In This Issue• Bleaching 101 Cover Page• The Brain Drain Uptime• Bike Racer Downtime• Mechanical Roll Eng. Serv. Up & Running

Copyright 2006 by TAPPI, all rights reserved.

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Volume 2, Issue7

Bleaching 101: The Basicsby Wayne Bucher. WB Consulting

Bleaching is the process of making pulp white to improve print-ing properties and its ability to absorb liquids. Bleaching alsoattacks some contaminants to reduce stray dark colored parti-cles in the final sheet of paper.

Bleaching processes add significantly to the total cost of makingpulp. Also, the environmental impact of bleaching has the closeattention of the government. Paper propertiesbesides whiteness and/or brightness areaffected by bleaching. So bleaching needs tobe optimized and managed well. Ignoring thebleaching process leads to higher operatingcosts, maintenance surprises like corrosionfailures, and regulatory problems. Small proj-ects that improve the bleaching system helpavoid major environmental expenses.

FFiibbeerr aanndd lliiggnniinn –– tthhee bbuuiillddiinngg bblloocckkss ooff ppaappeerrPapermaking fibers mostly come from wood,which is about half fibers and half dark-col-ored lignin - the glue that holds the fiberstogether. Removing lignin by cooking bright-ens the pulp. Bleaching then removes much ofthe remaining lignin. In the case of recycledfibers and mechanical pulp (made using pri-marily mechanical means with little or nochemical additives), bleaching brightens thelignin that remains in the fiber.

Chemicals used for bleaching fall into twomajor chemical categories—oxidative and reductive. Oxidationremoves lignin. Reductive chemicals are for brightening. Alkali isalso used to remove oxidized lignin. The box on the next pagelists the main chemicals and their symbols.

Frequently mills use enzymes in bleaching. Enzymes are chemi-cals made from fermented microorganisms and areenvironmentally friendly. Their complex structures are unique inattacking organic structures in the fiber. Enzymes can be very

cost effective. An example of enzyme use is controlling pitch inmechanical pulps.

TThhee TToowweerrss ooff BBlleeaacchhiinnggMost pulp bleaching systems use combinations of chemicals.The equipment is arranged in stages. Each stage starts withchemical mixing, then goes into a tower to provide retention time(measured in minutes or hours), and ends with a washer.

For chemical reactions to work, certain conditions must be met.These include the temperature, how much chemical is used, and

the pH. The pH is a measure of the acid orbase (alkaline) concentration. Adding sulfu-ric acid (H2SO4) lowers the pH. Addingsodium hydroxide (NaOH or “caustic”) raise thepH. See the left side of the Frontline Focus mast-head above to see the tower stages between thewoodpile and the papermachine.

WWhhaatt iiss ppuullpp ccoonnssiissttaannccyy??Pulp is usually moved through the variousprocesses as a water slurry. The percent ofdry fiber in this slurry is called consistency.

Pulp consistency = dry fiber weight/ wet weightof the sample x 100%

Measuring pulp consistency is necessary forcorrect dosage rate control of bleachingchemicals and it’s also an important internalaccounting function. The impact of this keyissue on overall process control is oftenoverlooked.

MMiixxiinngg iitt uuppMixing chemicals with pulp is a critical step. Uniform mixing ofgases with pulp requires more effort and attention than mixing ofliquids with pulp. The reaction time is limited by the volume avail-able after mixing (i.e. the tower size) and before the next process,pulp washing. Steam is usually added if the temperature must beraised to speed the reaction. Filtrates are recycled to conserveboth heat energy and residual chemicals.

TThhee ssttaaggeess ooff bblleeaacchhiinnggThe main work horse of bleaching is usually acidic chlorine diox-ide (ClO2), referred to as a D stage. Sulfuric acid may added tohelp lower the pH. Acids and ClO2 can be very corrosive so leaksand fumes must be controlled. The first D stage is always fol-lowed by an extraction (E) stage. This hot, high pH stage usescaustic to dissolve the lignin attacked, but not removed, in theprior stage. This darkens the pulp as more lignin is exposed.

