Critical locus, (vapor + liquid) equilibria, and coexisting densities of (carbon dioxide + propane) at temperatures from 311 K to 361 K

Niesen, Vicki G.; Rainwater, J.

doi:10.1016/0021-9614(90)90070-7

Cited by 92 publications

(40 citation statements)

References 42 publications

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“…For example, the critical pressures for the system CO 2 (1) + propane (2) from Poettmann and Katz [6] and from Reamer et al [8] are too high. Niesen and Rainwater [7], whose results agree with the results of this work, already pointed out that in the estimation of critical points from vapor-liquid equilibrium data Reamer et al were guided by the data from Poettmann and Katz. Too high critical pressures of the same authors [10,14,15] were also reported for the systems CO 2 (1) + n-butane (2) and propane (1) + n-butane (2).…”

Section: Resultssupporting

confidence: 89%

Experimental Determination of Critical Points of Pure Components and Binary Mixtures Using a Flow Apparatus

Horstmann

Fischer

Gmehling³

1999

Chem. Eng. Technol.

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Equations of state can be successfully employed for the description of the phase equilibrium behavior of multicomponent mixtures using binary data alone. Especially in the vicinity of the critical point often only a limited number of phase equilibrium data or data of low quality are available. Critical points of mixtures provide additional information about the location and border of the two-phase region. The PSRK model (Predictive Soave-Redlich-Kwong) [1] combines the SRK equation of state with the group contribution model UNIFAC by the PSRK mixing rule. For the extension of the range of applicability and the improvement of the results of PSRK or other group contribution equations of state the systematic measurement of data required for the fitting of the group interaction parameters is desired. In addition to phase equilibrium data also critical data are of great importance. For this reason a new flow apparatus for the measurement of critical data of pure components and mixtures was developed, which can be operated at temperatures between 280 and 470 K and pressures up to 35 MPa.A common approach for the determination of critical points of mixtures in closed systems is the isothermal or isobaric method connected with an analysis of the gas and liquid phases for the determination of the two-phase region ending at the critical point. Another usual method is the visual detection of critical points where the temperature is varied until the phase border disappears while the temperature increases, or the meniscus reappears while the temperature decreases. The corresponding pressure automatically results from the phase equilibrium pressure. A prerequisite for the measurement of critical points is the exact adjustment of the critical density which requires a variable volume cell.A flow apparatus for the measurement of critical properties of pure components was introduced by Rosenthal and Teja [2]. The variation of density in this apparatus is enabled with the help of a regulation valve at the outlet of the optical cell. Because of the flow mode short retention times are achieved. That is why this technique also allows the determination of critical points of components which show a thermal decomposition. The critical data are determined at different flow rates. Extrapolation of these data to the retention time t = 0 allows the determination of the critical data of such unstable components.The apparatus developed in this study also works in a flow mode and is applicable for pure components as well as binary and multicomponent mixtures. An advantage of this approach is that phase equilibrium is reached before the substances enter the cell. Moreover, the content of the cell is pushed aside so that cleaning and controlled filling of the cell is not necessary. Unfortunately, the critical volume cannot be determined and quite large amounts of substances are needed. Principle of MeasurementA schematic diagram of the apparatus is shown in Fig. 1. Two thermostatted chromatography syringe pumps (Model 260D, ISO) in which the pure...

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Section: Resultssupporting

confidence: 89%

Experimental Determination of Critical Points of Pure Components and Binary Mixtures Using a Flow Apparatus

Horstmann

Fischer

Gmehling³

1999

Chem. Eng. Technol.

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“…The available literature data are listed in [10] are also included in these figures. Some of these calculation results were obtained by the REFPROP ver.8 calculation in the region close to the critical temperature.…”

Section: Resultsmentioning

confidence: 99%

“…Plot of relative pressure deviations of the bubble point pressures (P bub ) for (CO 2 + propane) binary mixtures versus CO 2 mole fraction: d, This work; +, Niesen[10]; Â, Kim and Kim[7]; 4, Tanaka et al[8].…”

mentioning

confidence: 98%

The precise measurement of the (vapour + liquid) equilibrium properties for (CO2+ isobutane) binary mixtures

Nagata

Mizutani

Miyamoto

2011

The Journal of Chemical Thermodynamics

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“…Working pressures are also expected to be lower than with pure CO 2 . This may be illustrated for instance in Figure 1, which shows the critical line and some bubble and dew curves for the CO 2 + propane mixture [6]. In Figure 1 we can see that liquid vapor equilibrium takes place for example at 328 K (55 °C) and pressures below 6 MPa.…”

Section: Co 2 Based Mixturesmentioning

confidence: 94%

Experimental study of heat pump thermodynamic cycles using CO2 based mixtures - Methodology and first results

Bouteiller¹,

Terrier²,

Tobaly³

2017

AIP Conference Proceedings

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Abstract. The aim of this work is to study heat pump cycles, using CO 2 based mixtures as working fluids. Since adding other chemicals to CO 2 moves the critical point and generally equilibrium lines, it is expected that lower operating pressures as well as higher global efficiencies may be reached. A simple stage pure CO 2 cycle is used as reference, with fixed external conditions. Two scenarios are considered: water is heated from 10 °C to 65 °C for Domestic Hot Water scenario and from 30 °C to 35 °C for Central Heating scenario. In both cases, water at the evaporator inlet is set at 7 °C to account for such outdoor temperature conditions. In order to understand the dynamic behaviour of thermodynamic cycles with mixtures, it is essential to measure the fluid circulating composition. To this end, we have developed a non intrusive method. Online optical flow cells allow the recording of infrared spectra by means of a Fourier Transform Infra Red spectrometer. A careful calibration is performed by measuring a statistically significant number of spectra for samples of known composition. Then, a statistical model is constructed to relate spectra to compositions. After calibration, compositions are obtained by recording the spectrum in few seconds, thus allowing for a dynamic analysis. This article will describe the experimental setup and the composition measurement techniques. Then a first account of results with pure CO 2 , and with the addition of propane or R-1234yf will be given.

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Critical locus, (vapor + liquid) equilibria, and coexisting densities of (carbon dioxide + propane) at temperatures from 311 K to 361 K

Cited by 92 publications

References 42 publications

Experimental Determination of Critical Points of Pure Components and Binary Mixtures Using a Flow Apparatus

Experimental Determination of Critical Points of Pure Components and Binary Mixtures Using a Flow Apparatus

The precise measurement of the (vapour + liquid) equilibrium properties for (CO2+ isobutane) binary mixtures

Experimental study of heat pump thermodynamic cycles using CO2 based mixtures - Methodology and first results

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