Formation of HFC-134a hydrate by static mixing

Tajima, Hideo; Nagata, Toru; Yamasaki, Akira; Kiyono, Fumio; Masuyama, Tadashi

doi:10.1016/j.petrol.2005.08.005

Cited by 9 publications

(9 citation statements)

References 5 publications

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“…The hydrate plug has a target gas hydrate "shell" formed on the surface of the bubbles. Whereas the hydrate slurry consists of very small target gas hydrate particles in water and a hydrate shell rarely formed on the bubble surface (Tajima et al, 2007). The observation results imply that the formed hydrate peels and sheds from the bubble surface.…”

Section: Thermodynamic Conditionsmentioning

confidence: 81%

“…Static mixers are motionless mixing devices with fixed "mixing elements" arranged in a straight pipe. The Kenics static mixer experiments demonstrated that two fluids (drop/bubble and water) are efficiently agitated with the mixing elements and are subsequently converted to hydrate formed on the drop/bubble surface at specific temperature and pressure conditions (Tajima et al, 2004(Tajima et al, , 2007. Several structures of mixing element are designed for efficient agitation/mixing of fluids more than one.…”

Section: Semi-batch Flow Reactor With Static Mixermentioning

confidence: 99%

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Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Tajima¹

2011

Hydrodynamics - Optimizing Methods and Tools

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Section: Thermodynamic Conditionsmentioning

confidence: 81%

Section: Semi-batch Flow Reactor With Static Mixermentioning

confidence: 99%

Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Tajima¹

2011

Hydrodynamics - Optimizing Methods and Tools

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“…Once the hydrate conversion reached 25% (orange dashed line in Figure 4), the slope reverts to linear (black dotted line in Figure 4) and eventually reached a plateau after 200 min, which could be attributed to the change in density and hydrate-typed. 10,44,45 The HFC134a hydrate started slurrytyped along with the gas−liquid interface in the first stage. The density of the HFC134a hydrate was increased as the occupancy of HFC134a in the large cage of the structure II hydrate increased.…”

Section: Resultsmentioning

confidence: 99%

Dynamic Analysis of Growth of Ice and Hydrate Crystals by In Situ Raman and Their Significance in Freezing Desalination

Truong‐Lam

Seo

Jeon

et al. 2021

Crystal Growth & Design

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In this study, the thermodynamic properties and dynamic behavior of ice and hydrate crystal growth in the freezing desalination process were studied. Carbon dioxide (CO 2 ) and 1,1,1,2-tetrafluoroethane (HFC134a) were chosen for this study from various hydrate formers reported in our previous study. A novel approach for calculating the water conversion to ice using the volume change of a gas phase in a reactor was proposed. Under the same subcooling condition, ice and hydrate crystal growth experiments were conducted and compared in pure water and 3.5 wt % NaCl solution. With the experimental conditions of this work, the crystal growth rate results were as follows: In the pure water system, ice crystal > HFC134a hydrate > CO 2 hydrate. However, in the presence of 3.5 wt % NaCl, the order changed as follows: HFC134a hydrate > ice crystal > CO 2 hydrate. These results were consistent with the visual morphology observations and in situ Raman analysis. The variations of subcooling temperature and NaCl concentration were studied using the Hu-Lee-Sum correlation and freezing point depression equation to evaluate the desalination efficiency of freeze desalination. Based on the Raman spectral analysis, we could identify specific hydrate structures and distinguish between ice and hydrate crystals. In situ Raman analysis revealed that dynamic O−H band spectral trends of ice and CO 2 hydrates (structure I) are similar and contrasting with those of the HFC134a hydrate (structure II). These results were first observed during the crystal formation process and can be useful in the design of freezing processes in industrial applications.

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“…CH 3 CCl 2 F (HCFC-141b refrigerant) was also studied to characterize the flow properties of hydrate slurry formed by cooling in a circulating loop . Finally, HFC-134a refrigerant was used to study processes of continuous hydrate-slurry formation using static mixers …”

Section: Introductionmentioning

confidence: 99%

“…22 Finally, HFC-134a refrigerant was used to study processes of continuous hydrateslurry formation using static mixers. 23 As was previously explained, 5 gas hydrate slurries must fulfill other criteria to be considered as an efficient two-phase secondary fluid. First, hydrates must present pressure conditions suitable for refrigeration and air-conditioning systems.…”

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confidence: 99%

Rheological Properties of CO₂ Hydrate Slurry Flow in the Presence of Additives

Delahaye¹,

Fournaison²,

Jerbi³

et al. 2011

Ind. Eng. Chem. Res.

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This work investigates the flow properties of CO2 hydrate slurry in dynamic loop in the presence of additives (surfactants, antiagglomerants) for use as two-phase secondary refrigerant. To be considered as suitable for refrigeration systems, the use of hydrate slurries must overcome instability phenomena such as hydrate particle agglomeration. The additives were employed in the present work to prevent this phenomena, and thus to improve the stability and the homogeneity of the fluid. A multicriterion approach was used to select additive and to define the optimal operating conditions for its use. The selected additive was an EO/PO block copolymer. The flow properties of CO2 hydrate slurry in aqueous media in the presence of this additive were then measured in an experimental loop. It was possible to model the rheological behavior of the CO2 hydrate slurry in the presence of EO/PO block copolymer by an Newtonian-type equation. The present results were compared to previous results obtained without additive. This article provides new information on CO2-hydrate slurry rheology, which is important not only in the development of hydrate-based refrigeration systems, but also in the field of flow assurance in oil and gas pipelines or for other applications such as gas purification and storage processes using clathrate hydrates.

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Formation of HFC-134a hydrate by static mixing

Cited by 9 publications

References 5 publications

Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Dynamic Analysis of Growth of Ice and Hydrate Crystals by In Situ Raman and Their Significance in Freezing Desalination

Rheological Properties of CO₂ Hydrate Slurry Flow in the Presence of Additives

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Formation of HFC-134a hydrate by static mixing

Cited by 9 publications

References 5 publications

Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Gas Hydrate Formation Kinetics in Semi-Batch Flow Reactor Equipped with Static Mixer

Dynamic Analysis of Growth of Ice and Hydrate Crystals by In Situ Raman and Their Significance in Freezing Desalination

Rheological Properties of CO2 Hydrate Slurry Flow in the Presence of Additives

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Rheological Properties of CO₂ Hydrate Slurry Flow in the Presence of Additives