Effects of pore size, suspension concentration, and pre-sedimentation on the measurement of filter medium resistance in cake filtration

2001 ◽  
Vol 18 (5) ◽  
pp. 741-749 ◽  
Author(s):  
Sung-Sam Yim ◽  
Young-Du Kwon ◽  
Hyung-Il Kim
Keyword(s):  
Pore Size ◽  
Filter Medium ◽  
Cake Filtration ◽  
Suspension Concentration ◽  
Medium Resistance

Calculation of the filtration process when the filter medium resistance varies from cycle to cycle

1980 ◽  
Vol 16 (1) ◽  
pp. 33-37
Author(s):  
A. A. Grichenko ◽  
V. P. Abramov
Keyword(s):  
Filter Medium ◽  
Filtration Process ◽  
Medium Resistance

In Situ Examination of Effects of Pressure Differential on Compressible Cake Filtration

1990 ◽  
Vol 22 (12) ◽  
pp. 125-134 ◽  
Author(s):  
B. R. Bierck ◽  
R. I. Dick
Keyword(s):  
Activated Sludge ◽  
Pressure Differential ◽  
Filter Medium ◽  
Cake Filtration ◽  
Solids Concentration ◽  
Cake Formation ◽  
Thin Skin ◽  
Production Behavior ◽  
Concentration Changes ◽  
Filter Cakes

A synchrotron X-ray absorbance technique was used to monitor suspended solids concentration changes in compressible filter cakes formed at different constant pressure differentials. Results for a kaolin slurry and an activated sludge manifested the markedly higher compressibility of the latter sludge. A model developed to describe effects of pressure differential on filtrate production behavior of an ideal compressible slurry indicated that the kaolin slurry behaved as such. However, the activated sludge was not ideal because changes in pressure differential did not cause the idealized change in filtrate production rate. A thin skin of activated sludge solids at the filter medium accounted for the non-ideal compressive behavior. Porewater pressure data acquired 0.86 mm above the filter medium during activated sludge filtration provided evidence of skin formation and its effect - virtually the total pressure drop occurred within this 0.86 mm region throughout cake formation (after which shrinkage began). Hence, significant effective stresses required to consolidate the sludge cake did not develop in most of the cake until cake formation was complete and shrinkage began.

Filter medium clogging during cake filtration

AIChE Journal ◽  
1997 ◽  
Vol 43 (1) ◽  
pp. 273-276 ◽  
Author(s):  
D. J. Lee
Keyword(s):  
Filter Medium ◽  
Cake Filtration

Simulation of the Vacuum Infusion Process using Idealized Components: Effects of Pore Size and Suspension Concentration

1990 ◽  
Vol 55 (4) ◽  
pp. 989-993 ◽  
Author(s):  
ANN H. BARRETT ◽  
EDWARD W. ROSS ◽  
IRWIN A. TAUB
Keyword(s):  
Pore Size ◽  
Suspension Concentration ◽  
Vacuum Infusion ◽  
Vacuum Infusion Process

scholarly journals A Study of Cake Filtration Parameters Using the Constant Rate Process

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 746 ◽  
Author(s):  
Faiz Mahdi ◽  
Timothy Hunter ◽  
Richard Holdich
Keyword(s):  
Calcium Carbonate ◽  
Filter Cake ◽  
Cake Filtration ◽  
Initial Stage ◽  
Constant Rate ◽  
Medium Resistance ◽  
Material Sample ◽  
The Mean ◽  
Analytical Approaches ◽  
Constant Rate Process

The minerals calcium carbonate and talc were filtered under various conditions of filtrate flow rate and suspension concentration, using constant rate conditions with the aid of a peristaltic pump to draw the filtrate. Cake concentrations of between 0.41 and 0.53 v/v for calcium carbonate and 0.19 and 0.26 v/v for talc were recorded. The mean sizes of the two different minerals were very similar, but the average specific resistances obtained from the experiments were 5.9 × 1010 and 7.4 × 1011 m/kg for calcium carbonate and talc, respectively. These results do not agree with what would be predicted from an analytical equation for permeability, such as Kozeny-Carman. In addition, discontinuities were observed in all cases on the curves of filtrate volume with time for the initial stage of filtration. This behaviour is attributed to retarded packing compressibility (RPC) complicating the analysis of the filter medium resistance. RPC is an important component in determining the filter cake resistance and its functionality with cake forming pressure. It is found that there are additional effects that enhance the resistance to permeation in different cake materials, which is not recognised in the standard analytical approaches. These complexities can be related to shape, polydispersity, or agglomeration within the material sample and not to the experimental equipment or procedure. Furthermore, a complete and straightforward methodology is presented in this work for investigating the significance, or otherwise, of medium resistance on the later stages of the filtration.

