exchanger's configuration, is still required to achieve general applicability of the new particle dispersion model.