Service is key in Filtration Separation

Plant Operations TechnologyS everal years ago, a large U.S. cheeseplant added an ultrafiltration systemto recover whey proteins. The plantwas specified to run 2 million lbs of wheyper day, producing an 80% whey proteinconcentrate. But upon startup, the WPC wasonly 75-77%. The lower quality concentratehad to be sold in a different market at asubstantially lower price, costing the dairyabout $15,000 a month in lost profits.The plant manager called GEA Filtration,and the company’s membrane filtrationservice personnel visited the plant,evaluated the situation and found a problem with the process design. Theyrecommended changes, helped implementthem, and trained the operators to run thesystem, bringing the WPC product up tothe 80% spec.This is one example of how lost profitscan result from improper design,incorrect operation, and lack ofknowledgeable service for membraneseparation systems. But even underordinary operating conditions, consistentservice can help maintain peak efficiencyand maximize profits. Every dairy plant is unique, producingcustom products from complex organicstreams. Although all dairies process milk,milk streams differ depending on variousconditions. The dairy pool produces a verywide spectrum of products. Cross-flowmembrane filtration processes havebecome commonly accepted as the besttechnology for many sensitive dairyseparations. It is a cost-effective means ofproducing very specific separations at lowor ambient temperatures with no phasechange. There are several basictechnologies in widespread use:Reverse osmosis is an energy-efficientde-watering process often used to pre-concentrate dairy or food streams prior toevaporation.Nanofiltration can achieve very specificseparations of low-molecular-weightcomponents, used for recovery ofhydrolyzed proteins, concentration ofsugars, and de-ashing of dairy products.Ultrafiltration is used to concentrate andpurify medium-to-high-molecular-weightcomponents such as dairy proteins,carbohydrates, and enzymes. Diafiltration is often coupled withultrafiltration for additional productrecovery, using water injection to removesolubles and wash out low molecularweight materials.Microfiltration removes bacteria andspores from milk, separates suspendedparticles, and fractionates milk proteins, aswell as recovering cleaning chemicals.Separation membranes are made fromvarious materials, with the most commonand most cost-effective for typical dairyapplications being polymeric. Polymericmembranes are available in spiral wound forhigh-volume applications with minimal orno suspended solids. Tubular configurationsare resistant to plugging, so are typicallyused where there are suspended solids orfibrous compounds. Hollow fiberpolymeric membranes have an extremelyhigh packing density and open channeldesign ideal for low solids liquid streamswhere backwashing from the permeateside is desired. For strength andresistance to extreme conditions of pH,temperature or solvents, inorganicmembranes of ceramic or stainless steel aren Contributed by GEA FiltrationService Is Key in Filtration SeparationRegular service keeps membranes in top operating conditionPlant Operations Technologythe material of choice. Ceramic membranes are often used inmicrofiltration for bacteria and spore removal.Other applications of membrane separation in the dairy industryinclude:• Protein standardization of milk prior to cheese production toincrease yield.• Concentration and demineralization of whey to reduce energycosts.• Reduction of BOD/COD loading from evaporator condensate andpermeate streams to reduce the cost of wastewater treatment.• Salt brine cleanup.• Clean-in-place (CIP) caustic and/or acid clarification and re-use.The cleaning dilemmaTypical CIP systems require three factors for proper cleaning:turbulent flow, chemical concentration, and high temperatures. Mostpolymeric spiral membrane elements are temperature limited to 50ºC(122ºF). There are also pH limitations because the membranematerial is most often cast onto polyester backing. It is very easilyhydrolyzed at high and low pH, so concentrated chemical cleaning isundesirable. And membranes are somewhat limited by structuralintegrity as to how much velocity and turbulence they will accept. Soall three of the factors required for proper cleaning are limited. Over the past ten years great advances have been made toimprove the ease of cleaning and allow gentler, yet effective,cleaning. This has allowed more widespread use of membranes forseparations and eliminated some of the problems associated withinappropriate cleaning. In order to clean properly, mild caustic isrequired, with enzymes to help break down fouling molecules andchelators to hold the broken-down products in solution.In general, membrane separation systems have a low initialinvestment, but higher operating costs due to high cleaning cost.Procedures must be set for cleaning and followed strictly, with littleroom for deviations. Service is crucial to ensure dairy operators arerunning the plant