Dehumidification based preservation prolongs life of turbine

TATA Power


Tata Power is the largest power generation company in India aimed at providing uninterrupted power supply from its various plants located across India. In their Maharashtra plant they needed to preserve 6 Steam Turbines of 500MW capacity each for a minimum of 6 months idle period in humid conditions. Since moisture effect can corrode IP and LP side (Area) of the turbine, both IP Turbine (Ø3.3 mtr x Length 3.4 mtr) and LPTurbine (Ø6.0 mtr x Length 8.0 mtr) needed to be protected from moisture,


Rate of corrosion accelerates when Relative Humidity crosses the critical level of 35%. Since it was monsoon season, the ambient RH was above 80% and temperature was approx. 30oC. Due to moist ambient conditions, IP and LP turbine sides can start getting corroded during idle period which may lead to deterioration & decrease in the life of the parts and components and failure of the turbine in the long run.


Our Solution

The proposed solution was to preserve the turbines under dehumidified conditions to avoid moisture ingress. To keep both IP and LP Zones dry, RH was supposed to be maintained below 20% at the Dehumidifier outlet, so as to maintain RH of approx. 35% inside IP and LP zones of the turbine with positive pressure.
Total volume was 255 cu mtr of IP and LP turbines and open condenser box volume of approx. 500 cu mtr, with 7 air changes per hour. Considering the conditions, TDS provided dehumidifiers of total 3000 CFM through 3 openings with positive pressure in open loop. RH of around 30% is maintained inside turbine with DH outlet RH of 15-20% .

Dehumidifier was installed near the turbines. From the process inlet of the dehumidifier ambient air was taken in and from the process outlet of the dehumidifier, dry dehumidified moisture free air was supplied into the turbine. Dry air ensured that the turbine is under optimum preservation condition by controlling moisture and humidity during idle time.

The complete preservation service provided peace of mind to the client. The installed system worked perfectly with very pleasing results.


  • Dehumidified moisture free air ensured no rust development or corrosion of the turbine
  • It prolonged the life of the turbines

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