Alfa Laval - membrane filtration · 2018-06-06 · Alfa Laval – membrane filtration 5 Reverse osmosis (RO) Reverse osmosis uses the tightest possible membrane in liquid separation

Alfa Laval - membrane filtration

It’s all about size

Membrane filtration enables you to bring downoverall production costs, and boost product quality – both at the same time.

Alfa Laval’s experience within membrane filtrationdates back almost as far as the technology itself,and we wish to share our experience with you.

Membrane filtration complement our range ofseparation technologies and allows us to provide youwith the most efficient solution.

2 Alfa Laval – membrane filtration

What is membrane filtration?

Physical separationMembrane filtration is a physical sep-aration process in which the drivingforce is the difference in pressurebetween the two sides of a specialmembrane. This process is character-ized by the ability to separate mol-ecules of different sizes andcharacteristics.

Almost all industrial membrane filtrationis carried out as cross-flow filtration,where the liquid being filtered flowsparallel to the membrane at high vel-ocity and under pressure.

Physical barrierIn its most basic terms, membranefiltration involves passing a single feedstream through a membrane systemthat separates it into two individualstreams, known as the permeate andthe retentate. The membrane thatseparates them is a physical barrierwith highly specialized characteristics – a barrier that only certain selectedcomponents in the feed stream canpass through.

Passing throughThe pores of such membrane materialare so small that they are measured inAngstrom (10-10 m), and pressure isrequired to force the liquid throughthem. In fact, the pores in themembranes used for nanofiltration andreverse osmosis are so small that theycannot be seen even with a scanningelectron microscope.

Small-scaleTo put the size of these pores intoperspective – it has been said that ifone square foot of membrane materialwere the size of the entire PacificOcean, one single reverse osmosispore in that material would be roughlythe size of a US dime.

Types of membrane filtrationThere are four commonly acceptedcategories of membranes. These aredefined on the basis of the size ofmaterial they are required to separatefrom the feed liquid. The membranetypes are known as reverse osmosis,nanofiltration, ultrafiltration andmicrofiltration, in order of increasingpore size.


Alfa Laval – membrane filtration 5

Reverse osmosis (RO)Reverse osmosis uses the tightestpossible membrane in liquidseparation. In principle, water is theonly material that can permeate themembrane. All other materials (salts,sugars, etc.) will be unable to passthrough.

Nanofiltration (NF)Nanofiltration is not as fine a separationprocess as reverse osmosis, and usesmembranes that are slightly moreopen. Nanofiltration allows small ionsto pass through while excluding largerions and most organic components.

Ultrafiltration (UF)Ultrafiltration involves using membranesin which the pores are larger and thepressure is relatively low. Salts, sugars,organic acids and smaller peptides areallowed to pass, while proteins, fatsand polysaccharides are not.

Microfiltration (MF)In microfiltration, suspended solids,bacteria and fat globules are normallythe only substances not allowed topass through.

This makes it possible to operate acontinuous, automated filtrationprocess that results in a consistent,controllable product quality. No filteraids are needed, and the membraneshave an extended lifetime.

Membrane filtration provides manysignificant advantages when used inindustrial-scale applications wherereliability, consistency and operatingcosts are crucial considerations.

These advantages include:• Lower overall production costs• High end product quality• Flexibility

Lower overall production costsMembrane filtration systems are oftenless expensive than many otheralternative technologies. The installationcosts are lower, as are the energycosts.

Corporate Brochure 8

Membrane filtration – built-in advantages


Cross-flow filtration Dead-end filtration

Membrane filtrationMembrane filtration can be either dead-end filtration or cross-flow filtration.

Cross-flow filtration provides significantbuilt-in advantages over dead-endfiltration. Because the liquids beingprocessed flow continuously across themembrane, there is no filter cake thatcan lead to fouling and uneven flow.


Membrane filtration includes fewerprocessing steps and makes it possibleto achieve both a greater degree ofpurity and higher overall yields.

In addition, because membranefiltration does not result in a filter cake,there are no costs associated with theremoval and disposal of this residue.

High end product qualityMembrane filtration is a cleantechnology. The separation process iscarried out solely on the basis ofmolecular size, making the use ofadditives unnecessary. This results inan end product with top quality, andmakes it easier to comply with themany stringent requirements from bothconsumers and public authorities.

