Hydrodynamical interactions between particles and liquid flows in biochemical applications

Caulet, P.J.C.; Lans, R. G. J. M. van der; Luyben, K. Ch. A. M.

doi:10.1016/0923-0467(96)03086-2

Cited by 10 publications

(12 citation statements)

References 22 publications

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“…Therefore, the inertia force will not be considered in any force calculations in this work. For small particles, the inertia force generally is very small because these particles tend to follow the liquid streamlines (Caulet et al, 1996), which makes this a proper assumption. With larger particles, the inertia force may reduce or even prevent particle acceleration.…”

Section: Inertia Forcementioning

confidence: 99%

Strategy for selection of methods for separation of bioparticles from particle mixtures

Hee

Hoeben

Lans

et al. 2006

Biotech & Bioengineering

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The desired product of bioprocesses is often produced in particulate form, either as an inclusion body (IB) or as a crystal. Particle harvesting is then a crucial and attractive form of product recovery. Because the liquid phase often contains other bioparticles, such as cell debris, whole cells, particulate biocatalysts or particulate by-products, the recovery of product particles is a complex process. In most cases, the particulate product is purified using selective solubilization or extraction. However, if selective particle recovery is possible, the already high purity of the particles makes this downstream process more favorable. This work gives an overview of typical bioparticle mixtures that are encountered in industrial biotechnology and the various driving forces that may be used for particle-particle separation, such as the centrifugal force, the magnetic force, the electric force, and forces related to interfaces. By coupling these driving forces to the resisting forces, the limitations of using these driving forces with respect to particle size are calculated. It shows that centrifugation is not a general solution for particle-particle separation in biotechnology because the particle sizes of product and contaminating particles are often very small, thus, causing their settling velocities to be too low for efficient separation by centrifugation. Examples of such separation problems are the recovery of IBs or virus-like particles (VLPs) from (microbial) cell debris. In these cases, separation processes that use electrical forces or fluid-fluid interfaces show to have a large potential for particle-particle separation. These methods are not yet commonly applied for large-scale particle-particle separation in biotechnology and more research is required on the separation techniques and on particle characterization to facilitate successful application of these methods in industry.

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Section: Inertia Forcementioning

confidence: 99%

Strategy for selection of methods for separation of bioparticles from particle mixtures

Hee

Hoeben

Lans

et al. 2006

Biotech & Bioengineering

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“…Particle collisions originate in the relative movement of suspended particles in the liquid flow. Interactions between particles and a turbulent flow are very complicated (Caulet et al, 1996). In airlift reactors, the presence of air bubbles might be important.…”

Section: Particle Collisionsmentioning

confidence: 99%

Abrasion of suspended biofilm pellets in airlift reactors: Importance of shape, structure, and particle concentrations

Gjaltema

Vinke

Loosdrecht

et al. 1997

Biotechnol. Bioeng.

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The detachment of biomass from suspended biofilm pellets in three‐phase internal loop airlift reactors was investigated under nongrowth conditions and in the presence of bare carrier particles. In different sets of experiments, the concentrations of biofilm pellets and bare carrier particles were varied independently. Gas hold‐up, bubble size, and general flow pattern were strongly influenced by changes in volume fractions of biofilm pellets and bare carrier particles. In spite of this, the rate of biomass detachment was found to be linear with both the concentration of biofilm pellets and the bare carrier concentration up to a solids hold‐up of 30%. This implies that the detachment rate was dominated by collisions between biofilm pellets and bare carrier particles. These collisions caused an on‐going abrasion of the biofilm pellets, leading to a reduction in pellet volume. Breakage of the biofilm pellets was negligible. The biofilm pellets were essentially ellipsoidal, which made three‐dimensional size determination necessary. Calculating particle volumes from two‐dimensional image analysis measurements and assuming a spherical shape led to serious errors. The abrasion rate was not equal on all sides of the biofilm pellets, resulting in an increasing flattening of the pellets. This flattening was oriented with the basalt carrier inside the biofilm and independent of the absolute abrasion rate. These observations suggest that the collisions causing abrasion are somehow oriented. The internal structure of the biofilms showed two layers, a cell‐dense outer layer and an interior with a low biomass density. Taking this density gradient into account, the washout of detached biomass matched observed changes in volume of the biofilm pellets. No gradient in biofilm strength with biofilm depth was indicated. © 1997 John Wiley & Sons, Inc.

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“…Interactions between particles and a turbulent liquid flow are very complicated (Kuboi et al, 1972;Caulet et al, 1996). Particle motion is strongly influenced by liquid flow, but the presence of discrete particles also alters the turbulent field (two-way coupling).…”

Section: Theorymentioning

confidence: 99%

Abrasion of suspended biofilm pellets in airlift reactors: Effect of particle size

Gjaltema

Loosdrecht

Heijnen

1997

Biotechnol. Bioeng.

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The detachment of biomass from suspended biofilm pellets in three‐phase internal loop airlift reactors was investigated under non‐growth conditions, and in the presence of bare carrier particles. In the experiments the size of biofilm pellets and bare carrier particles was varied. Results show that an increase in particle size drastically increases the abrasion rate caused by particle collisions. This increase is larger than predicted by conventional collision theory, which accounts for changes in collision frequency and collision impact. However, collision theory was formulated for neutrally buoyant particles which follow the liquid flow. This condition does not hold for biofilm pellets and carrier particles. The difference might therefore be caused by differences in particle responses to flow fluctuations. An empirical relationship, including this flow response, was formulated. The collision impact is also strongly affected by the roughness of a bare carrier particle: sharp and edgy particles cause much more damage than smoother ones. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 206–215, 1997.

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Hydrodynamical interactions between particles and liquid flows in biochemical applications

Cited by 10 publications

References 22 publications

Strategy for selection of methods for separation of bioparticles from particle mixtures

Strategy for selection of methods for separation of bioparticles from particle mixtures

Abrasion of suspended biofilm pellets in airlift reactors: Importance of shape, structure, and particle concentrations

Abrasion of suspended biofilm pellets in airlift reactors: Effect of particle size

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