HRSG gas side
• Corrosion is due to the presence of sulfuric acid. This is less aggressive when the concentration increases, which it does upon dehumidifying the environment. According to the diagrams, the relative humidity required is 5%, although experience tells us that 20% is sufficient.
Basic operation: The main principle is to introduce dry air on the compressor side where it goes to the gas turbine, and from there it flows freely through the exhaust to the gas side of the boiler, which will be “bottled” (short, closed runs through the flue and manholes).
For effective conservation in this system, according to the environmental conditions of pressure, temperature and relative humidity, the equipment is supplied with 3,000-6,000 m3/h. FISAIR has them in its catalogue (DFRC). FISAIR will provide you with the optimal solution.
The air loss through the short flue runs is enough to keep the RH in the boiler and gas side at around 20-30%.
The conservation of this system can be approached from two locations:
- Through the inlet plenum, by means of shields.
- Through compressor bleed valves.