FlexibilityMembrane filtration can be used forfeed products with a range of differentviscosities, including high-viscosityproducts that can otherwise be difficultto process. A wide range of differentmembrane filtration products alsoensures that the best possible solutionis available for each particularapplication. This also eliminatesunnecessary energy costs.

Alfa Laval membrane filtrationequipment is designed on a modularbasis that gives a high degree offlexibility, as membranes are built intomodules, modules are built into loopsand loops are built into systems. Thedesign of a system can thus becustomized to meet any process needs

and it is easy to expand if productionrequirements increase. This means thatyour investment can follow anyrequired increase in productioncapacity, as and when you need it – and at relatively low additional cost.

At Alfa Laval, we take pride insupplying our customers withcomplete, optimized solutions that takeevery aspect of the process intoconsideration. These are designed onthe basis of feed product composition,production parameters, final productrequirements and costs. The solutionthen selected can be based on Plate &Frame, spiral elements or acombination of both.

Membrane filtration solutions

Diafiltrationwater

CIP water

CIP liquid recycle

CIP liquid recycle CIP liquid

recycle

Feed

Coolingwater in

Diafiltration water recycle from RO/NF permeate

Concentration/diafiltration

Concentration/diafiltration

Pre-concentration

Permeate

Coolingwaterout Cooling

water in

Coolingwaterout Cooling

water in

Coolingwaterout

Retentate

UF loop no. 1 UF loop no. 2 UF loop no. 3

Yield control


Figure 1: Ultrafiltration system incorporating diafiltration

Feed (permeate containing product from upstream MFS)

Permeate recycle for UF diafiltration water system

Permeate

Coolingwaterout

Coolingwater in

RO/NF loop no. 1

Coolingwater out

Coolingwater in

Retentate

RO/NF loop no. 2

Concentration Concentration

CIP liquid recycle

CIP liquid recycle

CIP waterCIP liquidrecycle

Concentration control

Figure 1 shows a Plate & Frameprocess, which is often used toprocess high suspended solids andviscous feed solutions.

Typical applications include therecovery of antibiotics from wholebroth, concentration of enzymes anddextrans and clarification of juice.

Figure 2 illustrates a spiral system ofthe kind typically used for applicationssuch as the concentration of

antibiotics, enzymes, yeast extract, eggwhite and juice, as well as for reducingthe alcohol content in beer.

The system can also be equipped withultrafiltration or microfiltration spiralmembranes for concentration,clarification and purification.

The processes in figures 1 and 2 canalso be combined, which gives theadvantage of using permeate from thespiral process as diafiltration water inthe Plate & Frame process. Thisreduces the need for process water.


Don’t forget:● Pre-treatment – to reduce fouling ● Automation – to secure the best overall plant operation● Cleaning procedure – to promote optimum membrane performance

Figure 2: Reverse osmosis or nanofiltration systemwith option for permeate recycling to upstream ultrafiltration process.

Spiral booster unit increases capacity by 50%“When we had reached the limits of ourcapacity, Alfa Laval provided us with analternative to extending the drying unit – byinstalling a "booster unit" in the form of aspiral section prior to the existing Plate &Frame unit".

This spiral-wound membrane filtration unitundertakes preliminary concentration of theblood plasma sent from the Danish Crownslaughterhouses, and increases the proteincontent fom 7 to 8.5%. This means that we

can now boost our production capacity by50% – without making any changes to thedrying unit. Obviously, it’s much cheaper toremove water by simply filtering it out, ratherthan having to use a relatively costly dryingprocess to remove it. An extra bonus is thatthe spiral membrane unit doesn’t take up anyfloor space – we were able to justmount it on the wall in the filtration room.”

Svend Aage Christensen, Plant Manager,Edidan/Danish Crown, Denmark

Membrane filtration can be used in a wide range of differentprocesses. Alfa Laval’s experience in this field dates back as faras the mid-sixties, soon after membrane filtration was introducedon a commercial scale. Our many reference installations can befound across a wide range of industries, which include:


AntibioticsRecovery and purification of different antibiotics, including lactames, aminoglycosides, polypeptides, tetracyclines andmacrolides. For increased efficiency and higher product quality.

EnzymesConcentration, purification and desalting following fermentation. Can also be used to recover enzymes from animal orplant tissue. For higher concentration and purity with a minimum loss of activity.

DextransConcentration and purification in one process at low cost.

Pyrogen removalFor high product quality and reduced contamination problems.

Yeast extractConcentration and purification, with recycling of permeate. High purity at minimum operating costs.

