A computational study has been carried out to assess the influence of pressure on the flow behaviors in dense gas-fluidized beds. Therefore the discrete particle simulation approach has been employed to study the regime transitions, local two-phase flow structures and the energy dissipation distribution. The results show that high pressure reduces the incipient fluidization velocity, widens the...

The fluidization characteristics of binary mixtures containing tobacco stem (TS) and cation exchange resin (a substitute for coal) were studied in a rectangular bed with the cross-section area of 0.3 × 0.025 m(2). The presence of herbaceous biomass particles and their unique properties such as low density and high aspect ratio resulted in different fluidization behaviors. Three fluidization vel...

in order to study the fluidization behavior of grains, a laboratory fluidized bed dryer (fbd) was designed and developed. forward blade centrifugal fan with 1.5 kw electric motor, was selected to be used based on the highest pressure loss calculated at minimum fluidization condition and airflow rate at terminal velocity of the selected grains (paddy, soybean, millet and barley). the dryer was c...

The mixing behaviors of dry and wet granular materials in gas fluidized bed systems were investigated computationally using the combined Computational Fluid Dynamics and Discrete Element Method (CFD-DEM). Dry particles were observed to mix fairly rapidly during the fluidization process due to vigorous relative motions between particles induced by the flow of gas. In contrast, due to the presenc...

Fluidized beds are being used in practice to gasify biomass to create producer gas, a flammable gas that can be used for process heating. However, recent literature has identified the need to better understand and characterize biomass fluidization hydrodynamics, and has motivated the combined experimental-numerical effort in this work. A cylindrical reactor is considered and a side port is intr...

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...

An experimental study is conducted to determine the effect of different types of nanoparticles on the gas fluidization characteristics of nanoparticle agglomerates. Taking advantage of the extremely high porosity of the bed, optical techniques are used to visualize the flow behavior, as well as to measure the sizes of the fluidized nanoparticle agglomerates at the bed surface. Upon fluidizing 1...

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...

numerous investigations have been devoted towards understanding the hydrodynamics of gas jets in fluidized beds. however, most of them address the problem from  macroscopic point of view, which does not reveal the true behavior in the jet region at the single particle level. the present work aims to understand the jet behavior from a more fundamental level, i.e. the individual particle level. a...

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