Thermal Conductivity of Ternary Aqueous H2O + Li2SO4 + Zn(NO3)2 Solutions at High Temperatures and Pressures

Abstract

The thermal conductivity of ternary aqueous H2O + Li2SO4 + Zn(NO3)2 solutions at high temperatures (from 298 to 573 K) and at two isobars of 10 and 30 MPa is reported in the present work. The measurements were made for five solutions with concentration ratios of Li2SO4/Zn(NO3)2 of 1:1, 2:1, 1:2, 1.75:2.00, and 0.7:0.3 (mol·kg–1) using a concentric cylinder (steady) method. The combined expanded relative uncertainties of thermal conductivity, pressure, concentration, and the absolute uncertainty of temperature measurements (at 0.95 confidence level, a coverage factor of k = 2) were estimated to be less than 0.02, 0.0005, 0.0002, and 20 mK, respectively. The measured data were used to confirm the reliability, accuracy, and predictive capability of the existing correlation methods for multicomponent aqueous electrolyte solutions. It was shown that the temperature and pressure behavior of the aqueous solutions is controlled by the water. The effect of Li2SO4 and Zn(NO3)2 concentrations on the thermal conductivity of H2O + Li2SO4 + Zn(NO3)2 solutions at various temperatures and pressures has been studied.