F. MILL OPPORTUNITIES, PROBLEMS AND SOLUTIONS
May 31, 1999
OPPORTUNITIES
Paul Herar, Pacifica, Powell River
One year since not with MB. Personnel changes. Trying to meet TRS and particulate. Put in oxygen to lower oxidized liquor, (strong BL) New precipitator for RB? Spending money on newsprint grades, new scanner on biggest machine. New winder.
Gary Berndt, Weyerhaeuser, Kamloops
Focussing on optimizing equipment in the B mill., O2 delig., flash dryer, Evaporator. mods., pressure disk filter. Early retirements and optimization. Moved R-8 and Recaust. controls to eliminate positions.
Jim Menard, Northwood, Prince George
1542 tpd 1998 prod. capacity. Recently signed a labour agreement. Installed a 2 stage pressurised black liquor fibre screening system. Added new primary screen to compensate for barrier screen conversion. Evap. rates went up greatly. New primary screen to A fibre line. Considering B line continuous slotted screens. No longer use of SO2 as antichlor. Metallurgy changed so didn’t need it anymore. Installed particulators on both recovery boilers. Implemented advance control package on #5 RB, controlling to consumed air. Just finished two month dredging of lagoon.
Bob Ostaff, Bowater, Thunder Bay
8% decrease in ClO2 by using pH control. Gen. ltd. New CEP labour agreement. Combined control areas. Installed new precip. on RB.
Roger Benard, Marsulex
4 million tonnes sulphur based products.
Fred Munro, EB Eddy, Espanola
Bleach Plant washers are CB filters. Running well 14% consistency. Moved R-10 control to BP. Recaust. looked after by Steam and Recovery. Will run PSS trials in summer both on SW and HW.
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OPPORTUNITIES, ctd.
Gord Homer, Air Liquide
Completed pilot plant on low consistency. Apply ozone to existing low consistency bleach line with one or two mixers. Student working at Paprican doing yield study – conventional and polysulfide Kappa 25 to 40 conventional and polysulfide.
Dave Thireault, Pope & Talbot, Halsey, OR
Two market curtailments last year. Still use Monox-L. Await ClO2 July 29th approval. D Eop Dn D sequence. Most capital last year – Recaust. upgrade. Put flowmeter on BL transferred over to Recovery. BL solids get generated from pulping. Shows effects poor washing. Totalize WL brought into Digesters. Solids made by WL, etc. to do yield determination without wood measurement. Run slotted baskets on screens – less wear. Epsom salt replaced by a product with less magnesium. in O2 delig. Reduce magnesium input/effect on green liquor settling. Wet zero span tensile test. Saw 7 points drop when Epsom salts off. Pulmac test.
Gerry Ferweda, Fletcher, Crofton
Last Nov. ’98 O2 delig. after Do – lot better delig. at 60 to 65%, yield improvement. 0.1 multiple to Do target 0.06. Metals mgmt. too after Do stage. A and B bleach. Tear tensile grades from both BP’s same. Unintentional trial with no ClO2 in Do. Kappa analyser last summer and another this summer. On O2 side. On A Bleach flipped sparger around put downstream of control valve. 1.4% applied through sparger now. Helped bleach costs. Don’t recycle O2 filtrate.
Tina Larsen, Weyerhaeuser, Grande Prairie
Front end FRP piping being replaces with titanium. Working on control loop health program – developing on-line. Org. redesign. Focus on leadership. Next 6 months all changing job roles. Milestone – 1 million hours loss time accident free. Will be eliminating SO2 to machine replace with H2SO4 then looking at sodium bisulfite. as antichlor. Pilot scale project AQ and PSS and O2 delig. then sent to Customers to see how ran on their machines. May install one day.
Brian Card, Fletcher, Mackenzie
Flexibility implemented to continue maintenance workforce reduction Recovery Boiler tertiary air upgrade to reduce TRS. Small bleach plant project include CO2 in BSW and with peroxide trials Capital is tight. Achieved ISO 1400 certification.
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OPPORTUNITIES, ctd.
