The segregation characteristics of char in a fluidized bed with varying column shapes

Park, Hoon Chae; Choi, Hang Seok

doi:10.1016/j.powtec.2013.06.019

Cited by 35 publications

(19 citation statements)

References 37 publications

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“…In this study, the experimental setup by Park et al [21] forms the basis for the simulation. The geometry of the rectangular fluidized bed with 200 mm width and 50 mm depth is schematically shown in Figure 1.…”

Section: Simulation Setupmentioning

confidence: 99%

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

Zhao¹,

Eri²,

Wang³

2017

Energies

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Abstract:In the present work, the effect of the restitution coefficient on the numerical results for a binary mixture system of sand particles and char particles in a bubbling fluidized bed with a huge difference between the particles in terms of density and volume fraction has been studied based on two-fluid model along with the kinetic theory of granular flow. Results show that the effect of restitution coefficient on the flow characteristics varies in different regions of the bed, which is more evident for the top region of the bed. The restitution coefficient can be categorized into two classes. The restitution coefficients of 0.7 and 0.8 can be included into one class, whereas the restitution coefficient of 0.9 and 0.95 can be included into another class. Moreover, four vortices can be found in the time-averaged flow pattern distribution, which is very different from the result obtained for the binary system with the similar values between particles in density and volume fraction.

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Section: Simulation Setupmentioning

confidence: 99%

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

Zhao¹,

Eri²,

Wang³

2017

Energies

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“…There are several ways to observe mixing and segregation phenomena in fluidized beds like magnetic particle tracking [17], electromagnetic tracking [18], bed-frozen method [19][20][21]. In case of the bed-frozen method, firstly an arbitrary, stationary fluidized state should be achieved with the mixture of the examined active particles and the bed material.…”

Section: The Bed-frozen Methodsmentioning

confidence: 99%

Experimental Investigation on Mixing and Segregation Behavior of Oxygen Carrier and Biomass Particle in Fluidized Bed

Szücs

Szentannai

2019

Period. Polytech. Mech. Eng.

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In this work, lab-scale cold fluidization equipment is designed and constructed to investigate the mixing and segregating phenomena of binary fluidized beds. The focus of the investigation is carbon reduction with the fluidized bed technology-based Chemical Looping Combustion (CLC). Nowadays, aspiration to carbon reduction focuses on the solid fuels. Therefore, it is of great importance to integrate the benefits of CLC technology with the use of solid fuels. The measurements of fuel particles in the fluidized bed are extended from the homogeneous and spherical shape to the inhomogeneous, non-spherical shape. During the tests, an iron-based oxygen carrier (OC) for chemical looping combustors is examined with different particle sizes. In addition, the tests included the examination of three different fuel samples (crushed coal, agricultural pellet, and Solid Recovered Fuel (SRF)), which can be utilized in chemical looping combustion with In-situ gasification. The experiments are carried out using the bed-frozen method. With this method, the vertical concentration of active particles could be measured. The results show that the particle size of the oxygen carrier does fundamentally influence its vertical placement, and the non-spherical character of most alternative fuels must also be considered for optimal reactor design.

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“…García-Ochoa et al [12] reported that this axial dispersion should not be neglected. The bubble mixing influence was experimentally approved by Park and Choi [27]. However, Formisani et al [28][29][30] reported independent segregation from excess gas velocity (bubbles) in the transition zone between the initial and final fluidization velocities.…”

Section: Complex-segregating Systemsmentioning

confidence: 96%

A Conservative Macroscopic Model for Binary-mixture Fluidized Beds

Alagha

Szentannai

2021

Period. Polytech. Chem. Eng.

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Two approaches are commonly used for modeling the vertical mixing of binary-mixture fluidized beds, Computational Fluid Dynamics (CFD) and macroscopic modeling. A common realization of the latter one is the Gibiralo–Rowe (G-R) model, which uses the Two-Phase Theory. This macroscopic model obviously overperforms CFDs regarding computational cost; however, determining its coefficients is a still challenging issue. Although several methods were published for solving this, the general problem with most of them remains their neglecting the conservation of mass. In the present new procedure, the mass conservation is applied to correct the values of the G-R model coefficients estimated from known equations. The present model was validated on a wide variety of fluidized bed systems. The results show that this conservative and macroscopic model gives more accurate predictions than the recently published other macroscopic models, and this one is, in general, better than the CFD model from the perspective of prediction accuracy as well.

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The segregation characteristics of char in a fluidized bed with varying column shapes

Cited by 35 publications

References 37 publications

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

Experimental Investigation on Mixing and Segregation Behavior of Oxygen Carrier and Biomass Particle in Fluidized Bed

A Conservative Macroscopic Model for Binary-mixture Fluidized Beds

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