Abstract
A new apparatus for the measurement of dielectric constants of high pressure gases has been constructed. The apparatus consists of a recirculating visual flow cell and a concentric cylinder dielectric constant flow cell. Measurement of the dielectric constant is made by a unique counter-oscillator circuit, in which the capacitance is determined by relaxation of a unijunction transistor oscillator circuit and counted by a crystal oscillator. Dielectric constants are reported for supercritical mixtures of carbon dioxide + argon and carbon dioxide + methanol at a temperature of 322.9 K and pressures to 25 MPa. The dielectric constant shows a sharp increase near the critical pressure. Dielectric constants were linear with densities calculated by the Suzuki equation-of-state. The dielectric constant for the methanol-carbon dioxide system was found to be less than a mole fraction average of the pure component dielectric constants.
Original language | English |
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Pages (from-to) | 162-168 |
Number of pages | 7 |
Journal | The Journal of Supercritical Fluids |
Volume | 3 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1990 Dec |
Externally published | Yes |
Keywords
- argon
- carbon dioxide
- dielectric constant
- high pressure
- methanol
- mixture properties
- relative permittivity
- supercritical fluids
ASJC Scopus subject areas
- Chemical Engineering(all)
- Condensed Matter Physics
- Physical and Theoretical Chemistry