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Transformative Technologies for the forest products sector

This kind of thinking was behind a recent initiative of the Canadian Forest Innovation Council (CFIC), a committee of senior industry and government representatives, which commissioned four White Papers on transformative technologies for the Canadian forest sector. They chose pulp and paper, biochemicals, bioenergy and wood products as four topic areas for the White Papers. We prepared the White Papers on pulp and paper and on biochemicals on behalf of PAPIER. All four White Papers received input from international reviewers, as well as from workshops in Quebec City and Edmonton. The mandate was to focus on aggressive, imaginative alternative uses for fibre and its derivatives. The White Papers were made public by FPAC at a news conference on May 10, 2006 at the Sheridan Wall Centre in Vancouver.

You may have already read about the biorefinery and the suite of proposed technologies for making co-products in pulp mills — many of these ideas are indeed truly transformative. And there are many more good ideas for the paper and wood products sectors. This brief review covers a few of the highlights from the four White Papers. Among them we hope to find the seeds of a brighter future for our sector.

Pulp and paper — what else could we possibly make?

In a well-established industry just coming off a century of very successful innovation, you could be forgiven for assuming that all has been invented already. But we often sell the world’s best fibres as commodities, and the real challenge here is to capture full value for the fibre by making products that cannot be matched by the competition. Ultra-filled mineral paper with low basis weight, a backbone of fine strong softwood fibre and a hemicellulose-based bonding agent is just such a product. Another is super reinforcement market pulp, straightened, dekinked, prefilled and optimized for papermakers to provide the stiffness, strength and opacity needed for very lightweight grades: it is time to move the goalposts.

For mechanical grades, higher energy costs have now taken on a new level of importance. When mechanical pulping uses as much as 10% of the electric power produced in a province like BC, the drive for energy efficiency is ever present. One new approach might be to lower the 90-95% yield target down to 80%, by pre-extracting hemicellulose and to make a ‘semi-mechanical’ grade with the remaining fibre: some early work suggests that 30% less electrical energy would be needed. The hemicellulose could be used as the basis for new bonding agents in ultra-filled mineral papers.

Higher costs for petroleum-based plastics have increased the incentive to use wood pulp as reinforcement in structural plastics. Bleached kraft pulp is now one third the price of a typical commodity plastic. Research is needed to establish how best to make wood fibres more hydrophobic for plastic reinforcement, but the potential market is large. When compared to the extraordinary sophistication embodied in coated papers with their exacting, high speed manufacture, a much broader role for wood fibre in the world of plastics looks like a more straightforward challenge, and may be an idea whose time has come.

Functionalized fibres can be used to reinforce plastic composites at three different scales: macro scale fibres, (30 microns wide) that we already use to make paper; micro scale fibrils (1 micron wide) which help with paper bonding; and nano scale cellulose nanocrystals (0.01 microns wide) which provide structural strength for the fibre. The nanoscale architecture of trees, with its flawless microstructure and liquid phase ordering, has remained largely unexplored to date, and offers a new world of product opportunities. The first step is to develop commercial scale extraction technologies for cellulose nanocrystals.

Bioenergy from forest biomass

The authors of the bio-energy white paper, Warren Mabee and Jack Saddler from the University of British Columbia, presented two transformative technologies for bioenergy and energy products from forest biomass. The two technologies are advanced thermochemical systems that involve pyrolysis and gasification, and secondly, bioconversion methods that involve enzymes to isolate the basic chemicals of wood.

Thermochemical conversion processes can liquefy or gasify wood and then reassemble the components for use as fuels or chemicals, as needed. One process, called fast pyrolysis, takes place at lower temperatures (450 to 550C) with 60-70% of the original wood feed stock ending up as liquid pyrolysis oil. Development work on this process has been mostly aimed at the elusive goal of making transportation fuels, a difficult task from a variable feedstock such as wood.

An alternate thermochemical process uses higher temperature pyrolysis (550 to 600C) followed by gasification to produce synthetic gas (or syngas). Pyrolysis and gasification could be used to generate energy, or with a further catalytic conversion step, to create liquid fuels and chemicals. Gasification systems offer the possibility of minimal impact energy self-generation for saw mills, and can in concept be used to make transportation fuels such as diesel oil from so-called Fischer-Tropschs fluids, or to make ethanol. Low quality and high variability of syngas are likely to be a challenge, particularly for subsequent catalytic production of fuels or chemicals.