properly and cleaning it adequately.Certain types of membranes can be cleaned with chlorine, butmany will not tolerate it. Ten years ago, membrane servicecompanies would get a couple calls per year because chlorine wasput into the system by mistake and had destroyed the polymericmembranes. Dairy operations are more sophisticated now, withsegregated systems, so chlorine cannot come into contact withpolymeric membranes. The essentials There are a number of things a dairy processor should expect inthe way of service from a filtration membrane supplier. Thesecan be broken down into four categories: training; oversight/optimization; replacement membranes; and processtesting/development/design.Training: When a membrane filtration process is firstintroduced into a plant, the operators usually know little about theprocess parameters and operation. The initial service requirementfrom the filtration service company is proper training for bothsupervisors and plant operators. Consistent operations areessential for reliable performance of membrane systems. A goodservice company is like a second set of eyes. Regular follow-upvisits by the service technician will reinforce the training andcorrect any bad habits the operators may have developed.Typically, when dairy management decides to implement amembrane filtration process, the membrane provider will designthe system and either install it for the dairy or supervise in-house installation. As a part of assisting in the startup, theservice company will train the operators for most efficientoperation. Once the system is up and running, the membranesupplier’s technical representative should stop in after one tothree months to check on the process. Often the servicetechnician will find that the operators have forgotten some vitalpoint of their training or developed a bad habit that adverselyimpacts the separation. Even with processes that have been inplace for years, periodic visits by the service company willensure proper operation.Oversight & Optimization: Proper operation of a dairyseparation process will prolong membrane life. Membraneswear out gradually with constant use, and at some point the endproduct is not of sufficient quali ty. For example, inconcentration of dairy proteins, the protein is perhaps 99.5%retained the first day. After a week or two it drops to 99.4%, andso on until the membrane must be replaced. The point ofreplacement depends upon the value of the protein. The decisionto replace the membranes depends on the particular dairy’sprocedures, the value of the products, effluent standards, andpossibly other factors, as well.“We work jointly with GEA Filtration to decide when it’stime to replace membranes,” says Rick Kaepernick, v.p. ofoperations for Hilmar Cheese Co., Hilmar, Calif. “It’s definitelya team effort.”Often dairy management makes the decision to replace themembranes, but sometimes managers will attempt to delay theexpense of replacement without considering the consequencesof the loss of valuable product. A good membrane servicecompany will assist the dairy in making the economic analysisand balancing the lost profit versus the membrane cost. This isan invaluable benefit to the dairy looking to maximize profit.Replacement Membranes: As noted above, organicmembranes used for separation have a limited life span and needPlant Operations Technologyto be replaced periodically, usually about once or twice a yeardepending on processing rates and conditions. The moreexperienced the service technicians are with a particular dairy,the better able they are to know the replacement history andpredict when new membranes will be needed. A good servicecompany will stock sufficient membranes so that they areavailable when needed. In the case of catastrophic failure of the membrane, e.g., if apolymer membrane is improperly cleaned or subjected to extremeconditions, quick supply is critical to keep plants operating.“Speed of replacement service is very important to us,” says LarryWintle of Agri-Mark/Cabot’s cheese plant in Middlebury, Vt.“Sometimes there’s no indication the membrane is going bad.They just let go all of a sudden. When that happens, we need ourmembrane supplier to get them to us very quickly.”A service company may stock replacement membranes at acentral storage location, have consignment stocks with themanufacturers, and even keep replacement membranes at strategiccustomers’ sites, just for that eventuality. Process Testing, Development & Design: Top membranesuppliers often work with clients beginning in the processdevelopment phase. A dairy or other food processor might wish toisolate a particular compound from a process stream because ofvaluable functional properties. Pilot testing will determine howbest to isolate the particular component. A few membranesuppliers have process engineering expertise, supplemented byapplications centers and pilot plant facilities to help customerslearn as much as possible about the compounds involved. A rentalpilot plant can be delivered directly to the customer’s site