Bleaching 101 (continued)Almost all modern stages operate continuously at about 10%-12%consistency (medium consistency).

After cooking, washing and screening the brown fiber, a typicalbleaching sequence consists of four stages: O-D-EOP-D. Oxygendelignification (O) is used to further reduce the lignin content by20%-70%. Then ClO2 is used in two stages with an E stage inbetween. Often this E stage has oxygen and/or hydrogen peroxideadded, hence the name “EOP”. This increases lignin removal andadds brightening between the two ClO2 (D) stages.

Mechanical pulps are usually bleached with an alkaline peroxidestage, a reductive stage, or both. Fiber brightening is usually themain goal rather than lignin removal. Some recovered fiber opera-tions have similar bleaching processes to brighten the fiber andany remaining ink or contaminants. Recycling’s raw material mustbe controlled and matched with the bleaching process to providestable brightness and final pulp properties.

TTaallkkiinngg bblleeaacchhiinnggTypical fiber quality parameters are brightness, a speck or dirtcount measurement (parts per million), and some aspect of thepulp fiber’s strength.

Viscosity is a common fiber strength test for virgin fiber. This testinvolves dissolving a small amount of fiber into its individual chem-ical strands. A liquid viscosity test tells a lot about final paperproperties.

As the fiber is bleached, some of the organic material is dissolvedin the effluent. The loss of weight is expressed as a yield loss.

Residuals are unconsumed chemicals at the end of the chemicalreaction. They are a waste product and can often interfere withdownstream process reactions. In some cases they will cause thebrightness to reduce, rather than continue to improve.

Trace amounts of dissolved metal ions can be a serious bleachingchallenge. Some sequences use special chemical additives calledchelants to capture and contain these metal atoms. Becausemetal ion contents in the wood and water vary a lot from place-to-place, or even season-to-season, chelant optimization must betailored to the specific situation.

EEnnvviirroonnmmeennttaall cchhaalllleennggeessIncreased environmental regulation has caused changes to pulpbleaching. Elemental chlorine and hypochlorite are heavily regu-lated by most countries and permitted now only in certainapplications. Air emissions are also regulated, usually from Dstages.

At Times I Wonder…

I wonder why our local community seems sosuccessful? It’s growing at a rapid rate.Shopping complexes and a jillion new homesare under construction. The Chamber ofCommerce just built a new building for them-selves. The old downtown area is being updat-ed and renovated. Our school system is wellregarded. Hmmmm…

I think a big part of the answer is people like you and me gettinginvolved in community affairs. Few of these folks are “professional”politicians. They’re just working people trying to make a difference.

In my paper industry career, I’ve known many papermakers that personified these characteristics. They put their money (time andenergy) where their mouth was. One was on the local school board.Another was a county commissioner. A third was mayor of his smalltown. None of these folks were professional politicians. Most hadcompleted high school and then entered the work force. All of themwanted to make their community a better place and found a way totake action.

I encourage you to take a personal inventory of your abilities and see where you can become active in your local community. Perhapsin politics or serving with the library, YMCA, or Scouting. Our localcommunity has a volunteer committee that plans the 4th of July activities. And of course there are the United Way and the manyorganizations that benefit from that effort. Ask your local industrialrelations manager which organizations your company supports andconsider lending your talents to them. If you have a good experience,to share please let me know and we’ll write about it.

I wish you success at work, at homeand in your community. Get involved!

Gene Canavan

The volume and quality of effluent—water borrowed from andreturned to the environment—are significant issues for bleachingoperations. Both environmental pressures and demand for freshwater from growing populations will continue to drive changes inbleaching. Reducing the amount of water discharged affects thebleaching chemistry because of trace chemical elements thatcome in, primarily with the wood.

Operating parameters should be optimized for each mill’s uniquesituation, including chemical cost, equipment limitations, and reg-ulations. Not only will this reduce operating costs, unique fiberand paper properties can be tailor-made, creating loyal cus-tomers. FF

Wayne Bucher is a process consultant for WB Consulting Inc.,Birmingham, Alabama, USA. Contact him at +1 205 408-1874 or byemail at wbucher@charter.net.

