Steam Solubilities for Combustion Turbine Steam Cooling

Steam cooling of combustion turbine parts provides significant advantages over air cooling. Steam potentially carries dissolved salts that can deposit on the cooled parts and cause corrosion. By maintaining the salt concentration below its solubility limit in the steam, deposition of salts may be avoided. A literature survey reveals that only sodium chloride and silica have adequate data for reasonable extrapolation to the steam cooling conditions. Estimates of steam solubility of sodium sulfate and sodium phosphate used liquid-vapor distribution coefficients for a solubility at saturation and sodium chloride as a model compound to extrapolate the solubility to other conditions. Copper oxide data were also insufficient to predict steam solubilities with confidence. The large potential errors in the sodium phosphate and sodium sulfate solubility estimates may add considerable cost to the water treatment system. Accurate experimental values for sodium sulfate and sodium phosphate solubilities in steam are needed.