High-pressure and high-temperature density and vapor-pressure measurements and derived thermodynamic properties of natural waters of Yardymli District of Azerbaijan

摘要

Density of eight geothermal and natural water samples from Yardymli District of Azerbaijan have been measured over the temperature range from (274 to 413) K and at pressures up to l00MPa. The measurements were made using the Anton Paar DMA HPM and DSA 5000 M VTD densimeters. The combined expanded uncertainty of the density, pressure, and temperature measurements at the 95% confidence level with a coverage factor of k 2 is estimated to be (0.01 to 0.03)%, (0.1 to 0.5) %, and 15 mK, respectively. For the same geothermal and natural water samples the vapor pressures were also measured using absolute and differential static, at low temperatures from (274 to 323) K, and absolute static methods at high temperatures from (323 to 413) K, The measured vapor-pressures (P_s-T_s) and single-phase PVT data were used to accurate estimate saturated liquid densities (p_s-T_s) for all studied geothermal and natural water samples using extrapolation technique lo complete the high-temperature and high-pressure PVT phase diagram of natural waters. The Riedel's characteristic density constant of the specific ions (ion contribution constants) for main ion species in the natural water samples were estimated on (he bases of measured PVT properties. Measured values of density were used to develop equation of state which reproduced the experimental densities within an uncertainly of 0.005% and can he used for engineering calculation of the other important thermodynamic properties such as adiahatic coefficient of hulk compressibility (K_s). isothermal coefficient of bulk compressibility (K_r). thermal expansion coefficient (α_p), thermal pressure coefficient (γ_v), internal pressure (P_(mt)), enthalpy difference (ΔH), entropy difference (ΔS), isochoric heat capacity (C_v), isobaric heat capacity (C_p), and speed of sound (W) of natural waters. The measured values of density of natural waters at atmospheric pressure have been used as a reference data for prediction high-temperature and high-pressure PVT properties. The present high-pressure and high-temperature PVT data for natural waters were used lo check and confirm the accuracy, reliability and predictive capability of the predictive methods.