Vic Morandini, Alberta Pacific, Boyle
6 years of op. 1800 plus tpd some days. New pin/fines screening system (Lywell ). Started a preliminary trial on hexaneuronic acids, prior to the bleach plant with Paprican. More photo grade pulp. Will install a larger talc delivery system. Firing recovery boiler at 80% solids up from 70-72%.
Grant Lund, Howe Sound Pulp & Paper
Installing a new chute to get consistency up from 8 to 12% to O2 delig. system Chip crusher is being installed for oversized chips WL Oxidizer to be commissioned soon. When up to 38 Kappa alkali use was too high. High shear mixer formerly used for chlorine mixing (Hastelloy) will be replaced with static mixer. Two hog presses installed for energy reduction – successful, a third on order. Underground carbon steel piping corroding. All being replaced by FRP with pH swings to blame. Cl2 scrubber conversion to Eo filtrate. R-8 tail gas scrubber going to inlet Cl2 scrubber. Pulp machine scanner installed and has improved air dry control.
Mike Beattie, Weyerhaeuser, Dryden
3 owners 3 months. Since last June all thick stock pumps eliminated BP. All MC now. DCS in BP last June. Use CO2 regularly in BSW.
Carlo Dal Monte, Fletcher, Elk Falls
ISO 14000 June . WL NCG scrubber as backup to kiln. Gone through restructuring. Hourly side 67 tradesman. But did get people from PaperCo. Created hourly waste reduction team resulting in recycling Do filtrate instead of fresh water, and # 2 BP D1 filtrate brought over to #1 BP. More TEA as measurement of pulp strength – hard since furnish hemlock and spruce. Tensile Energy Absorption. Kappa analyser planned for #2 BP. Power Boiler plume opacity issues from salt in hog fuel could pose future problems.
Jean Bouchard, Paprican, Montreal
Pilot Plant now can do full sequence including filtrate recycle and various bleaching chemicals. Paprican membership now open worldwide. Target is Canadian company with US mills. IP now Paprican member. Reason: was asked to reduce cost by 30%.
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OPPORTUNITIES, ctd.
Keith Thomas, Weldwood, Hinton
Downsizing 15% last year. First strike 2 weeks recently. 200 tpd more out of existing equipment. Rebuild wash line in BP. First washer last s/d. Will replace all 6 concrete with steel vats. Dilution factor and level control has improved Kappa factor. Kappa analyser now in front of BP – not sure yet whether better than brightness control. New larger Reboiler for R-8. What led to new Reboiler? Corrosion. Titanium 7. Tube leaks started shell problems.
Sheldon Imrie, Skeena, Prince Rupert
S/d "B" mill in April. Recovery Boiler limited. Kappa analysers – can’t seem to get optimised. Started adding peroxide in E2 - $2 to 3/tonne savings. Lots of fines and pins coming to Kamyr since "B" down. Recovery looking at installing FTRI. ISO 14000 started. $110 million capital expenditure program – other line starting up in Oct. 99. Recovery expanding. Transforming Kamyr to low solids. New ClO2 SVP-lite gen. Mod. BP including O2 delig. consolidating control rooms. 18 months. Now with A line 850 tpd RB ltd. 1600 tpd after capital – but 1400 r 1450 tpd.
Rae Cunnington, Sandwell, Vancouver
Vancouver office moved down street.
Jim Oei, Western, Woodfibre, Squamish
ISO 14000 in May. Scale inhibitor Drewfax for Recovery. Scale in multistage tower can be solved by jump stage. Millwide anti-harassment policy implemented Diagonal slotted screen in Digester to stop hang-up. CO2 to brown stock diffuser
Don McCabe, Irving, St. John
Now have two stage O2 delig system and are achieving up to 60 % delignification. Upgraded knotters. Sunds. Upgraded precipitator ash handling system, can sewer the precipitator catch. Shutdown woodroom. Eliminated CO2 . Evaluating BP washer upgrades. Vat change in the D1 stage and drop legs in the Eop stage.
