In waterwashing, the water pressure and temperature are controlled and chemicals added to maintain water quality, which is crucial to the cleaning action. Recent waterwash skids, however, incorporate Moisture Recovery Units (MRU) that generate pure water. The conductivity of water is a good measure of its purity. The less conductive the water is, the more pure. An MRU can provide the required megaohm level needed to assure foreign film deposition extraction during the 10 to 20 minute (turbine size) wash sequence.
IWM in conjunction with sister companies Dectron Internationale and Circul-Aire Inc. has developed a waterwash system based on an MRU.
The degradation of the blade profiles is a function of the deposition of impurities onto the front and back side of the blades. These impurities consist of both solid matter and gas phase matter at atmospheric pressures. The deposition of the above alters the aero dynamics of the blade profile increasing turbulence and increasing temperatures. These variations in turn reduce turbine operating efficiencies and reduce power etc.
There are two ways to increase the reactivity of a fluid for cleaning.
The simple alternative way is to add chemicals. This has been done for crank soak washing, however, to use chemicals on-line in conjunction with the heat from the operating turbine may cause deposition on the later stages due to the evaporated chemicals and in turn not allow for total cleaning.
The second, being the MRU is to deprive the water of 100% of its ions to force the water to become reactive itself. De-ionized water is considered an universal solvent that has the reactivity potential similar to sulfuric acids and alike, but not the harshness to attack the metallurgies and more importantly the coatings used to make up the turbine blades.
This water from the MRU is generated from atmospheric air. A proprietary system controls all aspects of the water production, water quality and delivery system to the turbine blades. Application areas are typically tropical warm and humid areas. The MRU will best function in a weather bracket of 100 F – 55 F with relative humidity of 40% – 100%. The MRU will stop generating water in ambient of less than 50 F.