The Benefits of Enzymes in Pulp & Paper Processes

Transcription

1 The Benefits of Enzymes in Pulp & Paper Processes Tom Woodward Director of Technology EnzKem Associates

2 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

3 Pulp & Paper Enzyme Applications Discussion Topics Deinking Pitch reduction Wet strength repulping Stickies control Biorefining Biobleaching Strength Improvement

4 Common Pulp & Paper Enzyme Types Cellulases Xylanases Lipases Esterases Amylases

5 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

6 Fiber Modification Biorefining

7 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

8 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

9 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

10 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

11 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

12 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

13 Enzyme Effects on Drainage & Strength of OCC Eik Eriksson, Hit Heitman, Venditi, NC State t % 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

14 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

15 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

16 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

17 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

18 Enzymes For Stickies Control Most stickies contain ester linkages that can be hydrolyzed (cleaved) by esterases and converted into innocuous substances bt

19 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

20 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 %.

21 EnzKem E-200 Application i EnzKem E-200 is added to the pulper at grams/ton Active ph range is 4.5 to 8.5 Ati Active temperature t range is 25to 60degrees Centigrade

22 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 Mi illions/ml INITIAL ARIL MAY JUNE JULY AUGUST Month

23 EnzKem E-300 AN ENZYME FOR REPULPING WET STRENGTH PAPERS

24 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 % 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

25 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

26 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.

27 EnzKem E-300 Application Conditions Feedrate g/ton Feedpoint Directly to pulper ph. 5.0 to 8.0 Temp 120 to 160F Time.. 30 minutes No oxidizer necessary

28 EnzKem E-300 Dosage effect of an enzyme for wet strength resin hydrolysis on fiber re-pulping time Mi inutes Enzyme Dosage (ml/t of fiber)

29 EnzKem Luminase Biobleaching With Xylanases

30 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

31 Biobleaching Objective Achieve a high level of pulp brightness with reduced chemical (ClO 2 ) usage through application of novel xylanase(s)

32 Operating Parameters EnzKem Luminase Retention time minimum 15 minutes ph range 5 to 7.5 Temperature range 100F to 200F HW ClO2 reduction % SW ClO2 reduction % Typically added to the Inlet of the Brown Stock HD

33 APPLICATION COMPARISON Mill Results - Southern US Hardwood ClO2, lb/adt 28 post O2 K 7.5 ph<7, T< min ret red NaOH B>0.5 pts 100 gms/t enz

34 Mill Results DoEpD1 Northern US SW Luminase PB Kappa # 150F, ph 6.8, 45 minutes Mill objective of 2 points 85.5 brightness increase was 85 achieved with PB Competitive enzyme did not work kin this system No Enz PB100 Comp Enz

35 Mill Results-Southern SW DoEopD1 25 Luminase achieved 20% reduction in chlorine dioxide i Competitive enzyme achieved 10 less than 12% reduction 5 0 Comp Enz PB100

36 Mill Results W Canada Hemlock/Cedar Brightness Enz On Enz Off

37 Refining Data, Econotech Laboratory, NW US SW DEopDED, kappa 17 PFI rev kf CSF UT kf CSF UT kf CSF g/t enz

38 Strength Data, Econotech Labs, Canada NW US SW, DEopDED, kappa 17 PFI rev Tensile Index UT T Tear Index UT T

39 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

40 MeadWestvaco, Hardwood Mill A 1 year in mill study of the effect of xylanase on yield showed no measurable effect

41 Questions?