• Specialty

  Noise / Vibration
  

• SECTOR

  Industrial
  

• TYPE

  Environmental Study
  Permitting / Compliance
  

• CLIENTELE

  Private Sector
  

• TIMESPAN

  2012-2013

• LOCATION

  Millinocket, ME

THERMOGEN INDUSTRIES

SERVICE:

Torrefied Wood Process Facility Sound Study

DESCRIPTION:

Tech Environmental conducted a sound study for Thermogen Industries for a proposed torrefied wood process facility in Millinocket, ME. Torrefying wood pellets, ­or torrefaction, is a simple process that offers many advantages. During torrefaction, wood is dried to remove all excess water and then compressed into bio-coal pellets. These pellets can be used in conventional solid fuel burners. Thermogen proposed a facility that would operate 24 hours a day, 7 days a week, and produce up to 100,000 metric tons of wood product a year. While the torrefaction process was introduced in the 1970s and 1980s, it has recently become increasingly popular. There are many small facilities that have been successful, and larger facilities are beginning to emerge, but the Thermogen facility would be New England's first. The Thermogen facility will incorporate numerous processes with mechanical equipment that have the potential to be nuisances and exceed the Maine Department of Environmental Protection (ME DEP) noise limits. Because of this, Tech performed sound modeling analysis and calculations to predict potential future sound levels from all the processes associated with this torrefaction facility.

Tech calculated the predicted maximum sound levels using the acoustic model, Cadna-A. Using conservative assumptions and the provided sound power levels, Tech calculated the sound levels at all the nearest residences to the facility. Tech identified the two major contributing sound sources of the facility to be a front end loader and a hammermill. While neither piece of equipment caused an exceedance of the ME DEP daytime or nighttime noise limits, Tech recommended the placement of a 10-foot earthen beam that would ensure sound levels remained below these limits. Tech performed a second round of acoustic modeling that included the proposed earthen beam and found that it would provide a sound reduction between 3-5 dBA at the nearest residences.

Tech also performed a construction modeling analysis using the Federal Highway Administration (FHWA) Construction Noise Model (RCNM) to confirm that the construction of the facility would comply with the ME DEP construction noise limits. The results of the construction noise modeling analysis revealed that the construction of the facility would comply with the MEDEP construction noise limit.

If you would like to know more about this project, please feel free to email Marc Wallace at mwallace@techenv.com.

 

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Key Points

• Tech performed acoustic modeling for a torrefaction facility in Millinocket, ME where concerns of the noise generated during the wood drying to bio-fuel creation process may impact nearby residences.
• Tech determined the proposed facility would comply with ME DEP noise regulations, but made mitigation recommendations to ensure a 3 to 5 dBA sound reduction at the nearest residences.