Solubility measurement of carbon dioxide in water in the presence of gas hydrate

Najafi, Mojgan; Mohebbi, Vahid

doi:10.1016/j.jngse.2014.10.006

Cited by 24 publications

(11 citation statements)

References 32 publications

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“…There are several experimental reports confirming the constant concentration of soluble gases during the hydrate growth stage. 44,45 Therefore, it is reasonable to assume that changes in the total pressure and number of moles in the gas phase during the hydrate growth stage is due to the hydrate formation and not the change in the solubility during this period. Gas mixtures were produced in an auxiliary tank with known internal volume, initially completely vacuumed, and then filled to a specific pressure by pure CO 2 , the tank pressure increased by injecting pure CH 4 in the second step.…”

Section: Methodssupporting

confidence: 86%

“…According to the kinetic modeling approach applied in this study, the mole fraction of hydrate former components remains constant in the aqueous phase during the hydrate growth stage. There are several experimental reports confirming the constant concentration of soluble gases during the hydrate growth stage. , Therefore, it is reasonable to assume that changes in the total pressure and number of moles in the gas phase during the hydrate growth stage is due to the hydrate formation and not the change in the solubility during this period.…”

Section: Methodsmentioning

confidence: 99%

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Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Feyzi

Mohebbi

2020

Energy Fuels

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Multifaceted benefits of natural gas as the cleanest fossil fuel resulted in significant shift from other forms of fossil fuels to natural gas in different sectors over the past years. Applying natural gas as the medium-term future energy source is an effective climate strategy. Recently, gas hydrate gained significant attention as a solution for purification and storage of natural gas. Additionally, naturally occurring methane hydrate deposits as the most abundant unconventional natural gas source can secure the global energy demand for decades. Macroscopic kinetic study and modeling of mixed CO 2 +CH 4 hydrate formation is necessary for commercialization of SNG technology as an applicable method for hydrate-based transportation of natural gas, hydrate-based biogas upgrading, and CH 4 -CO 2 hydrate replacement process for exploitation of naturally occurring methane hydrate reservoirs. Here, the results for CO 2 +CH 4 mixed hydrate formation experiments are reported over a wide range of operational conditions to investigate the kinetics of hydrate formation. The mass transfer limited hydrate formation kinetic approach was applied to model the kinetics of mixed CO 2 +CH 4 hydrate formation. Investigation of the effect of operational conditions revealed that the rate of mixed CO 2 +CH 4 hydrate formation is increased at higher pressures and higher mole fractions of CO 2 in the gas phase. At a constant degree of supersaturation, the mixed hydrate formation rate initially decreases by temperature, goes from a minimum around 277 K, and then increases by temperature. Kinetic parameters extracted from the kinetic modeling correlated as functions of pressure, temperature, and gas phase composition.

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Section: Methodssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Feyzi

Mohebbi

2020

Energy Fuels

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“…27 Therefore, several studies have focused onto this aspect of gas hydrates by analyzing the driving force to hydrate formation in terms of the fugacity of the hydrate-former gas. 28,29 Those studies revealed that the solubility of CO 2 in water shows little variability during the hydrate formation process and is time-independent.…”

Section: ■ Introductionmentioning

confidence: 99%

“…This suggests that the hydrate-based separation of feed gas mixtures with different methane and carbon dioxide compositions is actually controlled, at least to an extent, by their partition into the liquid phase, based on the respective solubilities . Therefore, several studies have focused onto this aspect of gas hydrates by analyzing the driving force to hydrate formation in terms of the fugacity of the hydrate-former gas. , Those studies revealed that the solubility of CO 2 in water shows little variability during the hydrate formation process and is time-independent.…”

Section: Introductionmentioning

confidence: 99%

Separation of CO₂ and CH₄ from Biogas by Formation of Clathrate Hydrates: Importance of the Driving Force and Kinetic Promoters

Profio¹,

Canale²,

d’Alessandro³

et al. 2017

ACS Sustainable Chem. Eng.