Pat Haggerty, Cariboo, Quesnel
ISO 14000 last fall. 100% ECF Jan. 2000. Problem is ClO2 limitation. Decrease ClO2 usage. Barrier screening for contaminant removal. Low solids cooking several trials with some problems with NCG venting. More trials planned.. D1 stage had channelling. Upgrading sensors.
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OPPORTUNITIES, ctd.
Lance Anderson, Canfor, Prince George
ISO 14000 rectification. CO2 on BSW at Prince George. AQ is being used at both mills about 80% of time. driven by liquor inventory. Intercon precipitator on Power Boiler. Intercon – no SO2 system now dilute acid system – sod. bisulphate. BS feed to BP will have Kappa analyser. Future. New chip handling. Blow lines to conveyors. 2 ½ to 3% improvement by having no cats on chip piles. DCS on pulp machine Prince George – high consistency refining for paper machine. Increasing from 300 to 500 tpd paper once done.
Stuart Scott, Repap, Miramichi
New stripper offgas system. Run trial to optimise Eop peroxide. Working on cost reduction. New D1 washer
Jim Collins, James River, Marathon
Enzyme trials underway some cost reduction but issues remain with pulp strength - 500 pts. tensile drop but increases refined tear. Reverse osmosis on boiler feed water. Down to 300 people by year end vs. 430 to 600. Thanks to Y2K will get new Provox data storing system. Continuing with ISO 14000 certification. Replaced FRP in Do stage piping. Plan magnesium sulphate trials in June. Modernising the chip rail handling system
Ross Anderson, Kemira Chemicals, Maitland
Dupont divested itself of last peroxide plant.
Eric Yee, Weyerhaeuser, Prince Albert
35 staff to get early retirement. 1/1 peroxide to ClO2 replacement. 0.6 kg/tonne peroxide in Eo. Planning to use ClO2 for mill water treatment Starting up a new potable water system. Tried low kappa factor in D0 stage and went from 0.21 to 0.16
Dan Davies, Degussa, Surrey
Degussa merging with Huls in Germany.
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PROBLEMS
Rae Cunnington, Sandwell, Vancouver
Q What is the shortest D1 can get away with – whole stage.
A. 1 hour 20 minutes at Canfor, 90 minutes at Woodfibre. 150 minutes at Marathon. Know of some mills some at 70 minutes but have bigger D2 stages.
Jim Oei, Western Pulp, Squamish
Q. What mills are using descaling agents in the Kamyr digester?
A. Cariboo, Intercon, Repap, Dryden, Northwood, FCC, Malette. Liquor heaters longer life is reason.
Don McCabe, Irving, St. John
Q. How are other mills controlling their antichlor addition?
A . Polorox at Kamloops underneath the washer before vat dilution. Many mills have shut off their SO2 and use no antichlor. They are not monitoring their corrosion
Pat Hagerty, Cariboo Pulp, Quesnel
Q. Have other mills received requests for wireless bales?
A Alpac, Hinton, (trying), FCM. PG mills can swing back and forth. Marathon looking at completely wireless.
Lance Anderson, Canfor, Intercon, Prince George
Q. Has anyone experienced Calcium carbonate buildup on E2 washer?
A. Alpac has a lot of buildup and also high pressure cleans their stage. A chelant trial was expensive and not too successful. Grande Prairie suggests the following: control the D0 pH below 2.5, use a calcium inhibitor added to E2 filtrate, and purge with fresh water.
Stuart Scott, Repap, Miramichi
Q. Currently experiencing a problem with 5th stage washer buildup of silica based material. Anyone else who using talc have problem?
A. Thunder Bay had the same problem with talc getting into the white water system and getting back to washer. Weyerhaeuser uses machine room white water but does not have a problem. Halsey stopped using talc and used Prosep from Vinings.
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PROBLEMS, ctd.
Jim Collins, James River, Marathon
Q. For those using enzymes, do you see any strength reductions?
A. Jeff Tolan – They had this problem with another mill and went to their customer to discuss the situation. Arrived at a new measurement of tear/tensile measurement and are currently using it. He was asked does he look at yield? No.
