Aqueous nonelectrolyte solutions. Part XIV. D-ice and D-hydrate freezing points of deuterium oxide – ethylene oxide solutions and the formula of congruent ethylene oxide D-hydrate

1996 ◽  
Vol 74 (10) ◽  
pp. 1830-1835
Author(s):  
David N. Glew ◽  
Norman S. Rath
Keyword(s):  
Ethylene Oxide ◽  
Composition Range ◽  
Deuterium Oxide ◽  
Hydrate Formation ◽  
Single Measurement ◽  
Method Of Least Squares ◽  
Cooling Method ◽  
Dynamic Cooling ◽  
Freezing Temperatures ◽  
Freezing Curve

D-ice freezing temperatures and D-hydrate formation temperatures have been measured by the dynamic cooling method for deuterium oxide – ethylene oxide (EO) solutions containing from 0 to 95.5 mol% EO. The D-ice and the congruent EO D-hydrate freezing temperatures exhibited standard errors (SEs) on a single measurement of 0.004 °C and 0.017 °C, respectively. The D-ice–D-hydrate eutectic temperature was observed at 1.500 °C with standard error (SE) 0.002 °C and at composition 2.207 mol% EO with SE 0.010 mol% EO. The congruent EO D-hydrate was found to freeze at 13.242 °C with SE 0.007 °C and at composition 12.60 mol% EO with SE 0.07 mol% EO. The formula of the congruent EO D-hydrate was EO•6.93D2O with SE 0.045 mol D2O/mol EO. Only one type of D-hydrate was found over the whole composition range down to −23 °C: the shoulder of the D-hydrate freezing curve above 40 mol% EO resulted from the high activity coefficients of dilute deuterium oxide in concentrated EO solutions. Equations and best values for the D-ice freezing temperatures and the D-hydrate formation temperatures together with their SEs were evaluated by the method of least squares. Properties of EO D-hydrate are compared with those of EO hydrate. Key words: clathrate D-hydrate of ethylene oxide, freezing of deuterium oxide – ethylene oxide, ethylene oxide D-hydrate, formula of ethylene oxide D-hydrate.

Aqueous nonelectrolyte solutions. Part XIII. Ice and hydrate freezing points of aqueous ethylene oxide solutions and the formula of congruent ethylene oxide hydrate

1995 ◽  
Vol 73 (6) ◽  
pp. 788-796 ◽  
Author(s):  
David N. Glew ◽  
Norman S. Rath
Keyword(s):  
Ethylene Oxide ◽  
Standard Error ◽  
Hydrate Formation ◽  
Standard Errors ◽  
Single Measurement ◽  
Method Of Least Squares ◽  
Oxide Hydrate ◽  
Dynamic Cooling ◽  
Freezing Temperatures ◽  
Freezing Curve

Ice freezing temperatures and hydrate formation temperatures have been measured by the dynamic cooling method for aqueous ethylene oxide (EO) solutions containing from 0 to 95 mol% EO. The ice and the congruent hydrate freezing temperatures exhibited standard errors on a single measurement of 0.004 °C and 0.013 °C, respectively. The ice–hydrate eutectic temperature was observed at −2.107 °C with standard error 0.001 °C and composition 1.991 mol% EO with standard error 0.008 mol% EO. The congruent hydrate was found to freeze at 11.083 °C with standard error 0.002 °C and composition 12.64 mol% EO with standard error 0.02 mol% EO. The formula of the congruent hydrate was EO•6.91H2O with standard error 0.013 mol water/mol EO. Only a single hydrate was found over the whole composition range down to −26 °C: the shoulder of the hydrate freezing curve above 40 mol% EO resulted from the high activity coefficients to dilute water in concentrated EO solutions. Equations and best values for the ice freezing temperatures and the hydrate formation temperatures together with their standard errors were evaluated by the method of least squares. Keywords: clathrate hydrate of ethylene oxide, freezing of water – ethylene oxide, ethylene oxide hydrate.

