The Benefits of Enzymes in Pulp & Paper Processes Tom Woodward Director of Technology EnzKem Associates
EnzKem Associates Tom Woodward, Jack Turner and John Gurganious Over 30 years experience each in Pulp & Paper Processes EnzKem Technologies - Enzymes for Pulp & Paper Biobleaching Stickies Control Wet Strength Repulping - Pulp Mill/Bleach Plant Scale Control - Deposit Control pitch/stickies - Felt/Fabric Cleaning/Conditioning - Polymer Technologies
Pulp & Paper Enzyme Applications Discussion Topics Deinking Pitch reduction Wet strength repulping Stickies control Biorefining Biobleaching Strength Improvement
Common Pulp & Paper Enzyme Types Cellulases Xylanases Lipases Esterases Amylases
Diki Deinking Primarily Cellulase and Amylases Break Ink-Cellulose linkage Degrade Some Inks Remove Fibrils on Ink Surfaces Open Pulp/Fiber Matrix 83% increase in dirt removal efficiency and 36% reduction in ppm dirt with 0.02% cellulase and 0.02% amylase Data from Buckman
Fiber Modification Biorefining
Cutting Fines Formation External Fibrillation Internal Fibrillation Refining Effects Most important is increasing fiber flexibility and fibrillation by roughening fiber surface and breaking down intrafiber walls to increase swelling Effects can be obtained with enzymes Problem is controlling damage to fibers
Enzymes For Fiber Modification (Biorefining) i Objective is to develop enzymes that will allow reductions in refining energy, improved physical properties and increased strength of recycled papers while minimizing fiber damage Data to date is mixed shows potential but enzymes were never optimized
Enzymes in High Density Papers-2000 Genencor, Nalco, VTT - Effect of enzymes thought to be result of fines hydrolysis and modification of colloidal polysaccharides on fiber surfaces Most reactive are endoglucanases Achieved significant decrease in freeness at same refining level Showed careful enzyme application can increase strength by improving fiber flexibility
Some Effects of Biorefining i Genencor Shift in refining curve Must be willing to unload refiners to see the change Enhanced sheet strength and surface properties Enhanced refining and washing efficiency Reduced energy and steam consumption Higher throughput and production rates Improved process water quality Lower wet end chemical use
Farrell, 1997, Cartapipon chips Showed some reduction in energy to refine pulp to given freeness and some increase in both tensile and tear at given energy consumption
Refining With enzymes Seo et al 2000 used cellulase rich/xylanase from Ciba Enzyme added before refining decreased time to given freeness 50 75% by weakening fibril chains improved drainage when added after refining Must use brushing refining to minimize cutting and fiber damage Enzyme treatment significantly reduced zero span tensile and tensile for SW but not for HW No enzyme application optimization was attempted
Enzyme Effects on Drainage & Strength of OCC Eik Eriksson, Hit Heitman, Venditi, NC State t 1997 0.2% enzyme treatment reduced freeness by 50% at equivalent refining Decreased average fiber length Increased fines Showed significant potential for decreasing refining to equivalent freeness Enzyme can cause significant fiber damage during refining Application must be optimized
Enhancement of Wood Pulps With Cellulolytic Activity Dyadic TAPPI Conference 2005 Decreased refining energy 18 66% Increased throughput Improved ddrainage Cleaner water loops Potential strength improvement No optimization
Lipases Objective is a reduction in pitch deposition by hydrolyzing triglycerides Problem has been the resultant formation of fatty acids The following pilot plant trial results summarize the issues of lipase technology for pitch control
Lipase Pilot Trial Results TMP - Enzyme treatments hydrolyzed up to 85% of the pulp triglycerides into fatty acids - Low level enzyme treatment resulted in 10% increase in cross directional tear-index probably due to liberated fatty acids hindering bonding. - Tensile index at low level enzyme treatment was unchanged with a small decrease (3%) at the high dosage, most likely due to liberated fatty acids that decreased bonding. - Brightness was improved by 0.5% units ISO Brightness. - Machine runnability was not affected by the enzyme EnzKem Experts I Pulp & Paper Processes
Pilot Trial Conclusions - Strategies to control accumulation of liberated fatty acids (washing/fixation) are required and would lead to a significant reduction in pitch deposition potential. - Enzyme addition at the latency chest should minimize fatty acid levels on the paper machine E K
Enzymes For Stickies Control Most stickies contain ester linkages that can be hydrolyzed (cleaved) by esterases and converted into innocuous substances bt
Stickies A descriptive term which encompasses a myriad of tacky contaminants ranging from tape adhesives to plastic films to hot melt glues that enter the papermaking system via recycled paper stock. Primary: Solid Sticky Particles Secondary: Potential stickies Formed From micro stickies and Dissolved and Colloidal Organics Macro: Rejected by 100 or 150 Micron Slotted Screen Micro: Accepted by 100 or 150 Micron Slotted Screen and > 2 microns
EnzKem E-200 EnzKem E-200 is an enzyme complex developed d to hydrolyze a wider spectrum of substrates than other enzymes being used thereby providing better stickies control Reduces stickies counts by more than 70 %.
