by Jim Van Valkenburgh
Froling Energy just celebrated the grand opening of their new PDC dried wood chip processing plant in Keene, N.H. where they improved processes and expanded output. The new plant assures customers of more consistent fuel quality and a larger delivery-ready inventory.
Construction began in January 2020. Covid-19 created difficulties, but the 30,000sf building was erected. One year later the first batch of PDCs came off the new, more efficient line.
Precision Dried Wood Chips, or PDCs, are a locally sourced, renewable heating fuel. PDCs start out as random sized, fresh-cut bole wood chips with +45% moisture content. They end up with 25% moisture content and are screened to a smaller size: 1.5 inches x 1.5 inches x 0.5 inch. PDCs can be blown into inexpensive above-ground silos which feed into highly efficient boilers that are designed to burn smaller, mid-moisture chips. PDCs come from managed forests within 50 miles of Keene where forest health and sustainability are priority, as directed by foresters.
The advantages of PDCs over green wood chips are lower infrastructure costs and a smaller boiler system footprint. PDCs provide more heat per ton and the cost of boiler system infrastructure is much less. PDCs significantly reduce heating costs, compared to oil and gas, and keep many more fuel dollars in Northern New England.
Froling Energy’s PDCs are currently delivered to over 20 customer sites in New Hampshire and Vermont: public and private schools, a 100 unit apartment complex, and commercial/industrial clients. Last winter, Froling truckers delivered 6500 tons of PDCs which offset the burning of 608,500 gallons of #2 fuel oil. Savings over oil are between 50% and 75%. Last year, one industrial client in New Hampshire offset 180,000 gallons of #2 oil with a net fuel cost equal to just 51 cents a gallon.
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 3,000 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 6 feet wide and 60 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 backup to provide heat to the dryer.
Efficiency is priority at the new plant in Keene: Once chips are loaded into the input bin, they move through the dryer and into the storage area untouched in a continuous process. Then a big loader fills our blower trucks for customer deliveries.
The future is bright at Froling Energy as they strive to make biomass an efficient and reliable renewable fuel for Northern New England.
Jim Van Valkenburgh is vice president of sales & marketing at Froling Energy.