Analytical study on the Heat-Transfer Characteristics of a Fluidized Bed Reactor Heated by Multi-Stage Resistance

A fluidized bed heated by multi-stage resistance heaters was utilized innovatively to realize independent heating of different inside zones. A steady-state physical and mathematical model was developed to study the effect of dense phase, freeboard, fluidized carrier gas on temperature distribution in the fluidized bed. The results showed that compared with the experimental values, the differences between the calculated temperature, heat transfer coefficient and fluid velocity at the outlet of fluidized bed by the model were within 15%, 17%, and 14% respectively, indicating that the model had high reliability. The model inversion illustrated that the heat transfer coefficient at the outlet of the fluidized bed increased gradually in the order of the fluidized carrier gas temperature, dense phase temperature, fluidized carrier gas velocity and freeboard temperature. The heat transfer simulation took the height of the dense phase and the freeboard as the input parameters of the model by hundreds of iteration, the calculated results confirmed again that the existence of particles in the dense phase increased its heat transfer efficiency with the gas and the wall, ultimately making the dense phase as the main heat transfer zone.