Gary Johnston, Skeena Bioenergy plant manager (left) with plant superintendent Nathan Bond. A major challenge for Skeena Sawmills was how best to establish and maintain a return from the significant quantities of bark, sawdust, chip fines, and planer savings generated from its sawmilling operation—and Skeena Bioenergy was the answer.

Not your typical WOOD PELLETS...

The new Skeena Bioenergy plant in B.C. is not a typical wood pellet operation—using proven European equipment, it is turning out high quality wood pellets from a feedstock of Western Hemlock, not SPF.

By Jim Stirling

Forest companies need to make practical use of all their available forest profile if they expect to prosper.
A major challenge for Skeena Sawmills was how best to establish and maintain a return from the significant quantities of bark, sawdust, chip fines, planer savings, etc. generated from its sawmilling operation. The company’s answer resulted in the creation of Skeena Bioenergy, its new wood pellet manufacturing plant.

Skeena Bioenergy is not a stereotypical wood pellet operation. It uses proven European-made equipment to produce high quality wood pellets manufactured from a feedstock of Western Hemlock, not SPF.

“It’s still early days, but so far our objectives are being accomplished,” reported Roger Keery, president of Skeena Bioenergy Ltd. The new company is a wholly owned subsidiary of Skeena Sawmills, a well-established, privately owned sawmill and planer complex adjacent to the pellet plant at Terrace, in northwestern British Columbia.

“We wanted a plant that would be productive, run safely and efficiently, and have a minimum impact on the environment,” he added. “There was doubt expressed in the industry about the ability to make quality wood products from hemlock,” explained Keery. Skeena Bioenergy’s $20 million plant has dispelled that concern. Hemlock dominates Skeena’s wood basket, with up to half of it comprised of pulp quality logs. Consequently, hemlock in various forms comprises its residual materials.

The company factored into the plant’s design the learning curve with the raw material.  “We built in an extra 30 per cent of capacity into the pellet plant,” said Keery. The original plant capacity was rated at about 60,000 tonnes/year with the option to increase that to 90,000 tonnes/year. Now about 100,000 tonnes/year is viewed as an achievable projection.

Skeena Bioenergy’s primary residuals for pellet manufacture come from a blend of sawdust and bark. They key word is ‘blend’. The feedstock ingredients have differing ages and qualities. They require constant monitoring to ensure the control and consistency of the fibre entering the pellet plant meet the prescribed product specifications.

Plant manager Gary Johnston is the quarterback on the Skeena Bioenergy team. Together, they work to ensure the end product meets quality standards.  Johnston has the background. He is also a project manager and consultant based in 100 Mile House, B.C. with a broad experience in pellet plant design dating to when the concept was seconded from the B.C. agricultural sector.

“Hemlock is very high in lignum which allows us to make a more durable wood pellet,” explained Johnston. But Skeena’s hemlock bark also has a high ash content. “The objective is to have less than 1.5 per cent ash. Our bark can have up to 2.5 per cent ash, so we must blend the mixture to meet the required percentages.”

Conceptual design on the project was done with the help of CWA Engineering and through that process, Prodesa, a Spanish engineering company specializing in biomass pelleting, was chosen to deliver a belt dryer to the plant. The design allows the dryer to run at a much lower temperature—a maximum 110 degrees Centigrade—than a conventional belt dryer. The feature helps produce lower emissions, a priority for Skeena given the plant shares an airshed with business and residential areas in Terrace. The belt dryer delivers the additional advantage of producing a higher energy and consistent wood pellet, added Johnston.

But Prodesa’s role was considerably expanded. The company demonstrated a “can-do” attitude to what they were trying to create with the new plant, Johnston explained. As a result, Skeena Bioenergy became the first complete pelletizing plant package to be designed and supplied by Prodesa in Canada.

