Water vapor concentration enhancement in compressed humid nitrogen, argon, and carbon dioxide measured by Fourier transform infrared spectroscopy

Knowledge of the dew point of compressed humid gases is needed for many new technical applications, e.g., compressed air energy storage (CAES), humid air turbine (HAT), or zero emission power plants. A new method was developed to measure the dew point, expressed as vapor concentration enhancement factor, by Fourier transform infrared (FTIR) spectroscopy. This method has already been successfully applied to compressed humid air (Koglbauer and Wendland, J. Chem. Eng. Data 2007, 52, 1672-1677). Here, measurements in pure air components were performed at temperatures from (20 to 100) degrees C and pressures up to 25 MPa for nitrogen and argon and up to 5.5 MPa for carbon dioxide. The estimated combined standard uncertainties (68 % confidence level) of the new experimental data are 0.02 K for temperature, 3.2 kPa for pressure, (0.12 to 1.2) % for the vapor concentration enhancement factor in argon and nitrogen, and (0.5 to 5) % for the vapor concentration enhancement factor in carbon dioxide.