scholarly journals A Coupled CFD-DEM Model for Resolved Simulation of Filter Cake Formation during Solid-Liquid Separation

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 826
Author(s):  
Vanessa Puderbach ◽  
Kilian Schmidt ◽  
Sergiy Antonyuk
Keyword(s):  
Filter Cake ◽  
Filter Medium ◽  
Particle Interactions ◽  
Cake Filtration ◽  
Liquid Separation ◽  
Flow Equations ◽  
Cake Formation ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Dem Model

In cake filtration processes, where particles in a suspension are separated by forming a filter cake on the filter medium, the resistances of filter cake and filter medium cause a specific pressure drop which consequently defines the process energy effort. The micromechanics of the filter cake formation (interactions between particles, fluid, other particles and filter medium) must be considered to describe pore clogging, filter cake growth and consolidation correctly. A precise 3D modeling approach to describe these effects is the resolved coupling of the Computational Fluid Dynamics with the Discrete Element Method (CFD-DEM). This work focuses on the development and validation of a CFD-DEM model, which is capable to predict the filter cake formation during solid-liquid separation accurately. The model uses the Lattice-Boltzmann Method (LBM) to directly solve the flow equations in the CFD part of the coupling and the DEM for the calculation of particle interactions. The developed model enables the 4-way coupling to consider particle-fluid and particle-particle interactions. The results of this work are presented in two steps. First, the developed model is validated with an empirical model of the single particle settling velocity in the transition regime of the fluid-particle flow. The model is also enhanced with additional particles to determine the particle-particle influence. Second, the separation of silica glass particles from water in a pressurized housing at constant pressure is experimentally investigated. The measured filter cake, filter medium and interference resistances are in a good agreement with the results of the 3D simulations, demonstrating the applicability of the resolved CFD-DEM coupling for analyzing and optimizing cake filtration processes.

Influence of the presence of open three-dimensional fiber structures on solid liquid cake filtration of limestone

2020 ◽  
pp. 152808372094927
Author(s):  
Markus Babin ◽  
Bo Liu ◽  
Gernot Krammer
Keyword(s):  
Filter Cake ◽  
Fine Particles ◽  
Three Dimensional ◽  
Solid Particles ◽  
Filter Medium ◽  
Dimensional Structure ◽  
Cake Filtration ◽  
Air Blowing ◽  
Pass Through ◽  
Set Up

Solid particles in a suspension can be separated effectively through cake filtration where the filter medium is decisive particularly during the initial stage when particle breakthrough can be high. To improve the filtrate quality and throughput, filtration aid additives are used, which are known to alter filter cake structure and thus reduce flow resistance but, in forming clusters, also stabilize fine particles that would otherwise pass through the filter (cake) easily. However, filter aids are costly, increase the complexity of the system and may have adverse effects for subsequent mechanical drying and washing. Instead of supplying additives, four alternative filter media were tested exhibiting an open, three-dimensional structure that reached deeply into the depth of the forming filter cake. An aqueous limestone suspension was investigated in a conventional laboratory test unit. Composite filter medium set-up delivered up to 15% faster filtration. The results indicate that the fiber structures give better performance that reach far into the cake and are oriented not only axially but also radially. In contrary to the initial hypothesis that an axial fiber structure would produce additional drainage channels along the surface of these fibers and thus support but deliquoring, the actual deliquoring performance with air blowing appeared to be slightly less efficient. Although not investigated yet, cake discharge with a 3-D filter layer present poses an additional challenge, rendering the concept of composite filters unpractical.

The Effect of Filter Cakes on Filter Medium Resistance

1994 ◽  
Vol 29 (16) ◽  
pp. 2179-2196 ◽  
Author(s):  
G. G. Chase ◽  
J. Arconti ◽  
J. Kanel
Keyword(s):  
Filter Medium ◽  
Medium Resistance ◽  
Filter Cakes

Transfer Technique for Electron Microscopy of Membrance Filter Samples

1974 ◽  
Vol 32 ◽  
pp. 554-555
Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Pore Size ◽  
Membrane Filters ◽  
Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

The microstructure of functionalized poLyacrylonitrile beads for bioseparations

1990 ◽  
Vol 48 (4) ◽  
pp. 1094-1095
Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley
Keyword(s):  
Aqueous Solution ◽  
Affinity Chromatography ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Coverage ◽  
Vacuum Impregnation ◽  
Thin Sections ◽  
Selective Staining ◽  
Low Viscosity ◽  
Diamond Knife

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.

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