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This paper relates to the upgrading of model biogas mixtures, typically 60/40 CH 4 /CO 2 , by clathrate (gas) hydrates, which have recently been considered as a safe alternative to high-pressure or liquefied gas storage, and as an economic, chemical-free process for the separation of gas mixtures. Several factors affecting the driving force to hydrate formation are considered, such as the degree of overpressurization and the presence of chemical promoters. Promoters used were several anionic and zwitterionic surfactants which are demonstrated to affect the hydrate-forming ability of water. Some lignin derivatives were also tested. Promoted hydrates were also compared to hydrate-based separation starting from nonpromoted water. Separation experiments were conducted under pressures of 4 and 2.5 MPa at 274 K, under either pressure-dropping or constant pressure conditions. Results show that the separation ability of clathrate hydrates as determined by the separation factor S is highest when no promoters are added to the water phase; the well-known promoter sodium dodecyl sulfate (SDS) shows a value of S which is approximately half the value of that in pure water while higher separations were obtained with some lignin derivatives and a non-surface-active naphthalenesulfonate derivative. We also show that the contribution of CO 2 solubility in water to S is a main player in the overall process. Finally, the separation ability of hydrates seems to be inversely proportional to the amount of gas mixture enclathrated, i.e., the occupancy.

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“…Our results showed a positive relationship between CO 2 and CH 4 efflux at the water‐air interface and T w (Table ). This may be largely ascribed to the decreasing solubility of CO 2 with increasing water temperature (Najafi & Mohebbi, ). Further, the higher microbial activity under warmer water might also induce a significant CO 2 and/or CH 4 production (Nydahl et al, ).…”

Section: Discussionmentioning

confidence: 99%

Hydrologic and Edaphic Controls on Soil Carbon Emission in Dongting Lake Floodplain, China

Deng

Xie

et al. 2018

JGR Biogeosciences

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Wetlands play a critical role in mitigating carbon emission. However, little is known about soil carbon emission and their environmental controls from inland floodplain wetlands. This study aimed to determine the effects of hydrologic and edaphic controllers (water table depth [WTD], soil temperature [Ts], and soil water content [SWC]) on soil C emission in Dongting Lake wetland, China. One-year emissions were measured in Carex meadow and mudflat using static chambers during 2013 to 2014, including nonflooded season (NFs) and flooded season (Fs). The results showed that soil C emission in the Carex meadow and mudflat was 307.8 and 264.3 g C·m À2 ·year À1 , respectively, and 50-66% of soil C were emitted during NFs. Compared with NFs, CO 2 emission was significantly decreased by 57% but CH 4 emission was significantly increased by 38 times during Fs in the Carex meadow. Stepwise regression combined with structural equation model analysis showed that CO 2 and CH 4 flux were mainly influenced by Ts during NFs, and they were controlled by water temperature (Tw) during Fs. During NFs, CO 2 flux increased with increasing Ts and SWC but decreased significantly when SWC was over 66% and 52% in the Carex meadow and mudflat, respectively. CH 4 flux showed an emission pulse at SWC and Ts of 65% and 17.2°C, respectively. These results indicate that flooding significantly inhibited soil CO 2 emission but stimulated CH 4 emission. The continuous decrease of flooding days caused by anthropogenic disturbances may induce soil C loss in Dongting Lake wetlands.

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Solubility measurement of carbon dioxide in water in the presence of gas hydrate

Cited by 24 publications

References 32 publications

Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Separation of CO₂ and CH₄ from Biogas by Formation of Clathrate Hydrates: Importance of the Driving Force and Kinetic Promoters

Hydrologic and Edaphic Controls on Soil Carbon Emission in Dongting Lake Floodplain, China

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Solubility measurement of carbon dioxide in water in the presence of gas hydrate

Cited by 24 publications

References 32 publications

Mixed CO2+CH4 Hydrate Formation Kinetics: Experimental Study and Modeling

Mixed CO2+CH4 Hydrate Formation Kinetics: Experimental Study and Modeling

Separation of CO2 and CH4 from Biogas by Formation of Clathrate Hydrates: Importance of the Driving Force and Kinetic Promoters

Hydrologic and Edaphic Controls on Soil Carbon Emission in Dongting Lake Floodplain, China

Contact Info

Product

Resources

About

Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Mixed CO₂+CH₄ Hydrate Formation Kinetics: Experimental Study and Modeling

Separation of CO₂ and CH₄ from Biogas by Formation of Clathrate Hydrates: Importance of the Driving Force and Kinetic Promoters