Experimental investigation of hydrodynamics of gas‐solid flow in an internally circulating fluidized bed

Abstract

Hydrodynamic study of gas and solid flow in an internally circulating fluidized bed (ICFB) is made in this paper using a high-speed camera and pressure probes for the laboratory 0.3 m  0.27 m column having an internal draft tube. Experiments were conducted using sand particles of Geldart B and Geldart B-D groups. At each run the standard pressure-flow curves for both the draft tube and annular region beds, and the moving wall particle velocity in the annular bed region were measured. The effects of superficial gas velocity, static bed height, and draft tube gap height on pressure drop profiles, solid circulation patterns, and gas bypassing dynamics for the ICFB were investigated extensively. Unlike the conventional CFB, the pressure drop in ICFB is further decreased with superficial gas velocity after the minimum spouting fluidization, followed by yielding a crossover in the pressure drop of the annular bed compared to the draft tube. Pressure drop in the draft tube increases with an increase of static bed height and gap height between the draft tube bottom and the air distributor. The gas bypassing fraction increases with an increase in gap height and decreases with increased bed height and mean particle size. The mechanism governing the solid circulation and the pressure losses in an ICFB has been elaborated based on gas and solid dynamics obtained from the experimental data.

Effect of Drag Models on the Numerical Simulations of Bubbling and Turbulent Fluidized Beds

“…Figure 1. 2D and 3D meshes used for (a) bubbling fluidized bed with central gas jet [3,4] and uniformly fed turbulent fluidized bed simulations [7], (b) grid independence test in a bubbling fluidized bed. 4 Results and Discussion…”

“…Hence, it is a challenging task to measure the internal flow hydrodynamics accurately. Over the years, numerous experimental techniques such as imaging, tomography, and optical fiber probe have been adopted to measure the qualitative and quantitative flow properties of fluidized beds [3][4][5][6].…”

Experimental Investigation of Particle Circulation in an Internally Circulating Clapboard‐Type Fluidized Bed

“…Due to the complexity of gas‐solid interaction, macro‐controlling of multi‐fluidization regimes and turbulence, the hydrodynamic characteristics of the gas‐solid flow in the ICFB have not been fully understood , . Meanwhile, the particle circulation rate G S is a key hydrodynamic parameter for rationally designing and operating the ICFB , .…”

“…Meanwhile, the particle circulation rate G S is a key hydrodynamic parameter for rationally designing and operating the ICFB , . That is the reason why many published articles have reported valuable information about the G S values in an ICFB with a draft tube , , . For example, Ahn et al , using hot sand as a tracer, employed a thermistor probe to measure the particle downward velocity.…”

Numerical Simulation of Heat and Mass Transfer Processes in Large-Scale Fluidized Bed Complex Structure Apparatus as an Example of the Reactor of Isoparaffins Dehydrogenation

“…Experimental studies with internal elements in a liquidsolid fluidized bed are presented in [9]. Investigations of fluidized bed processes in the column with an inner cylinder were experimentally made in [10]. Modelling and comparative analysis of two large fluidized bed units with various feed gas supply devices is carried out in [11].…”