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Turning the wood residue power switch on
Using European technology, B.C.’s Nechako Lumber will soon have a new plant to capture surplus heat created through the utilization of wood residue, and convert it to electrical power.
By Jim Stirling
Capturing surplus heat created through wood residue utilization and converting it to electrical power opens a whole new realm of possibilities for the Canadian sawmilling industry.
Nechako Lumber Co Ltd., in Vanderhoof has been quick off the mark to recognize the technological potential. A new plant to make the system a reality is under construction at Nechako’s mill in site in central British Columbia.
“We have always been a very integrated operation,” outlines Alan Fitzpatrick, general manager and director of the three Vanderhoof forest companies, Nechako Lumber, L&M Lumber Ltd., and Premium Pellet.
“When we eliminated use of the beehive burner about 11 years ago, we used the sawdust and shavings in the pellet plant,” he says. Similarly hog fuel and bark was directed to heat thermal oil for dry kiln operations. “We like to say we use every part of the tree except the shadow,” he says.
Around 2005, the pellet plant was expanded and the capacity of the energy system increased. Meanwhile, the infamous mountain pine beetle epidemic was exploding. The Vanderhoof region is among the hardest hit by the beetles. A side effect of the infestation is huge increases in dry, dead beetle wood volumes. They require less drying time in the kilns creating an excess capacity, explains Fitzpatrick. The challenge became how to successfully utilize that capacity.
An answer was found in Italy and a company called Turboden.
“The technology we developed is very simple,” explains Alessandro Foresti, Turboden’s director. “It is also flexible and easy to operate. It can be used on full load or part load.” Turboden has worked on an installation of the technology in Saskatchewan, but the Nechako Green Energy Project represents the first sawmill application in Canada.
It’s been a different story in Europe, with the first commercial-sized Turboden installation for the Swiss Army in 1998. Foresti says Turboden was still a small company in 2000 with about five people on the payroll. Now that number is approaching 200. The growth was driven by installations of Turboden’s energy saving technology and systems in Austria and Germany, followed by clients in other parts of eastern and Western Europe, recaps Foresti.
About two years ago, Turboden began looking for expansion potential beyond Europe. It struck a fruitful business relationship with Pratt & Whitney Power Systems, based in East Hartford, Connecticut. Foresti says Pratt & Whitney, a United Technologies company, now owns a controlling interest of 51 per cent in Turboden.
The partners’ technology system is called Organic Rankine Cycle Power (ORC). The ORC power generation equipment is based on a vapourized steam cycle using an organic fluid with a higher density and lower liquid-to-vapour temperature than water.
Nechako Lumber provided a brief description of the system. Key is the hot temperature thermal oil system used primarily to provide heat in Nechako Lumber’s dry kilns. A turbogenerator uses the thermal oil to pre-heat and vapourize an organic heating fluid. Vapour from that powers a turbine directly coupled to an electric generator. The exhaust vapour flows through a re-generator where it heats the organic fluid. The vapour is then cooled by water flow. The organic liquid is then pumped to the re-generator and an evaporator as part of the closed loop circuit.
The ORC system is essentially a method of local energy production, points out Turboden’s Foresti. “It’s a local resource used locally and the resource is heat."
Nechako Lumber’s tradition of innovation continues with energy project
A tradition of innovation is continuing at Nechako Lumber’s mill in Vanderhoof, British Columbia.
Recently retired local owners Mike Manojlovic and Torall Scott were always looking for new ways to improve their mills. The tradition includes the first HewSaw in North America and being the test site for log crack detection systems in the sawmill. On the planer side, it was the first in the industry for lumber grade scanning with Comact.
The mill also introduced high speed planer technology with Gilbert, hog fueled energy systems to heat dry kilns with Del-Tech and the first large scale wood pellet plant in B.C.
The tradition is continuing with the Nechako Green Energy Project, a ‘waste’ heat recovery system that’s the first of its kind in the Canadian sawmilling industry.
The existing Del-Tech biomass burning system uses all the hog made by the 200 million board feet/year stud mill operation. All the sawdust, shavings and fines stay on site for the 145,000 MT/year pellet plant. The existing hog fueled system had excess heat going up the stack and that’s where the green energy project comes in.
“By capturing the excess heat we are able to generate up to one-third of our total electrical demand, enough to almost completely power our pellet plant operation,” says Alan Fitzpatrick, general manager. “We are looking within our operations for additional sources of generating electricity and we selected a unit that will also let us use the remaining heat for future products, possibly to heat our buildings or pre-dry our sawdust for the pellet plant for example,” he adds.
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