Experimental investigation of different factors influencing the replacement efficiency of CO2 for methane hydrate

Chen, Ye; Gao, Yonghai; Zhao, Yipeng; Chen, Litao; Dong, Changyin; Sun, Baojiang

doi:10.1016/j.apenergy.2018.05.126

Cited by 55 publications

(33 citation statements)

References 32 publications

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“…Stanwix et al [31] reviewed pure CO 2 replacement experiments, reporting up to 50% CH 4 recovery. There are many hydrate-focused review studies which also provide excellent summaries of CH 4 -CO 2 replacement in hydrates [32][33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

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: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…To obtain the removal rate of the injected gas, the actual gas state equation was used. The number of moles of gas dissolved in the solvent in the reactor was calculated using the pressure and temperature of the buffer tank and those of the reactor, as shown in Equations (1) and (2) [18][19][20].…”

Section: Amount Of Gas Dissolved As a Function Of Pressure And Tempermentioning

confidence: 99%

“…Increasing the concentration of 2-amino-2-methyl-1-propanol and adding piperazine affected the absorption capacity, where the CO 2 absorption capacity of the solvent increased under a high operation pressure and low operating temperature. Manic et al [7] measured the solubility of CO 2 in seven ionic liquids in the [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] MPa pressure range and at temperatures of 313.2 and 323.2 K. They found that the solubility of CO 2 increased when the pressure increased and the temperature decreased.…”

Section: Introductionmentioning

confidence: 99%

The Performance of Low-Pressure Seawater as a CO2 Solvent in Underwater Air-Independent Propulsion Systems

Park

Choi

2020

JMSE

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Air-independent propulsion systems have improved the performance and decreased the vulnerability of underwater weapon systems. Reforming systems, however, generates large amounts of water and CO2. The recovery or separation of CO2, a residual gas component generated in vessels, entails considerable cost and energy consumption. It is necessary to understand the characteristics of the interaction between CO2 and seawater under the conditions experienced by underwater weapon systems to design and optimize a CO2 treatment process for dissolving CO2 in seawater. In this study, numerical analysis was conducted using the derived experimental concentration and MATLAB. The diffusion coefficient was derived as a function of temperature according to the CO2 dissolution time. Experiments on CO2 dissolution in seawater were conducted. The concentration of CO2 according to the reaction pressure and experimental temperature was obtained. The diffusion coefficient between CO2 and seawater was found to be 6.3 × 10−5 cm2/s at 25 °C and 7.24 × 10−5 cm2/s at 32 °C. CO2 concentration could be estimated accurately under vessel operating conditions using the derived CO2 diffusion coefficients. Optimal design of the residual gas treatment process will be possible using the derived seawater–CO2 diffusion coefficients under the actual operating conditions experienced by underwater weapon systems.

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“…Chen et al [32] have studied the effect of injection pressure of CO 2 gas on replacement efficiency and suggested that lower injection pressure leads to dissociation of methane hydrate and that higher injection pressure would lead to accelerating CO 2 formation. However, a change in injection pressure does not show a strong influence on replacement efficiency.…”

Section: Figure 10mentioning

confidence: 99%

Hydrate Stability and Methane Recovery from Gas Hydrate through CH4–CO2 Replacement in Different Mass Transfer Scenarios

Pandey

Solms

2019

Energies

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CH4–CO2 replacement is a carbon-negative, safer gas production technique to produce methane gas from natural gas hydrate reservoirs by injecting pure CO2 or other gas mixtures containing CO2. Laboratory-scale experiments show that this technique produces low methane volume and has a slow replacement rate due to the mass transfer barrier created due to impermeable CO2 hydrate layer formation, thus making the process commercially unattractive. This mass-transfer barrier can be reduced through pressure reduction techniques and chemical techniques; however, very few studies have focused on depressurization-assisted and chemical-assisted CH4–CO2 replacement to lower mass-transfer barriers and there are many unknowns. In this work, we qualitatively and quantitatively investigated the effect of the pressure reduction and presence of a hydrate promoter on mixed hydrate stability, CH4 recovery, and risk of water production during CH4–CO2 exchange. Exchange experiments were carried out using the 500 ppm sodium dodecyl sulfate (SDS) solution inside a high-pressure stirred reactor. Our results indicated that mixed hydrate stability and methane recovery depends on the degree of pressure reduction, type, and composition of injected gas. Final selection between CO2 and CO2 + N2 gas depends on the tradeoff between mixed hydrate stability pressure and methane recovery. Hydrate morphology studies suggest that production of water during the CH4–CO2 exchange is a stochastic phenomenon that is dependent on many parameters.

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Experimental investigation of different factors influencing the replacement efficiency of CO2 for methane hydrate

Cited by 55 publications

References 32 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

The Performance of Low-Pressure Seawater as a CO2 Solvent in Underwater Air-Independent Propulsion Systems

Hydrate Stability and Methane Recovery from Gas Hydrate through CH4–CO2 Replacement in Different Mass Transfer Scenarios

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