Liquid Propane + Water Phase Equilibria at Hydrate Conditions

Makogon, Yuri F.

doi:10.1021/je020143w

Cited by 12 publications

(18 citation statements)

References 6 publications

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“…The literature data in the Lw−H−C 3 H 8 (l) region were all within an AD = ±0.2 K except for the data reported by Makogon (2003). 18,22,27,28 As opposed to the Lw− H−C 3 H 8 (g) region, temperature deviation from this model does not correlate with the C 3 H 8 purity. For example, the reported data for Makogon (2003) and Mooijer-van den Heuvel et al (2001) was 99.995 mol % C 3 H 8 purity, 22,27 whereas the data fo Mooijer-van den Heuvel et al show a significantly lower deviation.…”

Section: Rt V Ln(1 )supporting

confidence: 54%

“…For example, the reported data for Makogon (2003) and Mooijer-van den Heuvel et al (2001) was 99.995 mol % C 3 H 8 purity, 22,27 whereas the data fo Mooijer-van den Heuvel et al show a significantly lower deviation. 22 The large difference for the Makogon (2003) 27 data can be attributed to the technique used for measuring the dissociation point, which relied on visual determination of phase transition from one phase to another, where propane hydrates may float out of view. The Reamer et al (1952) data show the lowest deviation to this model for >99 mol % C 3 H 8 .…”

Section: Rt V Ln(1 )mentioning

confidence: 91%

“…2,26 The Clausius− Clapeyron equation reported in this study and Maekawa correlation also compared favorably with the model to within an average temperature of −0.05 K. 24 The number of data points, purities, AD, and pressure and temperature ranges compared to the model presented in this study along the Lw−H−C 3 H 8 (l) locus are presented in Table 5, while the experimentally measured and calculated conditions with their corresponding deviations along the Lw−H−C 3 H 8 (l) phase boundary are shown in Figure 6. 18,22,27,28 The model calculates the dissociation temperature to an AD = 0.01 K (for this data only). The literature data in the Lw−H−C 3 H 8 (l) region were all within an AD = ±0.2 K except for the data reported by Makogon (2003).…”

Section: Rt V Ln(1 )mentioning

confidence: 99%

“…18,22,27,28 The model calculates the dissociation temperature to an AD = 0.01 K (for this data only). The literature data in the Lw−H−C 3 H 8 (l) region were all within an AD = ±0.2 K except for the data reported by Makogon (2003). 18,22,27,28 As opposed to the Lw− H−C 3 H 8 (g) region, temperature deviation from this model does not correlate with the C 3 H 8 purity.…”

Section: Rt V Ln(1 )mentioning

confidence: 99%

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Hydrate Decomposition Conditions for Liquid Water and Propane

2017

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Because of the industrial importance of C 3 H 8 and because C 3 H 8 hydrate is a reference material for other sII hydrates, the C 3 H 8 hydrate dissociation conditions were independently measured using the phase boundary dissociation and isochoric methods for T = 273.63−278.75 K and p = 0.1887−18.2622 MPa. Along the liquid water Lw−H−C 3 H 8 (g) phase boundary, two different purities of 99.5 and 99.999 mol % C 3 H 8 were studied. Data have been used to optimize two semiempirical correlations for rapid calculation of the phase dissociation conditions for p < 20 MPa. For a more rigorous model, the highest purity data have been fit using the van der Waals and Platteuw model and reference quality reduced Helmholtz equations-of-state (EOSs) for the hydrate phase and fluid phases, respectively. The optimized thermodynamic-based model agrees with the experimental data to within the estimated uncertainty of δT = ±0.1 K. The results were also compared to the highly variant literature data for the Lw−H−C 3 H 8 (l) phase boundary, where the deviations can be attributed to measurement difficulties when a hydrate is less dense than the liquid hydrate former in the liquid region.

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Section: Rt V Ln(1 )supporting

confidence: 54%

Section: Rt V Ln(1 )mentioning

confidence: 91%

Section: Rt V Ln(1 )mentioning

confidence: 99%

Section: Rt V Ln(1 )mentioning

confidence: 99%

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Hydrate Decomposition Conditions for Liquid Water and Propane

2017

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“…Depth was converted to hydrostatic pressure in seawater. Pressure‐temperature values were compared to phase diagrams of methane‐propane mixes in seawater for fractions of propane up to 0.3, beyond which the phase boundary does not change noticeably (hydrate from pure propane dissociates to the liquid phase at these pressures; Makogon, ). We assumed only propane as sII‐hydrate forming gas because of a lack of information on gas composition, and thus, these calculations are qualitative.…”

Section: Methodsmentioning

confidence: 99%

A Fluid Pulse on the Hikurangi Subduction Margin: Evidence From a Heat Flux Transect Across the Upper Limit of Gas Hydrate Stability

Pecher

Villinger

Kaul

et al. 2017

Geophysical Research Letters

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A transect of seafloor heat probe measurements on the Hikurangi Margin shows a significant increase of thermal gradients upslope of the updip limit of gas hydrate stability at the seafloor. We interpret these anomalously high thermal gradients as evidence for a fluid pulse leading to advective heat flux, while endothermic cooling from gas hydrate dissociation depresses temperatures in the hydrate stability field. Previous studies predict a seamount on the subducting Pacific Plate to cause significant overpressure beneath our study area, which may be the source of the fluid pulse. Double-bottom simulating reflections are present in our study area and likely caused by uplift based on gas hydrate phase boundary considerations, although we cannot exclude a thermogenic origin. We suggest that uplift may be associated with the leading edge of the subducting seamount. Our results provide further evidence for the transient nature of fluid expulsion in subduction zones.

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