Experts in filtration and separation

We advance and disseminate knowledge in the design and use of filtration and separation techniques in industry, commerce and other walks of life.

2015 programme The Filtration Society programme for 2015

Testing, Characterisation & Filter Media 7: Conference, Exhibition and Training Course
30th November (Training Course) and 1st December (Conference and Exhibition)

Filter testing is a critical feature of quality control during filter element manufacturing and integrity validation during filter operation. Equally important in filter applications is a good understanding of the feed to be filtered and the filter medium itself, which require characterisation in many different ways.

This two day event will bring together people interested in characterisation, testing and filter media technologies that are being applied in industry, as well as those that are about to become industrially accepted methods. From tightening legislation to the growing number of finer, more demanding, filter processes, new filter media developments are constantly being driven by customer requirements. This, and newer regulatory frameworks and standards, require ever better test methodologies.

Many new developments have taken place in recent years in both gas and liquid applications. The conference will feature key elements of these developments, and will be of particular interest to process engineers, designers, technical and R&D staff, research institutes and decision makers.

An exhibition of characterisation and test equipment will complement the conference, where some of the latest technologies in the market place will be demonstrated by manufacturers and suppliers.

A training course will take place on the day preceding the conference and exhibition. The course is a review of the processes involved in testing, characterisation and filter media. It will draw upon the presenters in-depth knowledge of industrial applications and extensive R&D experience, and the emphasis will be on practical aspects with theoretical information presented only where needed to support understanding of the applications. There will be an opportunity for delegates to gain hands-on experience with the latest testing equipment.

The conference flyer, including a draft technical programme and registration details, is available here.

If you need more information about attending the conference or exhibiting then please contact the Honorary Secretary, Dr Steve Tarleton at steve.tarleton@ntlworld.com.

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2014 Abstracts from the FILTRATION journal

Use the links below to view abstracts from FILTRATION volume 14:

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Volume 14, Issue 4 Abstracts from the FILTRATION journal

DEVELOPMENTS AND CASE STUDIES IN HOT GAS FILTRATION FOR
GASEOUS WASTE STREAMS
Ian Chisem and Richard Lydon (pages 208-210)

Over recent years Clear Edge has been developing its range of specialised filter element technology for a set of challenging applications in hot gas filtration markets.  The solutions have been driven by the pressing need for industrial processes to control emissions to meet tighter regulatory standards, both inline and with ‘end of pipe’ technology.  As global emissions in the developed world have tightened from PM10 to PM2.5 (particulate matter 2.5 μm), Clear Edge has been developing and testing hot gas filters in a range of industrial processes to meet even tighter emission limits whilst maintaining high flow rates and energy efficient systems.  The paper outlines some of the new technology in this family and the next generation of filter products offering commercially competitive air pollution control (APC) solutions.

MEASURING FILTER CUT POINTS AND PORE SIZE DISTRIBUTIONS USING GLASS MICROSPHERES
Graham Rideal (pages 211-216)

In this paper challenge testing with narrow particle size distribution glass microspheres is shown to be a powerful method of measuring both the cut points and pore size distributions of woven stainless steel wire meshes.  The key to accuracy and reproducibility was the use of microscopy and image analysis where it was possible to electronically remove any non-spherical particles in the filter calibration standard.

INTRODUCING FUNCTIONALITY TO FILTER MEDIA
Bhavani Vijayakumar, Allan Rennie, Neil Burns, Darren Travis and Paul Battersby (pages 217-222)

Pumps are major consumers of electricity in the process industries and filters are an integral part of the pumping process.  This paper discusses the reduction in energy consumption in the filtration process by using additive manufactured, geometrically optimised, conical, in-line filter supports.  These are then compared with those currently fabricated by more conventional means.

Based on computational fluid dynamic (CFD) simulations, a new filter support was designed and fabricated using Additive Manufacturing (AM) technology.  The comparison was achieved by testing both types of filter supports of similar dimensions with filter mesh in a bespoke test rig at Croft Engineering Services.  A 20 gauge, 900 µm filter mesh was used to test the two filter supports with flow rates between 0.0018 m3/s and 0.0062 m3/s.  Comparison of the experimental results revealed that the AM filter support mesh arrangement was superior to the conventional filter support mesh arrangement.  In comparison to the conventional approach, the AM filter support pressure drop was 0.443 kPa lower when operated in the forward flow direction and 1.852 kPa lower in reverse flow.  The reduction in pressure drop correspondingly reduced the energy consumption by 10 kW/h in forward flow and 29 kW/h in reverse flow.