BeerDealcoholization, which typically involves reducing alcohol content by a factor of 8–10 and provides a quality in line withstandard beer at low cost. Filtration of beer as alternative to traditional kieselguhr or diatomaceous earth filtration for highbeer quality with no waste disposal. Sterile filtration of beer prior to packaging for high shelf-life with no heat impact.

Food gumsConcentration and purification of substances such as carrageenan, agar, agarose, xanthan and pectin, with recycling ofpermeate. Inexpensive and reliable way to remove water and low molecular weight impurities.


JuiceClarification and concentration of apple, strawberry, orange, blackcurrant, pear, hawthorn, pineapple and date juices. Forhigh-quality products at low operating costs and with a minimum use of additives.

EggsConcentration and purification of egg white and whole egg. Dewatering of egg white prior to drying. For gentle treatmentand high-quality products.

SugarRemoval of haze and colour from sugar syrup. Concentration of sugar water. Environmentally friendly process that resultsin highly uniform products.

Animal blood plasmaConcentration and purification of blood plasma, with recycling of permeate. For high-quality product at low operatingtemperatures.

GelatineFractionation, concentration and purification. For gentle processing to avoid denaturing.

VinegarSubstitution of many steps in the traditional clarification/filtration process. Reduces storage time and requires no use offilter aids.

In addition to these specific applications, we are continuously developing and expanding our know-how in these fields.Our experience with membrane filtration can bring significant advantages to many industrial processes.


The product range

MembranesThe range of membranes from AlfaLaval covers all filtration processes – reverse osmosis, nanofiltration,ultrafiltration and microfiltration. Theyare resistant to high temperatures anda wide pH range. All materials complywith EU Commission Directive 90/128EEC + amendments and FDAregulations (CFR), Title 21.

Our range of flat sheet membranes isavailable by the metre, as 20x20 cmsheets and for all Alfa Laval Plate &Frame configurations. We have acomprehensive range of spiralelements, with different combinationsof membrane, diameter, length andspacer. The spiral elements all feature afull-fit sanitary design.

Membrane filtration systemsAlfa Laval designs, manufactures andinstalls complete cross-flow membranefiltration systems. These can be basedon either our unique Plate & Framemodules or on spiral elements ofvarying sizes. For some applications, acombination of both types can be usedto give the best possible solution.

We develop our systems in closecooperation with customers and canprovide batch and continuousoperation as well as sanitary andindustrial design. Validation support isavailable, as is support in installationand commissioning.

Alfa Laval Plate & Frame modules aredesigned to handle a wide range ofviscosities and can therefore matchvarying feed product characteristics.Our spiral modules are a compact,inexpensive solution that is easy to use.

Pilot laboratory equipmentIn order to ensure the optimumsolution, it is often advisable toconduct experiments on a small scale.These can be used to establishprocess feasibility, determine designdata for scale-up, optimize existingproduction lines or even carry outsmall-scale processing of high-value/low-volume products.

Alfa Laval provides pilot laboratoryequipment both for testing on site inconnection with other processequipment and for testing at our ownstate-of-the-art pilot facilities inNakskov, Denmark. In both cases, wealso provide highly skilled processconsultancy services.


Service and spare partsTo ensure maximum benefit frommembrane filtration systems, it isimportant that customers plan serviceintervals carefully and use the rightspare parts.

Using Alfa Laval service programmesand genuine spares helps ensure:● better plant economics ● maximum service efficiency ● more reliable operations

To do this, Alfa Laval providescustomers with:● tailormade Alfa Laval service

agreements. These can include performance analysis, upgrading, remembraning and operator training.

● membrane replacement using genuine top-quality membranes and other spare parts

● plant component audits that help boost both output and quality

● appropriate Cleaning-in-Place (CIP) procedures to ensure optimum performance at all times

The Alfa Laval Parts & Serviceorganization ensures customers ahighly efficient service and spare partsinfrastructure with visible bottom-linebenefits.

This overall concept is called Alfa LavalNonstop Performance, and aims atensuring that our customers’processes always run at peakperformance.

Reliable performanceThrough 16 years of collaboration, Alfa Laval has installed, restored andreplaced a number of membranefiltration systems. “For us, theimportant things are an informal yetclose collaboration, mutual trust,willingness to cope with problems, anda high degree of professionalism.

It is a pleasure to work with a companythat acts like a real partner, rather thana mere supplier. It’s exactly what we’re trying to provide for our owncustomers.”