Eric Yee, Weyerhaeuser, Prince Albert
Q. Problem with tubes plugging in chiller.
A. Dennis Owen has tube cleaning system name. Raisio product Blastoff used by FCE. Miramichi shuts down every 6 to 8 weeks and suspects the water treatment area is to blame - alum
Vic Morandini, Alberta Pacific, Boyle
Q. What are mills using for a ratio of O2 to peroxide in Eop stage particularly those who have O2 delig?
A. EB Eddy doesn’t run it because found in lab there was no need. In Kamloops found after O2 delig. that there was no benefit to running oxygen in Eop.
Mike Beattie, Weyerhaeuser, Dryden
Q. Experiencing some problems with mechanical seals on pressure screens. Any input?
A. Northwood uses with no problem. Eddy doesn’t run.
Steve Haynes, Alberta Pacific, Boyle
Q. Is anyone experiencing problems with doctor boards on R-8 saltcake filter?
A Yes. Sterling has a type with sprays that shoot up for undercutting – keep doctor board free. Eric uses but at least once per shift must clean under the doctor board. Same with FCE.
Brian Card, Fletcher, Mackenzie
Q Current inline stack ClO2 monitor doesn’t work well – Rosemount. What are other mills using?
A HSPP use Ametek but it is expensive. FCE has EIT it is cheap but works well. Sterling says EIT stopped making this probe. New technology presented at TAPPI Environmental in Tennessee and will get him name.
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PROBLEMS, ctd.
Carlo Dal Monte, Fletcher, Elk Falls
Q. What is the optimum temperature for a D1 stage with upflow/downflow tubes? Currently run at 75 C now and when too hot there is gassing off and when too cold there is no consumption of ClO2.
A Powell River cooled the tower down 10 deg F and found better ClO2 consumption, now plans to go even lower. Prince Albert runs to a gas phase concentration of 150 ppm. Grande Prairie presently runs at 140 deg F and has no problem Espanola runs to a set tube residual knowing where they run into gassing off problems. Dennis Owen commented this a large source of ClO2 loss based on his scrubber surveys .
Keith Thomas, Weldwood, Hinton
Q. Who uses pH feedback control for caustic addition in their E stages? A Grande Prairie use a Vagner pH sensor in line. Repap uses an in house extraction unit with a TBI sensor. Marathon base load their caustic addition – ratio control with good success.
Sheldon Imrie, Skeena, Prince Rupert
Q. Is adding enzymes beneficial?
A Repap saw a benefit of about $2-3 per ton. Enzyme is more effective with pH control Using third generation enzymes. Marathon thinks they are getting $2 to $3 per tonne. Q Can Marathon separate benefits of enzyme vs. acid? Run both so don’t know. Repap have run separately – lost acid but still saved with only enzymes. Couldn’t find at PG. 1 ½ years ago. Were doing for higher brightness first two stages.
Irene Yaraskavitch, Dow, Nepean
Q. Is anyone used OWL in the extraction stage?
A. Fred Munro ran 100% OWL replacement and had CaCO3 scaling everywhere. It works well but plugged a lot. Q. Was dissolved calcium in the WL causing the problem? Also suggested Irene talk to CFI who have done it.
Doug Pryke
Q. Do mills find the 10 mg/l AOX test repeatable?
A. Irving’s is at least 10%.
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PROBLEMS, ctd.
Don Olson, Fletcher Mackenzie
Q. Who uses SQC where Operators chart control points?
A. Mackenzie: All departments plot 1 to 3 control points hourly and are
required to keep within a target range. If they go outside the range
they must record what action they are doing to get back within range.
Suggested actions for various contingencies are written in their
operating manuals, but they are free to try other actions as well. BP
control points are CEK No., D1 brightness, and D2 brightness. Have seen
significant reduction in CoV for most control points.
Prince Rupert: tried control charts for TTA (little effect) and %CE
(some improvement).
Prince George: forced operators to do it, lots of hassle, little benefit
Irving: chart many variables, operators have guidelines to follow
when control points get outside target range, have seen some reduction
in CoV.
Owen: Saw lots of mills implementing SPC in R8 plants 3-4 years ago,
but not many still do it. This could be because they got the benefit
they were looking for, so no longer need to continue.
