Extracting nucleation rates from ramped temperature measurements of gas hydrate formation

Barwood, Mark T.J.; Metaxas, Peter J.; Lim, Vincent W.S.; Sampson, Catherine C.; Johns, Michael L.; Aman, Zachary M.; May, Eric F.

doi:10.1016/j.cej.2022.137895

Cited by 15 publications

(12 citation statements)

References 36 publications

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“…The kinetic nucleation parameter, A , is described by CNT as the product of the Zeldovich factor (0.01 < z < 1), the number of available heterogeneous nucleation sites, N 0 , and the frequency of monomer attachment to the growing nucleus, f The thermodynamic parameter, B′ , reflects the work required for nucleation on the active heterogeneous nucleation (HEN) sites. This parameter includes the volume of the solid-forming (hydrate) building unit, v , shape factor of the formed solid cluster, c , and the surface energy of the new solid–fluid interface, σ ef , at the HEN site To extract values of A and B′ from J (Δ T ) data, eq can be linearized: ,,, where Measured (Δ T , J ) data exhibiting a linear trend in the x – y coordinate system defined by eqs and are then characterized by a single pair of A and B ′ parameters. Figure b shows the nucleation rate data presented in Figure a using these linearized coordinates.…”

Section: Resultsmentioning

confidence: 99%

“…The kinetic nucleation parameter, A , is described by CNT as the product of the Zeldovich factor (0.01 < z < 1), the number of available heterogeneous nucleation sites, N 0 , and the frequency of monomer attachment to the growing nucleus, f A = italiczf N 0 The thermodynamic parameter, B′ , reflects the work required for nucleation on the active heterogeneous nucleation (HEN) sites. This parameter includes the volume of the solid-forming (hydrate) building unit, v , shape factor of the formed solid cluster, c , and the surface energy of the new solid–fluid interface, σ ef , at the HEN site B ′ = 4 c 3 v 2 σ ef 3 27 k normalB normalΔ s normale 2 To extract values of A and B′ from J (Δ T ) data, eq can be linearized: ,,, y = ln nobreak0em.25em⁡ J − normalΔ s normale normalΔ T k normalB T = italicln ( A ) − B ′ T normalΔ T 2 = italicln ( A ) − B ′ x where y = ln nobreak0em.25em⁡ J − …”

Section: Resultsmentioning

confidence: 99%

“…Integration of the PDF produces the corresponding cumulative distribution function (CDF) (Figure 5c). 24 Nucleation rates can be extracted from ramped temperature formation probability distributions using a method described by Barwood et al 25 which is based on the hazard function, h(t) 26−28 (commonly used in survival analysis 29 ). The hazard function method is useful for describing formation in systems where the driving force for nucleation changes continuously because it accounts for the system's history in the solid stability region.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Aqueous Solid Formation Kinetics in High-Pressure Methane at Trace Water Concentrations

et al. 2023

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Natural gas containing trace amounts of water is frequently liquefied at conditions where aqueous solids are thermodynamically stable. However, no data are available to describe the kinetics of aqueous solid formation at these conditions. Here, we present experimental measurements of both solid formation kinetics and solid–fluid equilibrium for trace concentrations of (12 ± 0.7) ppm water in methane using a stirred, high-pressure apparatus and visual microscopy. Along isochoric pathways with cooling rates around 1 K·min–1, micron-scale aqueous solids were observed to form at subcoolings of (0.3–8.6) K, relative to an average equilibrium melting temperature of (253 ± 1.9) K at (8.9 ± 0.08) MPa; these data are consistent with predicted methane hydrate dissociation conditions within the uncertainty of both the experiment and model. The 36 measured formation events were used to construct a cumulative formation probability distribution, which was then fitted with a model from Classical Nucleation Theory, enabling the extraction of kinetic and thermodynamic nucleation parameters. While the resulting nucleation parameter values were comparable to those published for methane hydrate formation in bulk-water systems, the observed growth kinetics were distinctly different with only a small percentage of the water in the system converting into micron-scale solids over the experimental time scale. These results may help explain how cryogenic heat exchangers in liquefied natural gas facilities can operate for long periods without blockages forming despite being at very high subcoolings for aqueous solids.

