Q: What are the HW mills doing to control the first 2 stages?

A: E.B. Eddy - run to residual

A: Portage-du-Fort - CEK

Q: How many mills on kappa factor control? benefits? sensors used?

A: Crestbrook uses it

A: Howe Sound - has gone back to Kajaani compensated brightness - kappa factor control is not enough

A: Canton - just installed kappa analyzer, will use for kappa factor control

A: Crofton - BTG brightness control didn’t work so went to kappa factor control based on manual test

A: Portage - Kajaani compensated kappa factor

Q: Who uses Do post tower brightness for closed cycle control? feed forward for Eop?

A: Harmac - had them, but very unreliable on low consistency towers

A: Powell River - looking at possibly closing loop

A: Portage - did not control well

A: Hinton may be doing it

Q: What low consistency transmitters in use? nuclear? rotary? microwave?

A: Harmac - use Valmet hockey sticks - track nicely but may not be absolutely correct

A: low consistency: 3 optical, 1 microwave, 15 mechanical, 1 nuclear

A: medium consistency 2 optical, 2 mechanical

Q: D1 stage brightness meter after chemical addition had problems with green coating on lens, relocated sensor ahead of chemical addition, okay now, but not as good a control strategy. Any one else?

A: Valmet - only on D1, ultrasonic cleaning and new lens have come out in the last few months, can be retrofit

A: EBEddy - yes at 50%

A: Portage - yes at 50%

A: Harmac - get blinding on sensors both before and after ClO₂ addition (pitch?)

Q: Anybody using a continuous residual H₂O₂ sensor?

A: Howe Sound - polarox ClO₂ sensor with DCS switch so can be used for both ClO₂ and H₂O₂

Q: What temperature, flow of hot water to BP?

A: Harmac - 150^oF - 160^oF , 1100 gpm hot water for 600 tpd

Q: ClO₂ heat exchangers?

A: yes - Gold River, Western, Domtar, lots in use

Q: Automatic level control in R8?

A: Celgar and Powell River - yes on SVP Lite - DP cell

A: Sterling - generally done on makeup water to generator, none have closed the loop on steam

Q: Any one have a novel approach to eliminate water for R8 saltcake mixtank?

A: Harmac - dilute with hotwater

A: Marathon - hotwater

A: Sterling - some have tried adding directly to black liquor, but none successful, H₂S risk is to great, kept getting fires inside filter because H₂S and ClO₂ react violently. With R10 will eliminate the water.

Q: Floating ClO₂ storage roofs? Running higher ClO₂ strength

A: Harmac - yes, now running up to 12 gpl, problems with strength analyzer

A: Crofton - yes, 12.5 gpl, also problems with analyzer

A: Sterling - should be able to store 14 gpl, but hard to make because need very cold chilled water, large absorber and so control is very critical to keep efficiency up - lots of things to think about, so anybody trying to go to higher concentrations should get help from Sterling.

A: Western - hold off because one mill had a cracking problem

A: Sterling - yes, Terrace Bay had a problem since they had been stored rolled up in cold weather, so cracked

A: Owen - Eka Nobel have similar problems, so consult them before going to higher concentrations

A: Cariboo - installed, have SpectroTech analyzer, evaluating it

A: Sterling - SpectroTech is low cost, but had difficulty getting agreement with lab test

A: Owen - Domtar just purchased SpectroTech as well

Q: static mixer for ClO₂, MC mixer, should we split flow?

A: ElkFalls - no change when shut off second mixer

A: Harmac - recently noted that belts were broken on hi-shear mixer (for two months), very small difference

A: Howe Sound - 60%/40%, no residual after first mixer, so worth doing

Q: MC pumps to D1 and D2 hi-shear mixers, have to put more ClO₂ on to keep amps down. Why?

A: Thurso - could not increase consistency for same reason

A: Crofton - bigger motor?

Q: metallurgy problems for ECF?

A: no

Q: Want to install a ClO₂ scrubber. Does anyone measure J-tube ClO₂?

A: ElkFalls - 30% ClO₂ by volume

A: Owen - must do separate analysis for Cl₂ and ClO₂ . High temperature, lots of vapour

Q: Would like to get rid of SO₂. What do people use instead?

A: Celgar, Gold River - use sodium bisulphite

A: Mackenzie, ElkFalls - don’t use SO₂, use H₂SO₄ or caustic if needed

Q: Current sequence OpQEopP, proposed sequence chelation before O₂ delignification. Any problems?

A: Owen - papers published on this at International Bleaching Conference

A: FMC - detrimental

A: DuPont - issue was scaling due to chelation before

Q: anyone have suggestions to get less than 100 OX in pulp (customer driven)?

A: UofT - final peroxide in HiD will reduce OX

A: Harmac - well washed can get down to almost 100

A: Paprican - Richard Berry has done work in this area

Q: sawdust digester with hot stock screens, found lots of scrap metal. What do people do to protect screens?

A: EB Eddy - Pea gravel is a problem, old Devron trash system was removed, planning ADS to protect slicer, but cost is high, installation is doubtful

A: Crofton - knotters - rock trap, pea gravel is PRODUCED by screens

A: Mackenzie - 85 thou holed barrier screens before slot screens

Q: 40 ppm TRS emission from bs washer hood - how are mills eliminating TRS

A: Portage - dedicated incinerator

A: Elk Falls - Quaker Chemical has a chemical called "EnviroScrub". Tried and found it was very application sensitive.

A: Is this an issue that the Environmental Committee should look at?

A: Harmac - HVLC collection system

A: E.B.Eddy - AH Lundburgh designed a system

A: Crofton - Paprican has a trial biofiltration system that they want to put into a mill. Miramichi using WL as a scrubber for TRS. There is a Finnish mill doing something - see ???

Q: ISO 14000 required for our suppliers?

A: 10 mills responded they will comply with ISO 14000, 1997-98 typical timing. 1 mill indicated they would not go to ISO 14000. CXY doing internal ISO 14000, will only go external if customers require it.

A: Northwood - yes, just as our suppliers have to have a quality system in place

A: Mackenzie - no, since the Responsible Care program that the suppliers have in place is excellent. However, we will require they keep records

Q: What do mills use Internet for, and how is the security?

A: Praxair - Encrypt and compress all files before sending outside mill network

A: ICI - don’t trust firewalls, so don’t have direst access, encrypt, don’t do any pricing over the Internet