Grande Prairie: All test data is entered in computer and SPC charts are
generated automatically for the daily production meetings. Bleach Plant
control points are Eop, D1 and D2 brightness. GP has reduced the number
of tests operators do, and this has resulted in variation reduction,
possibly because operators do less tweaking now. In addition, the mill
operating strategy has changed. Historically the bleach plant operating
strategy was to keep the brownstock HiD empty and the bleached stock HiD
full. Their corporate strategy now is to reduce pulp variability by
reducing the number of rate changes per day. Ideally they want to keep
plant running at constant rate all day.
Alpac: SPC can be counterproductive if operators come up with ways to
reduce variability with the expectation that management will spend the
money, then those modifications do not get done.
Carlo Dal Monte, Fletcher, Elk Falls
Q How do mills flush their MC upflow towers.
A. At PR for upflow towers start slowly – one hour or so.
Q. ISO 14000 – does anyone have comprehensive spill management plan for ClO2 spill control.
A. Western, Port Alice. Jim Hopmans says U.S. has 1 ppm ClO2 limit. Need to put in system.
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PROBLEMS, ctd.
Paul Herar, Pacifica, Powell River
Q DEoD bleach plant on softwood with 85 –87 brightness. Want to go to 88+, what are the options and pitfalls?
A. Marathon and Canfor have experience and will share. FCM D Eop D with 89 brightness.
Gary Berndt, Weyerhaeuser, Kamloops
Q. Who uses Kappa factor control on Do stage?
A. Dryden and Alpac, Irving, Northwood are using it. Northwood using compensated – Kappa factor control off CEK. Sets ClO2 charge then looks at compensated brightness. Kappa factor set by Operator. More mills are using Kappa factor control than at last meeting.
Jim Menard, Northwood, Prince George
Q. Do other mills get a calcium scale up in their caustic lines? Scale is calcium hydroxide.
A. Grande Prairie has in the past and had to acid clean once per year and now are down to once every 4 years. They lime soften the mill water down to 60 ppm hardness. Alpac has no scaling issues but use demineralized water to make down caustic.
Dave Thireault, Pope & Talbot, Halsey, OR
Q. How many mills running a DnD stage?
A. Espanola, Elk Falls, Celgar, HSPP, Kamloops was – now just DD. Kamloops has found it trickier to get final brightness.
Fred Munro, EB Eddy, Espanola
Q. We have had problems with the recirculating pump on our ClO2 generator since its conversion to R10. We have bent or broken three shafts and worn out three impellers Anyone else same problem? Anyone using Goulds in same situation?
A. Mackenzie, Elk Falls and EKA licences use Goulds pumps. Sterling suggests these problems occur on spring mounted bases when millwrights overtighten springs resulting in pump casings getting stretched. The springs should only be tightened to fit the pump. Replace the springs and reset the base.
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PROBLEMS, ctd.
Bob Ostaff, Bowater, Thunder Bay
Q. Has anyone overadded H2SO4 in the Do and/or D2?
A. Northwood – pulp suffered with 6 viscosity. Prince Albert didn’t see benefits of adding acid to Do – Kappa factor 0.21. Alpac found pumps have to work harder as pH drops. Ralph Lunn presented paper at PacWest discussing mills that acidify. Jeff comments overacidification only done at mills trying to get rid of metals. Jim Collins asks that copy of Ralph’s paper be put on Website.
Dennis Owen
Q. Are there any reliable ambient monitors/sensors for ClO2?
A. Mackenzie using Draeger type units. Repap just installed 8 Drager units – very durable. Alpac also Draeger. FCE found issue with calibration. Used to use chlorine for calibration now have portable ClO2 gen. for calibration of sensor.
Tina Larsen, Weyerhaeuser, Grande Prairie
Q. Who has a Trane Absorption chiller and has it been converted to DCS?
. Yes at Alpac, Kamloops and PG pulp.