INDISPENSABLE POLYPROPYLENE MATERIAL IN COMPOSITEFIBROUS MEDIA COALESCER FOR OIL-IN-WATER EMULSION SEPARATION
Sunil Kirloskar and H. Veeramani (pages 222-225)

This paper outlines the development of baseline data for the treatment of emulsions with alternative composite media from readily available fibrous materials.  The aim was to evolve suitable configurations of composite media that would manifest a moderate pressure drop whilst giving complete phase separation and maximum recovery of oil from oil-water emulsions by coalescence.

EFFECT OF XHANTAN GUM AND PARTICLE SIZE DISTRIBUTION ON THE
PERMEABILITY OF MUD-CAKE PRODUCED DURING DRILLING OPERATIONS
José Angel Sorrentino (pages 226-235)

During drilling operations the drilling mud is injected to the well under pressure, with some solids being added to the mud formulation in order to build a mud-cake on the reservoir walls and prevent further invasion of solid and fluid.  Unlike in typical filtration applications, mud-cakes are supposed to be as impermeable and thin as possible.  Some water-based drilling muds include in their formulation a polysaccharide (Xhantan Gum) to give the mud a pseudo-plastic rheology.  This paper presents the results of mud-cake permeability variations with particle size distribution (PSD) of the bridging material (limestone) for a basic drilling mud composed of water, Xhantan Gum and calcium carbonate in fixed ratios.  Most of the results do not agree with the estimations made using the Kozeny-Carman equation, the permeabilities being up to three orders of magnitude smaller than those predicted based solely on particle characteristics.

The suggested hypothesis postulates that the polysaccharide (Xhantan Gum), which hydrolyses with a large amount of water, forms a ‘hydrated macromolecule’ mixed with some free water.  This mixture behaves sometimes like a thick fluid (passing with some difficulty through the voids caused by the solid particles) and other times like a particulate system (part of which is able to be retained within the interstices of the porous system).  In experiments cakes were prepared using limestone of different PSD with median sizes between 15 and 50 μm and geometric standard deviations ranging between 1.5 and 3.  A modified permeability, S, was used to minimise the influence of errors in estimating porosity.  A plot of S /(D3,2)2  against D3,2 allowed identification of the conditions where the Kozeny-Carman functionality is fulfilled (i.e. S /(D3,2)2 is independent of D3,2).  These results support the hypothesis of a ‘hydrated macromolecule’ binding the voids, as when the pores are big enough then the Kozeny-Carman functionality is satisfied.

THE EFFECT OF FILTER DESIGN AND SURFACE AREA ON FILTER
PERFORMANCE
Iyad Al-Attar (pages 235-240)

The increasing public concern regarding indoor air quality in residential and commercial buildings has led to major developments in high efficiency air filters.  Clean air is required for Heating, Ventilation and Air Conditioning (HVAC) systems in buildings, clean rooms, pharmaceutical industries, all enclosed environments, engine intakes and exhausts.  Equally important, air filters are an essential component in providing a large mass of clean air to operate gas in order to generate energy.  Whether it is intake or exhaust, air filtration remains a common denominator in the mathematics of applications requiring particle removal.  This paper describes the importance of effective surface in a filter and the reasons which may cause losses in filter surface area that can lead to a loss in performance.

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Volume 14, Issue 3 Abstracts from the FILTRATION journal

POREX® TUBULAR MEMBRANE FILTER (TMF™) APPLIED IN A PLASTIC PLATING WASTEWATER RECLAIM SYSTEM
Doug Frick (pages 140-145)

A large auto parts manufacturer located in the Zhejiang province of China was in need of a wastewater treatment system to address the complex wastewater produced by their plastic plating processes.  Several streams of heavy metal contaminated wastewater are generated from their workshops that need to be treated before discharge.  In addition, the company is very environmentally conscious and wanted to reduce their overall fresh water consumption by reusing the wastewater from the process.  In 2012, a new system was built by a certified water treatment company to fulfil the client’s expectation for a ‘treat and reuse’ process.

There are four different streams of wastewater (WW) from the customer’s workshop:

  1. 312 m3/day acid/alkaline and copper WW
  2. 144 m3/day nickel WW
  3. 287 m3/day chromium WW
  4. 274 m3/day combined WW (including electroless nickel WW)

These four streams are treated separately with a reaction stage (alkali precipitation and coagulation, plus a reduction stage for chromium WW), Porex Tubular Membrane Filter (TMF™) stage for solid/liquid separation, and single or double pass reverse osmosis (RO) for desalination.  The product water is then sent back to the workshop for reuse as process water.

System commissioning began in October 2012 and performance has met the design standard.  Conductivity of the treated water (for reuse) is less than 10 μS/cm.  The recovery rate of the inner reclaim system is 80%, with the recov­ery rate of the whole factory at 66%.  Final discharge water (RO reject water, with a further treatment process) has met the required limit values and in two months 22,300 m3 of wastewater was reused.  That equates directly to an equal amount of fresh water being saved.  The Porex TMF benefits were demonstrated as a key process linking the wastewater treat­ment system to an RO desalination system.

