Pulp & Paper: West Fraser Hinton mill makes strides on lignin recovery
West Fraser Timber has secured a licence to operate a 30-tonne-per-day lignin recovery facility attached to its pulp mill in Hinton, Alta., and is at in the process of commissioning the plant. It hopes to begin commercial output this summer.
Lignin is a polymer that gives trees their physical strength. It can be extracted from a pulp production by-product called black liquor. Once extracted, it works as a natural adhesive with many potential industrial uses — not least of which is within the wood products industry itself.
The industry manufactures staple products for both the construction and energy industries, such as plywood, oriented strandboard (OSB), laminated veneer lumber (LVL) and wood pellets. All are high-value, high-production commodities that require a binding agent.
Research has proven that lignin can work as an effective binding agent in these applications. Once commissioned, the one-of-a-kind facility in Hinton will ramp up lignin production 1,000 fold, using Canadian-developed, breakthrough lignin recovery technology first demonstrated at a pilot-scale plant in Thunder Bay, Ont. That plant is only capable of producing 12.5 kilograms per hour. The technology was developed by a consortium involving FPInnovations, Canada’s wood product research institute, and B.C.-based NORAM Engineering.
The consortium is marketing the technology under the name Ligno- Force. Rod Albers, West Fraser’s manager of energy and bio-product development, says one significant benefit of this technology is it can be bolted into an existing pulp mill without interrupting production flow. A huge sigh of relief can be heard throughout the wood product industry as a result of breakthrough work like this lignin recovery method.
For the past decade, the industry has been funding research to find alternatives to penol-formaldehyde resins currently used in the manufacture of panelboard products. These resins have been identified as suspected carcinogens by organizations such as the Environmental Protection Agency in the United States and World Health Organization.
There is a real fear that Canada could eventually lose markets for its many panelboard products if it doesn’t find alternatives to penol-formaldehyde resins. Banning of penol-formaldehyde resins without a benign alternative could result in the loss of billions of dollars annually in panelboard sales. And it isn’t just a Canadian problem.
While it is not the only solution being investigated, use of lignin in the development of a new, benign family of panelboard adhesives is seen potentially as a huge win for the industry, especially with the solution coming from the wood industry itself and, as an added bonus, the production of a new value-added product specifically from the pulp sector.
Albers says its work with FPInnovations in investigating the commercial potential of lignin is why West Fraser agreed to pay $9 million as part of the overall $22-million project cost for the Hinton lignin recovery plant. It could see an immediate application in-house to test lignin- based resins as an adhesive at its three plywood plants and LVL production facility.
Other financial contributors to the Hinton plant included $10 million from Natural Resources Canada through its Investments in Forest Industry Transformation (IFIT) Program and $3 million from the Alberta government though Alberta Innovates Bio Solutions (AI Bio) and its Advanced Materials and Chemicals Program. As part of its contribution, West Fraser has agreed to pay $1.5 million back to AI Bio’s lignin research fund to help the organization research additional lignin uses and markets.
Lignin and capturing this wood-based extract is not new. What is new is the LignoForce method, which uses an acidifying agent such as carbon dioxide coupled with filtration and washing to produce high quality, dry lignin. West Fraser is currently working with chemical supplier Hexion to develop lignin-based resin formulations that are aimed at maximizing lignin volume without sacrificing panel performance.
It has already supported considerable research and testing of formulations and performance of lignin-based panelboard adhesives within organizations such as FPInnovations. Albers says, so far, use and testing of the lignin- based adhesives in its panelboard products have met or exceeded West Fraser’s performance standards. He adds that proving its commercial use in-house is part of showing other forest companies that lignin-based resin alternatives will also work for them.
The company has already spoken with other forest companies currently using Hexion products about switching to lignin- based adhesive alternatives developed by the chemical producer. Although lignin extraction won’t provide the opportunity for additional pulp production in Hinton because the pulp mill currently has excess boiler recovery capacity, Albers says extraction of lignin from the black liquor stream could result in an opportunity to increase pulp production at other pulp mills that are recovery boiler limited.
Pulp mills require black liquor in their pulp production process as a source of fuel to recycle cooking chemicals and to generate heat and power. However, if a portion of the lignin is removed from the black liquor stream, it creates more capacity in the recovery boiler where the black liquor is burned, and therefore creates the potential for increased pulp production. Additionally, pulp mills will be producing a marketable commodity.
These benefits have definitely caught the industry’s attention. With its panelboard facilities, Albers says West Fraser has a ready-made, in-house market for about 10 per cent of its lignin production, which means it needs to find a market for the remaining 90 per cent. An obvious place to look is the chemical industry are companies like Hexion as users of the raw material for the development of lignin-based resin formulations, which they can then market to all panelboard producers as an alternative to penol-formaldehyde resins.
But what has West Fraser, the federal government and AI Bio excited are the many additional market where lignin could find a use, particularly as industries look for more environmentally friendly alternatives to existing products. West Fraser is actively involved in supporting that research.
Among the industrial products where raw lignin could find a downstream use are packaging, carbon black, activated carbon, epoxy resins, adhesives in foundry resins, wood pellet adhesives, thermoplastic composites, surfactants and binders, and polyol in polyurethane foams.
About the author: Tony Kryzanowski writes a bout forestry, alternative energy, and natural sciences for a variety of national and international publications, and is headquartered in St. Albert, Alta.