Energy production based on the use of gas turbines (in single cycle or in combined cycle), is widely used in countries without a highly developed nuclear power plant fleet.
Such power stations make possible to have large production capacities within a relatively short period of time in order to satisfy the growing needs of the populations.
In many cases, these facilities base the very existence of the electrical network of regions or countries.
In other cases, gas-fired power stations are used to manage electricity consumption peaks when other modes of production, even at full capacity, are temporarily insufficient in view of increased demand e.g. due to exceptional circumstances.
Such facilities involve very powerful thermodynamic rotating machines using fossil fuels being in particular gaseous (e.g. natural gas) or liquids (e.g. fuel oil, crude oil) whose noise emissions are very high and require means of preventing nuisance for the personnel of the power plant as for its neighbors.
ITS will participate in the construction of sound enclosures for two high-power gas turbines (more than 120 MW in single cycle, more than 190 MW in combined cycle) for a power plant in the Middle East.
The overall acoustic performance of these industrial soundproofing equipment, that sound enclosures for gas turbines are, will be due to their ability to prevent the propagation of noise - very important in terms of sound power level: typically 135 dB (A) and very broad in terms of frequency spectrum: typically 20 to 20 kHz - towards the outside of the power plant, not only through its walls and roof, but also through the components of the sophisticated ventilation systems required for proper operation.
Therefore, careful design and manufacture will be required for the walls of the acoustic enclosure (including doors for accesses, hatches and removable panels for maintenance), which will be constructed with modular, metallic acoustic insulation panels:
- with sound absorption properties: this will be to avoid sound wave reflections inside the sound enclosure, which could increase the internal sound level, and, all other things being equal, the sound level outside
- with acoustic attenuation properties: it will be a question of limiting the transmission of noise towards the outside, both through the acoustic insulation panels themselves and at the joints ensuring the connections on the one hand between themselves, and on the other hand at the limits of the acoustic enclosure
In this perspective, a multi-layer acoustic structure will be considered for the partitions:
- with a sound-absorbing inner layer: including a mineral wool filling (the choice of density will be made to reconcile airflow resistance that must be low enough because it conditions the sound absorption properties and a sufficient density to contribute to sound reduction according to the mass law) surfaced by a glass cloth (anti-defibration) and protected by a perforated sheet
- with a non-perforated steel outer sheet that will significantly contribute to the sound reduction index
The openings intended for ventilation will be fitted with soundproof louvers or silencers (the sizing of the fans - whose noise must also be attenuated - is generally part of the scope of supply).
The modalities of assembly and dismantling / reassembly of these equipments (sound enclosures for gas turbines) will be functionalities significantly impacting their quality and their durability, taking into account the site data (e.g. climatic conditions, seismic risks) and local building codes superimposing on international rules and standards being otherwise all important challenges for such a project.