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Making the pest of it all

Time and rot wait for no log.


July 1, 2008
By Pulp & Paper Canada

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Time and rot wait for no log.

If expert projections hold, by 2015 the mountain pine beetle (MPB) is expected to kill 76% of merchantable pine in the BC Interior. In all, about 900 million cubic metres of wood will be affected; the industry expects to salvage at least half of this before the wood topples, decays and becomes unusable.

A lot of wood, little time . . . what to do with it?

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Cellulose-based biofuel is one possibility. For example, bio-firm Lignol Energy Corporation estimates that utilizing a mere 0.2% of the available beetle-dead wood per annum could produce enough ethanol to satisfy the BC government’s target of 5% ethanol/gasoline blend by 2010.

In 2002, Ottawa launched its Mountain Pine Beetle Initiative (MPBI), spearheading it with a six-year $40-million package administered by Natural Resources Canada to help soften the impending MPB crisis. In early 2005, the BC provincial government and Ottawa launched a three-year $100-million action plan against the MPB.

The multi-pronged attack ranges from managing timber flow, improving fibre quality and shelf life, examining the viability of MPB timber in various domestic and export product applications (e. g. railway ties and low-grade dimensional ‘cants’ for export and re-manufacturing in China), identifying new markets, sustainable development, assisting post-MPB communities and so forth.

Crown agency Forestry Innovation Investment (FII) is responsible for the Wood Products R&D of the BC provincial MPB action plan. FII contracts research work to eligible funding recipients to identify new processes and products to use and absorb large volumes of dry, dead, stained MPB wood. On the pulp and paper side, FPInnovations-Paprican, is heavily involved in the MPB initiatives.

There are no ivory towers. If they’re to win funding, the research proposals must demonstrate real value to the industry. Consultation with industry, feedback and evaluation decide the cut. Result updates, detailed reports, follow-ups to stakeholders and industry partners are all part of the mandate. As FII notes in its recent 3-Year Status Report: “The research is only as useful as its use by the industry.”

Robert Parisotto, director of the FII Mountain Pine Beetle Program, says acceptable projects need to demonstrate the opportunity for “quick uptake and quick benefit” for the industry to gain maximum value of MPB wood “before it falls over and decays eventually.”

MPB-affected wood has two shelf lives: biological and economic.

Biological shelf life refers to the time that remains before a standing dead tree weakens and falls over. Once it falls, it becomes much more difficult to harvest and the serviceability of the fibre deteriorates rapidly. Soil, weather, aspect geography, elevation, age and various other factors all affect biological shelf life, but generally five to seven years after tree death, the fibre is past its due date.

Economic shelf life is the inherent amount of value in the affected fibre and, says Parisotto, has a “cost side and a revenue side” – it takes effort, time and money to extract the latent value, which depends upon shifting market conditions. In turn, any new processes developed by the funded research must be cost-effective. “From the mill gate through to the market,” says Parisotto, “is where our focus and mandate has been.”

Early efforts focused on the primary solid-wood sector, fibre quality, manufacturing processes and identifying and accessing potential markets for the stained wood. Now the focus is beginning to widen and include research on how pulp mills can make better use of ever increasing amounts of fibre as it moves from green to red, to grey stage, becoming harder, drier and more problematic.

So far, Forestry Innovation Investment has funded 50 recipient-managed MPB projects. Fiscal 2008/09 has a dozen projects on the go. Three are of particular interest to the BC pulp and paper industry and -should the MPB break out across the northern boreal – the North American industry in general. Two of the three pulp and paper projects focus on new and better ways of bleaching stained wood chips. The other project assesses the strength and physical properties of grey MPB-affected wood chips made from whole logs. (For more information on these and other MPB research projects, check the FFI website: www.bcfii.ca/mpb.)

Pulp mills feed on cheap, plentiful quality wood chips. Every sawmill closure cuts into the supply and ups the cost. MPB wood could be another source. Question: Can this wood be chipped in its whole-log form into cost-efficient usable chips?

Operating out of a satellite chipping yard, Dr. Barbara Dalpke, lead project scientist for FPInnovations-Paprican, delved into the mechanical chipping of whole logs of mature red-and grey-stage MPB wood. The wood yields good chips but with more pins and fines, up to 10%. Says Dalpke, “It’s a little on the high side but that’s something you expect when you chip very dry wood.”

For kraft and TMP pulping, the results were also good, although the drier wood was harder to mechanically chip for TMP and there was a brightness problem courtesy the blue stain in the wood. When blended with regular residuals, up to half and half, there was also a small drop in pulp’s overall fibre length but like the affect on blue-stain/brightness, the small drop in quality wasn’t unexpected.