IMPACT OF POOR DIESEL FUEL QUALITY ON AN URBAN FLEET
Barry Verdegan, Cliff Burbrink, Dakota Johnson, Sherif Abou-Rayan, Henry Amirkhanian and Amit Baddi (pages 145-152)

Modern HPCR diesel engines are more powerful, compact, reliable, quieter, and run cleaner than their predecessors.  Clean fuel is a key enabler to accomplish this.  In 2009, the New York City Transit Authority (NYCTA) experienced a series of failures that underscore the importance of clean fuel and what it takes to achieve it.  Injector deposits and dimensional changes lead to the rash of failures.  The deposits were largely attributed to elevated levels of metal carboxylates in the fuel.  The dimensional changes were the result of abrasive wear caused by particulates in the fuel.  The problems were solved through the use of detergent additives to prevent soap deposits and clean previously stuck injectors.  The use of an advanced fuel filter containing nanofibres was found to improve fuel cleanliness to acceptable levels, even under dynamic operating conditions which are common in urban driving.

INFLUENCE OF WINDING PARAMETERS ON THE PERFORMANCE OF STRING WOUND FILTER CARTRIDGES – PART 2
Someshwar S. Bhattacharya and Pragnya S. Kanade (pages 152-157)

The performance of a string wound filter cartridge is greatly dependent upon its winding conditions as well as the test conditions.  The winding variables have an obvious role to play in the filtration behaviour of any string wound cartridge used in the field.  The transmission ratio (traverse ratio/coil angle), winding on tension and the gain are important winding parameters but other than these, full package diameter, number of circumferential diamonds, speed and yarn count are equally important and play a crucial role in determining filtration behaviour.

This paper deals with the effects of the winding variables and tries to establish their influence on the performance of a string wound filter cartridge tested under otherwise identical conditions.  An attempt is also made to interpret the findings of particle size analyses so as to judge filtration behaviour.  It was found that the change in full package diameter may not be beneficial in all circumstances, whereas the circumferential diamonds formed will affect porosity of the cartridge.  A change in speed has a similar influence to an increase in winding on tension.  The fineness of the feed material is a strong factor but may be rendered ineffective if the fineness of fibres of which it is composed is not changed.

VALIDATION OF ADSORPTIVE FILTERS AND PRESSURISED AIR FILTERS
UNDER EXTENDED OPERATIONAL CONDITIONS
Hartmut Finger, Wolfgang Mölter-Siemens, Stefan Haep and Dieter Bathen (pages 158-163)

This paper describes a range of experimental test facilities and initial results for adsorptive filters and pressurised air filters.  The underlying reasons for developing the apparati are discussed and related to the various relevant testing standards.

CHALLENGES FOR CURRENT AND FUTURE WATER/DIESEL SEPARATION SYSTEMS
Dagmar Winkler, Steffen Schütz, Pius Trautmann, Jochen Reyinger, Uwe Staudacher and Harald Banzhaf (pages 164-174)

The separation of dispersed water droplets from diesel fuel is an essential process in fuel conditioning to protect the sensitive parts of modern diesel injection systems from the damaging results of the water.  The basic design idea of almost all filter solutions for water/diesel separation comprises the serial combination of hydrophilic (water coalescer) and hydrophobic (water barrier) media in various sequences.  Experimental investigations show that a range of dynamic parameters of the water/diesel system as the interfacial tension, the contact angle and the droplet size distribution influence the water separation efficiency.  Computational fluid dynamic (CFD) models for two phase flows with free interfaces are applied to analyse the influence of the flow conditions on droplet separation and release at fibrous filter media.

FOAM-AIDED SLUDGE TREATMENT
Karita Kinnunen-Raudaskoski, Pentti Pirkonen, Jani Lehmonen and Tuomo Hjelt (pages 174-180)

Both industry and domestic households produce huge amounts of wastewater and, as a result, effective sludge management is required.  One route is to reduce the amount of water in the final sludge cake.  This paper introduces a foam-assisted thickening method to improve the effectiveness of biosludge dewatering.  The method, foam-assisted dewatering (FAD), has previously been used in a paper production process in the 1980s.  The current work shows that in both static and dynamic experiments, FAD is also applicable for sludge treatment.  Foam addition to the dewatering process of biosludge from a paper mill increased the dry solids content of the wet cake and shortened the dewatering time.  In addition, the turbidity of the filtrate fell indicating enhanced microparticle retention.  Results could be utilised in industrial belt thickening and the vacuum filtration of slurries.  The expected benefits could be higher dry solids content of filter cakes, a faster dewatering rate and lower flocculent consumption.

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