Pulp and paper biorefineries out of the woods
By Gabrielle Bauer BioFuelNet
By Gabrielle Bauer BioFuelNet
Dec. 6, 2016 – It’s no secret that demand for newspaper is waning. Even a decade ago, it was common to see public transit commuters absorbed in the “broadsheets” splayed on their laps. Today, not so much. If you hop on a subway, you’re liable to see most commuters, especially younger ones, staring at a smart phone or e-book. At the same time, businesses of all stripes, from insurance firms to medical offices, are slowly but surely eschewing paper in favour of electronic record-keeping systems.
These winds of change have pushed pulp and paper (P&P) mills across the country to that proverbial fork in the road: either adapt or gradually fade away. BioFuelNet (BFN) is betting on the first outcome, and BFN’s integrated biological biorefinery Task Force is making rejuvenation of the P&P industry a priority.
Specifically, the Task Force’s chief initiative seeks to harness the abundant woody and residue-based feedstocks in Canada and the world-class expertise of the Canadian P&P industry to develop Biorefineries that yield high-quality, affordable bioproducts. A strong P&P infrastructure already exists, so it makes sense to make use of this asset,” says Dr. Jack Saddler, a professor at the University of British Columbia and Task Force lead. BFN’s integrated biological refinery platform hopes to address challenges and explore opportunities along the Canadian forest sector value chain.
The traditional pulping process breaks wood down into cellulose and hemicellulose sugars along with lignin, which functions as a kind of glue holding everything together. To put it very simply: remove the lignin, separate and reorganize the cellulose fibres, and voilà, paper. The biorefinery model takes this P&P expertise up a notch by converting the cellulose and hemicellulose sugars into a range of fuels and chemicals including ethanol, butanol, and farnasane while using the lignin to create high-value coproducts ranging from plastics to the carbon fibres in bullet-proof vests. These coproducts increase profitability and make the biorefinery model more attractive,” says Dr. Saddler. Lignin can also be used to generate power with a lower carbon footprint than traditional methods.
The devil is in the details, of course. Getting to the end of the rainbow — a good biofuel yield and a suite high-value coproducts – involves an intricate series of steps, each with its own challenges. That’s where the Task Force’s collective expertise can help.
The first part of the process, called pretreatment, “opens up” the biomass so that enzymes originating from wood-degrading fungi can access and break down (hydrolyze) the cellulose in wood to smaller sugars, says Dr. Richard Chandra, the researcher in charge of coordinating the bioconversion process. This step isn’t as straightforward as it may seem. As Dr. Chandra puts it, “we’re trying to break apart something that nature created to stay together.”
The way nature works — leaving the wood to biodegrade via microorganisms and their enzymes — takes many months and years, an obviously impractical timeframe. To speed things up, researchers linked to the task force have been overlaying chemomechanical treatments, such as sulfonation or hydrogen peroxide, to existing P&P processes. “We’ve been able to show that combining mechanical and chemical treatments opens up the biomass faster,” says Dr. Chandra. The pretreatment process helps “fractionate” the biomass components — cellulose, hemicellulose, and lignin — into separate streams.
Next comes hydrolysis: breaking down the cellulose into sugars. To this end, the bioconversion group turned to Novozyme, a Denmark-based multinational company that produces the right enzymes for the job. The final step in the process, fermentation, helps convert the sugar to the desired end-products. The bioconversion project has several university research groups focusing on just this step.
The work goes far beyond an academic exercise. “One of the project’s goals is to produce end-products on a large enough scale that industry partners realize we’re not just shaking test tubes,” says Dr. Saddler. That’s why the group has ramped up production from lab scale to the PDU [Process Development Unit] level and hopes to collaborate with industry partners to reach full commercial scale in due course.
In fact, commercial interest in the biorefinery model has been quietly growing throughout the world. For example, In Norway, the biorefinery company Beauregard makes alcohol from forest materials while in Finland, Neste converts pine-tree tall oil into biodiesel. Advanced biofuel plants (using biomass feedstocks) are already operating in Italy, Denmark, Brazil and the US.
Closer to home, several Canadian technology providers and forest product companies are keeping a close eye on the biorefinery approach. “The Task Force has been fortunate enough to get input from world-class Canadian groups such as FPInnovations, Alberta Pacific, Fortress and Port Hawksbury,” says Dr. Saddler. “Each of these companies is currently assessing the potential benefits of using biorefineries to process forest biomass.” In collaboration with such partners, Task Force members plan to demonstrate how a biorefinery approach can give Canada the bioproducts currently derived from fossil fuels. As it happens, Canada has close to 40 per cent of the world’s sustainably managed forests, and the forest sector has effective supply chains in place, “so we have solid ground to build on.”
That said, a major reason for adopting the biorefinery model is global sustainability. “We can’t keep emitting greenhouse gases from finite fossil resources,” says Dr. Saddler, adding that “we need to take a generational view of this work. It typically takes two to three human generations for trees to grow in Canada. Establishing a Canadian forest based biorefinery industry may not change your life or my life all that much, but our grandchildren will surely benefit.”
A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. Just like oil refineries, which produce multiple fuels and products from oil, biorefineries can maximize the value of biomass by turning it into a variety of end-products. For example, a biorefinery could produce a high volume of liquid transportation fuel, while at the same time generating heat for internal use, electricity for sale, and the chemicals and plastic-like polymers we are used to deriving from oil — all while reducing greenhouse gas emissions.
Biorefineries operate using different “platforms” to promote different product slates. For example, biorefineries using a “sugar platform” focus on fermentation of sugars extracted from biomass feedstocks — the focus of the task force bioconversion product. Other platforms, such as the syngas platform, use thermochemical processes to gasify the biomass into a different set of end products.