Tomasz Cieslewski, site manager,Lonza Biotec, s.r.o., Czech Republic

Complete familiarityBuying membrane filtration solutionsfrom Alfa Laval means you are tappinginto the know-how and experience thatcomes from complete familiarity withevery step of the process. The expertAlfa Laval staff are probably unique intheir ability to address your needs atwhatever stage of the process chain.This is because we ourselves develop,manufacture, install and service themembrane filtration systems.

And with experience extending as farback as 1965, Alfa Laval specialistscan develop and fine-tune a solutionthat meets your exact needs,combining your expertise in yourparticular field of processing with ourunparalleled membrane filtration know-how.

Complete consistencyWhen you include membrane filtrationtechnology in your process solutions,you need to know that you can rely onit completely.

At Alfa Laval, we can be sure of thequality of the membranes we provide.We are one of the few companies inthis field with the capacity, expertiseand experience to manufacture themourselves.

Completely testedWe are also one of the very fewcompanies in the world that can scaleits membrane filtration know-howseamlessly from R&D, testing and trialsup to full-scale manufacture, andprocess implementation that you andyour company can rely on – completely.

Alfa Laval has its own extensive testfacilities in Nakskov, Denmark. Thesefacilities allow us to invite you to workalongside with our expert staff todevelop solutions for your specificprocess. We also have a wide range ofpilot laboratory equipment available if itis more convenient for you to do thework on your own premises.

Membrane filtration and Alfa Laval


Size mattersThe pores of the membranes used inmembrane filtration are so small thatthey are invisible to the naked eye.

Yet separation on this diminutive scale,working on the basis of molecular sizealone, results in benefits that arecorrespondingly great in importance.

Alfa Laval membrane filtration systemsmake it possible to achieve a greaterdegree of purity, higher overall yieldsand lower costs.

Small size can make a very bigdifference.

Experience countsOur experience within membranefiltration extends almost as far back asthe technology itself – and Alfa Lavalsolutions give you the full benefit of allthat accumulated experience.

Membrane filtration complements ourrange of other separation technologiesand ensures that we are always in aposition to provide you with the idealsolution for your particular process. Byusing membrane filtration alone or incombination with our range ofcentrifuges, decanters or evaporators.


Complete spectrumAlfa Laval can provide customers withsolutions from the full spectrum ofseparation technologies.

This means that when you contact Alfa Laval, you can always be sure ofgetting a solution tailored to yourspecific process requirements. At Alfa Laval, we have the capacity andthe technology spread to be able toconsider all the parameters – knowingthat we can provide a highly efficientsolution using the best technology forthe job. Or a combination oftechnologies if this will improve thetotal performance.

Membrane filtration crucial

for artificial plasma

Serumwerk Bernburg in Germany

installed its first membranes from Alfa Laval

in 1996, to produce hydroxyethyl starch for

medical uses as artificial plasma.

Membrane filtration proved to be crucial in

the manufacture of pure hydroxyethyl starch.

Advanced ultrafiltration membranes are

needed to remove by-products and ensure

that only molecules of a specific size are

retained. It is also important to ensure that

the processed products are sterile, and

“ultrafiltration at high temperatures is how we

stop the growth of germs, a hugely

important criterion for our choice of

membranes,” says Werner Zimmermann,

head of technology at Serumwerk Bernburg.

Due to the modular design of the

membrane filtration system, it was easy

for Serumwerk Bernburg to double the

company’s production capacity in 2002

and Werner Zimmermann states, “We want

to achieve another doubling of capacity

next year...”

Werner Zimmermann, head of technology,

Serumwerk Bernburg, Germany

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Alfa Laval in brief

Alfa Laval is a leading global provider ofspecialized products and engineeredsolutions. Our equipment, systems andservices are dedicated to helpingcustomers to optimize the performanceof their processes. Time and time again.

We help our customers to heat,cool, separate and transport productssuch as oil, water, chemicals,beverages, foodstuffs, starch andpharmaceuticals.

Our worldwide organization worksclosely with customers in almost 100countries to help them stay ahead.

How to contact Alfa LavalUp-to-date Alfa Laval contact details forall countries are always available on ourwebsite at www.alfalaval.com

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Alfa Laval - membrane filtration · 2018-06-06 · Alfa Laval – membrane filtration 5 Reverse osmosis (RO) Reverse osmosis uses the tightest possible membrane in liquid separation