Acoustic method of measuring critical properties of thermally unstable substances / Nikitin ED,Pavlov PA,Skutin MG // FLUID PHASE EQUILIBRIA. - 1999. - V. 161, l. 1. - P. 119-134.

ISSN/EISSN:

0378-3812 / нет данных

Type:

Article

Abstract:

An acoustic method of measuring critical temperatures and pressures of thermally unstable substances is described. In the cell with the liquid under investigation there is a wire probe, 0.02 mm in diameter, which is heated by electric-current pulses with a duration of 0.025 to 0.25 ms. At the moment of liquid boiling-up in the layer that surrounds the probe, one can observe an acoustic wave, which is registered by a ceramic piezoelectric element on a base (PbZrO3 + PbTiO3). The probe temperature at the moment of boiling-up is determined from its resistance. With an increase of the pressure in the cell with the substance under investigation the amplitude of an acoustic signal decreases. The cessation of boiling-up and disappearance of the acoustic signal show that the critical state is reached. A more precise critical pressure is found by linear extrapolation of the amplitude of the acoustic signal to zero in an amplitude-log (pressure) plot. The paper reports the experimental critical temperatures T-c and the critical pressures p(c) of reference substances: n-hexane, n-heptane, n-decane, benzene, and of thermally unstable n-alkanes: docosane and tetracosane, and also the critical curve of the system n-hexadecane-benzene. The critical constants of reference substances were measured by this acoustic method with an error that does not exceed 0.015 T-c and 0.015 p(c). (C) 1999 Elsevier Science B.V. All rights reserved.

Author keywords:

experimental method; critical state; vapor-liquid equilibria; data; normal alkanes LIQUID CRITICAL PROPERTIES; CRITICAL-TEMPERATURES; CARBON-ATOMS; NORMAL-ALKANES; PRESSURES; ELEMENTS

DOI:

10.1016/S0378-3812(99)00169-7

Web of Science ID:

ISI:000080922400009

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL 1
Publisher	ELSEVIER SCIENCE BV
Address	PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Language	English
Keywords-Plus	LIQUID CRITICAL PROPERTIES; CRITICAL-TEMPERATURES; CARBON-ATOMS; NORMAL-ALKANES; PRESSURES; ELEMENTS
Research-Areas	Thermodynamics; Chemistry; Engineering
Web-of-Science-Categories	Thermodynamics; Chemistry, Physical; Engineering, Chemical
Number-of-Cited-References	24
Usage-Count-Since-2013	5
Journal-ISO	Fluid Phase Equilib.
Doc-Delivery-Number	207EH