Making even better use of Canadian wood

There are many uses of wood chips for products other than pulp

Part Three: Uses of chips in the absence of a pulp mill

While a pulp mill is the original biorefinery, there are pathways from wood chips to a multitude of non-pulp products. First, though, co-location of a novel biorefinery plant next to an existing pulp mill has significant advantages in terms of shared utilities.

Shared utilities

While a biorefinery does not rely on the existence of a pulp mill the way a lignin or methanol plant does, there are advantages to co-locating a biorefinery next to a pulp mill in a so-called eco-industrial site.

Wood handling is the first obvious shared utility: road or rail access to bring in wood, log unloading and handling, debarking and chipping, chip handling and reclaim systems, chip screening and cleaning systems. Log handling, debarking and chipping may be located at the sawmill, with chip handling forward at the pulp mill/biorefinery. At the very least, an existing pulp mill will be able to unload sawmill chips from trucks or rail cars, store them and meter them into the process.

Energy needs are also likely to be of similar type: unloading, storing, drying, shredding and handling bark, metered bark into power boilers, feeding high-pressure steam to turbine-driven generators. This provides heat and power to onsite users as well as the grid and district heating if relevant.

Most processes for disassembling wood use water as the primary solvent. Biorefineries, like pulp mills, will need access to a treated fresh water supply and some form of effluent treatment plant.

In all cases, expanding current equipment rather than building from scratch will likely be cheaper.

Products targeting markets dominated by oil and gas:

Once you’ve got utilities, there are a range of products that can be made from clean white wood chips.

Some products will be identical to the existing molecule, and will be easy to sell into existing markets with no changes needed to downstream processing. In other cases, making an exact molecular replicate may not be easy or even possible, but a different molecule with similar performance characteristics may be possible, at the cost of some disruption to downstream processing steps.

In parallel, some of these products, coming as they do from plants or wood, may be biodegradeable or compostable; but some, especially those which are molecularly identical replicates of petroleum-based molecules, may face the same end-of-life recycling issues.

Finally there is a broad characterisation in terms of end-use: the product can be intended as an energy-carrier or a fuel, or something more durable.

Fuels

Biofuels, bio-chars, bio-coal, bio-oils and wood pellets are products generally intended to substitute for fossil-based fuels. Generally, wood is expensive given the costs of dragging it out of the bush, so bio-fuels or bio-energy are economically challenging if the price of the fossil alternative does not include some form of policy support in the form of carbon accounting. Further, the more valuable wood chips should be reserved for more valuable end-products, while less valuable materials such as bark should be directed to energy uses.

Biofuels used to include biodiesel and ethanol, but as the world moves to electric vehicles, these markets will decline. A dense liquid fuel is still needed in aviation, so the sustainable aviation fuel (SAF) market is growing.

Bio-chars can be used for soil amendment. Bio-coal is designed to replace coal, especially metallurgical coal for making steel. Bio-oils have been displaced heavy fuel oil in central heating plants on university campuses or hospital grounds. Wood pellets have been used for partial substitution of coal in EU generating stations. Some of these pathways are robust, in the sense that demand is not going to go away in the short or medium term, but all require low-cost feedstocks.

Biochemicals

Finland’s forestry company UPM is building a true biorefinery at the chemical park in Leuna, Germany: multiple products are made from whole beech logs, but no lumber or pulp is produced.

The plant will make 220,000 tonnes annually of bio-based functional fillers and glycols, both common building blocks provided by the petrochemical industry. The plant is still in start-up phase, and like most systems bearing Serial Number 001, is running behind schedule and over budget. It will be very interesting to see how this plays out, and to what extent they are capable of hitting product quality targets.

UPM and its Finnish competitor Stora Enso make a range of lignin-based products for replacing phenolic resins. UPM’s lignin comes from a pulp mill in Plymouth, NC. Stora-Enso’s pulp mill in Sunila, Finland, used to produce lignin but was forced to shut when Russian wood imports stopped.

In Canada, the pulp mill at Hinton, AB, once operated by West Fraser, had a lignin plant that supplied West Fraser’s plywood mill with phenolic glues, but the lignin plant was removed following the sale of the mill as the new owner needed the space for other uses. Currently there are no lignin plants in Canada.

With the Hinton and Sunila lignin plants shut, there is now a worldwide shortage of lignin; in response, Swedish firm Södra Cell is building a large new lignin plant at its pulp mill in Mönsterås, Sweden. Tellingly, Södra Cell has announced confirmed sales contracts for an unspecified portion of the total capacity before the first shovel went in the ground; the two customers are UPM and Stora Enso.

Substitutes for petrochemicals can also be made from sugar cane, sugar beet and corn, or from canola, soya, plantation palm trees and used animal fats from restaurants or meat processing plants. All produce viable, non-fossil products, but all require good agricultural land and are thus susceptible to the old food-versus-fuel debates. Canadian wood is certified sustainably harvested, grows on soil too poor to support food crops, and provides 60+ years of support for biodiversity between harvests. At the present time, due to the steep decline in demand for our pulp and paper products, we are only cutting half what the various provincial forest ministries deem sensible and sustainable. It is time to make better use of this resource for the benefit of all Canadians and, most importantly, the Indigenous communities located in the forests.

So there you have it: A complete forest sector eco-system removes potential deadfall from forests, reducing the risk of out-of-control wildfires, and provides solid wood, energy and a range of bio-products that can store carbon and reduce our dependence on fossil-based products. All components of the forestry eco-system are important and if one falters, it damages the others. Government support for the lumber industry, as announced by the Carney administration recently, is most welcome but won’t be sufficient if there is no place to put the chips.