Solubility of hydrogen sulfide in pure water and in NaCl solutions, from 20 to 320°C and at saturation pressures

Abstract

The solubility of hydrogen sulfide in pure water and in NaCl solutions has been studied experimentally from 20 to 320°C and at saturation pressures. Hydrogen sulfide solutions in equilibrium with their vapor phase were contained in a pressurized titanium bellows of known total volume. The bellows transmitted inside-vapor pressures via a thermally stable oil (pressure medium) to a high-precision pressure sensor. Temperatures were measured by a sheathed thermocouple immersed into the oil surrounding the bellows. Values for the Henry constants were derived from measurements of equilibrium vapor pressure, volume, temperature, and bulk composition. The Henry constants agree well with previously published data up to about 200°C, but then deviate towards lower values (higher solubilities) at higher temperatures. Henry constants from 20 to 320°C and at saturation pressures may be obtained from the correlation log k H ( T, P sat,1 ) = +0.6342702616 e + 3 + 0.2709284796 e + 0 · T − 0.1 113202904 e − 3 · T 2 − 0.1671907660 e + 5/ T −0.2619219571 e + 3 · log T, where k h is in units of bar/molality and T in Kelvin. The experimental Henry constants have been fitted to a scaled particle theory model and have been tested by a recently proposed linearization procedure. The salting-out effect of NaCl on H 2S solubility is nearly independent of temperature up to about 250°C, but then increases sharply as temperatures approach the critical point of water. Skeleton tables to 365°C and for ionic strengths μ = 0, 1, 2, 3 have been prepared.