OXIDATIVE

• Chlorine (C)

• Chlorine dioxide (D)

• Oxygen (O)

• Ozone (Z)

• Hypochlorite (H)

• Hydrogen peroxide (P)

REDUCTIVE

• Hydrosulfite (Y), usuallysodium based

• FAS (formamidinesulfinic acid)

UptimeThe Brain Drainby William F. Hauserman

“Knowledge is better than blind practice.”Chinese Proverb

If you are a senior operator or mainte-nance technician expecting to retire inthe next several years then this article isdefinitely for you. But, if you are a morejunior employee with a number of yearsleft in your company, don’t stop reading.This article is just as valuable for you.

A recent Industry Week magazine articlerecently reported on a U.S. CensusBureau projection. Every day this year,and likely in the next several years, 7,918people will celebrate their 60th birthday.That works out to 2.89 million folks a yeargetting ready to retire. If you are a mem-ber of this baby boom retirementmigration, congratulations and thank youfor all you have contributed in your worklife.

But it also means that when you walk outthe door, walking out with you are yearsof irreplaceable troubleshooting knowl-edge and experience. That knowledgeand experience is a valuable asset foryour company and for those moving up totake your place

So what can be done to prevent the braindrain and prepare the organization forthe future? How should paper companiestake advantage of all that cumulativeknowledge and experience and skills?What’s the best way to extend your trou-bleshooting expertise? A couple of wayscome to mind.

TThhee GGoooodd BBooookkIf you are one of the future retirees, I betyou have a pocket notebook you havecarried during the years you haveworked at your mill. Or perhaps it’s a log-book or notes in your locker. In thoserecords are problem histories, machinenotes, facts about how grades or prod-

ucts run and a whole host of troubleshoot-ing information that covers the types ofproblems you’ve seen. In it will be criticalthings like what you did to correct a problem,different solutions you tried, problem fixesthat didn’t work, who was involved in theproblem solving effort - and much, muchmore. That’s valuable information that needsto be passed on to the next generation ofpapermakers and maintenance techs.

PPaassss IItt OOnnBut how do you do that? Probably the sim-plest means is to hand over your notes,providing they are in a readable format. Butwhat about what is stored in your humancomputer, in your gray matter? Maybe you

sit down with other folks and talk themthrough what you know. That’s useful, butyou likely have more accumulated knowl-edge and experience than could beexplained in a lifetime.

A better way is to enter what you know intoyour company’s knowledge managementsystem, knowledge repository, machine orproduct history files, CMMS files or otherknowledge management systems. Thattakes a coordinated effort, but it’s worth itfor those that follow you. The ability toaccess problem history files, for example,at any time of the day to discover what was

Famous Quotes“You want to have consistant and uniform muscle development across all of your muscles? It can’t be done. It’sjust a fact of life. You just have to accept inconsistant muscledevelopment as an unalterable condition of weight training”–Response to Arthur Jones, who solved the “unsolvable”problem by inventing Nautilus.

done to solve the problem - and, equallyimportant, what problem fixes were triedbut discarded - is the difference betweenworld class organizations and everyoneelse. If your organization has not createda method of storing and accessing thisvital papermaking knowledge – yourknowledge legacy – they should!

TThhee KKnnoowwlleeddggee LLeeggaaccyyKnowledge empowers people to great-ness and gives them a sense of purpose,just like it did for you. You can help stopthe brain drain by giving back to yourcompany your wisdom, knowledge andexperience if you are about to retire. Ifyou are moving up in your company, pick

the brains of these experts.Inquire about how this valu-able troubleshooting data isbeing captured and storedand how it can be accessedand retrieved to help yousolve problems quicker andcheaper and fix them right toprevent recurrence.

