PAPTAC Bleaching Committee
1.
Presentation by Ross
Stacey (Marsulex) on Safety Handling of
SO2.
The presentation is attached to the minutes.
Luke
Monk, Kimberly Clark, Terrace Bay, Ontario Installed steam
injectors, MC pumps, also both D1 and D2 upflow tubes were replaced. We also completed significant Kappa analyzer
calibrations in order to establish and maintain their accuracy.
Shane
Svendson, KC-NS Installed
Kappa analyzer D1 on Kappa control.
Pressure screens 6000 slot.
Upgraded dryer coils. Cold blow
pump failure on start up.
Laurier
Morrisette, BTG Americas
Design improvement to filtrate extractor for hardwood on Eop stage to measure
pH. Redesign sampler for batch digester
blowline. Brown stock washing control
strategy and test.
Mike
Beattie, Weyerhaeuser, Dryden
Lots of construction at Dryden.
Office building project just complete.
New Recovery Boiler construction in progress. Just completed annual kraft mill maintenance shutdown. Notable projects: Digester new outlet device and smart filtrate cold blow
dilution system, Bleach Plant new
Corudeck III washer drum installed in D1, modifications to brown stock vacuum
washer, Chemical Plant
new/refurbished R10 filter installed.
Chlorate/caustic storage/unloading and handling projects planned for
2002 2003.
Tim
Gilliss, St. Anne Nackawic
ECF production is increasing and brings its own capacity challenges in terms of
Cl02 and chlorate production.
Improved drying as a result of a lazy steam shower installation on 1st
press of the pulp machine. Increased
hog fuel burning has helped to lower oil consumption. Installing Do compensated brightness controls in
June. Enzyme trial scheduled to begin
in August.
Tom Mullen, Air Products Paper presented at PAPTAC Annual Meeting, Using White Liquor Oxidized to Thiosulphate in the Bleach Plant Can Reduce Caustic Purchases by 20%. A copy will be available with the minutes. Contact Tom Mullen at [email protected] for copy.
Rob
Laurendeau, Canfor Intercon 1.
FTNIR analyzer for online moas/control of SVP generator, chemical
concentrations. 2. Kappa-Brite analyzer for after tower
brightness. 3. Looking at Cl02 pre-heaters product. Slide at knuckle plates in
Chipbin/Supercoils on dryer headbox upgrade.
Kari
Rae, Tembec, Skookumchuck - Formaldehyde
bleaching trial. Consistency controller
on Do. Spent acid addition
to Do Stage to control pH in D1 and D2. Installing Kappa sampler (40 minute frequency). C02 trial. Filtrate extractor on 2nd post
oxygen washer (conductivity). Cogen
running well!
Erik Tremblay,
Metso Automation Few months ago, our Company bought the Pulp Expert Company, which is
now part of Kajaani product family.
Mark Healy,
Iogen Bio-Products Starting up a new application.
First good stab at application on 02 delig. line. Very preliminary results are positive. Not enough data to draw conclusions yet.
Ralph
MacDonald, Alpac - 1. ISO 14001 certification, 2001.
2. 2001 established new weekly,
monthly and annual production record of 612,000 ADT/year, 2,038 ADT/day, and 1,940 ADT/day 3.
Set new softwood production target of 1,750 ADT/day (3 stage bleaching).
Guy
Normandeau, DMI Peace River Kappa/Brite analyzer installation in July (2nd Kappa
analyzer). Down flow low solids upgrade
to digester. Fall of 2002. Safest mill in Canada. MCC kappa analyzer installation this
fall. Mass/flow meter for chlorate
addition to R-8. 70% reduction in Cl02
emissions by piping vent scrubber to bleach scrubber. Paper presented in Montreal on scale reduction in DMI bleach
plant.
Chris Kanters,
Paprican
I am now with Paprican. New Director
Contracts and Licensing. Responsible
for Papricans relations with allied industry as well as Papricans
intellectual property.
Ted Tam,
Cariboo
In the process of installing new lagoon, cant dredge final lagoon which is
full of solids for fear of stirring up dioxin.
Installed an improved version of sootblowers in the boilers, saw 28
30% reduction in steam usage for sootblowing.
Achieved a record monthly production of 1,014 ADT/day, 13 ADT/day over
the previous record.
Jim Collins,
Marathon Pulp Inc. Ran formaldehyde trial in Feb. 2002.
Installed Kappa analyzer in 2001 started Kappa factor control in Do
stage July 2001. D1 kappa
factor control 0.18. D0 KF
with enzymes 0.20 without enzyme.
Working well. Scrapped Pulmac
(0-span tester in July 2001), now using Kajaani FS-200. Pulp machines upgrade new style steam
coil. AD's up 2 to 3%. Lots of small
cost reduction projects, e.g., Ti heat exchanger, old Cl02 heat exchanger that
was never installed on line to recover more heat from Eo filtrate. Looking at 02 delig., probably
mini 02. Good results on
stack testing for bleach plant no emission found. Cl02 vent scrubber is problem though. Safety now 1,050 days without lost time
accident. 1.6 million hours, but DCC up
to 17 this year (6 in 2001). Chlorate
mass flowmeter installed in fall 2001.
