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Froling Energy’s New Dry Wood Chip Processing Plant

Froling’s new precision dried wood chip facility in Keene, NH (All courtesy photos)

Jim Van Valkenburgh

Froling Energy just celebrated the grand opening of their new precision-dried wood chips (PDC) processing plant in Keene, New Hampshire where they have both expanded their output of dry chips and improved their processes. The goals for this move were to assure their customers of better fuel quality, improve production rates, reduce their own carbon footprint and to increase available inventory to overcome market fluctuations.

In January 2020, Froling Energy purchased 10 acres in Keene and began construction of a new, larger and more efficient dry wood chip refining plant. Soon after, Covid-19 shut down normal business activity in the Northeast, but Froling Energy crews persevered. One year later, the first batch of Froling Energy’s PDCs was processed in Keene. This was perfect timing as their supply of PDCs made six months earlier at their old Peterborough plant, was just running out.

The new Schmid UTSR steam boiler has a maximum output of 5.33 million Btu/h. The steam is pushed into a steam turbine generator which generates enough electricity to run the whole plant.

What are PDCs? Precision Dried Wood Chips—a locally sourced renewable heating fuel that Froling Energy delivers to customers in New Hampshire and Vermont. PDCs start out as random sized, green bole wood chips with about 45% moisture content. They end up with 25% moisture content and are no larger than 1.5” x 1.5” x .5”. With these qualities, PDCs burn efficiently in specialized dry wood chip boilers. PDCs come from managed forests within a 50-mile radius of Keene where logging is directed by foresters who prioritize forest health and sustainability.

What advantages do PDCs have over green chips? PDCs are blown into and stored in low-cost, above-ground steel silos (without freezing into a solid mass when it’s -10° F outside). PDCs provide more heat per ton, and dry wood chip boiler systems are much less costly than comparable green wood chip systems.

PDCs are currently delivered to over 20 customer sites consisting mostly of public and private schools, but also some large commercial and industrial sites and a 100-unit apartment complex. The use of PDCs reduces heating costs and keeps many more fuel dollars in Northern New England. Last winter, Froling truckers delivered 6,500 tons of PDCs to customers which offset the burning of 608,500 gallons of #2 fuel oil and saved their customers at least $1 million a year, in total.

Froling Energy’s Peterborough, NH plant was operational for seven winters, processing ever more chips each year, finally reaching a high limit. It was on a land-locked site so expansion there was impossible.

Cogeneration is the most significant improvement at the new plant where a 100-kilowatt steam turbine generator provides all of the heat and electricity required in the chip screening and drying processes. How it works: A Schmid wood chip-fired boiler (5.6 million BTU/hr) produces high-pressure steam that spins the turbine generator, creating electricity. Then low-pressure steam exits the turbine and condenses in a heat exchanger which transfers all remaining heat energy into a 3000-gallon buffer tank which supplies heat into the chip dryer.

Green (wet) wood chips are fed into one end of a continuous belt dryer that is six-feet wide, sixty-feet long. Chips come out as dry PDCs just 45 minutes later. A 3.4 million BTU/hr Viessmann wood chip-fired hot water boiler is also available as a back-up to provide heat to the dryer.

Dried and finished wood chips in the warehouse ready to be trucked to a customer.

In Peterborough, the unprocessed chips were stored out in the open, vulnerable to rain and snow which added even more water that had to be driven out in the PDC drying process. In Keene, green bole wood chips will be dropped off and stored in a large paved and covered structure, keeping them out of the weather and reducing the amount of heat required by the dryer.

At Froling Energy’s old plant, chips needed to be moved three times by a diesel loader from one stage to another. In Keene, chips are moved by a loader only once, every three hours, into the feeding system. From there chips are passed from process to process with no human intervention–significantly reducing the use of diesel fuel.

With the entire dry chip making process indoors, no longer are the screener, re-chipper or chip dryer exposed to winter wind, ice and snow. Machinery works better in a warm and dry environment and employees should be happier, too.

The future is bright at Froling Energy as they strive to make biomass a secure and efficient part of the renewable energy mix in Northern New England.

Jim Van Valkenburgh is the Vice President of Marketing at Froling Energy.

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