A Flow Calorimeter for Condensable Gases at Low Temperatures and High Pressures. 1. Design and Evaluation

Abstract

A flow calorimeter has been developed for measuring enthalpy-temperature curves of condensable gases. Measurements can be carried out over small temperature intervals and at low temperatures and high pressures. Rather low mass flow rates are used so that recirculation of the sample is unnecessary. A correction for heat losses is made. The absolute error of the final results is within 1 %.

Enthalpy increment measurements on liquid ethane between the temperatures 146.0 K and 256.2 K, at pressures (≈1.6, 3.20, and 5.07) MPa

“…There is also a maximum error in the temperature interval of 0.002 K. These differences are insignificant in this comparison, and are not corrected for. There is an average deviation of 2.12 per cent between our measurements and the measurements by Van Kasteren et al (5) In table 2 our isobaric Dh measurements on ethane are compared with calculations from the Friend et al …”

“…These are Van Kasteren et al (5) and Furtado. (6) Our measurements are compared with the measurements from these sources in table 3.…”

“…(6) Our measurements are compared with the measurements from these sources in table 3. Our measurements have been performed as close to the experimental conditions used by Van Kasteren et al (5) as possible, but a small mismatch is given. This mismatch from the reference condition is on average 0.085 K. The change in c p from this mismatch is negligible, and therefore no correction was made.…”

“…The heat capacities measured by Furtado (6) were carried out on ethane of mass fraction 0.996, and the presented values are interpolated by Lammers et al (7) to match equal conditions. The heat capacities measured by Van Kasteren et al (5) were carried out on ethane of mass fraction 0.9995 and the authors claim a standard uncertainty of 21.0 per cent. Our measurements were performed on ethane of mass fraction , equal to 0.21 per cent of the measured enthalpy increment.…”

Crossover equation of state for the thermodynamic properties of mixtures of methane and ethane in the critical region

“…In Fig. 5 we show a comparison of our crossover equation with experimental Ce data reported by Kasteren and Zeldenrust [39] and by Jones et al…”