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World Pulp & PaperTHE INTERNATIONAL REVIEW FOR THE PULP AND PAPER INDUSTRY

2012

WORLD PULP &

PAPER 2012

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WORLD PULP &

PAPER 2012


WORLD PULP &

PAPER 2012


WORLD PULP &

PAPER 2012


Cover Spread (CS5).indd 1 05/03/2012 15:04

“Buckman GREEN. Our color. Ourcommitment”. This statement conveysBuckman’s dedication to being asustainable company. It is animportant part of our culture and acornerstone of our business model. Buckman has been front and centre

in the development of enzyme-basedproducts for the pulp and paperindustry. This started many years agowith the introduction of the Neoteric®products for microbial deposit control.The Neoteric product range includesenzyme-based products andbiodispersants that break down themicrobial slime that form deposits.Another important advancement inenzyme-based solutions was theintroduction of the Optimyze® productline for stickies control. Since then, thisrange of products has been expandedwith the new Optimyze Plus products.Buckman has enzyme-based productsfor other applications includingcleaning, deinking, bleaching, andstarch conversion, to name a few.One of the newest enzyme based-

product lines is the Maximyze™ family.Maximyze is composed of enzyme-based products that modify or fibrillatefibre to give the same effect asmechanical refining with less of thenegative aspects. The Maximyze products’ mode of

action is discussed and case studiespresented.

MAXIMYZE YOUR FIBRE BASKETEnzymes have been used in variousindustrial processes for hundreds ofyears. The yeast used in beer and winemaking, for example, contains enzymesthat produce fermentation. Now,enzyme products can be and areproduced that contain one specificenzyme. This has allowed the industrial

By David R. Jones, Industry Specialist, Paper Technologies - Buckman

Maximyze your fibre basket

“BuckmanGREEN.

Our color.Our

commitment”This

statementconveys

Buckman’sdedication to

being asustainablecompany. It is an

importantpart of our

culture and acornerstone

of ourbusinessmodel

Figure 1 Typical Enzyme Temperature and pH Curves

WORLD PULP&PAPER 37

ENZYMATIC FIBRE MODIFICATION

use of enzymes to expand. One areawhere the use of enzymes isexpanding is in the pulp and paperindustry. Some pulp and paperprocesses that utilise enzymes includedeinking, bleaching, deposit controland starch conversion. An innovativeuse of enzymes is in fibre modification.Buckman introduced the Maximyze

product line six years ago. Since theintroduction of Maximyze, over 60mills around the world are reaping thebenefits of this technology.What are enzymes? They are

nature’s catalysts. Enzymes areprotein-based molecules that catalyzethe various reactions in all livingthings, i.e., respiration, nutrients and

PAP4p37-40Buckman_Layout 1 29/02/2012 15:58 Page 37

growth. Enzymes are true catalysts inthat they are not consumed in thereaction, and each enzyme moleculecan catalyze thousands and thousandsof reactions per second. Enzymes arevery specific to the reaction that theydrive. Each individual type of enzymedoes one thing and one thing only.Enzymes are complex molecules andtheir shape determines their function.The reaction rate of an enzyme

varies with pH and temperature. In thecase of temperature, as thetemperature increases, the reactionrate or enzyme activity rate increases.This increase is fairly linear until atemperature comes to a point wherethe enzyme molecule breaks down.This breakdown is called denaturingand is not reversible. The pH effect isdifferent; each enzyme type has a pHwhere the activity is at the highest. Asthe pH goes up or down from thatpoint, the enzyme activity decreases.The effect of this is that each enzymetype has an effective pH range. ThepH effect is reversible. For example, ifa given enzyme has a maximumactivity at pH 7 and the enzyme is in apart of the process that has a pH of 5,then the activity will be lower than themaximum. However, if you change theprocess pH to 7, then the enzyme willonce again be at maximum activity. The temperature and pH activity

curves vary from enzyme to enzyme.The curves above are examples andare not specific to any of the Maximyzeproducts. It is important to know thetemperature and pH curves for theenzymes that you are utilising toensure that system parameters matchthe product. Other factors that affectthe activity of enzymes are inhibitingand denaturing compounds. A goodexample of a denaturing compound is

chlorine; most enzymes can onlytolerate a fairly low level of freechlorine. This denaturing isirreversible. Inhibiting compoundsblock the activity of the enzyme. Theinhibiting compound can block the siteof the reaction or attach to theenzyme. Inhibiting compounds do notdenature the enzyme; they just inhibitthe enzyme’s activity. The compoundsthat inhibit activity vary from enzyme toenzyme.In any enzyme application system,

system knowledge is essential.Temperature, pH and processadditives need to be known anddocumented. Other essentialinformation includes tank and chestvolumes, levels and flows. Thisinformation is important to calculateretention time in the system. The morecontact time there is the more eachenzyme molecule can do. Systemknowledge is one of the Buckman 8Business Management Standards thatensure communication and a truepartnership between all stakeholders.


