Experience With Active Control of Exhaust Noise From a Large Frame Combustion Turbine
Low frequency noise generated by combustion turbine exhaust is one of the most difficult environmental impacts to control. When a combustion turbine power plant is located near residential areas or other sensitive receptors, it is imperative to minimize the low frequency noise being emitted. In the past, available technology was limited to passive and reactive silencers and massive enclosures or barrier walls. These techniques are expensive and can have significant impacts on megawatt output and heat rate. Active noise control technology offers an alternative for applications near sensitive receptors. An active noise control system was installed on the exhaust stack of a combustion turbine with an objective to cancel exhaust noise at frequencies below 35 Hertz (Hz). Unlike passive and reactive low frequency silencing, the active noise control system does not impact combustion turbine performance. The technology can be applied to new apparatus and can be retrofit to existing facilities with minimal changes to the design.