Nanopowders are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process nanoparticles. However, nanoparticles cannot be fluidized individually; they fluidize as very porous agglomerates. Often, it is needed to apply an assisting method, such as vibration or microjets, to obtain proper fluidization. I...

The particle pressure is the surface force that is exerted due to the motion of particles and their interactions. This paper describes measurements of the particle pressure exerted on the sidewall of a gas-fluidized bed. As long as the bed remains in a packed state, the particle pressure decreases with increasing gas velocity as progressively more of the bed is supported by fluid forces. It app...

Melosh [1996] has suggested that acoustic fluidization could provide an alternative to theories that are invoked as explanations for why some faults appear to be weak. We show that there is a subtle but profound inconsistency in the theory that unfortunately invalidates the results. We propose possible remedies but must acknowledge that the relevance of acoustic fluidization remains an open que...

Fluidization of non-spherical particles is widely practised in chemical engineering processes. In this work, the mixing and dispersion behaviours a bubbling fluidized bed (BFB) are explored by computational fluid dynamics-discrete element method (CFD-DEM) featuring super-quadric model to describe particle morphology. After validation, general flow patterns, solid mixing, ellipsoid studied, toge...

The fluidization of certain biomasses used in thermal processes, such as sawdust, is particularly difficult due to their irregular shapes, varied sizes, and low densities, causing high minimum velocities (Umf). addition an inert material causes its Umf drop significantly. determination the binary mixture however hard obtain. Generally, predictive correlations are based on a small number specifi...

Fluidized beds can be used to gasify biomass in the production of producer gas, a flammable gas that can replace natural gas in process heating. Modeling these reactors with computational fluid dynamics (CFD) simulations is advantageous when performing parametric studies for design and scale-up. From a computational resource point of view, two-dimensional simulations are easier to perform than ...

A mathematical model for the fluidization of polydisperse suspensions is developed. The stationary concentration configurations for a given fluidizing velocity are analyzed and a mixing condition for bed inversion is derived. A central finite difference scheme is applied to the simulation of the fluidization of a bidisperse suspension. The numerical simulations agree with the experimentally rep...

Fluidized bed has many advantages such as high heat and mass transfer rates, temperature homogeneity and good mixing property. However, conventional fluidized bed has some limitations; operation at high gas velocity leads to slugging and there exists minimum particle size for the uniform fluidization. Recently, a rotating fluidized bed (RFB) has attracted special interest, since it has a possib...