Aqueous Nonelectrolyte Solutions. Part IX. Enthalpies of Mixing of Water and Deuterium Oxide with Ethylene Oxide

1971 ◽  
Vol 49 (11) ◽  
pp. 1830-1840 ◽  
Author(s):  
D. N. Glew ◽  
Harry Watts
Keyword(s):  
Hydrogen Bonding ◽  
Ethylene Oxide ◽  
Composition Range ◽  
Deuterium Oxide ◽  
Enthalpy Of Mixing ◽  
Water Systems ◽  
Oxide System ◽  
Water Proton ◽  
Oxide Systems ◽  
Enthalpies Of Mixing

Calorimetric enthalpies of mixing have been measured over the whole composition range for the water – ethylene oxide system at 10.75 and 20.00 °C and for the deuterium oxide – ethylene oxide system at 13.45 and 20.00 °C. Less extensive measurements have been made for dilute ethylene oxide solutions in water at 0.6 °C and in deuterium oxide at 4.1 and 7.3 °C. The experimental S-shaped, enthalpy of mixing – composition curves are interpreted in terms of solution hydrogen bonding changes, with particular reference to the hydrogen bonding of water. At low ethylene oxide mole fractions the deuterium oxide systems are more exothermal and at high ethylene oxide mole fractions more endothermal than the corresponding water systems. A good correlation is found between the enthalpy of mixing and the water proton magnetic resonance chemical shift for solutions with greater than 0.55 mol fraction of ethylene oxide.

Experimental Study on the Effect of Gas Hydrate Content on Heat Transfer

2015 ◽  
Author(s):  
Remi-Erempagamo T. Meindinyo ◽  
Runar Bøe ◽  
Thor Martin Svartås ◽  
Silje Bru
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Ethylene Oxide ◽  
Deep Water ◽  
Gas Hydrate ◽  
Atmospheric Pressure ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Equilibrium Temperature ◽  
Gas Hydrate Formation

Gas hydrates are the foremost flow assurance issue in deep water operations. Since heat transfer is a limiting factor in gas hydrate formation processes, a better understanding of its relation to hydrate formation is important. This work presents findings from experimental study of the effect of gas hydrate content on heat transfer through a cylindrical wall. The experiments were carried out at temperature conditions similar to those encountered in flowlines in deep water conditions. Experiments were conducted on methane hydrate, Tetrahydrofuran hydrate, and ethylene oxide hydrate respectively in stirred cylindrical high pressure autoclave cells. Methane hydrate was formed at 90 bars (pressure), and 8°C, followed by a cooling/heating cycle in the range of 8°C → 4°C → 8°C. Tetrahydrofuran (THF) and ethylene oxide (EO) hydrates were formed at atmospheric pressure and system temperature of 1°C in contact with atmospheric air. This was followed by a heating/cooling cycle within the range of 1°C → 4°C → 1°C, since the hydrate equilibrium temperature of THF hydrate is 4.98°C in contact with air at atmospheric pressure. The experimental conditions of the latter hydrate formers were more controlled, given that both THF and EO are miscible with water. We found in all cases a general trend of decreasing heat transfer coefficient of the cell content with increasing concentration of hydrate in the cell, indicating that hydrate formation creates a heat transfer barrier. The hydrate equilibrium temperature seemed to change with a change in the stoichiometric concentration of THF and EO. While the methane hydrate cooling/heating cycles were performed under quiescent conditions, the effect of stirring was investigated for the latter hydrate formers.

Kinetics of formation of ethylene oxide hydrate. Part I. Experimental method and congruent solutions

1968 ◽  
Vol 46 (24) ◽  
pp. 3857-3865 ◽  
Author(s):  
D. N. Glew ◽  
M. L. Haggett
Keyword(s):  
Heat Transfer ◽  
Ethylene Oxide ◽  
Experimental Method ◽  
Hydrate Formation ◽  
Controlling Factor ◽  
Oxide Hydrate ◽  
Mechanical Stirring ◽  
Magnetic Stirring ◽  
Kinetics Of Formation ◽  
Kinetics Of

A dilatometer was constructed for studying the formation of ethylene oxide hydrate. In unstirred, congruent solutions heat transfer appeared to be the significant rate-controlling factor. Initial hydrate formation rates were independent of stirring at speeds greater than approximately 100 r.p.m. Magnetic stirring was inadequate due to hydrate build-up on the walls of the dilatometer bulb. Mechanical stirring eliminated this build-up and gave satisfactory results.

scholarly journals Kinetic Behavior of Quaternary Ammonium Hydroxides in Mixed Methane and Carbon Dioxide Hydrates

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 275
Author(s):  
Muhammad Saad Khan ◽  
Cornelius Borecho Bavoh ◽  
Khor Siak Foo ◽  
Azmi Mohd Shariff ◽  
Zamzila Kassim ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Alkyl Chain ◽  
Surface Adsorption ◽  
Hydrate Formation ◽  
Tetrabutylammonium Hydroxide ◽  
Tetraethylammonium Hydroxide ◽  
Tetrapropylammonium Hydroxide ◽  
Cooling Method ◽  
Gas Hydrate Formation ◽  
Chain Lengths