The raw materials for pellet production are trucked to Skeena Bioenergy from storage areas at the nearby sawmill. “Our quality control starts with the front end loader operator in our yard,” continued Johnston. “We try to stay on top of quality and preventive maintenance. We have tried to eliminate unnecessary steps to keep the process as simple as possible.”

Prodesa and Skeena designed the pellet mill with separate infeed systems to control the blend of feedstock. A German-made Bruks-Siwertell hammermill handles the green product prior to delivery to the belt dryer. A further feature of the belt dryer is its one-and-a-half pass drying ability. The extra half-a-pass acts like a filter for a more consistent moisture control.

A French-made ProMill dry hammermill follows the drying process. A pneumatic conveyor and filter system moves the dried product to three 450 horsepower ProMill pelletizer machines.

It’s not just about running a plant—it’s about running it safely, says Johnston. “When Roger Keery gave us the go-ahead he said ‘design me the safest plant, design me the cleanest plant you can come up with.’” Some of the ways of achieving that are reflected in small things, both visible and technologically driven.

The SonicAire dust control fan system works unbelievably well, said Johnston. The system comprises small ceiling fans that rotate 360 degrees, strategically placed throughout the plant. The air flow created by them stops dust from settling on flat surfaces, directing it instead to floor level where it is contained and removed. Other pro-active safety devices have been installed within equipment. For example, Fike chemical explosion suppression systems have been installed in high risk zones throughout the pellet manufacturing process. Similarly, thermal sensing and water deluge systems from Firefly, a Swedish manufacturer of industrial fire protection devices, have been installed in the dryer.

High tech is great, but it’s people who will get the most benefit from it. “We’re doing some pretty intensive training right now,” said Johnston. “But we have an amazing crew that has become a real team during the training process.”

Marketing Skeena Bioenergy’s wood pellet production was an essential part of the company’s development strategy. Skeena Bio has signed a long term off-take agreement with Pacific Bioenergy Corporation. The company operates a 350,000 tonnes per year pellet plant in Prince George. Skeena Bioenergy’s pellets are shipped by rail from Terrace to Prince George, and then south to Fibreco’s terminal in North Vancouver. The Skeena pellets are mixed there with other Pac-Bio products. They are then shipped in bulk from North Vancouver to power producing customers, mainly in Japan with lesser volumes exported to Korea.

Skeena Bioenergy is the first complete pelletizing plant package to be designed and supplied by Prodesa in Canada. Prodesa is a Spanish engineering company
specializing in biomass pelleting.

Upgrades in the works for Skeena Sawmills

Attention is switching to Skeena’s sawmilling operation in Terrace, B.C., now that the company’s wood pellet manufacturing plant is settling into production mode. A primary goal is the installation of a reconfigured and updated small log canter line. Skeena Sawmills’ wood supply is in a transition from an older growth regime to the next generation of merchantable trees.

“Traditionally, the mill was only intended for material down to an eight-inch top,” recapped Roger Keery, Skeena Sawmills President. “Now it is four-inch tops.” 

Keery said Stolberg Engineering was retained to re-design the mill flow to allow for installation of a replacement canter line. The mill’s existing Chip-N- Saw will be replaced with an Optimil canter with shape scanning system as the main breakdown unit. It will be able to accommodate diameters from 16 inches down to 3.5 inches.

The Optimil canter was opportunistically acquired by Skeena from its original installation at The Pas Lumber, when it became surplus to the company’s needs. It will be refitted for its new assignment, a process to include replacing the electrical system and overhauling the machine’s hydraulics, and installing an inline profiler unit.

“We hope to achieve a much better throughput—it’s very important for us to get value from more of the stand and make sure we’re being flexible with the grades we can produce,” explained Keery.

A new 22-inch dual ring debarker will be added concurrently and the downstream equipment—including the band mill resaw system—will remain in service. 

Several other upgrades to the plant are in the works as well, including new optimization equipment on the headsaw, a trimmer optimizer in the planer mill and new lumber dry kilns. All of these projects are expected to be completed by the end of 2020.