Temperature influence on minimum fluidization velocity: Complexity, mechanism, and solutions

Abstract

Fluidized-bed reactors are widely employed in various high-temperature industrial processes. Thus, it is crucial to understand the temperature effect on various fluidization phenomena, specifically the minimum fluidization velocity (Umf) that governs various aspects of fluidized bed behavior. In this study, we comprehensively analyze Umf data from the literature to unravel the complexity and underlying mechanisms of temperature influence on this critical velocity. The research examines experimental data encompassing a wide range of temperatures, pressures, and solid particles. The analysis reveals that the influence of temperature on Umf is fundamentally determined by the relative importance of hydrodynamic forces and interparticle forces within fluidized beds and is realized by three distinctive temperature-induced changes: gas properties, bed voidage, and physiochemical characteristics of particles. On this basis, an equation is derived to enable predictions of temperature influences on the minimum fluidization velocity under broad temperature conditions.