The use of electrode probes in determinations of filter cake formation and batch filter scale-up

Tarleton, E.S.

doi:10.1016/s0892-6875(99)00111-9

Cited by 9 publications

(3 citation statements)

References 26 publications

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“…These were positioned at 1 mm vertical intervals above the filter medium and protruded circa 2 mm from the cell walls; previous work has shown that such intrusions cause negligible effects on cake formation [Tarleton, 1999b]. Signals to each electrode pair were switched by the computer via electronic circuitry to give electrical resistance measurements of changing cake thickness and solids concentration.…”

Section: Methodsmentioning

confidence: 99%

Cake filter scale-up, simulation and data acquisition—A new approach

Tarleton

2008

Journal of the Chinese Institute of Chemical Engineers

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This paper details the capability of a unique, automated filtration apparatus and the newly developed Filter Design Software (FDS) which facilitate equipment selection, scale-up and simulation through an integrated experimental and theoretical approach.By way of example, experimental data were obtained with the apparatus over constant, variable and stepped pressure regimes. Inherent suspension properties were maintained throughout by utilising a computer controlled pressure controller and cake formation was monitored by micropressure transducers capable of providing up to seven independent measures of liquid pressure within 3.3 mm of the filter medium surface. For constant pressure and moderately compressible talc cakes the liquid pressure increased with cake height in a non-linear manner and generally exhibited a concave profile. When a pressure step was applied following a period of constant pressure filtration, the cake structure typically required up to 30 s to reach a new pseudoequilibrium state. During this time the reciprocal filtrate flow rate vs. filtrate volume plot was nonlinear and the liquid pressures in the cake increased rapidly before remaining nearly constant. When the cake was thicker or the pressure step larger, the liquid pressure measured closer to the filter medium remained either constant following the increase in pressure or increased slowly over the 360 s duration of the pressure step which indicates potential difficulties with the stepped pressure test.The filtration data were analysed using FDS to obtain scale-up coefficients and the impact of using incorrect scale-up coefficients on likely filter performance at the process scale is shown. The simulation capabilities of FDS are also highlighted through a case study in which, by way of example, the influence of crystal formation and other operating parameters on the filter cycle for a pharmaceutical product are shown. Simulations quantify how crystal form can detrimentally influence all phases of a cycle and lead to, for instance, slower filtration and wetter filter cakes.

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Section: Methodsmentioning

confidence: 99%

Cake filter scale-up, simulation and data acquisition—A new approach

Tarleton

2008

Journal of the Chinese Institute of Chemical Engineers

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“…equation and/or force analysis have been developed to estimate cake porosity [2][3][4][5]. Use of electrode type sensing probes [6] and high-energy radiation [7] have also been attempted to measure the cake porosity. Nevertheless, these methods have a limitation that they are nothing but indirect analysis of cake porosity.…”

Section: Introductionmentioning

confidence: 99%

Determination of cake porosity using image analysis in a coagulation–microfiltration system

Park

Lee

2007

Journal of Membrane Science

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“…The effective pressure increases from the top of the filter cake downward to the filter medium as a result of the frictional drag between the liquid and the solid particles 27–30. Furthermore, compressible filter cakes become compressed when the effective pressure increases, so solid volume fraction is higher near the filter medium than at the top of the cake 7, 30–32. Moreover, solid volume fraction is important when modeling filtrations because the specific filter‐cake resistance is a function of solid volume fraction, as described previously.…”

Section: Traditional Cake Filtration Theorymentioning

confidence: 96%

Filtration model for suspensions that form filter cakes with creep behavior

Christensen

Keiding

2007

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Waste-activated sludge was filtered and the formed filter cake studied. It was shown that average specific filter-cake resistance increases during filtration. A stress-relaxation experiment was performed and the two relaxation times found were of the same order of magnitude as the duration of the filtration stage. It was therefore concluded that the local solid volume fraction of sludge filter cakes changes not only with effective pressure but also with time. In contrast, it is usually assumed in filtration modeling that solid volume fraction is a unique function of effective pressure. A new filtration model was thus developed by adopting the concept of filter-cake creep and applying it in conventional models. It was shown that the model developed, unlike conventional filtration models, satisfactorily describes the experimental data in the case of waste-activated sludge. Furthermore, the model is capable of being scaled with respect to feed concentration and volume.

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The use of electrode probes in determinations of filter cake formation and batch filter scale-up

Cited by 9 publications

References 26 publications

Cake filter scale-up, simulation and data acquisition—A new approach

Cake filter scale-up, simulation and data acquisition—A new approach

Determination of cake porosity using image analysis in a coagulation–microfiltration system

Filtration model for suspensions that form filter cakes with creep behavior

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