Coal pulverizing sound source

Sample Power Plant Noise Control Projects:
Some representative power plant noise control projects where we've been the primary acoustical consultant. 

1,100 MW Combined Cycle
Noise Goals: 49 dB(A) at nearest residence located across road.
The project was a 1,100 MW combined cycle power plant based on four General Electric Frame 7FA GTG, HRSGs with duct firing, and two General Electric model D11 steam turbine generators. The facility cooling was through a multi-cell wet cooling tower.

Power Acoustics, Inc was involved at all stages starting with a "green field" plant developer and ending with community noise testing at the facility's completion.  At early stages, we obtained ambient sound measurements and performed preliminary noise modeling analysis.  The early analysis enabled us to set sound level goals that assured negligible community response.  We later performed a facility acoustical design study for Duke-Fluor Daniel and completed the project with sound level compliance testing.

The facility coexists within the community with no known complaints from any nearby neighbors.

120 MW Gas Turbine Units
Problem: The gas turbine had a poorly performing inlet silencing system do to a bad batch of materials used by the OEM.
Power Acoustics, Inc performed an evaluation of the site and found tonal noise sources and sound levels in excess of 110 dB(A) in front of the inlet filter house.  Complicating the issue was an asymmetrical ducting arrangement that impeded flow from entering one side of the existing vertically aligned silencer.  Power Acoustics designed a retrofittable muffler rotated 90 degrees from the original to improve flow distribution.  The retrofit was located in a small section of empty ducting.  Although the retrofit silencer was approximately 1/3 the length of the original, it provide approximately 20 dB(A) of additional insertion loss and reduced sound levels to an acceptable level. 

Power Acoustics, Inc. has designed approximately 350 successful inlet or exhaust silencers or mufflers for both end users, such as the utilities, and silencer manufacturers such as C&W Fabricators, an original equipment supplier for most major gas turbine manufacturers such as GE and Siemens and Westinghouse. 

800 MW CC Power Plant
Sound Level Goal: 70 dB(A) at 90 ft from equipment.
This facility was in the middle of an industrial park with no residential or commercial zones within several thousand feet.  We designed the least expensive noise control available consisting of a sound wall adjacent to the property line - just to meet the local noise ordinance.

The facility achieved the requirements with a 1 dB(A) margin.

1.6 MW Diesel Generator
Issue: Frequency dependent sound pressure level requirements were imposed at the nearest residential neighbors - located few hundred feet away. Criteria were set for all octave band frequencies between 31.5 Hz and 8000 Hz. 
Sometimes the plant is just too close to the neighbors.  We evaluated this facility and developed a plan to achieve the noise goals which would require extensive modifications and silencing to all eight units.

450 MWPeaker Units
Requirements: Frequency dependent sound pressure levels were imposed including a low frequency limit of 69 dB at 31.5 Hz at the nearest residential neighbors - located approximately 800 ft away. Additional criteria were set for all frequencies between 31.5 Hz and 8000 Hz. 
Power Acoustics, Inc was involved at the power plant design/construction stages by evaluating the design for Harza Engineering. The critical low frequency sound pressure levels were achieved at all residential locations.  Although ignored by many acoustical consultants, low frequency noise, or infra sound, can be observed as vibration in homes and is often the primary complaint from neighbors located near gas turbine installations.

Expert Witness Support
Working with our customers to solve problems before the plant is built and when the rules change.
Power Acoustics, Inc. typical involvement is related to projects in need of special use permits or zoning approvals.  However, we also perform work in eminent domain issues, criminal cases, and various other situations requiring legal support and acoustical expertise. 

Our most notable case as an expert witness was related to an existing power generation facility that was located in a fully industrial location in 2004.  An empty property adjacent to the power plant site was slated for use as a balefill operation.  However, the balefill property was later sold to a housing developer wanting to build homes several hundred feet from the power plant.  Working for the utility's lawyers, we successfully presented testimony and sound test data that supported a modification to the existing state noise regulations.  Although the state's attorney general opposed the petition, the pollution control board accepted our clients request and issued a revision to the noise regulation requirements for the client's facility. Prior to this ruling, no changes had been issued by the state since the 1970's.


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