Bioconversion has had lots of recent publicity with TV ads in Canada and remarks from the US President about cellulose ethanol. The concept here is that ethanol production from sugars and starches using enzymes could be adapted for use with hemicellulose and cellulose from agricultural and forest biomass. Ethanol is the focus because it can be used as an additive with gasoline in automobiles. Since hemicelluloses are more accessible for bioconversion than cellulose, they are the first new candidates as feedstock for conversion to ethanol. There is great interest in hemicellulose pre-extraction prior to pulping because this could provide a contaminant-free source of hemicellulose which is compatible with pulp production. All the wizardry of biotechnology, proteomics and metagenomics will be needed to identify the new enzymes that will enable wood-based feed stocks to compete with agriculturally-derived starches.

Biochemicals from forest biomass

Amazing as it might seem to anyone who is not a chemist, just as large a range of chemicals and plastics can in theory be produced from biomass carbohydrates as can be made from petrochemical hydrocarbons. Energy security concerns have motivated the US to set a target to obtain 25% of its chemicals from biomass by 2030. They have already confirmed that they have enough biomass and identified 12 building block chemicals that can be derived from hemicellulose and cellulose. Large market products such as resins, polymers and food additives are the targets. Similarly, lignin can be converted to phenols, resins and many polymers. Structural plastics alone have a world market similar in size to paper products. In this area, it is not so much a question of whether it will happen but when, and what will be the most appropriate feed stock, with tailored agricultural crops as the main competition to forest biomass.

Co-production in an existing pulp mill will be one useful way that feed stock sources and process technologies can be established for making biochemicals from forest biomass. For this to happen, hemicellulose pre-extraction before pulping, as mentioned above, will need to be perfected in a way that preserves the pulp properties, particularly for softwood pulps where strength is critical. Similarly, pulp mills will look for opportunities to precipitate lignin, initially to displace fossil fuels within the mill, and then to develop and market lignin-based chemicals. Lignin is a high calorific fuel and presumably would qualify for carbon credits if exported to Europe to displace fossil fuel.

Pharmaceuticals and nutraceuticals represent much more proprie
tary, high value, small volume markets. Tree extractives are a rich source for these kinds of bioactive compounds which have received little attention to date in Canada; there appears to be a significant opportunity in new pharmaceuticals and nutraceuticals from Canada’s boreal forest awaiting discovery.

Transformative technologies for the wood products industry

The white paper on this topic was written by Alan Potter of Forest Research Opportunity BC. Many opportunities were identified and three are highlighted here. Fully engineered building systems for residential and non-residential construction might not sound transformative, but in fact they would be, and not just to overcome US import restrictions on lumber. Factory-made floor and wall assemblies would allow much more flexibility in house design, with more open spaces and more efficient construction.

These new systems could usefully incorporate new forms of composite lumber that could be developed from oriented strand board (OSB) technology. Oriented strand lumber (OSL) would be a stronger, composite version of structural lumber that could be exploited in the new engineered building systems. Finally, new log processing techniques could be developed to direct more wood to composite lumber manufacturing, particularly the stronger mature wood near the outside of the tree. The weaker juvenile heartwood might eventually be left to the papermakers, who generally prefer the finer fibres for their flexibility and superior reinforcement properties.

Back to the forest

New sensing and tracking technologies could transform wood flow management in Canadian forests using detailed knowledge of wood and fibre quality to maximize end-product margins. These methods could establish a certifiable chain of custody record from forest to recycle. They could also provide genomics information for improved seedling selection for the desired wood quality attributes. In this way, maximum benefit could be extracted from Canada’s wide diversity of fibre and some portion of new forests could be planted with end-uses in mind.

Summary

Four White Papers from the Canadian Forest Innovation Council (CFIC) on Transformative Technologies for the Forest Sector have just been released covering Pulp and Paper, Bioenergy, Biochemicals and Wood Products. Highlights are outlined in this article among which are suggestions of technologies which could create a brighter future for the Canadian Forest Sector. Copies of these White Papers are available from CFIC Executive Director Dan Wicklum at dwicklum@fpac.ca who was the driving force behind this undertaking.

Authors

Dr. Andrew Garner, Principal of Andrew Garner and Associates, specializes in corrosion, materials engineering and research planning for the Forest Sector. He can be reached at andygarner@telus.net.

Dr. Richard Kerekes is the Director of PAPIER, the Canadian Pulp and Paper network for Innovation in Education and Research. He can be reached at kerekes@ppc.ubc.ca

The directors of PAPIER provided overall guidance in the preparation of the White Papers on Pulp and Paper and Biochemicals. Copies of these white papers are available on the websites of FPAC www.fpac.ca, or the Canadian Council of Forest Ministers www.ccfm.org, or from CFIC Executive Director Dan Wicklum at dwicklum@fpac.ca who was the driving force behind this undertaking. P&PC

PULP & PAPER CANADA * 107:6 (2006) *