Knowledge is better thanblind practice. The more wecan extend troubleshootingexpertise through knowl-edge management, the morewe can extend the future,increase productivity, quality

and customer service, decrease costsand in the long run, enhance job security.And a healthy company better protectsyour retiree health and pension benefits,right? FF

Bill Hauserman is a principal consultantwith the Application Solutions Group. ASG isa TAPPI Recognized Education Provider. Formore information visit www.asgops.com.

www.npt2.net

will drop by 30%. That’s 30% less energy that you put out,because the guys in front are doing the work. When you go outfront and lead, you really have to work—but everyone behind youbenefits.”

It’s the same in the mill, says Lawrence. “It takes a lot of peopleworking together to achieve success. On a paper machine, every

person must fulfill his or her responsibilitiesto make the paper safely, efficiently, andfast. I know—I work with some of the bestpapermakers in the business.” The idea ofdrafting even extends to attitude, saysLawrence; when a team works welltogether, people are drawn along, and theywant to be a part of it.

Safety is a focus for both his mill team andhis cycling team. “When you’re cycling,there are certain rules to follow to keep fromcausing someone else to fall or stumble. Youneed to train together to develop a fluidmotion. For a machine crew to accomplishthe same thing, they need to work together,too.”

Last year, Lawrence and two of his cycling buddies tackled theDahlonega Three-Gap 50 in the north Georgia mountains. “Thatfirst climb was five miles straight up of hairpin turns. When wegot to the top—and believe me, I was not at the front!—therewere people hollering, just like you’d imagine at the Tour de

France. The real rush was coming down; those first coupleof turns, I was really shaking! But then you get into the flowof it, and it’s quite a rush. This year, we’re planning on doingthe Six Gap (100 miles).”

Lawrence’s love of speed started in 1975, when he joined hisfirst crew at Bowater’s mill in Catawba, South Carolina. “Themill had an opening on Old Blue, which at one time was thefastest paper machine in the world,” he recalls.

Lawrence is always quick to credit thepeople around him—his family, his crew atthe mill, and one special mentor: industryveteran Omega Rodgers. “I loved to listen tohim talk about his papermaking adventures.Omega had the personality to bring peopletogether and find the best in them,”Lawrence says.

“I’ll always stay active and try to take care of myself, for my familyand for work, too,” he concludes. “I have a great place to work, and

a bunch of great people to work with. I alwayswant to be an asset to the company, not a liability.By staying fit, I can still do that.” FFQuestions or comments on this story can be emailedto : jbottiglieri@tappi.org

Downtime

www.tappi.orgTo receive Frontline Focus at your mill eachmonth for FREE, contact Mary Beth Cornell

at 770 209-7210; mcornell@tappi.org

Bike racer has the need for speedby Jan Bottiglieri, TAPPI

With his crew at the mill or cruising the hills, for Robert Lawrence,life is a team sport. At work, Lawrence is crew leader on the #2Paper Machine at SP Newsprint in Dublin, Georgia. In hisdowntime, he spends hourseach week riding and racinghis bike. “People ask me how Ifind the time,” he said. “Theway I see it, I had threeoptions: fast cars, fast women,or fast bicycles. I chose thebicycles, because if anybodygot hurt, it wouldn’t beanybody but me!”

Lawrence started as a runner,but an injury sidelined himabout three years ago, at age46. That’s when he startedcycling with friends. “Afterspending 31 years working onconcrete in the paper mill, it’sone thing that I can do and nothave any pains.

“I like competition,” he continues. “Bike racing allows me to showmy level of fitness against other guys my age, and it’s just fun. Itstill reminds me of when I wasa kid; there’s a lot of freedomto it.”

PPuulllliinngg ttooggeetthheerrDuring a race, a bike team usesa technique called drafting toincrease performance. Thelead riders break the windbarrier, allowing the riders inback to be drawn along in thedraft, which saves their energy.(NASCAR drivers use thesame technique to save fuel.)

“The more people you have infront of you, the more yourheart rate drops,” Lawrence explains. “On average, ifyou’ve got three or four people riding ahead of you, your heart rate

Lawrence (kneeling) with his#2 PM crew.

Lawrence (center, aboveand in orange at right)with his cycling buddies.