WORLD PULP&PAPER 38

Figure 2 Buckman’s 8 Business Management Standards

The Maximyze products are enzymesthat work on the cellulose chain in thefibre. Mechanical refining is used toimpart various characteristics to fibre,depending on the grade and type ofwood. Mechanical refining is employedto increase tensile, internal bond andother sheet properties. The mechanicalrefining ‘beats’ the fibre, damaging thefibre wall. This weakening leads to wallstripping, delamination, collapse andfibrillation. This increases the sites forfibre-to-fibre bonding and, therefore,increases sheet strength propertiessuch as tensile.Maximyze does on a molecular level

what mechanical refining does on amacro level. By breaking bonds in thecellulose chain the fibre is weakenedand wall stripping, delamination,collapse and fibrillation occur. TheMaximyze is working at the bond levelso there is less fibre cutting and finesgeneration than with mechanicalrefining. You can think of the fibre as arope made up of many strands. Ablade can cut the rope. This is similar

Replacingsoftwoodkraft withhardwoodkraft andreducing

mechanicalrefining givesimproved

softness, animportantquality for

tissue grades

PAP4p37-40Buckman_Layout 1 29/02/2012 15:58 7

WORLD PULP&PAPER 39

Figure 3 Maximyze Activity – Before (left) and After (right)

to what occurs in mechanical refiningto some extent and is one of thedownsides. Thinking about the samerope, Maximyze would have to cuteach individual strand to cut all theway through the rope. Given enoughtime, this could occur, but a well-designed application will prevent thisfrom happening. In most cases,Maximyze is added before themechanical refining. Maximyzepreconditions the fibre and widens thewindow of refining. In some mills,mechanical refining has beencompletely bypassed and all refining isdone with Maximyze. Thephotomicrographs above show theeffect of Maximyze on fibre. It can beseen that fibres are collapsing andflattening out. Maximyze is providingpositive ROI to many mills usingbleached kraft. These mills produce anumber of different paper grades.Tissue mills can especially benefit fromthe use of Maximyze. The benefitsinclude reduced production cost by thereplacement of softwood kraft with

hardwood kraft or by replacing virginkraft with deinked MOW (mixed officewaste) pulp. Another benefit for tissuemills is improved sheet characteristics.Replacing softwood kraft withhardwood kraft and reducingmechanical refining gives improvedsoftness, an important quality for tissuegrades.

CASE #1 – MAXIMYZE 2545APPLICATION IN A NAPKIN GRADEOne of the first applications forMaximyze was a tissue mill producinga napkin grade using virgin kraft anddeinked MOW pulp. The furnish mixwas targeted at 33% kraft and 67%MOW. To meet sheet strength targetsrequired increasing kraft content up to40%. Maximyze 2545 was introducedinto the pulper at 1.0 kg/tonne andnow this napkin grade is producedwith 100% MOW and no refining. Thecost differential between the virginkraft and the deinked pulp results in avery positive ROI (return oninvestment).

CASE #2 – MAXIMYZE 2545APPLICATION IN A PREMIUM BATHGRADEMaximyze has also allowed a tissuemill to improve sheet qualities on apremium bath grade. To meet sheetstrength targets the mill needed tomechanically refine a 100% virgin kraftfurnish. The refining resulted in a lossof sheet softness. Maximyze 2545 wasagain the product of choice, and itsapplication resulted in the eliminationof mechanical refining. This resulted inan increase in bulk to basis weightratio and improved sheet softness.Maximyze 2545 was added to thepulper at 1.0 kg/tonne.