Rae Cunnington
Q. Which mills are running open screen rooms?
A. Powell River, PG, Miramichi, Prince Albert and FCE.
Q. Any plans to close?
A. No.
Don McCabe, Irving, St. John
Q. How are other mills controlling their O2 delig. systems?
A. Northwood had developed models with Paprican looking at pressure, temperature incoming Kappa - control to final K number. Kamloops set temperature and drop if Kappa gets too low coming in, alkali charge set but residual tested every 3rd day. Kamloops will change temperature targets if the incoming K#’s get too high or too low. Kamloops also has a 2 stage delig system and split both O2 and alkali charges. EB EDDY controls to final K number control with caustic. PG - Control temp. to 95 degrees looks at incoming K number Kappa analyser before and after, model, most work done on feed forward if K number high coming in then more caustic. Alpac similar to PG. HSPP – control outlet Kappa and caustic See Gerry Pageau’s paper at International Bleach Conf. No mills control to a constant delignification.
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PROBLEMS, ctd.
Brian Card, Fletcher, Mackenzie
Q. What are mills doing for titanium welding?
A. Miramichi and Marathon outsource for big but do little jobs themselves. Espanola train. Marathon train for small stuff. GP have two on welding crew – trained to do small stuff. Ellett in Coquitlam, Liquid Air have a trailer and do titanium welding training. Powell River have 2 or 3 on-site who do it but so seldom it is hard to keep personnel trained.
Steve Haynes, Alberta Pacific, Boyle
Q. Two years ago refibreglassed dump tank for R-8. Recently found blistering and heating coil moved off base. After dump then hot water flush and drain. What are the procedures for dumping and flushing of tank?
A. Sterling found usually related to thermal shock – sits at ambient temp. then subjected to hot liquor. Suggest Derakane 510N (but Alpac already using) relining. If possible preheat the tank with mill water and raise temperature with the steam coil.
Carlo Dal Monte, Fletcher, Elk Falls
Q. Recently converted washer drum in D1 stage FROM Corrudeck to FRP drum have poor wire life – 8 weeks. What type of banding is used?
A. Les Kosiak at Smooth Rock did same. EB Eddy machined banding grooves on the ends. Miramichi uses Hastelloy bands and Thunder Bay uses 317 bands.
Stan Heimberger
Q. Is anyone using acid addition to D1 for cost control?
A. Espanola and Grande Prairie are adding acid for pH control and are added before the mixer.
Sheldon Imrie, Skeena, Prince Rupert
Q. Who is running AQ with a hemlock balsam fir mix and what are the results?
A. Repap has no hemlock but use AQ and get 1 to 1.5% increase in yield. Reduced ClO2 by 35% at Repap. Domtar, Cornwall use for sulfidity. Skeena run 34 to 37 sulfidity on TTA and has heard high sulfidity mills don’t see yield improvement. Eddy who are at high sulfidity ran two AQ trials, (jackpine/spruce), didn’t see any effect. Eddy run high sulfidity since 1983, no corrosion problems except in the batch digesters. No evaporator corrosion and Kamyr OK. Cariboo and Harmac have also run AQ. Halsey have run AQ for several years with hemlock and Douglas Fir 10% less AA Digesters and 1% absolute increase on yield. Not instantaneous effect – need to run at least a day. Run it on DF chips. 26% sulfidity at Halsey. Recovery and Lime Kiln limited and there are lime savings with AQ.
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PROBLEMS, ctd.
Don Olson, Fletcher Challenge, Mackenzie
Q Do mills have a formal process in place to ensure control loops are in tune and are they checked automatically?
A Northwood has allocated people trained by Entec to look at frequency response and variability. Check for stiction, backlash, loop tuned correctly. Have equipment that measures at higher frequency than DCS. Grande Prairie developing on-line monitor to feed the DCS. Had Entec program for quite awhile but trying to develop on-line monitors. Data will be fed into DCS – goes into historical database which is analysed by another software program which dumps onto email each week. Each loop is prioritised. Also get two other reports – alarm mgmt. and process changes. John Ball of Canfor has been developing loop health program – call him. Bowater asks if Operators first notice problems. Grande Prairie indicates want to go to predictive program so find before becomes seen by Operators. Thunder Bay is considering sending people to Entec.
