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

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.

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.

Perancangan Pengkondisian Udara pada Ruangan Steril Rumah Sakit Mitra Medika dengan Standard Cleanroom Menggunakan Instalasi Ducting

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fremmy Raymond Agustinus
Keyword(s):  
Air Conditioning ◽  
Static Pressure ◽  
Filter Medium ◽  
Positive Pressure ◽  
Design Tools ◽  
Microsoft Excel ◽  
Cooling Unit ◽  
X 24 ◽  
Air Passage ◽  
Booster Fan

Desain penyejuk udara juga dapat diterapkan di bidang kesehatan, dengan standar Cleanroom dapat diperoleh suhu, kelembaban, kenyamanan dan kebersihan yang dibutuhkan untuk ruang steril (ruang bedah). Perancangan pendingin udara dalam hal ini dilakukan dengan menentukan beban pendinginan yang diperlukan untuk ruang steril (ruang bedah), kemudian menentukan ukuran ducting, jalur ducting, dan jumlah penggunaan ducting. Desain ini menggabungkan unit split saluran yang dimodifikasi, kipas booster, filter pra, filter medium, dan filter HEPA dengan menggunakan saluran aluminium preinsulated sebagai saluran udara. Desain dilakukan dengan menggunakan perangkat lunak AutoCAD 2012, Design Tools Duct Sizer, dan Microsoft Excel. Dari hasil perhitungan dan desain didapatkan kebutuhan kapasitas 3 ruang bedah yaitu ducted ducted 100.000 BTUH sebanyak 3 unit, booster fan 3.3 - 4 Di WG sebanyak 3 unit, pre filter 24 "x 24" x 2 "6 set, filter menengah 610 x 610 x 290 mm 6 set, dan filter HEPA 1220 x 610 x 70 mm 12. Untuk ruang steril, tekanan statis yang dihasilkan oleh unit pendingin harus lebih besar daripada tekanan statis yang dihasilkan dari unit yang ada. di ruang semi steril. Dengan kata lain, ruang steril harus memiliki tekanan positif terhadap ruang semi steril. Hal ini dimaksudkan agar udara di ruang semi steril tidak masuk ke ruang steril ketika pintu antar ruangan dibuka. Desain dan perhitungan ruang bedah, suhu nyata yang diperoleh adalah 23 ° C ± 2 ° C dan kelembaban relatif yang diperoleh adalah 60% ± 2%.   Air conditioning design can also be applied in the health field, with cleanroom standard can be obtained temperature, humidity, comfort and hygiene needed for sterile room (surgical room). The design of air conditioning in this case is done by determining the cooling load required for the sterile room (surgical room), then determining the ducting size, ducting path, and the amount of ducting usage. This design combines modified ducted split unit, booster fan, pre filter, medium filter, and HEPA filter by using preinsulated aluminum duct as an air passage. The design is done by using AutoCAD 2012 software, Design Tools Duct Sizer, and Microsoft Excel. From the calculation and design result obtained the capacity requirement of 3 surgical room that is split ducted 100.000 BTUH as many as 3 units, booster fan 3.3 - 4 In WG as many as 3 units, pre filter 24"x 24" x 2" 6 sets, medium filter 610 x 610 x 290 mm 6 sets, and HEPA filter 1220 x 610 x 70 mm 12 sets. For the sterile room, the static pressure generated by the cooling unit shall be larger than the static pressure generated from the unit present in the semi sterile room. In other words, the sterile room must have positive pressure to the semi sterile room. It is intended that the air in the semi sterile room does not enter into the sterile room when the door between room opened. In this surgical room design and calculation, real temperature obtained is 23 °C ± 2 °C and the relative moisture obtained is 60% ± 2%.

