In a power plant with gas turbines (combustion turbines), some airborne noise is emitted by the various subsets making up each turbomachinery (in addition to noise emissions associated with the mouths for air intake and exhaust not included in the current project, although regularly studied and subject of simulation and design work by ITS as part of other projects in the field of energy production):
- the turbine compartment i.e. compressors, combustion chamber, turbine
- the auxiliary compartment
- the load compartment
- the portion of the envelope of the intake duct enclosed
- the portion of the envelope of the exhaust duct enclosed
- related equipments: e.g. gas module, generator
This noise is so powerful that it is potentially causing noise pollution for personnel of the operator operating in the vicinity as for the neighborhood (including long distance). It is often necessary to use in such cases a soundproofing equipment of high technology to ensure compliance of the installation of one hand with respect to the legislation on noise at work and on the other hand with respect to the regulation in terms of environmental protection.
ITS will participate in the design of soundproofing devices for several sub sets of 2 gas turbines with high power output (more than 120 MW for simple cycle, more than 190 MW for combined cycle) for a power generation unit in the Indian sub-continent. For each turbine, the turbine compartment, the gas module compartment and the generator enclosure will be accounted.
This soundproofing equipment will have a sound reduction particularly important (the overall sound power level to be considered is greater than 135 dBA for one of the sub sets and noise emissions are with a very wide frequency spectrum), requiring a specific design of the partitions and of the ventilation system which is one of the major features of the soundproofing equipment.
The optimization of the cost and of the duration of intervention for assembly and disassembly operations are key factors of success of the efficient soundproofing concept considered for those sub sets of gas turbines.
The simulation of the sound attenuation of partitions, of the insertion loss (with and without flow noise) and of the total pressure loss of ventilation silencers as well as the simulation of the impact after soundproofing on the one hand in terms of sound power level and on the other hand in terms of sound pressure level at specified positions will be performed
Specific materials and construction systems to meet ambitious and varied targets in terms of technical performance will be integrated into the design as required.
Related features such as weather resistance, disassembly of the whole and of subsets, securities, lighting, electrical works ... will be integrated according to the needs for the soundproofing devices for sub sets of gas turbines.
Taking into account the extreme conditions on site in relation to efforts due to wind and to seismic risks will be a major challenge of the project, necessitating a special design of enclosures with a metal frame considerably strengthened when compared to the most demanding load cases encountered elsewhere.