Ready for the future
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 moneyand 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 energyand 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 futurebut 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 woodprimarily barkthrough 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 list26 in totalof 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.
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 levelaround 68 per centbut 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 Fand 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 burnerwe’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 sitethey 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