EnzKem E-200 Application i EnzKem E-200 is added to the pulper at 25 45 grams/ton Active ph range is 4.5 to 8.5 Ati Active temperature t range is 25to 60degrees Centigrade
EnzKem E-200 Monthly average values of Total Stickies Count at the wire pit of an OCC recycling mill using the wide spectrum esterase. The red bar indicates the Base Line value. 36.00 31.00 Mi illions/ml 26.00 21.00 16.00 11.00 6.00 100 1.00 INITIAL ARIL MAY JUNE JULY AUGUST Month
EnzKem E-300 AN ENZYME FOR REPULPING WET STRENGTH PAPERS
Wet Strength In Paper Polyaminoamide-epichlorhydrins (PAE) are the most common wet strength agents used in the paper industry Typical resin level in paper p 0.4 1.0% Materials with wet strength resins are very difficult to repulp because of the structural stability of the polyamide chain These chains need to be cleaved with high ph, temperature and oxidizing agents to separate fibers
Wet Strength Repulping Methods Unbleached paper & board - High ph (11+) - High temperature (70C) -High mechanical energy input (60 min+) Typically get 50% repulped din 60 minutes Bleached paper & board - High ph - High temperature - High mechanical energy input - Oxidizing agents (e.g. hypochlorite) Can get 60% repulped in 60 minutes
EnzKem E-300 EnzKem E-300 is an enzyme complex for wet strength resin hydrolysis. The enzyme hydrolyzes the wet strength resins, breaking the linkages and reducing the structural stability of the polymer, which allows fibers to be separated with a minimum amount of energy.
EnzKem E-300 Application Conditions Feedrate. 40 60 g/ton Feedpoint Directly to pulper ph. 5.0 to 8.0 Temp 120 to 160F Time.. 30 minutes No oxidizer necessary
EnzKem E-300 Dosage effect of an enzyme for wet strength resin hydrolysis on fiber re-pulping time. 6.0 5.0 4.0 Mi inutes 3.0 2.0 1.0 0.0 0.0 40 60 80 100 120 Enzyme Dosage (ml/t of fiber)
EnzKem Luminase Biobleaching With Xylanases
What is Xylanase? Xylanases are enzymes that hydrolyze xylan polymers The most important are the endo-1,4-ß-xylanases This enzyme degrades xylan to short-chain xylooligosaccharides of varying lengths This allows increased efficiency of Chlorine Dioxide
Biobleaching Objective Achieve a high level of pulp brightness with reduced chemical (ClO 2 ) usage through application of novel xylanase(s)
Operating Parameters EnzKem Luminase Retention time minimum 15 minutes ph range 5 to 7.5 Temperature range 100F to 200F HW ClO2 reduction 20 25 % SW ClO2 reduction 18 20 % Typically added to the Inlet of the Brown Stock HD
APPLICATION COMPARISON Mill Results - Southern US Hardwood ClO2, lb/adt 28 post O2 K 7.5 ph<7, T<160 30 min ret red NaOH B>0.5 pts 100 gms/t enz 26 24 22 20 18 1 2 3 4 5 6 7 8 9
Mill Results DoEpD1 Northern US SW Luminase PB100 24 Kappa # 150F, ph 6.8, 45 minutes 88 87.5 87 86.5 86 Mill objective of 2 points 85.5 brightness increase was 85 achieved with PB100. 84.5 Competitive enzyme did not work kin this system No Enz PB100 Comp Enz
Mill Results-Southern SW DoEopD1 25 Luminase achieved 20% reduction in chlorine dioxide i 20 15 Competitive enzyme achieved 10 less than 12% reduction 5 0 Comp Enz PB100
Mill Results W Canada Hemlock/Cedar 90 89.6 89 Brightness 88 87 87.1 86 85 Enz On Enz Off
Refining Data, Econotech Laboratory, NW US SW DEopDED, kappa 17 PFI rev 0 1000 2500 5000 10000.26 kf CSF UT 548 434 309 224 122.35 kf CSF UT 555 451 329 210 115.26 kf CSF 544 440 322 229 120 340g/t enz
Strength Data, Econotech Labs, Canada NW US SW, DEopDED, kappa 17 PFI rev 1000 2500 Tensile Index UT 47.6 50.8 T 45.7 52.1 Tear Index UT 8.55 7.97 T 8.71 8.60
Brazilian Eucalyptus Mill During 2 month trial the effect of enzyme on refinability, i i machine runnability i and paper properties was carefully studied and no effect was observed
MeadWestvaco, Hardwood Mill A 1 year in mill study of the effect of xylanase on yield showed no measurable effect
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