Going green with new wood room

by | Jun 28, 2024 | 2024, Logging & Sawmilling Journal, May/June 2024

The Mercer Peace River (MPR) pulp mill has taken a significant step toward reducing its overall generation of carbon emissions with a $75 million investment into a green-powered wood room, and switching away from in-block chipping.

Owned by Mercer International, which was founded by UBC Chemical and Biological Engineering grad Jimmy S.H. Lee, the pulp mill located in Peace River, Alberta was purchased from Daishowa-Marubeni International (DMI) in 2019 for $465 million.

The pulp mill, which began operations in 1990, produces both hardwood and softwood pulp and manages 2.7 million hectares of forest in northwestern Alberta.

DMI shut down its wood room in 2004, opting for in-block chipping for its hardwood chip source and partnering with companies like Peace River Logging which operated four in-block chippers before the transition to whole tree logging began in 2021. The chips were transported from the block to the pulp mill in standard chip vans.

The transition back to chipping cut-to-length (CTL) hardwood logs at the pulp mill was announced in 2021 as MPR’s Fibre Procurement Project.

In addition to major investments in new equipment at the pulp mill, the project also included the establishment of a new log haul company, Peace River Transport (PRT), which is owned by MPR. It has purchased 22 trucks and trailers to reliably transport primarily 18’ and 21’ CTL logs from the cutblocks to the mill, with the aim of eventually expanding its fleet to 40 trucks. At present, their fleet consists of 16 Western Star 49X and six Kenworth T800 trucks. Their trailers consist of three Doepker King B’s, five Manac King B’s, 15 Peerless King B’s, and four Gerry’s King B’s. The trucks are operated with a combination of PRT employees and owner-operators. Logging to supply the pulp mill is mainly done on a seasonal basis from October to March.

 

“The decision to reactivate the wood room was made to improve both the efficiency and sustainability of our operations,” says Roger Ashfield, MPR Managing Director. “This way of processing hardwood improves MPR’s environmental performance sustainably.”

The overall project is expected to reduce MPR’s fossil fuel emissions by over 900,000 tonnes of CO2e and sequester 2.6 million tonnes of CO2e through forest conservation.

“By eliminating diesel hardwood chippers in the forest to chip, we have significantly reduced greenhouse gas emissions,” Ashfield adds. “Also, when we were using the diesel wood chippers, unfortunately they left some wood chips in the forest. The new debarker utilizes the whole log, so we now need to harvest less hardwood to produce our pulp.”

He says that by harvesting less hardwood, MPR is conserving the carbon capturing processing that naturally exists with trees within the forest.

The pulp mill has also improved the utilization of its harvested wood fibre by more efficiently using all parts of the tree at the mill, with more efficient retention of waste wood materials through improved debarking at site. The bark is used to generate green energy. Burning the bark as hog fuel results in less natural gas burned at the facility. All the new equipment installed in the re-commissioned wood room will operate on electric power generated by the pulp mill, as it has the capability of generating 69 megawatts of power.

“Our onsite debarker, wood chipper, and Sennebogen 870E (material handler) run on green energy generated by MPR,” says Ashfield. “The equipment provides some of the most innovative debarking, chipping and monitoring technologies.”

The massive Sennebogen material handler used to feed logs into the mill is a diesel/electric hybrid unit, which the company says is able to reduce operating costs by 30 per cent.

The new batch-style rotary debarker at the front end of the Mercer Peace River wood room was custom designed and built by Industrial Equipment Manufacturing. It is the largest batch debarker operating in Canada and can process 400 cubic metres per hour. Andritz supplied its horizontally-fed HHQ chipper (below) to the project— it’s said to be is the biggest chipper installed in Canada.

Sennebogen is a major world-wide supplier of material handling equipment and is no stranger to Canada’s forest industry. It offers the 870E hybrid material handler in weights from 97 to 145 tonnes, with a maximum reach up to 27 meters. It also comes in drive variants from 250 kW to 261 kW. The machine has a fuel storage tank in the rear and, depending on the type of machine, one or more additional hydraulic cylinders on the boom.

When the operator lowers the boom, the system stores the energy and makes it available to use during the next lift with virtually no loss. The stick can be customized to match its intended usage, and there are also a wide range of undercarriage options available.

In terms of the wood room, a number of companies were involved in the overall design and equipment supply of this critical section of the pulp mill.

The project began in earnest during the first half of 2021 when excavation for the new wood room, plus demolition, engineering and material ordering began. International Quest Engineering handled the civil and mechanical engineering on the project. Salem Contracting worked on the civil, mechanical and structural components. Electrical work and piping was supplied by Flint Energy, and Mercer logging contractor Peace River Logging (see page 32 of this issue for a feature story on Peace River Logging) worked on the excavation and demolition. Rentco provided rental equipment and mobile units, as needed, while Pro-West Refrigeration Ltd provided HVAC and dust collection equipment. Hydraulic power units and associated tubing was supplied by Applied Industrial Technologies.

In terms of internal hardware, Surrey, B.C.-based, Industrial Equipment Manufacturing (IEM), provided the batch-style, bottom discharge, rotary debarker for the project. It was custom made for the MPR wood room and is the biggest batch debarker in Canada. It has five rolls plus two recirculating rolls to process 400 cubic metresper hour.

Kelowna, B.C.-based, Versatile Fab and Machine (VFM) provided a step feeder to singulate and convey the logs within the wood room.

ANDRITZ supplied its horizontally-fed HHQ chipper to this project, which is the biggest chipper installed in Canada. The chipper is best-suited for long logs, but it works with short logs, as well, because the infeed chain conveyor will orient short logs during chipping. The chipper disc is equipped with long-lasting TurnKnife-IV blades and the Helical Face Technology (HFT), which reduces log bounce-back and improves chip uniformity.

“The improved cutting geometry and optimized cutting speed produce thinner rectangular chips, with a profile best-suited for today’s cooking or refining processes,” says the company.

The Mercer Peace River pulp wood room project tapped a number of Canadian suppliers for the $75 million project, including Kelowna, B.C.-based Versatile Fab and Machine which supplied a step feeder to singulate and convey logs.

Logs are fed directly into the HHQ chipper through a large horizontal spout by a chain conveyor at a controlled speed. The chips are side discharged to a screw hopper placed above floor level. The gentle discharge reduces chip damage as well as the amount of fines and pins produced. Tests conducted by ANDRITZ show that the chips are of such high quality that they can be compared to screened chips.

The bark recovered from the rotary debarker is collected and conveyed to a Grizzly mill, a hogger supplied by B.C.-based Brunette Machinery Company. It grinds up the bark material into smaller pieces, to burn efficiently at the pulp mill’s power boiler. Brunette says that the rugged heart of the Grizzly mill hog is an extremely heavy duty, solid steel, offset helix rotor that shears material from two directions against an anvil and grate. The rotor turns at half the speed of a conventional hammermill rotor, resulting in substantial savings in maintenance costs.

The MPR Fibre Procurement project received financial support from a number of grant programs aimed at projects that reduce greenhouse gas emissions. Among them were $7.5 million from Emissions Reduction Alberta, $8.5 million from the federal government’s Investments in Forestry Industry Transformation program, and $7.5 million from the Alberta government’s Sector-specific Industrial Energy Efficiency (SIEE) grant program.

Tony Kryzanowski

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