Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor

Agu, Cornelius Emeka; Moldestad, Britt Margrethe Emilie

doi:10.3384/ecp18153248

Cited by 2 publications

(3 citation statements)

References 5 publications

(5 reference statements)

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“…The sFBB design was conceptualized as a one-piece central column fitted with a sintered glass flow distributor. Some systems do not include a flow distributor, reasoning on channeling effects created by this feature (i.e., preferential circulation of fluid through specific arteries generating points of fast moving particles interspersed with stagnant ones), and that without it the bioreactor still performs accordingly ( Agu and Moldestad, 2018 ). However, the majority describes the distributor and its design as the key parameter for the performance of the FBB.…”

Section: Discussionmentioning

confidence: 99%

Small-Scale Fluidized Bed Bioreactor for Long-Term Dynamic Culture of 3D Cell Constructs and in vitro Testing

Silva

Erro

Awan

et al. 2020

Front. Bioeng. Biotechnol.

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With the increasing interest in three-dimensional (3D) cell constructs that better represent native tissues, comes the need to also invest in devices, i.e., bioreactors, that provide a controlled dynamic environment similar to the perfusion mechanism observed in vivo. Here a laboratory-scale fluidized bed bioreactor (sFBB) was designed for hydrogel (i.e., alginate) encapsulated cells to generate a dynamic culture system that produced a homogenous milieu and host substantial biomass for long-term evolution of tissue-like structures and "per cell" performance analysis. The bioreactor design, conceptualized through scale-down empirical similarity rules, was initially validated through computational fluid dynamics analysis for the distributor capacity of homogenously dispersing the flow with an average fluid velocity of 4.596 × 10 −4 m/s. Experimental tests then demonstrated a consistent fluidization of hydrogel spheres, while maintaining shape and integrity (606.9 ± 99.3 µm diameter and 0.96 shape factor). It also induced mass transfer in and out of the hydrogel at a faster rate than static conditions. Finally, the sFBB sustained culture of alginate encapsulated hepatoblastoma cells for 12 days promoting proliferation into highly viable (>97%) cell spheroids at a high final density of 27.3 ± 0.78 million cells/mL beads. This was reproducible across multiple units set up in parallel and operating simultaneously. The sFBB prototype constitutes a simple and robust tool to generate 3D cell constructs, expandable into a multi-unit setup for simultaneous observations and for future development and biological evaluation of in vitro tissue models and their responses to different agents, increasing the complexity and speed of R&D processes.

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Section: Discussionmentioning

confidence: 99%

Small-Scale Fluidized Bed Bioreactor for Long-Term Dynamic Culture of 3D Cell Constructs and in vitro Testing

Silva

Erro

Awan

et al. 2020

Front. Bioeng. Biotechnol.

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“…Several studies have been conducted on design of the distributor plate and the influence of the distributor plate on the reactor performance (Geldart and Baeyens 1985;Saxena et al, 1979). However, the number studies on operation of a bubbling fluidized bed reactor without an air distributor and comparing the fluid dynamics behaviour of the bed operated with and without distributor are scarce (Agu et al, 2018).There are a few studies on operation of a fluidized bed reactor without an air distributor where large size particles are used at the lower region of the bed and the bed is fluidized by passing the gas through the bed of stationary large particles (Agu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…In a single study, reported on the operation of reactor without an air distributor Agu et al has studied the bed behaviour with different types of particles and gas velocity based on the pressure and solid circulation using CPFD simulation. However, no information is provided about the grid size and number of computational cells in the article (Agu et al,2018). The grid number or computational domain in such simulations have significant impact on the fluid dynamics behaviour of the bed and the pressure and flow boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Influence on the fluidization pattern of a freely bubbling fluidized bed with different modes of air supply

Jaiswal¹,

Eikeland²,

Moldestad³

et al. 2022

Linköping Electronic Conference Proceedings

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Bubbling fluidized bed (BFB) reactors are extensively used in several process applications like gasification, pyrolysis, drying, and combustions due to their excellent mixing properties and good temperature control. The bubble dynamic and particle movement in the reactor is primarily responsible for uniform heat and mass transfer and mixing. The properties of bubbles in BFB are governed by the gas distribution inside the reactor or supply of the fluidizing gas. This work investigates the influence on the fluid dynamic behaviour of the BFB reactor at different fluidizing gas injection systems using the Computational Particle Fluid dynamic model. Three different modes of fluidizing gas injection include uniform injection, air injection via twenty-five nozzles, and air supply via side nozzles along the reactor height in a gasification reactor of 10.04 cm diameter. Air is used as the fluidizing gas and silica sand as the bed material. The CPFD model is developed in Barracuda Virtual reactor 20.01. The CPFD model is validated against the experimental data obtained from the Electrical Capacitance Tomography (ECT) sensors. The result depicts the better fluidization quality of the bed with uniform air supply as flow boundary and air injection via twenty-five nozzles located at the bottom of the reactor. With air injection via two side nozzles along the reactor height, the bed is fluidized with large bubbles and particle entrainment in the freeboard zone of the reactor. A method is proposed to improve the fluidization quality of the bed while using side nozzles as inlet flow Boundary Conditions (BC) for air injection. The proposed method includes addition of four nozzles along the reactor wall instead of two which improves the fluidization quality of the bed in terms of smaller size bubbles without particle entrainment in the freeboard region.

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Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor

Cited by 2 publications

References 5 publications

Small-Scale Fluidized Bed Bioreactor for Long-Term Dynamic Culture of 3D Cell Constructs and in vitro Testing

Small-Scale Fluidized Bed Bioreactor for Long-Term Dynamic Culture of 3D Cell Constructs and in vitro Testing

Influence on the fluidization pattern of a freely bubbling fluidized bed with different modes of air supply

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