Elektrische Leitfähigkeit wäßriger Lösungen bei hohen Temperaturen und Drucken. III [2, 3]. Kaliumchlorid in überkritischen Wasser‐Argon‐Mischungen

Messungen der elektrischen Leitfähigkeit von Elektrolytlösungen bei erhöhten Temperaturen erfordern besondere Korrosionsschutzmaßnahmen. Eine unter diesem Gesichtspunkt konstruierte Apparatur für Temperaturen bis 350°C und Drucken bis 8 kbar wird beschrieben Meßwerte an 0,01 m wäßriger KCI‐Lösung werden angegeben. Die Äquivalentleitfähigkeit nimmt von etwa 140 Ohm−1 cm2mol−1 bei Zimmertemperatur auf 680 Ohm−1 cm2 mol−1 bei 350°C und 6 kbar (dies entspricht einer Dichte von 1 g cm−3)zu. Die Erhöhung des Drucks von 1 kbar auf 8 kbar bringt bei konstanter Temperatur eine Abnahme der Äquivalentleitfähigkeit um etwa 25%.

Elektrische Leitfähigkeit wäßriger Lösungen bei hohen Temperaturen und hohen Drucken IV. Kaliumchlorid bis 350°C und 8 kbar

Renkert

Franck

1970

Hydrothermal Solutions

Tödheide

1982

A survey is given of recent results on the properties of pure water and binary and ternary mixtures at high temperatures and high pressures with emphasis on the geochemically important systems H 2 0 -CO 2 , H 2 0 -NaCl, and H 2 0 -CO 2 -NaC!. Among the properties discussed are phase diagrams, PVTx data, thermodynamic and transport properties, dielectric constant, electrical conductivity, and ionic equilibria. Concepts for predictive calculations of thermodynamic properties are briefly described.At about 200 kbar the melting temperature reaches 700 K.

The System Water—Carbon Dioxide—Sodium Chloride to 773 K and 300 MPa

Gehrig

Lentz

Franck

1986

Experimental results are reported for fluid‐fluid phase equilibria of the ternary system H2OCO2NaCl. Measurements were extended to 773 K and pressures to 300 MPa. A “synthetic” method was used: Known quantities of the three components were filled into an autoclave at room temperature. The autoclave with a sapphire window and variable volume is described. Transition points to homogeneous one‐phase conditions could be determined from recorded p—T‐curves at constant volumes and from visual observation. From the transition points p—T‐curves on the three‐dimensional phase equilibrium boundary surface at constant compositions, “isopleths”, were obtained. Data for 20 isopleths with CO2‐concentrations between 0.2 and 85 mol% and with 6 weight YO of NaCl are presented together with a few additional results for higher salt concentrations. Molar volumes were measured at the phase boundary surface and within the one‐phase region. Excess molar volumes are given. In comparison with the binary H2O‐CO2 system, the addition of NaCl shifts the range of partial immiscibility to higher temperatures by up to 100 K; for example from 573 to 673 K at 100 MPa for 48 mol% CO2. Results are in agreement with earlier data of Takenouchi and Kennedy. Considerations of the ternary phase diagram H2OCO2NaCl within a wide range of conditions are given.