Ready for the future

Interfor’s Adams Lake sawmill is getting ready for the future—a future that includes a new $100 million sawmill— with a new wood-fired energy system that is going to deliver savings. By Paul MacDonald

The Adams Lake sawmill of International Forest Products Limited (Interfor) is getting ready for the future. This past spring, Interfor— one of the top producers in the Pacific Northwest, with lumber production capacity of 1.4 billion board feet— announced it will invest $100 million in a new sawmill at Adams Lake, BC, to replace the existing facility (please see details on this project in the sidebar story on page 12).

Interfor’s Adams Lake project manager Heinz Torbohm (left) and Craig Carlyle, energy manager of Interfor, with the energy system, kilns—and Adams Lake—in the background.

But central to this larger project are some $ 8 million of infrastructure improvements completed earlier this year, all of which position the sawmill for the future. By far the biggest part of that particular project was the installation of a new wood-fired energy system which is saving the company a large amount of money—and earning the mill praise from its neighbours in the Shuswap region of southern BC. The mill is located directly on Adams Lake and has dozens of cottages and homes nearby. Area residents were pleased, to say the least, to see the retirement of the mill’s burner and the adoption of a state-of-the-art, woodwaste- to-energy system.

The existing energy system for the Adams Lake mill had been operating for the better part of a decade using liquefied natural gas, which was trucked in and then vaporized on site, principally to provide heat for the kilns to dry lumber. While that system has worked fine over the years, the mill was looking at the options that might be available to generate energy—and give them more control over energy costs, explains

Interfor’s Adams Lake project manager Heinz Torbohm. “You never know where natural gas prices are going to go in the future—but over the longer term, they’re not likely to go down.”

The mill, like many operations in the area, had historically dealt with its waste wood—primarily bark—through burning.

More than a year ago, Adams Lake started working towards an energy and waste wood solution, looking at the different energy systems in the marketplace, and putting together a business plan for the project. The energy savings are compelling, but it’s important to remember the capital investment for the energy system was also significant.

In addition to the new energy system, the $ 8 million budget also covered a long list—26 in total—of energy system and general mill improvements. Related to the new energy system, there was a new debarker, a new hog system leading to a new hog conveyor system to the energy system, and the existing natural gas burners had to be removed and thermal oil piping installed. General mill improvements included site upgrades; the mill, on a site going up the hillside from Adams Lake, had been on five different elevations. Logging trucks and mobile equipment now only have to deal with two elevations.

One of the challenges Interfor Adams Lake had was how to deal with its very wet waste wood. All of the logs are stored in booms on the lake and are drawn up into the mill as required.

Mill personnel did their due diligence, including touring a number of energy systems being used in the industry. A team was put together, consisting of Torbohm as project manager, construction manager Rick Ross and safety co-ordinator David Murray. Also assisting on the project was Craig Carlyle, energy manager of Interfor. Caryle has been involved with an extensive list of energy projects in his career, including Tolko’s co-gen plant in Armstrong, not too far from Adams Lake.

Carlyle is working on a number of projects for Interfor, as part of a company-wide effort to improve energy efficiency. “We want to make sure we are competitive in energy costs per thousand board feet at our mills, and if it is practical and makes sense, be a technology leader,” he says. After a thorough review, Adams Lake selected an energy system from Wellons Canada, and the company took on the project on a turnkey basis. Wellons supplied the conveyor system from fuel storage, the combustion/thermal oil heater system, the thermal oil circulation systems and the electrostatic precipitator. The contract included building foundation, mechanical, electrical, fire protection and commissioning.

“We provided the whole package,” says Ken McClure, sales and marketing manager for Wellons Canada. He notes that most of the equipment for the new energy system was manufactured by Wellons Canada or within the Wellons group. “One of the advantages we believe as a company to bring together all the components for a project like this.” Wellons presented what Torbohm termed an “impressive” wood-fired energy solution for Adams Lake.

“Whatever questions we had, they had the answers,” he says.

One of the questions the company had was how to deal with its very wet waste wood. All of the logs are stored in booms on the lake, and are drawn up into the mill, as required.

“We were looking at an average 55 per cent moisture content for the waste wood, which is mostly bark,” says Torbohm. Their pine/spruce runs around about 57 per cent moisture content, the fir was around the 45 to 48 per cent range. Balsam had the highest moisture level—around 68 per cent—but it represents only about five per cent of their cut.

