Equilibrium properties and crystal growth of <scp>D<sub>2</sub>O</scp> + cyclopentane hydrate for sustainable tritium separation

Maruyama, Meku; Ohmura, Ryo

doi:10.1002/cjce.24493

Cited by 13 publications

(3 citation statements)

References 55 publications

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“…The dendritic structures created wrinkles on the drop interface along the direction of the front propagation, giving the hydrate film a macroscopically rough appearance (Figure b(ii)). The transition from polyhedral to dendritic crystals as a function of Δ T sub was also considered by Sakemoto et al and Maruyama and Ohmura for cyclopentane hydrates (Type sII) as well as other formers of sI and sH hydrates. From these studies, it can be concluded that all three types of hydrate structure undergo similar morphological changes at different Δ T sub .…”

Section: Resultsmentioning

confidence: 94%

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Kamel

Lobasov

Narayan

et al. 2023

Crystal Growth & Design

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Liquid cyclopentane is frequently used in hydrate formation studies as an analogue of natural gas because cyclopentane hydrates are stable above the ice melting point at ambient pressure. In this study, hydrate growth was established on a sessile water drop of 11 mm in diameter and 4.5 mm in height (volume of 0.25 mL) immersed in liquid cyclopentane. The hydrate formation mechanism and growth processes were observed optically over an extended range of subcooling temperatures from 5.1 to 15.2 °C, with the cyclopentane bulk temperature maintained in different experimental runs between 2.6 and −7.5 °C. Qualitative and quantitative comparisons were performed to confirm the absence of ice freezing during hydrate formation, and thus, the lack of contamination of the latter from the former in the experiments. Different transformations in the hydrate film morphology were registered from macroscopic observation over the considered range of subcooling temperatures, with the hydrate crystals composing the film taking the form of polyhedral, dendritic, or spherulitic structures. It was also found that the hydrate growth rate varied depending on the subcooling temperature, with the variation of the growth rate as a function of this temperature changing from a power to an (approximately) linear law with an increase in the degree of subcooling. We postulate that hydrate film growth can be governed by different mechanisms, whose roles change over the range of explored subcooling temperatures.

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Section: Resultsmentioning

confidence: 94%

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Kamel

Lobasov

Narayan

et al. 2023

Crystal Growth & Design

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“…Ohmura et al observed the growth of CH 4 hydrate crystals in CH 4 -presaturated liquid water; they revealed that the crystal morphologies of hydrate vary from polyhedral via columnar to dendritic depending on thermodynamic conditions. Since then, the crystal growth of hydrates formed using various guest compounds has been experimentally examined to systematically classify their dynamics and morphology depending on the driving force. − As a first example of D 2 O-based hydrate, Maruyama and Ohmura performed crystal growth observation of cyclopentane + D 2 O hydrate and summarized the variation in the morphology of hydrate formed at the D 2 O-cyclopentane interface. Owing to uninflammability, nontoxicity, and accessibility for industrial use, CO 2 is considered to be a promising option for guest compounds compared to other candidates tested in previous studies.…”

Section: Introductionmentioning

confidence: 99%

Crystal Growth of Clathrate Hydrate Formed with Carbon Dioxide and Deuterium Oxide: Implications for Hydrate-based Tritium Separation

Maruyama,

Dogi,

Ohmura

2024

Energy Fuels

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Tritium separation technology is a key method for treating contaminated water from nuclear power plants. Recently, a novel tritium separation method using deuterium oxide (D 2 O)based clathrate hydrate has attracted attention because it can reduce the tritium concentration in contaminated water from 4.77 × 10 5 Bq/kg to 1.55 × 10 3 Bq/kg. In this hydrate-based tritium separation method, tritium is concentrated on the surface of a D 2 O-based hydrate substrate. The mechanistic characteristics and formation kinetics of D 2 O-based hydrates need to be clarified to develop an efficient process for substrate formation. This study contributes to the process design by revealing the crystal growth of the CO 2 + D 2 O hydrate. The crystal growth behavior of the hydrate formed in the CO 2 + D 2 O system was experimentally observed under different subcooling temperatures (ΔT sub ) at 3.0 MPa. At all ΔT sub , hydrate crystals were formed at the gas−liquid interface and extended along the interface. After the interface was covered, hydrate crystals grew in the liquid phase. The variation in the morphology of CO 2 + D 2 O hydrate depended on ΔT sub . At ΔT sub = 1.6 K, polygonal crystals with side lengths of 0.2−0.6 mm were formed. At ΔT sub = 2.7 K, columnar crystals with a length of 1−2 mm were formed. At ΔT sub ≥ 3.3 K, dendritic crystals were formed. With an increase in ΔT sub , the size of the dendritic branches increased. The crystal growth dynamics and morphological tendency of the CO 2 + D 2 O hydrate were comparable to those of the CO 2 + H 2 O hydrate at fixed ΔT sub . Detailed theoretical discussions on the obtained results of surface kinetics, mass transfer, and heat transfer during hydrate formation from H 2 O and D 2 O were provided, considering the chemical potential, viscosity, and heat transfer of the liquids.

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“…Truong‐Lam et al [ 15 ] describe the thermodynamic stability, kinetic behaviour, and effectiveness of a water desalination/purification process that is based on the use of tetra‐ or penta‐fluoroethane gas hydrates. Maruyama and Ohmura [ 16 ] explore the design implications of their thermodynamic and crystal growth results for a hydrate‐based isotopic water separation process. Bollineni and Daraboina [ 17 ] investigate the use of clathrate formed from tetra‐n‐butyl ammonium chloride (TBAC) and methane for the treatment of produced water from oil and gas operations.…”

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confidence: 99%

Preface to the special issue section honouring Professor P. Raj Bishnoi

Englezos

Mehrotra

2022

Can J Chem Eng

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Equilibrium properties and crystal growth of D₂O + cyclopentane hydrate for sustainable tritium separation

Cited by 13 publications

References 55 publications

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Crystal Growth of Clathrate Hydrate Formed with Carbon Dioxide and Deuterium Oxide: Implications for Hydrate-based Tritium Separation

Preface to the special issue section honouring Professor P. Raj Bishnoi

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Equilibrium properties and crystal growth of D2O + cyclopentane hydrate for sustainable tritium separation

Cited by 13 publications

References 55 publications

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Hydrate Growth over a Sessile Drop of Water in Cyclopentane

Crystal Growth of Clathrate Hydrate Formed with Carbon Dioxide and Deuterium Oxide: Implications for Hydrate-based Tritium Separation

Preface to the special issue section honouring Professor P. Raj Bishnoi

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Equilibrium properties and crystal growth of D₂O + cyclopentane hydrate for sustainable tritium separation