1.85 tons short of monthly production record in May (535 t/d
average). ISO 14001 certification July 2001. Tristar D2 stage washer drum
installed in Feb. 2002. Regular enzyme
usage continues. Biobrite UHB working
on autodosage program for brown stock HD level. Redesigned blowline samplers for Kappa analyzer so that they
would not get hit by bricks. Will be
working toward Kappa control at Digesters.
Replaced FRP Eo stage seal tank with new stainless seal tank last
shutdown May 2002. Inspected bottom Cl02
absorption tower (in service since Nov. 1989, inspected annually). This shut (May 2002) showed severe
delamination (80%). No evidence of
problem previous inspection. Bottom
section relined. Will be doing complete
inspection next year, removing packing, etc.
Inspection of top absorption tower showed no problems. Ratio caustic addition in D1 stage
to Cl02 addition rate started beginning of 2002 very effective since
Cl02 addition on D1 stage on Kappa factor control.
Lou Legall,
Kimberly Clark, Terrace Bay, Ontario Wedge curve as mill slot. 02 bleach with advanced
controls. New safety initiative
(emphasis on air quality), new pulp and process offer (turn towers).
Jean Bouchard,
Paprican
Jay Chen who was a member of this committee, has left Paprican. Hua Jiang will replace him. Federal Government announced a $ 30 million
grant for 2 years to the 3 institutes Paprican, Ferric, and Forintek.
Don McCabe,
Irving Pulp & Paper, Ltd - Achieved
a 12 month RIR ( for a short period of time ) of less than three. 2001 was a
record production year. 2002 annual
mill shutdown was the best ever, from a planning execution and safety point of
view. Continue to optimize the MBB to the point where methanol will be trialled
in the near future. Recently completed a reduced kappa factor trial with
promising results. Installed a new vent scrubber on the ClO2 generator.
Jim Hopmans,
Sterling Pulp Chemicals Limited Our parent Company, Sterling Chemicals Inc.
recently emerged from Chapter 11 Bankruptcy Protection in the U.S. Under the proposed re-organization plan
filed with the U.S. Bankruptcy court, Sterling Pulp Chemicals Limited (the
Canadian subsidiary) will be controlling by the secured creditors who have
indicated they will offer the company for sale following approval of the
re-organization plan. All Sterling
Pulps present operations are expected to remain together.
Q. - Currently
we dilute our brown stock with 300 US gal/min of scrubber water at 40oF.
- Where would be a good place to use it so that we do not see
the negative cooling effects?
A. - No answer
recorded
Q. Now using
bleach plant defoamer in Do and D1 also the E1.
A. Recycled more
white water back to bleach plant.
Entrained air dilution in washer vat. Consistent vacuum and drainage is
critical. Check dilution and vat
consistencies. Defoamer in bleach is
not uncommon, however should not need it in D1.
Q. What are the
mills testing for cleanliness?
A. KC
Terrace Bay and quarterly for change for ISO certification. Irving Pulp & Paper Muetek on pulp.
Q. Who is using
D1 tube residual measurement for control purposes?
A. Irving,
Terrace Bay. Some mills are automated.
Q. What are mills
using for antichlor?
A. Survey
available. Run low residuals and machine
white water, S02 at Irving.
Q. What are mills
using for MC standpipe level measurement/control?
A. Dryden
redundant DP and Drexel Brock.
MacKenzie nuclear. Grand Prairie
no problem with nuclears. Cariboo
nuclear no problem. Grand Prairie looking
to get rid of remaining DP.
Q. How
do you measure wear or efficiency loss over time on high shear oxygen mixer?
A. On/off
bump test on 02. Check mixer gap every
6 months. Check pressure gauge. Have
supplier check 02 uptake.
Ralph Lunn, Celgar ( via Rae
Cunnington )
Q. What type of
caustic control are mills using?
A. Irving
feed forward control based on Cl02 addition time shifted to Marathon 10
years same. Canfor same plus feedback
pH cascade loop.
Q. H202
split between Eop and Ep.
A. Average about
3 Kg/ADT on Eop, and 2 Kg/ADT on Ep.
Q. I
would like to know if there is any way to measure chlorite? Any technical paper?
A. Jim
Collins, Marathon The mill developed their own method to measure chlorite.
Q. Are
any mills still using C02 in brown stock for pH control (to reduce
pH)? Economic impact? How much?
How low in pH can you go?
A. Dryden
significant 8.0 to 8.5 pH for them because brown stock limited. St. Felicien 8.0 to 9.0 in as low as
anyone goes.
Q. What
Eop caustic control strategy is used?
Any use of Do feed forward for caustic control?
A. Irving
uses ratio caustic to Cl02 charge on Do no feedback compensation. Marathon same
as Irving. Prince George same, but use
feedback from pH. St. Anne installed
extractor in feedline and works on control, but frequently scale pH probe. None have gone
to any other form of feed forward control, i.e., brightness, Kappa #. Powell River was trialling conductivity
prior to mill shutdown, but no results reported.