Wellons’ McClure put these numbers in perspective. “That’s extremely wet fuel. At that level, out of 100 pounds of fuel, you’re talking about 68 per cent being water and 2 per cent being fiber, and having to create combustion with that. You’d be trying to evaporate two pounds of water with one pound of wood, and still try to have enough residual BTU’s to make the whole energy system work.”

Adams Lake selected an energy system from Wellons Canada, and the company took on the project on a turnkey basis. One of the things that Wellons brings to the energy systems table is a variety of combustor and heater options that can be used depending on the solutions required by a customer, and their site.

That 68 per cent level represents the moisture level of the balsam, of course. So the approach is to have a mix of species fueling the system. Wood shavings from the mill’s planer are also included, to achieve an overall average moisture level of 57 per cent.

“If you get much above that, there are not enough BTUs in the wood to evaporate the moisture and provide residual heat for heat transfer,” says McClure. Interestingly, they are helped by the fact that a large part of their harvesting is currently being done in mountain pine beetle-affected wood, which has dryer bark.

“We had to do a lot of testing on the moisture of the bark, and how much bark we were getting,” says Torbohm. They provided all of that information to Wellons so the right combustion and energy system could be designed and installed.

The energy system production process is fairly straightforward. There are two fuel storage facilities, the wet fuel bin and the The real heart of the combustion system, McClure explains, is the step grate, a staircase-like combustor where fuel is fed in at the top, with a combustion zone in the middle, and an ash completion zone is at the bottom. The 20-foot wide step grate, made up of two 10-foot sections, is designed and manufactured exclusively by Wellons. “The type of combustor we used at Adams Lake is a very flexible way of combusting fuel because there is the ability to have a bit of a drawing zone at the top of the grate,” says McClure.

The system is thermal oil, so the hot gas produced from the combustion process goes up and across a series of tubes containing the thermal oil, which is heated to 525 degrees F. Through an extensive piping network, the thermal oil is pumped out to the kilns for lumber drying, and to heat exchangers, for use for general mill heating purposes. The piping network moves the oil back to the energy system for re-heating.

The gas being discharged from the thermal oil heater is high temperature— 575 degrees F—and is run through an air to air heat exchanger to cool it to 00 degrees F. This air is brought back into the system, in the combustion process.

“That air stokes the combustion process and helps increase its efficiency,” explains McClure. A series of fans provide a set amount of combustion air to optimize the process. The flue gas goes through to a precipitator and is then released.

“This system is a huge improvement over a burner—we’re releasing clean gas into the atmosphere,” says McClure.

“Adams Lake is essentially taking fuel that had been burned before, combusting it in an energy system that replaces the natural gas system they had, and they have clean fuel gas coming out of the stack. Environmentally, these systems are a huge improvement.”

One of the things that Wellons brings to the table with energy systems, says McClure, is that they have a variety of combustor and heater options that can be used depending on the solutions required by a customer, and their site.

“The solutions are different for each site—they are custom designed. We work to understand what customers are trying to achieve, and we build a solution back to that. We recommended the best equipment solution to satisfy the specific conditions for Interfor.” Adams Lake is getting as much out

“Most energy systems are installed to satisfy the energy requirements of kilns or plant heat loops,” says McClure. “But what Interfor Adams Lake has done is install a system that is larger than their energy needs, to manage the waste wood in an environmentally safe way.”

Interfor’s Heinz Torbohm adds that the energy project is a winner on a number of fronts—environmentally and energywise. “There’s no more fly ash and smoke coming out of the burner, and aside from the cost of operating the plant, we’re not paying anything for our fuel.”

Torbohm notes that the system requires power engineering coverage, and they have put 14 employees through Class Five Engineering. They will also have two Class Four certified employees on site. “We should have lots of coverage, 24/7. The certified people could be doing another job in the mill, but if there is an alarm on the system, they are ready to look after it.”

While it is currently releasing that extra heat, Adams Lake is looking at adding another lumber kiln—the mill currently has five kilns—as part of the $100 million expansion, and is open to other possibilities for using the heat.

“But wherever we can, we are using as much of that heat within the mill,” says Torbohm. “Our thermal load is 100 per cent supplied with the new system.” The switch to the new system has also delivered some unexpected results: the heat load per thousand board feet in the kilns is lower, they’re seeing fewer lumber defects and planer productivity has increased, with fewer jam-ups.

And, Torbohm adds, things are now set up nicely for the new mill, and they’ve already started work on that. The project office for the new energy system has been converted to the project office for the new mill.

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