The Measurement and Prediction of Hydrate Formation in Liquid Hydrocarbon-Water Systems

Ng, Heng‐Joo; Robinson, Donald B.

doi:10.1021/i160060a012

Cited by 156 publications

(77 citation statements)

References 5 publications

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“…Among the important molecular parameters involved in predicting hydrate equilibrium conditions are the potential parameters which describe the gas-water interaction in the hydrate phase; most current models use the spherical core Kihara potential function for describing such interaction (Parrish and Prausnitz, 1972; Ng and Robinson, 1976; Holder and Hand, 1982).…”

Section: Scopementioning

confidence: 99%

Measurement and prediction of dissociation pressures of isobutane and propane hydrates below the ice point

Holder

Godbole

1982

AIChE Journal

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A gravimetric technique has been developed for measuring three phase vaporice-hydrate (VIH) equilibria. This technique has been used for measuring VIH dissociation pressures for propane and isobutane hydrates to temperatures as low as 241.4 K. Kihara parameters, based upon the experimental dissociation pressure data, have been obtained. Because the range of experimental three phase equilibrium data has been considerably extended, the parameters based on this data should be more useful in predicting hydrate dissociation pressures.

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Section: Scopementioning

confidence: 99%

Measurement and prediction of dissociation pressures of isobutane and propane hydrates below the ice point

Holder

Godbole

1982

AIChE Journal

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“…The methods for predicting the formation conditions are based on the statistical thermodynamics model of van der Waals and Platteeuw (1959). An algorithm for the predictions was developed by Parrish and Prausnitz (1972), and subsequently improved by Ng and Robinson (1976), Holder et al (1980), and John et al(1 985). When electrolytes or molecular species like methanol are present in the liquid water, the hydrate formation is inhibited.…”

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confidence: 99%

Prediction of gas hydrate formation conditions in aqueous electrolyte solutions

1988

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Gas hydrates are solid clathratc compounds. They are formed by the enclosure of light nonpolar gases, such as natural gas components, in a lattice-like structure of water molecules. They have been extensively reviewed recently by Berecz and BallaAchs (1983). Hydrates are known to occur naturally in vast quantities on ocean floors and in the permafrost regions of the world (Makogon, 1974(Makogon, , 1987. Majority of the thermodynamic studies on gas hydrates have focused on formation from pure water. The methods for predicting the formation conditions are based on the statistical thermodynamics model of van der Waals and Platteeuw (1959). An algorithm for the predictions was developed by Parrish and Prausnitz (1972), and subsequently improved by Ng and Robinson (1976), Holder et al. (1980), and John et al.(1 985). When electrolytes or molecular species like methanol are present in the liquid water, the hydrate formation is inhibited. Inhibition of gas hydrate formation is of particular interest to the oil and gas industry. In the present work, only the studies on the effect of electrolytes are investigated. Makogon (1 974) and Berecz and Balla-Achs (1 983) discuss the inhibiting effects of various salts and classify them according to their inhibiting activities. Knox et al. (1961) investigated the seawater desalination process via propane hydrate formation. Recently Kubota et al. (1984) also studied the propane hydrate formation.In both studies, data are reported on the formation from sodium chloride solutions. Roo et al. (1983) studied methane hydrate formation from NaCl solutions. Their experimental data were useful in examining the possibility of gas storage in the crust of the earth. Menten (1979) and Menten et al. (1981) reported experimental data on the cyclopropane hydrate formation conditions from water containing KCI or CaCI,. In addition, they presented a predictive method for the calculation of the hydrate forming conditions in the single salt solutions. The method is based on calculating the activity of water by using freezing point depression data. This is the only available predict k e method for the effect of single electrolytes on gas hydrate formation. In the present work, a computer implementable methodology is developed (Engleios, 1987) for the prediction of hydrate formation conditions in systems containing light hydrocarbon gases and aqueous solutions of single or mixed electrolytes. No adjustable parameters are needed in addition to those for the thermodynamic model for predictions from pure water and for the activity coefficient models for the salts in aqueous solutions, which are available from the literature. Methodology water solution may be represented by the following equationEquilibrium among the solid hydrate, the gas, and the liquid &l:= p:.( 1 )In writing Eq. I the amount of water vapor present in the gas phase is considered negligible. In addition, it is assumed that the salts are present only in the liquid solution. Since the salts do not enter the hydrate lattice, the statistic...

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“…It has both the provision to operate in semi-batch or batch manner. The reactor bomb is made of stainless steel, having a capacity of 500 cm 3 and possesses two Plexiglas windows to allow visual observation. There are three temperature sensors within the reactor, to measure the instantaneous temperature of the liquid, gas-liquid interface and gas phase, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The thermodynamic equilibrium conditions under which the gas hydrates exist were extensively studied by van der Walls and Platteeuw [1], Parrish and Prounitz [2], Ng and Robinson [3], John et al [4], and Holder et al [5]. Vysniauskas and Bishnoi [6,7], Englezos et al [8,9], Kim et al [10], Dholabhai et al [11,12], and Subramanian and Sloan [13,14] have all made remarkable progress in efforts to reveal the kinetics of formation and decomposition of methane and ethane hydrates.…”

Section: Introductionmentioning

confidence: 99%

Study of the Kinetics and Morphology of Gas Hydrate Formation

Hussain

Kumar

Laik

et al. 2006

Chem. Eng. Technol.

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The kinetics and morphology of ethane hydrate formation were studied in a batch type reactor at a temperature of ca. 270-280 K, over a pressure range of 8.83-16.67 bar. The results of the experiments revealed that the formation kinetics were dependant on pressure, temperature, degree of supercooling, and stirring rate. Regardless of the saturation state, the primary nucleation always took place in the bulk of the water and the phase transition was always initiated at the surface of the vortex (gas-water interface). The rate of hydrate formation was observed to increase with an increase in pressure. The effect of stirring rate on nucleation and growth was emphasized in great detail. The experiments were performed at various stirring rates of 110-190 rpm. Higher rates of formation of gas hydrate were recorded at faster stirring rates. The appearance of nuclei and their subsequent growth at the interface, for different stirring rates, was explained by the proposed conceptual model of mass transfer resistances. The patterns of gas consumption rates, with changing rpm, have been visualized as due to a critical level of gas molecules in the immediate vicinity of the growing hydrate particle. Nucleation and decomposition gave a cyclic hysteresis-like phenomena. It was also observed that a change in pressure had a much greater effect on the rate of decomposition than it did on the formation rate. Morphological studies revealed that the ethane hydrate resembles thread or is cotton-like in appearance. The rate of gas consumption during nucleation, with different rpm and pressures, and the percentage decomposition at different pressures, were explained precisely for ethane hydrate.

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The Measurement and Prediction of Hydrate Formation in Liquid Hydrocarbon-Water Systems

Cited by 156 publications

References 5 publications

Measurement and prediction of dissociation pressures of isobutane and propane hydrates below the ice point

Measurement and prediction of dissociation pressures of isobutane and propane hydrates below the ice point

Prediction of gas hydrate formation conditions in aqueous electrolyte solutions

Study of the Kinetics and Morphology of Gas Hydrate Formation

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