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Section: Resultsmentioning

confidence: 99%

“…The kinetic nucleation parameter, A , is described by CNT as the product of the Zeldovich factor (0.01 < z < 1), the number of available heterogeneous nucleation sites, N 0 , and the frequency of monomer attachment to the growing nucleus, f A = italiczf N 0 The thermodynamic parameter, B′ , reflects the work required for nucleation on the active heterogeneous nucleation (HEN) sites. This parameter includes the volume of the solid-forming (hydrate) building unit, v , shape factor of the formed solid cluster, c , and the surface energy of the new solid–fluid interface, σ ef , at the HEN site B ′ = 4 c 3 v 2 σ ef 3 27 k normalB normalΔ s normale 2 To extract values of A and B′ from J (Δ T ) data, eq can be linearized: ,,, y = ln nobreak0em.25em⁡ J − normalΔ s normale normalΔ T k normalB T = italicln ( A ) − B ′ T normalΔ T 2 = italicln ( A ) − B ′ x where y = ln nobreak0em.25em⁡ J − …”

Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Aqueous Solid Formation Kinetics in High-Pressure Methane at Trace Water Concentrations

et al. 2023

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“…Comparison of the Nucleation Rate of CO 2 Hydrate and That of Other Gas Hydrates in the Presence of Solid Walls. Barwood et al 50 used a 2 nd -generation highpressure stirred automated lag time apparatus (HPS-ALTA) to investigate the methane hydrate nucleation in the presence of a stainless-steel wall using the linear cooling ramp experiment at two cooling rates (1 and 3 K/min). For comparison, we normalized the experimental nucleation rates derived from their study by the water−methane interfacial area and the length of TPCL reported by Lim et al 51 Maeda derived the nucleation rate of C1/C3 mixed gas hydrate in the presence of a stainless-steel wall, without stirring, over a pressure range of 7.0−12.5 MPa using linear cooling ramps.…”

Section: Analysis Of Co 2 Hydrate Nucleation Kinetics Within the Fram...mentioning

confidence: 99%

Nucleation Curves of Carbon Dioxide Hydrate in the Absence of a Solid Wall

Wei

Maeda

2023

Energy Fuels

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Nucleation kinetics of clathrate hydrate is poorly understood because of the difficulties in determining the essential parameter, nucleation rate. Nucleation rate enables quantitative comparisons of the impacts of various additives and solid walls on nucleation. We made a setup that determines the nucleation curves of structure Iforming CO2 hydrate in quiescent quasi-free water droplets supported by a bulk of liquid perfluoromethyldecalin under isobaric conditions. The results were compared to the nucleation rates of CO2 hydrate in quiescent water that was in direct contact with stainless-steel walls. We assessed the convergence of the nucleation curves with the increasing numbers of nucleation data and compared our results to the nucleation rates of methane/propane mixed gas hydrate in quiescent quasi-free water droplets and the nucleation rates of gas hydrates of various guest types in the presence of solid walls reported in the literature. We found that (1) 400 nucleation events were sufficient to construct a reliable nucleation curve; (2) the addition of stainless-steel walls promoted the nucleation kinetics of CO2 hydrate, as it did to methane/propane mixed gas hydrate; (3) the kinetic parameter was significantly lower than the theoretically expected value, whereas the thermodynamic parameter was comparable to both the theoretically expected value and the experimentally determined value reported in the literature; and (4) CO2 hydrate nucleated over a substantially shallower supercooling range and had higher nucleation rates than those of methane/propane mixed gas hydrate, both in the presence and in the absence of a solid wall.

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“…New SFE data are presented that enable the model predictions within the ThermoFAST software package to be made more accurate via regression 9,14,34,35 . Measurements of CO 2 solid formation kinetics under ramped temperature conditions are presented and analyzed using the hazard‐function method to extract subcooling‐dependent nucleation rates 36 . These rates compare well to those extracted from slower fixed‐temperature induction time measurements.…”

Section: Introductionmentioning

confidence: 99%

Experimental solid–liquid equilibria and solid formation kinetics for carbon dioxide in methane for LNG processing

et al. 2023

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In cryogenic liquefaction processes, CO 2 poses a solid-formation risk even in trace concentrations. We present solid-fluid equilibrium (SFE) data for CO 2 in liquid methane at CO 2 concentrations from (52 to 500) ppm, extending the available data and indicating that models tuned to existing data over predict the solubility of CO 2 at LNG storage temperatures ($112 K) by nearly a factor of 3. The new data are used to improve the SFE model in the ThermoFAST software package. The formation kinetics of CO 2 solids in liquid methane are elucidated at conditions relevant to cryogenic gas processing. Repeated, ramped-temperature formation measurements provide a statistical basis for quantifying solidification risk. Nucleation rates extracted from the ramped-temperature data, consistent with those measured at fixed temperature, were used to extract parameters describing CO 2 solid formation in methane.These results significantly improve the ability to predict CO 2 solid formation risk in cryogenic natural gas processing.

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Extracting nucleation rates from ramped temperature measurements of gas hydrate formation

Cited by 15 publications

References 36 publications

Aqueous Solid Formation Kinetics in High-Pressure Methane at Trace Water Concentrations

Aqueous Solid Formation Kinetics in High-Pressure Methane at Trace Water Concentrations

Nucleation Curves of Carbon Dioxide Hydrate in the Absence of a Solid Wall

Experimental solid–liquid equilibria and solid formation kinetics for carbon dioxide in methane for LNG processing

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