Q. Are any mills
able to make previous generation light-scattering sensors?
A. Yes,
Prince George-Intercon specifically requires frequent lab sampling and calibration
and per service reps may require a shift to a different light spectrum. Filtrate color will influence light
scattering.
Q. Irving
Pulp presentation described a loss of tear and tensile development with 02
delig upgrade. Rae Cunnington
talked about a loss of tear (10%) at constant burst, with change from CEH to
HEH. What are mills doing to improve
strength characteristics?
A. MgS04
on Eop stage trial. Cariboo increased K
# at blow line. Canfor-Intercon 25 K
#. Increased white liquor sulphidity
can help. Loss at dryer? Norm Liebergott recommends to cool 02 delig.
blowing. Digester is the largest variable.
Q. When
chemical dosage is at optimum and a shutdown occurs, low brightness can occur.
Filtrates are lost and hot water make up occurs. How important is filtrate residual, and how are mills adjusting
dosing around shutdowns? Before and
after?
A. St.
Anne when making high bright pulp, need to put on a higher Do charge for
initial dose and then walkdown. Alpac
see the same thing. Requires a higher
initial charge.
Q. What
tactics have been used to minimize loss of pulp viscosity across the bleach
plant?
A. Ted
Tam, Cariboo increase sulphidity as allowed by TRS. Don McCabe, Irving considering MgS04. Also, can you blow colder?
Guy Normandeau, DMI Peace River Took
H202 out for viscosity/strength sensitive customer. Check
for incomplete mixing of H202. When customer complaint occurs, they go back to the pulp mill.
Q. What
filtrate routing scheme is used at your mill?
Counter current, jump stage CC, split flow JSCC?
A. Refer to
E-mail question to bleach committee route list.
Q. We
are looking at taking out the D1 washer.
For those mills that have switched from D1, E2, D2 sequence to DND, what
do you see in terms of chemical usage's, scaling or plugging issues?
A. Not recorded
Q. Has anyone
been using oil refinery spent caustic as make up?
A. Check
with Harmac and Grande Prairie. Be
careful with sulphur, organics and metals. Smell can be an issue.
Jim Collins, Marathon Pulp Inc.
Q. Have
problem acid mist coming out of acid day tank every time H2S04 acid
transferred.
Acid supplier has come up with a seal pot device to pipe
vent from acid day tank. Seal pot is
filled with limestone to react with acid mist.
Another experience with this.
Also installing P trap
on overflow from tank.
A. Acid supplier
has come up with a seal pot device to pipe vent from acid day tank. Seal pot is filled with limestone to react
with acid mist. Another experience with
this. Also installing P trap on overflow from tank.
Q. Cl02
savings with Eo at high substitution?
A. Cornwall
not using Eo. Paul Earl 3 mills in
U.S. (hardwood) not seeing benefit when using
peroxide. St. Anne 2.5 Kg Cl02/5 Kg
peroxide at 50%. Will trial ECF. Irving
Q. Norske
Canada, Crofton have 4 FRP chlorine dioxide storage tanks, 12 gpl Cl02. Used batch addition of TBP, now cant
increase in methanol. Floating roofs, 2
tanks out of service 6 months.
Corrosion through to structural layers. Floating roofs will not replace. Early inspection may have caught the
problem prior to penetration of structural layer.
Q. I
want to respond to a question (via E-mail) that was raised by France Champagne
of Thurso, regarding Eo stage mixing.
Apparently Thurso observed that their Eo mixer (IR series 600) was not
working. I want to point out that about
15 years ago, this committee conducted a survey of Eo mixer performance. The best performance was by this IR
mixer. I contend that under normal
circumstances, a properly maintained high shear mixer will give good benefits.
A. Tom
Mullen said that the Thurso mixer was inspected and found to be in good
mechanical condition. However, with a
high Kappa factor at Thurso, the actual benefits for Eo versus E may be
limited. Jean Bouchard said that for a
mill with 8 to 10% consistency, the oxygen bubble size increases and gives poor
Eo performance (reference Portland Paper in 2002). Don McCabe, Irving said that at Irving, they found that good maintenance was necessary
to ensure optimum performance of this mixer. They checked every 6 - 12 months.
Q. For
a mill about to put in an oxygen sparger in an Eo stage, which side of the MC
pump level control valve do you install the sparger?
A. Of
the mills present, 4 locate it before and 4 locate it after the level control
valve.
Don McCabe, Irving Pulp &
Paper, Ltd.
Q. Recently
have seen an build up of scale in the Eop stage which is mostly calcium
carbonate.
A. Refer to paper
by Chris Ho from scaling round table. Precipitate is due to Cacium ion
concentration. Do pH may not be low enough. Shouldn't have a problem if D0 end
pH is below 2.5. Some mill routinely acid wash their stage.
A. One, Marathon.
Q. Are there any mills willing to share bleach plant
viscosity/strength profiles?
A. Kimberley
Clark -Terrace Bay, KCNS, DMI Peace River, Alpac, Cariboo, Ste Anne Nackawic.