High Pressure Phase Equilibria andPVT‐Data. of the Water‐Nitrogen System to 673 K and 250 MPa

Abstract

A high pressure autoclave equipped with sapphire windows is described. With water‐nitrogen mixtures of thirteen different concentrations (x) determinations were made of liquid‐gas phase equilibria conditions along “isopleths” between 523 and 673 K and 20 to 270 MPa. Molar volumes of the mixtures were measured at the three‐dimensional (PTx) phase equilibria surface and in the supercritical homogeneous region at 673 K. The critical curve, an envelope of the isopleths, begins at the critical point of water (647 K), has a temperature minimum (639 K) at about 75 MPa and proceeds to 250 MPa at 659 K. Phase equilibria and critical curve data are given. Values for the Henry‐constant to 647 K for mixtures dilute in nitrogen and for the nitrogen solubility from 300 to 600 K and from 10 to 200 MPa are presented. Excess volume, VE, values have been calculated for 673 K from 30 to 250 MPa. All VE values are positive. The maximum is 57 cm3 mol−1 at 70 mol per cent of H2O at 30 MPa and about 2 cm3 mol−1 at 40 mol per cent H2O and 250 MPa. Excess Gibbs energy‐values and activity coefficients are presented.

Reactive atomistic simulations of shock-induced initiation processes in mixtures of ammonium nitrate and fuel oil

“…We also observe a phase separation between H 2 O and N 2 that has been seen previously [25][26][27][28]. Shown in figure 5 is a final snapshot of the layered ANFO shocked along the [010] direction with a steady-state shock velocity of 9 km/s after 80 ps.…”

Measurements of the (p, ρ,T) properties and virial coefficients of pure water, methane,n-hexane,n-octane, benzene, and of their aqueous mixtures in the supercritical region

“…This was done by expressing the virial coefficients B and C as a function of temperature using expressions derived from the square-well (17,(24)(25)(26)(27)(28) and Kihara (20,24,(29)(30)(31)(32)(33)(34)(35)(36)(37) potentials. In these models, the second virial coefficients are given by…”

“…Richards et al (14) used excess enthalpy measurements of (water + nitrogen) vapour to derive cross-term second virial coefficients over the temperature range from 373.15 K to 423.15 K. In 1984, Rettich et al (15) measured the solubility of nitrogen in water at pressures from 45 kPa to 115 kPa. These results are used to obtain cross-term second virial coefficients at ten temperatures between 278 K and 323 K. Wormald and Lancaster, (16) using excess enthalpy measurements for (water + n-alkane), derived B 12 values at temperatures between 373.2 K and 423.2 K. Japas and Franck (17) measured the molar volumes of (water + nitrogen) in the supercritical homogeneous region at T = 673 K. From these values, the cross-term second virial coefficients B 12 for (water + nitrogen) at T = 673 K was determined using the extrapolation technique V E m (p 4 0). Second virial coefficient measurements for the pure components have been reviewed.…”

Supercritical water oxidation: A technical review

“…9,10 SCW shows complete miscibility with "permanent" gases, such as nitrogen, oxygen, and carbon dioxide. 11,[12][13][14] In contrast, inorganic salts are almost insoluble in SCW. 2,15 SCW also presents high diffusivities and low viscosities.…”