Multipurpose filters with ion-exchanger for the equalization of ammonia peaks

1995 ◽  
Vol 32 (7) ◽  
pp. 199-206 ◽  
Author(s):  
Martin Oldenburg ◽  
Ivan Sekoulov
Keyword(s):  
Operation Time ◽  
Ion Exchanger ◽  
Filter Medium ◽  
Nitrification Rate ◽  
Ion Exchangers ◽  
Flow Rates ◽  
Hydraulic Loading ◽  
Influent Concentration

In this study the use of zeolites as ion-exchangers for equalization of ammonia peak loadings in aerated biological activated filters was investigated. For this use zeolites were mixed with a filter medium and the nitrifying filter was loaded with ammonia peaks for two hours at different flow rates. It could be demonstrated that during the phase of higher inflow concentrations the zeolite was collecting ammonia. When the influent concentration decreased ammonia was desorbed from the zeolite and could be nitrified by the bacteria growing on the filter medium. It was shown that additional zeolites can equalize variations of ammonia, especially in filter units which are working at a high nitrification rate and which are very sensitive to varying influent conditions. During the operation time of the filter no separation of the zeolite by higher hydraulic loading or by backwashing could be recognized. So the upgrading of nitrifying filters with zeolite represents an additional security for effluents containing oscillating ammonia concentrations.

KINETIC SORPTION OF CONTAMINANTS OF EMERGING CONCERN BY A PALYGORSKITE-MONTMORILLONITE FILTER MEDIUM

2016 ◽  
Author(s):  
Jonathan Levy ◽  
◽  
Tedros Berhane ◽  
Mark P.S. Krekeler ◽  
Neil Danielson
Keyword(s):  
Filter Medium ◽  
Contaminants Of Emerging Concern ◽  
Kinetic Sorption

Characterization of the emission behavior of pulse-jet cleaned filters using a low-cost particulate matter sensor/Charakterisierung der Emission von druckstoßgereinigten Oberflächenfiltern mit einem Low-Cost-Feinstaubsensor

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (11-12) ◽  
pp. 443-450
Author(s):  
P. Bächler ◽  
J. Meyer ◽  
A. Dittler
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Low Cost ◽  
Particle Emission ◽  
Filter Medium ◽  
Emission Measurement ◽  
Pm2.5 Concentration ◽  
Pulse Jet

The reduction of fine dust emissions with pulse-jet cleaned filters plays an important role in industrial gas cleaning to meet emission standards and protect the environment. The dust emission of technical facilities is typically measured “end of pipe”, so that no information about the local emission contribution of individual filter elements exists. Cheap and compact low-cost sensors for the detection of particulate matter (PM) concentrations, which have been prominently applied for immission monitoring in recent years have the potential for emission measurement of filters to improve process monitoring. This publication discusses the suitability of a low-cost PM-sensor, the model SPS30 from the manufacturer Sensirion, in terms of the potential for particle emission measurement of surface filters in a filter test rig based on DIN ISO 11057. A Promo® 2000 in combination with a Welas® 2100 sensor serves as the optical reference device for the evaluation of the detected PM2.5 concentration and particle size distribution of the emission measured by the low-cost sensor. The Sensirion sensor shows qualitatively similar results of the detected PM2.5 emission as the low-cost sensor SDS011 from the manufacturer Nova Fitness, which was investigated by Schwarz et al. in a former study. The typical emission peak after jet-pulse cleaning of the filter, due to the penetration of particles through the filter medium, is detected during Δp-controlled operation. The particle size distribution calculated from the size resolved number concentrations of the low-cost sensor yields a distinct distribution for three different employed filter media and qualitatively fits the size distribution detected by the Palas® reference. The emission of these three different types of filter media can be distinguished clearly by the measured PM2.5 concentration and the emitted mass per cycle and filter area, demonstrating the potential for PM emission monitoring by the low-cost PM-sensor. During the period of Δt-controlled filter aging, a decreasing emission, caused by an increasing amount of stored particles in the filter medium, is detected. Due to the reduced particle emission after filter aging, the specified maximum concentration of the low-cost sensor is not exceeded so that coincidence is unlikely to affect the measurement results of the sensor for all but the very first stage of filter life.

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