CASE #3 – MAXIMYZE 2530APPLICATION IN A PREMIUM BATHGRADEA mill is producing a premium bathtissue grade with a mix of virgin kraftand deinking MOW pulp. To meet thetarget for tensile the mill had tooverweight the sheet by 0.5 g/sqM anduse a dry strength additive. The use of



WORLD PULP&PAPER 40

the dry strength additive required theaddition of a cationic coagulant forcharge control. The coagulant resultedin a brightness loss and, therefore, itwas necessary to use an opticalbrightening additive (OBA) to meet thebrightness target. Maximyze 2530 was introduced and

the results were dramatic. The mill isnow able to produce this grade attarget basis weight with no dry strengthadditive, no cationic coagulant and noOBA. Furthermore, the mill has beenable to eliminate mechanical refining.The application rate for the Maximyze2530 is 0.25 kg/tonne. All of thebenefits from the introduction ofMaximyze 2530 add up to a reductionin production costs of US$30/tonne.

CASE #4 MAXIMYZE 2535 APPLICATIONIN AN UNCOATED FREE SHEETA mill has to mechanically refine at ahigh level to meet its targets forstrength and porosity. The high refininglevels caused excessive cutting andfines generation. This led to reduceddrainage and loss of strength. Thestrength loss meant that filler levelswere limited and a higher percentageof softwood kraft was needed in thefurnish mix. When Maximyze 2535was started the mechanical refiningwas decreased. This allowed thefollowing results to be achieved:reduced softwood kraft by 5% (basedon total softwood), increased fillercontent by 1% and increasedproduction rate by 6% This was allachieved with improvements in sheetqualities such as internal bond andsmoothness. Overall, the total ROI isequal to US$29/ tonne.

CASE #5 MAXIMYZE 2563 APPLICATIONTO CONTROL VESSEL ELEMENTSMaximyze is proving to be a greatasset to pulp and papermakers in

many areas. One area that has been achallenge to many papermakers isvessel elements. Vessel elements are abig problem in mills using fast-growingtropical hardwoods. In printing papersvessel elements can cause picking andlinting. In the printing process thesevessel elements can be pulled fromthe sheet and deposited on printingrolls. This leads to breaks andproblems with print quality. Maximyze has proven to be a

successful solution to vessel elements.The enzymes in Maximyze work on thevessel elements to weaken them. Theeffect on the vessel elements is greaterthan on the fibre as the vesselelements have a greater surface area.The weakened vessel elements arethen more susceptible to being brokenup in mechanical refining. A mill is producing offset paper with

a furnish of 100% tropical hardwood.Vessel elements were causing issueswith picking. To control this picking themill needed to increase mechanicalrefining and use increased levels ofstarch at the size press.Maximyze 2563 was introduced at

an application rate of 0.5 kg /tonne.The results were a reduction of 20% inmechanical refining energy andreduced size press starch usage.Picking as measured with the IGT testwas reduced by 60%. The reduced picking allowed the mill

to increase the selling price of itspaper. The increased revenue, alongwith the starch and energy savings, isestimated to be worth at leastUS$1,000,000 per year.One important aspect of the use of

enzymes in industrial processes is the‘green’ aspect. Enzymes are naturallyoccurring in nature and have lowenvironmental impact. Enzymes have alow health hazard to workers whencompared to many industrial

chemicals. Buckman is heavilyinvolved in supplying enzyme solutionsto pulp and paper, and our R&DDepartment is working on expandingexisting applications and developingnew innovative applications forenzymes. Being a sustainable companyis important to Buckman.Buckman’s sustainability message is

captured with “Buckman GREEN. Ourcolor. Our commitment.” As well asensuring that Buckman’s internalprocesses are sustainable, we work aspartners with our customers to assistthem to reach their sustainability goals.A good example of this is replacing adry strength additive with Maximyze.This reduces toxicity to the effluent andalso has ROE (return on theenvironment) for reduced shipping.The volume of a dry strength additive ismuch greater than for Maximyze, sotrucking costs and the use of fossil fuelis greatly reduced.Maximyze is proven technology that

has delivered ROI and ROE to manymills around the world. This innovativeenzyme based product line works onthe fibre to produce the same effectsas mechanical refining with less of thedownside of mechanical refining suchas fibre cutting and the production offines. Maximyze is delivering benefits inpulp substitution, improved sheetqualities and elimination of otherstrength additives. Mills experiencingissues with vessel picking are alsobenefiting from the application ofMaximyze. Other pulp and paper grades that

are investigating the potential benefitsof a Maximyze program are marketkraft pulp mills and lightweight coatedoperations. Buckman continues toresearch further applications of theMaximyze product line, an exampleof which is use in mechanical pulpssuch as TMP.

Thisinnovativeenzymebased

product lineworks on the

fibre toproduce the sameeffects asmechanicalrefining withless of thedownside ofmechanicalrefining, such

as fibrecutting and the

production of fines


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