Paul Herar, Pacifica, Powell River
Q. Has anyone noted any changes in their bulk density when using peroxide to Eop? A Irving can get data. Eddy haven’t noticed nor have Skeena. 2 ½ to 3 ½ kg peroxide per tonne trial. Add little more caustic and this may be affecting bulk says Dan Davies.
Gary Berndt, Weyerhaeuser, Kamloops
Q Who is monitoring in process pitch?.
A. EB Eddy, Marathon, Miramichi all use pitch plates. Miramichi has pitch plates in several locations including the D2 stage. Pitch counts are done by supplier.
Jim Menard, Northwood, Prince George
Q. Are any mills receiving peroxide at 70%?
A. Many mills receive 70%. Peroxide but dilute down to 50 % for storage. Special storage tanks are required to safely store 70%. Marathon stores at 60% - this is done to lower freezing point of the peroxide.
Bob Ostaff, Bowater, Thunder Bay
Q. Has anyone replaced a Do washer vat with new FRP vat.
A. Talk to Smooth Rock. Mackenzie recently had to reline theirs and Grande Prairie has never had problem.
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PROBLEMS, ctd.
Tina Larsen, Weyerhaeuser, Grande Prairie
Q. What kind of PM’s are done on Kajaani probes?
A. Repap has on PM routing list – e.g. pull Kajaanis every 4 days. Canfor pull probes weekly. The same at Prince George. Monthly at HSPP. Alpac suggests a service contract.
Rae Cunnington
Q. Are high sulfidity pulps easier to bleach?
A. FCM runs high mid 30’s and pulp is easier to bleach. Randy W. says there was work mainly on strength not on bleachability. GP had unplanned trial – went from 28 to 36 in 2 weeks. Didn’t see any difference in bleaching. Skeena haven’t tracked – noticed increase in viscosity that hasn’t translated to strength but have not seen a cost benefit. Randy W. says ran in to problems in RB when got higher than 30, got high TRS, smelt temperature depression and blocked off smelt spouts, etc.
Jim Collins, James River, Marathon
Q. Who uses MgSO4 in the Eop stage ?
A. Howe Sound, Crofton, Western Pulp, Fort James Camas, Fort James Wauna, and Fort James Nehola.
Vic Morandini, Alberta Pacific, Boyle
Q. Who uses Sunds twin roll presses and what are their discharge consistencies?
A. PG, Irving, Northwood. Irving two pre and two post O2. Consistencies are in the 25 – 30% range and can be as high as 36%.
Brian Card/Don Olson, Fletcher, Mackenzie
Adding peroxide at 5% strength and why? Safety reason. FCE do add at 50% and argue less piping, equipment, etc. and potential for more opportunities. Add into standpipe not chem. injection points. FCM add at 50%. GP are at 15% - anyone else? Yes, Canfor.
Q. What are the issues between in-line probes and filtrate extractors for pH measurement in D1stage.
A. Intercon, Alpac, Grande Prairie, Powell River and Repap us in-line probes. Irving Cariboo and Crofton use samplers. There were no real issues with in-line probes although there is an issue with access to the probes.
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PROBLEMS, ctd.
Stan Heimberger
Q. Is anyone measuring COD in pulp to D1 stage?
A. EB Eddy monitors COD in the lab on pulp from the deckers. The bleaching equipment subcommittee is addressing the issue.
Paul Earl, Sterling
Q. Is anyone using ClO2 for process water disinfection or paper machine biocide?
A. Domtar, Cornwall tried for paper machine biocide but the fumes were not acceptable. Prince Albert plans to use for water treatment. R-8 type generator ClO2 contains methanol and formic acid so don’t use it for potable water treatment. Ashdown, AK use for paper machine biocide.
Vic Morandini, Alberta Pacific, Boyle
Q. Inspect methanol storage tank. Any recommendations on inspection.
A. Marathon looked into tank to clean and found there was layer of grease in tank. Flush tank with water and collect drainings to water treatment. Dennis says it is important to put into service right away or will get excessive corrosion and some are padding with nitrogen.