This study evaluates the kinetic hydrate inhibition (KHI) performance of four quaternary ammonium hydroxides (QAH) on mixed CH4 + CO2 hydrate systems. The studied QAHs are; tetraethylammonium hydroxide (TEAOH), tetrabutylammonium hydroxide (TBAOH), tetramethylammonium hydroxide (TMAOH), and tetrapropylammonium hydroxide (TPrAOH). The test was performed in a high-pressure hydrate reactor at temperatures of 274.0 K and 277.0 K, and a concentration of 1 wt.% using the isochoric cooling method. The kinetics results suggest that all the QAHs potentially delayed mixed CH4 + CO2 hydrates formation due to their steric hindrance abilities. The presence of QAHs reduced hydrate formation risk than the conventional hydrate inhibitor, PVP, at higher subcooling conditions. The findings indicate that increasing QAHs alkyl chain lengths increase their kinetic hydrate inhibition efficacies due to better surface adsorption abilities. QAHs with longer chain lengths have lesser amounts of solute particles to prevent hydrate formation. The outcomes of this study contribute significantly to current efforts to control gas hydrate formation in offshore petroleum pipelines.

scholarly journals Experimental Study on the Effect of Combination of Thermodynamic Inhibitors’ and Kinetic Inhibitors’ Hydrate Inhibition

2021 ◽  
Vol 9 ◽  
Author(s):  
Yonghai Gao ◽  
Yanlong Wang ◽  
Guizhen Xin ◽  
Xiangdong Wang ◽  
Cheng Yue ◽  
...  
Keyword(s):  
Induction Time ◽  
Low Dose ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Well Testing ◽  
Gas Well ◽  
Cooling Method ◽  
Mixed Use ◽  
Wellbore Temperature ◽  
Temperature And Pressure

In deepwater gas well testing, the high-pressure and low-temperature environment in the wellbore provides conditions for hydrate formation. When the thermodynamic inhibitor is used, it needs a large amount and is difficult to inject. Low-dose hydrate inhibitors such as kinetic inhibitors are rarely used in high supercooling and natural gas–dominated environments. The mixed use of thermodynamic inhibitors and kinetic inhibitors provides a new way. By simulating the wellbore temperature and pressure conditions during the deepwater gas well testing, the inhibiting effect of the mixtures of PVCap and methanol with various concentrations was experimentally tested by using rocking cells with a step-cooling method at 21MPa. The effect of PVCap and its mixture with methanol on hydrate plugging was evaluated by monitoring the movement of slider in the rocking cell. The results showed that 5 wt%, 16 wt%, and 20 wt% methanol mixed with 0.5 wt% PVCap could prolong the induction time, and the higher the methanol concentration, the longer the hydrate induction time. Among them, the best combination of 20wt% methanol and 0.5wt% PVCap can inhibit the hydrate for 379 min. The hydrate was formed but did not block the rocking cell, indicating that the combination of PVCap and methanol could not only prolong the hydrate formation time but also avoid the blockage after hydrate formation. The hydrate formation rate with various inhibitor concentrations was calculated; it may provide some guidance for making a shut-in plan for on-site wells.

Aqueous Nonelectrolyte Solutions. Part XII. Enthalpies of Mixing of Water and Deuterium Oxide with Tetrahydrofuran

1973 ◽  
Vol 51 (12) ◽  
pp. 1933-1940 ◽  
Author(s):  
David N. Glew ◽  
Harry Watts
Keyword(s):  
Hydrogen Bonding ◽  
Proton Magnetic Resonance ◽  
Composition Range ◽  
Deuterium Oxide ◽  
Enthalpy Of Mixing ◽  
Water Systems ◽  
Water Proton ◽  
Oxide Systems ◽  
Enthalpies Of Mixing ◽  
Water Hydrogen

Calorimetric enthalpies of mixing have been measured over the whole composition range for the water–tetrahydrofuran and the deuterium oxide – tetrahydrofuran systems at 10.00 and 25.00 °C. The experimental S-shaped, enthalpy of mixing –composition curves are interpreted in terms of changes of the water hydrogen bonding in solution. At low tetrahydrofuran mole fractions the deuterium oxide systems are more exothermal and at high tetrahydrofuran mole fractions more endothermal than the corresponding water systems. A good correlation is found between the enthalpy of mixing and the water proton magnetic resonance chemical shift for solutions with greater than 0.55 mole fraction of tetrahydrofuran.

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