Many North American mills run older,or even obsolete, paper machines.Harsh market conditions have forcedsome of these North Americancompanies to shut down. So… ishaving the latest and greatesttechnology a requirement for survival?No!

However, you are expected to be morecompetitive in terms of machinespeeds, reliability and productionefficiency. Metso Paper offers tailoredMechanical Roll Engineering Services.This includes scheduled rollmaintenance as well as reconditioningand modernization of rolls. Here aretwo typical examples of how you cansolve roll related process problems,without expensive section rebuilds.

EEddggeeBBllooww™™To ensure good sheet threading andrunnability, the suction pick-up roll ona paper or board machine must holdthe sheet firmly all the way to thetrimmed sheet edge, while the sheet istransferred to the press section andthe edge trims are cleanly separatedto the pulper. Possible problems withthe sheet or trim handling are normallyseen as web breaks due to edge trims“trying” to follow the pick-up felt to thepress, or as a sheet drop-off from thepick-up felt. As a patented MetsoPaper product for suction pick-up rolls,the EdgeBlow optimizes the sheettransferring and edge trim separatingprocesses.

Weyerhaeuser in Plymouth, NC, USAwas experiencing chronic trimseparation problems, difficult threadingand lengthy lost production times ontheir NC1 linerboard machine, until theyenlisted the help of Metso Paper inAiken, South Carolina. By modernizingtheir existing pick-up roll with EdgeBlow,the mill has eliminated the edgefollowing and web drop-off problemsthat plagued them consistently.

“The trim was not separating and theedge was dropping off on the machinedrive side,” explains John Lewis,former NC1 ProductionSuperintendent, describing thethreading problems before installingEdgeBlow. “We had lots of breaksthere.” Weyerhaeuser made a quickdecision to install EdgeBlow and, inresponse, the Metso Paper roll servicecenter in Aiken made a quick delivery,within a tight sixteen-day schedule.The effect on NC1 runnability has beendramatic. “There was a night and dayimprovement,” states Lewis. “We arevery happy with the retrofit. It is thebest relatively small investment ofmoney that we have ever spent on themachine.” Over eighty suction pickuprolls have been modernized with theEdgeBlow system worldwide.

TTrriippllee RRaaccee BBeeaarriinngg mmooddiiffiiccaattiioonn wwiitthh aadduuaall ssttaannddaarrdd bbeeaarriinngg ddrriivvee The MeadWestvaco mill in Charleston,SC, faced a chronic bearing reliabilityproblem common to manypapermakers who use original Beloit-designed CC (controlled crown) rolls.The drive-side bearing of all LX 389-model CC Rolls is a triple race design.After a successful retrofit to a Metso-supplied dual standard bearing designin December 2005, the mill has seenmuch lower vibration levels and hasmore faith in long-term roll

performance according to DavidBabson, Maintenance Supervisor. “Wecould not get one of the triple racebearings to run for more than oneyear,“ says Babson.

Like many mills, the Charleston millfound that the cost of replacing thebearing was getting much too highsince they are no longer standardproduction line items and areconsidered to be a special order.Delivery times for the obsoleteequipment can be very long. Byevaluating the high cost of the triplebearing replacement, expensivewrecks and unplanned downtime, theycalculated the return on investment forthe Metso Paper solution to be veryattractive. Babson reports that theinstallation was very easy. “The designis simple and easy to work with. Thedrive center line remained the sameand that is important because we donot have a lot of room on the machinedrive side,” he says. The roll’s initialperformance looks promising. “The rollis running great and the vibrationlevels are down considerably. Thevibration monitoring people could notbe any happier,” states Babson.

CCoonncclluussiioonnThe above are just two examples ofhow Metso Paper has helped millssolve their troubling process issues.Metso is committed to the future offiber and paper, and is the truefrontrunner and OEM presence in theindustry.

For more information, please contact:markku.tuhkala@metso.comtel: (803) 215 7301

Mechanical Roll Engineering Services – Ensuring Reliable Roll Operation

Drive lay-out after upgrade, no changesdue to roll modernization