“Other than that,” says Dr. Dalpke, “the whole-log chips seem to perform similar to what the pulp mills usually get from [sawmill] residuals.” More good news? There are a lot of MPB-killed whole logs out there.

Bad news?

It takes more energy to chew up hard wood and energy isn’t cheap. “These chips are fairly expensive,” confirms Dalpke. “A lot more expensive than sawmill chips for sure.” At best, she says, MPB whole logs might be a useful, albeit higher-cost supplement to traditional chip supplies. “In the long run, just going to whole-log chipping in a satellite chip yard is probably too expensive.”

Over at the chemistry department of the University of British Columbia, Professor Emeritus Brian James is singing the blues … blue-stained pulp, that is. Dingy blue-stained chips makes for dingy, blue-ish paper. Compared to green healthy wood, mechanical pulps from MPB lodgepole fibre have much lower brightness.

Bleaching grey-stage MPB pulp with alkaline hydrogen peroxide helps somewhat, but it isn’t enough. The resulting brightness gap is commercially unacceptable.

James and his FII-funded UBC research team hope to jump the gap via a new and less expensive route, to a proven, yet costly, bleaching agent. There is an existing water-soluble chelating phosphine compound which is extremely effective at bleaching MPB stain but carries what James calls a “ridiculous price” of around $150 a gram. (It also carries a tongue-twisting name: bis[bis(hydroxymethyl) phosphino]ethane commonly abbreviated as BBHPE.) In a sort of chemical reverse engineering, James hopes to create a cost-effective synthetic route to BBHPE -and at a far cheaper price.

The costs have already been reduced significantly. First, the team improved on the literature prep and eliminated an expensive platinum catalyst. Next, they plan to switch to inexpensive, non-flammable ethylene glycol as the precursor, or base chemical. Says James, “I think we’re making very good progress and we’ve got one very good way to make it more cheaply.”

It is still in the early stages, but James says the research, testing and brightness assessment, scheduled for a mid-2009 completion, show promise. Assuming all goes well, the next step is to find a company willing and able to scale-up production of this BBHPE from lab-size amounts to full commercial production. Ideally, it would price in at around three to four dollars a kilo, or similarly to alkaline hydrogen peroxide.

“I think it will work,” says James. “It’s just a question of getting enough [BBHPE] material and a cheaper me
thod. And, hopefully, it’s something people in the industry could certainly use.”

At the red stage of MPB attack, TMP made from the chips lose five points of brightness on the international brightness scale. Seven years after tree death, the brightness can be almost eight points lower.

Traditional methods of bleaching simply don’t cut it for print readability and buyer acceptance, notes Dr. Thomas Hu, lead scientist for FPInnovations-Paprican. Treating MPB pulp with alkaline hydrogen peroxide after the refiner stage “yields less than the desirable benefit” and, notes Hu, using sodium hydrosulphite after the refiner stage “actually makes the situation worse.”

The FPInnovations-Paprican project has come up with a better way. Inrefiner bleaching with sodium hydrosulphite combined with post-refiner bleaching, improved the brightness scale by 4.4 points.

The chips were green/early grey-stage (two years dead) lodgepole pine. The research team tested in-refiner bleaching by either replacing tap water for the dilution phase with a water/sodium hydrosulphite mix (4.83 grams/litre) or added DTPA sodium salt and alkaline hydrogen peroxide to the impregnation and dilution water.

When sodium hydrosulphite was used for post-refiner bleaching, the brightness jumped by 4.4 points even with the worst chips (100% early-grey). When sodium hydrosulphite was used in the refiner and alkaline hydrogen peroxide was used post-refiner, the bleached pulp brightened by 3.4 points. The research team also noted that using water with lower conductivity with the alkaline hydrogen peroxide helps and further optimization may be possible with higher doses of DTPA and caustic.

For a TMP mill with an output of 600 tonnes/day, Hu says the improvement can mean a savings of $2.9 million per annum over other MPB bleaching methods.

Even the best research is useless, unless it’s used. MPB program director Robert Parisotto says the industry must continue to help researchers identify and fill the knowledge gaps in order to battle the beetles and further cement what he refers to as the very good working relationship between the industry and researchers. The key component of the R&D effort? Parisotto says it’s to ensure that “real, thorough communication and information gets into the hands of those who need it.

“Because ultimately that’s the test at the end of the day.”

PPC


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