in this study, a laboratory scale continuous plug flow fluidized bed dryer was designed and constructed. a backward-curved centrifugal fan with a 4 kw electromotor was selected based on the maximum pressure drop in the minimum fluidization state and the ability to produce the velocity required for fluidization of the most granular agricultural materials. the fluidization chamber was a rectangul...

The fluidization behavior of silica gel was tested in a fluidized bed under different sound pressure levels and sound frequencies. It has been found that the particle mixtures can be fluidized smoothly with sound assistance at low sound frequency owing to the sound energy disrupting large size of agglomerates. The minimum fluidization velocity was found to decrease with increasing sound frequen...

............................................................................................................................. xi CHAPTER 1: INTRODUCTION ................................................................................................ 1 1.1 Motivation ............................................................................................................................. 1 1....

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...

In this study hydrodynamics of a fluidized bed reactor with fumed silica nano particles was modeled using CFD method. Hydrodynamics parameters such as gas and solid velocity and void fraction have been investigated. The minimum fluidization velocity was around 0.0115 m/s at solids volume fraction of 0.0077. Fluidization process was involving a high expansion ratio of bed and without large bubbl...

The present work is focused on the study of fluidization behaviour of biomass and sand mixtures in a laboratory scale test set up. The biomass materials used during the experimentation were rice husk, bagasse and sawdust. Two different particle sizes of silica sands were used in forming the mixture. The percentages of biomass in the mixtures were 2%, 5%, 10% and 15% by weight. The minimum fluid...

We report on the fluidization dynamics of an attractive gel composed of non-Brownian particles made of fused silica colloids. Extensive rheology coupled to ultrasonic velocimetry allows us to characterize the global stress response together with the local dynamics of the gel during shear startup experiments. In practice, after being rejuvenated by a preshear, the gel is left to age for a time t...

Hydrogen-based direct reduction of iron oxide powder in gas-fluidized beds has become an emerging technology. Agglomeration fine at elevated temperatures is however one key issue hindering the technological development. To obtain better knowledge high-temperature agglomeration mechanism, (de-)fluidization behavior micron-sized combusted particles experimentally studied this Part I. Effects vari...

Fluidization of initially segregated binary mixtures has been investigated for particle systems of the same material. This paper reports experiments conducted in 0.055m diameter fluidizes bed for binary mixtures composed of sands whose sizes ranged from 450 to 1450mm. An empirical relationship, Utf = 0.95 UF (dR)0.87, was derived in terms of the minimum fluidization of the smaller particle, UF ...