toestablish separation data. The usual procedure is to begin with asmall pilot unit to screen various membranes for feasibility, andonce the best type of membrane is determined, further testing on aunit specific to the membrane type will refine process parameters.Where the customer is looking at an established process with notesting required, the supplier’s process engineers can design a plantand generate a proposal based on capacity and product quality.Models for optimum operationThere are as many service programs as there are membranecompanies, but the best service comes from suppliers with processexpertise. Unlike the membrane manufacturing companies, whounderstand materials science and production techniques, but notprocess applications, a membrane filtration company should havea broad spectrum of process design capabilities. Service options are best described by looking at a particularexample. GEA Filtration, a leader in cross-flow membrane filtration,has established a membrane service program with three levels ofservice designed to meet the needs of any user. The three levels ofservice are the Membrane Replacement Plan, the Membrane ServiceAgreement, and the Membrane Maintenance Program.Membrane Replacement Plan is quite simply the supply ofmembranes that enhance process performance at a competitiveprice. A large membrane stock and a very quick replacement timeare key components. Such a program should come from acompany that has relationships with all major membranemanufacturers. The program includes occasional visits by servicetechnicians. GEA Filtration’s plan is available to any dairy, eventhose who originally bought from another supplier.Membrane Service Agreement is a middle level of service.Service technicians and engineers assist the client by performingprocess audits and making recommendations for the bestperformance of all filtration systems in the plant. The clientreceives all the benefits of the Membrane Replacement Plan, withthe addition of having regular service visits that help optimizeoperations and keep processes running at peak efficiency. Theclient also has access to design and process engineering expertisefor any needs that arise.Membrane Maintenance Program is the top level of service. Aclient signs a contract for a period of time, usually three years, andpays a monthly fee for process monitoring and all the membranesrequired. A dedicated service technician makes sure that all themembranes and process systems are in tiptop shape and operatingappropriately. Constant observation through personal visits andreporting of data gives the service technician the informationneeded to optimize replacement time, and at that pointreplacement membranes are provided. If there is any type ofproblem, a call to the service technician should bring instant help.Hilmar’s Kaepernick utilizes a Membrane MaintenanceProgram for the company and says it has been very successful. The Membrane Maintenance Program has a number of majoradvantages for the customer. The service company assumes theresponsibility for membrane performance, and all membranes arekept operating at optimum levels for maximum profit. The risk ofmembrane failure is shifted to the service company. The customerhas a fixed budget. And the service program is customized for eachindividual client.Engineering, design, fabrication, and installation of membranefiltration systems are all very important. But the day-to-dayoperation, maintenance and servicing of a system are the keys tomaintaining profit levels for dairy owners. nGEA Filtration dedicated skilled technicians are able to offermany levels of customized service. The service technicians aresupported by a large process engineering department at GEAFiltration headquarters in Hudson, Wis. For more informationvisit www.geafiltration.com or call 715/386-9371.Reprinted with permission from Dairy Foods, March 2005 © 2005 GEA FiltrationNiro Inc.1600 O’Keefe RoadHudson, WI 54016Tel: +1 715 386 9371Fax: +1 715 386 9376Email: info@geafiltration.comFor European inquiries:GEA Liquid Processing Scandinavia A/SNoerskovvej 1bDK-8660 Skanderborg, DenmarkTel: +45 70 15 22 00 Fax: +45 70 15 22 44Email: info@geafiltration.dkwww.geafiltration.comCross-Flow Membrane Filtration Due to the significant growthand expansion ofourmembrane filtration activityworldwide, we at Niro Inc.are bringing the diverseexpertiseand strengths fromall the divisions of GEA underone umbrella – tobenefit youGEA FiltrationWhen it comes to dairy processing,don’t just look for components. Lookto the company that understandsyour total process and providescomplete system solutions. Look to GEA FiltrationApplication expertise includes:• Concentration of dairy products• Demineralization of dairy products• Fractionation of dairy proteins and value added components• Standardization of milk proteins for cheese production• Removal of bacteria from milk and brine• Recovery of product, water and CIP chemicalsCall GEA Filtration for membranereplacement and service.Leading Technologies. Individual Solutions.