The effect of hydrate promoters on gas uptake

Xu, Chun‐Gang; Yu, Yingning; Ding, Ya-Long; Cai, Jing; Li, Xiao-Sen

doi:10.1039/c7cp02173a

Cited by 53 publications

(14 citation statements)

References 33 publications

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“…Experiments 5-8 had initial methane hydrate saturations varying from 28% to 35% caused by differences in gas uptake due to the presence of different chemicals [87] and pure CO 2 injection pressure varied from 50 to 60 bar. Due to initial water saturation above 40%, it was assumed that the hydrate morphology was pore-filling [84,88].…”

Section: Ch 4 Recovery and Co 2 Storage At Same Initial Water Saturation In The Presence Of Different Hydrate Formers And Watermentioning

confidence: 99%

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

et al. 2020

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CO2-rich gas injection into natural gas hydrate reservoirs is proposed as a carbon-neutral, novel technique to store CO2 while simultaneously producing CH4 gas from methane hydrate deposits without disturbing geological settings. This method is limited by the mass transport barrier created by hydrate film formation at the liquid–gas interface. The very low gas diffusivity through hydrate film formed at this interface causes low CO2 availability at the gas–hydrate interface, thus lowering the recovery and replacement efficiency during CH4-CO2 exchange. In a first-of-its-kind study, we have demonstrate the successful application of low dosage methanol to enhance gas storage and recovery and compare it with water and other surface-active kinetic promoters including SDS and L-methionine. Our study shows 40–80% CH4 recovery, 83–93% CO2 storage and 3–10% CH4-CO2 replacement efficiency in the presence of 5 wt% methanol, and further improvement in the swapping process due to a change in temperature from 1–4 °C is observed. We also discuss the influence of initial water saturation (30–66%), hydrate morphology (grain-coating and pore-filling) and hydrate surface area on the CH4-CO2 hydrate swapping. Very distinctive behavior in methane recovery caused by initial water saturation (above and below Swi = 0.35) and hydrate morphology is also discussed. Improved CO2 storage and methane recovery in the presence of methanol is attributed to its dual role as anti-agglomerate and thermodynamic driving force enhancer between CH4-CO2 hydrate phase boundaries when methanol is used at a low concentration (5 wt%). The findings of this study can be useful in exploring the usage of low dosage, bio-friendly, anti-agglomerate and hydrate inhibition compounds in improving CH4 recovery and storing CO2 in hydrate reservoirs without disturbing geological formation. To the best of the authors’ knowledge, this is the first experimental study to explore the novel application of an anti-agglomerate and hydrate inhibitor in low dosage to address the CO2 hydrate mass transfer barrier created at the gas–liquid interface to enhance CH4-CO2 hydrate exchange. Our study also highlights the importance of prior information about methane hydrate reservoirs, such as residual water saturation, degree of hydrate saturation and hydrate morphology, before applying the CH4-CO2 hydrate swapping technique.

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Section: Ch 4 Recovery and Co 2 Storage At Same Initial Water Saturation In The Presence Of Different Hydrate Formers And Watermentioning

confidence: 99%

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

et al. 2020

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“…Thermodynamic promoters, for example, tetrahydrofuran (THF), are capable of forming gas hydrates themselves at moderate conditions in terms of pressure and temperature, allowing other guests to fill the remaining empty cavities, whereby these other molecules are entrapped in the gas hydrate phase as well [34]. Furthermore, the polarity of the thermodynamic promoter affects gas diffusion via the gas-liquid interphase, which influences the selectivity and gas uptake of a gas hydrate separation process [35]. The mode of operation of kinetic promoters, essentially surfactants, is based on accelerating gas hydrate formation by reducing the surface tension, which leads to improved mass transport of gas into the liquid phase [36].…”

Section: Introductionmentioning

confidence: 99%

Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Filarsky¹,

Wieser²,

Schultz³

2021

Molecules

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Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

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“…CO 2 hydrate was once thought as one of the potential intermediates for carbon capture and separation . It has been reported that CO 2 hydrate is of structure I (s‐I) including 46 H 2 O molecules and up to 8 CO 2 molecules with both small (5 12 ) and large (5 12 6 2 ) cages in a ratio of 1:3 . It should be noted that CO 2 molecules are reported to approximately occupy most large cages and few small cages .…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of CO₂ hydrate formation in porous media by proton NMR

Zheng

Yang

et al. 2019

AIChE Journal

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Gas hydrate is a nonstoichiometric crystal compound formed from water and gas. Most nonvisual studies on gas hydrate are unable to detect how much water is converted to hydrates, and thus, the hydrate stoichiometry calculations are inaccurate. This study investigated the CO 2 hydrate formation process in porous media directly and quantitatively. The characteristics of the time-variable consumption of hydrate formation indicated a two-stage formation, hydrate enclathration and continuous occupancy. The enclathration stage occurred in the first 20 min of the formation when considerable heat is released. The continuous occupancy stage lasted longer than the hydrate enclathration because the empty cages in previously formed hydrates would also be occupied. The higher formation pressures can accelerate water consumption and increase cage occupancy. The compositions of completely formed CO 2 hydrates at 2.7, 3.0, and 3.3 MPa and 275.15 K were determined as CO 2 Á6.90H 2 O, CO 2 Á6.70H 2 O, and CO 2 Á6.49H 2 O, respectively.

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The effect of hydrate promoters on gas uptake

Cited by 53 publications

References 33 publications

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Quantitative analysis of CO₂ hydrate formation in porous media by proton NMR

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The effect of hydrate promoters on gas uptake

Cited by 53 publications

References 33 publications

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Quantitative analysis of CO2 hydrate formation in porous media by proton NMR

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Product

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Quantitative analysis of CO₂ hydrate formation in porous media by proton NMR