Measurements of isobaric heat capacities of gases from 323.15 to 573.15 K up to 30 MPa

Dordain, L.; Coxam, Jean Yves; Grolier, J.-P.E.

doi:10.1063/1.1144560

Cited by 16 publications

(6 citation statements)

References 4 publications

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“…These cells were placed inside a cylinder surrounded by a heating element. The difference between the heat needed to raise the temperature of the measuring cell and that needed to raise the temperature of the reference cell by the same temperature increment was obtained by continuously measuring the difference in the power received by the two cells and integrating over time [26].…”

Section: Methodsmentioning

confidence: 99%

On the isobaric specific heat capacity of natural gas

Jarrahian

Karami

Heidaryan

2014

Fluid Phase Equilibria

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Section: Methodsmentioning

confidence: 99%

On the isobaric specific heat capacity of natural gas

Jarrahian

Karami

Heidaryan

2014

Fluid Phase Equilibria

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“…To avoid this convection, Coxam et al operated their C80 DSC in an inverted mode; this approach worked because they only operated their calorimeter at temperatures greater than ambient, which meant that the sample was always less dense in the calorimetric cell than in the tubing leading from the cell. An alternative approach was used by Dordain et al − and by Schrödle et al to prevent convection from occurring in their connecting tubes. Dordain et al employed a custom-made “preheater” to maintain the top of their Setaram C80 DSC at a higher temperature than the calorimetric cell throughout the scan.…”

Section: Apparatusmentioning

confidence: 99%

Isobaric Heat Capacity Measurements of Liquid Methane, Ethane, and Propane by Differential Scanning Calorimetry at High Pressures and Low Temperatures

et al. 2012

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A commercial differential scanning calorimeter (DSC) was adapted to allow accurate isobaric heat capacity, c p , measurements of cryogenic, high-pressure liquids. At (subcritical) temperatures between (108.15 and 258.15) K and pressures between (1.1 and 6.35) MPa, the standard deviation in the measured c p values was 0.005·c p for methane, 0.01·c p for ethane, and 0.015·c p for propane, which is comparable to both the scatter of c p data for these liquids measured using other techniques and with the scatter of those data sets about the reference equation of state (EOS) values. Three key modifications to the commercial DSC were required to enable these accurate cryogenic, high-pressure liquid c p measurements. First, methods of loading and removing the liquid from the calorimeter without moving the sample cell were developed and tested with high boiling temperature liquids; this modification improved the measurement repeatability. Second, a ballast volume containing a high-pressure vapor phase at constant temperature was connected to the DSC cell so that the liquid sample’s thermal expansion did not cause significant changes in pressure. A third modification was required because the boil-off vapor from the liquid nitrogen used to cool the calorimeter resulted in a temperature inversion, and hence convection, along the tubing connecting the DSC’s sample cell to the ballast volume, that lead to an unstable calorimetric signal at T > 130 K. The modifications to the specialized DSC were tested by measuring c p values for heptane, methylbenzene, and a heptane (1) + methylbenzene (2) mixture with x 1 = 0.38 at atmospheric pressure and temperatures of (228.15, 238.15, 303.15, and 313.15) K. The measured values had relative deviations from those measured adiabatically by Holzhauer and Ziegler (J. Phys. Chem. 1975, 79, 590–604) of less than 0.006·c p , indicating that the specialized DSC could be used for liquids and liquid mixtures at conditions relevant to liquefied natural gas production.

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“…The main leaks are caused by convection between the sample being heated in the cell and the same sample at ambient temperature in the upper tubing. A metallic block, which is used as an auxiliary thermostat, was installed on the lid of the calorimeter (this device had already been used by Dordain et al [2] in their calorimeter adapted for measuring heat capacities of gases). The T-shaped connection in the cells and the capillary (5) N70 linking the cell and the pressurization system are enclosed in this block.…”

Section: The Apparatusmentioning

confidence: 99%

“…Consequently, in order to collect experimental information on enthalpic properties, which are among the basic thermophysical properties, we developed an experimental device which allows us to measure, under extended ranges of pressure (up to 100 MPa) and temperature, the isobaric heat capacity C P and density of liquids containing dissolved gas. The heat capacity measurement method is similar to the process already used for determination of the heat capacities of liquids or gases under pressure [2,3]. Nevertheless, the main difficulty of these manipulations lies in the fact that the components are miscible only at high pressures.…”

Section: Introductionmentioning

confidence: 99%

Apparatus for simultaneous determination of the densities and heat capacities of liquids and of liquids with dissolved gas under an extended range of pressure (0.1-100 MPa)

Bessières

Saint-Guirons

Daridon

et al. 2000

Meas. Sci. Technol.

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This design note describes an experimental device, based on a Setaram C-80 calorimeter and an Anton Paar 512P densimeter, developed in order to measure densities and heat capacities at constant pressure of liquids and of liquids with gas dissolved. Pressure ranges from 0.1 to 70 MPa for the density measurement and from 0.1 to 100 MPa for the heat capacity determination, at temperatures from 303 to 473 K. The specific arrangement incorporated in the apparatus and the method of transfer of samples into the measurement vessels required for the study of these mixtures are also detailed. The functioning of this instrument was tested by measuring the heat capacity of liquid n-hexane, with calibration performed with water. Comparison with literature data obtained by an indirect method indicates that the deviation is less than 0.6%. The results of an investigation of a binary mixture, of n-decane and carbon dioxide, which has two phases under normal conditions, is also given.

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Measurements of isobaric heat capacities of gases from 323.15 to 573.15 K up to 30 MPa

Cited by 16 publications

References 4 publications

On the isobaric specific heat capacity of natural gas

On the isobaric specific heat capacity of natural gas

Isobaric Heat Capacity Measurements of Liquid Methane, Ethane, and Propane by Differential Scanning Calorimetry at High Pressures and Low Temperatures

Apparatus for simultaneous determination of the densities and heat capacities of liquids and of liquids with dissolved gas under an extended range of pressure (0.1-100 MPa)

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