Replacement of CH<sub>4</sub> in Hydrate in Porous Sediments with Liquid CO<sub>2</sub> Injection

Zhang, Yu; Xiong, Lei; Li, Xiao-Sen; Chen, Zhaoyang; Xu, Chun‐Gang

doi:10.1002/ceat.201300840

Cited by 26 publications

(11 citation statements)

References 27 publications

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“…Presently, some exploitation techniques have been proposed and investigated for several decades. These techniques can be classified into four basic schemes: (1) depressurization, , (2) thermal stimulation, , (3) chemical stimulation, , and (4) replacement of CH 4 by carbon dioxide (CO 2 ). , Besides, some combination technologies have also been developed. Hot brine injection is the one that combines thermal stimulation with chemical stimulation.…”

Section: Introductionmentioning

confidence: 99%

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Cai

Zhang³

et al. 2018

Energy Fuels

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In this work, the temperature characteristics of hydrate slurry related to transition heat in the cyclopentane (CP)/methane (CH4) hydrate formation process were systematically investigated. A crystallizer with a special heat-insulating layer of aerogel was designed to hold the transition heat, and the hydrate slurry could be heated in the crystallizer. Temperatures were measured in the process of the hydrate formation under the conditions of different operating pressures, volumes of solution, methods of gas injection, and volume ratios of CP to water. The highest temperature of hydrate slurry (T h) and the maximum temperature difference (ΔT max) relative to the initial temperature were adopted to evaluate the influence of different conditions. The experimental results indicated that the hydrate formation interface and thermal interface obviously move from the initial gas/CP interface and CP/water interface toward the bulk solution. Both the increase of operating pressure and the decrease of solution volume have positive effect on enhancing the hydrate slurry temperature. In addition, the volume ratio of CP to water also significantly affects the fluctuation of the hydrate slurry temperature. The hydrate slurry could be heated up to 294.45 K and the ΔT max of 16.30 K could be obtained, and such high heat could be effectively collected and used elsewhere.

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Section: Introductionmentioning

confidence: 99%

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Cai

Zhang³

et al. 2018

Energy Fuels

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“…They defined the driving force as the gas fugacity deviation between gas and hydrate phase and treated the CH 4 escaping and the CO 2 entrapment process independently. This model was successfully applied in the replacements taken place in hydrate bearing sediments, but unable to describe the gas distributions inside the hydrate phase. , Lee et al related the shrinking core model with the Avrami equation to quantify the gas exchange in hydrate particles and proposed that gas diffusion inside the hydrate layer is considered as rate limiting step . Schicks et al complied the experimental data and noted that the conversion process should be described as a series of hydrate dissociation and reformation, which were driven by the gradient of the chemical potential between the hydrate phase and the environmental gas phase …”

Section: Introductionmentioning

confidence: 99%

Multiscale Analysis on CH₄–CO₂ Swapping Phenomenon Occurred in Hydrates

2016

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Swapping CH 4 with CO 2 in hydrocarbon hydrates is renowned as an eco-friendly method for potential energy production and climate change mitigation. To fully understand the CH 4 −CO 2 replacement process, in situ Raman spectroscopy combined with long-term macroscopic measurements were carried out by putting CH 4 hydrates into gaseous CO 2 at temperatures ranging from 273.2 to 281.2 K. A kinetic model based on gas diffusion theory was modified. Results showed that the gas swapping process started with surface reaction followed by gas diffusion in hydrate phase. At hydrate surface, the average occupancy of CH 4 decreased without dramatic fluctuations, suggesting that the replacements were not simply composed of a series of dissociation and reformation process. A rise in temperature was found to effectively increase the gas swapping rates and strengthen the gas diffusion in hydrate phase. In situ Raman results together with gas consumption data were fitted by the kinetic model. The calculated gas-hydrate interfacial area revealed the foamy nature of hydrates. Fitting parameters representing the gas diffusion coefficient were of the same order of magnitude as the water mobility in hydrate phase, which implied that the replacements were limited by the mobility of water molecules.

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“…The driving force of the CH 4 replacement in the CH 4 hydrate with liquid CO 2 was considered as the fugacity difference between the liquid and the hydrate phase. Zhang et al [344] changed the experimental conditions in the replacement reaction by use of liquid CO 2 at the different temperatures and initial pressures, and the experiment was conducted in porous sediment. His research showed that the recovery ratio of CH 4 can reach approximately 45 % after 288 h, while in Ota's experiment, [338] the recovery ratio is about 37 % after 307 h and the recovery ratio is 18.6 % after 96 h in Zhou et al's experiment.…”

Section: Experimental Simulation Via Co 2 -Ch 4 Replacementmentioning

confidence: 99%

Investigation into gas production from natural gas hydrate: A review

et al. 2016

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Natural gas hydrates (NGHs), which extensively exist in sea-floor and permafrost regions, are considered as an alternative energy in the future for the fossil fuels approaching depletion with the gradually increasing energy consumption. Because of the particularity of NGH stabilizing only in the conditions of the high pressure and the low temperature, the exploitation of NGH is distinguished from those of petroleum and natural gas. Researchers over the world are devoting themselves to developing the technologies of NGH exploitation. However, till now, few NGH exploitation technology is identified and employed to exploit commercially NGH. Although there do be two cases of short-term NGH exploitation in Mackenzie Delta (CAN), Alaska North Slope (USA) and Nankai Trough (JAP) in the past 10 years. It is mainly because some characteristics of the flow (gas, water, gas-hydrate slurry, quicksand, etc.), the issues of heat and mass transfer, the risk assessment and the economic evaluation are still not comprehensively recognized. Presently, the researches of NGH exploitation are mainly carried out from three aspects, numerical simulation and analysis, experimental simulation and field trial exploitation for the different technologies. In this paper, we comprehensively review the relevant studies of NGHs and propose our comments. We not only represent the achievements for the NGH exploitation researches, but also discuss the limitations and challenges, raise some questions and put forward some suggestions from our points of view.

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Replacement of CH₄ in Hydrate in Porous Sediments with Liquid CO₂ Injection

Cited by 26 publications

References 27 publications

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Multiscale Analysis on CH₄–CO₂ Swapping Phenomenon Occurred in Hydrates

Investigation into gas production from natural gas hydrate: A review

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Replacement of CH4 in Hydrate in Porous Sediments with Liquid CO2 Injection

Cited by 26 publications

References 27 publications

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Study on Temperature Characteristics of Hydrate Slurry during Cyclopentane–Methane Hydrate Formation

Multiscale Analysis on CH4–CO2 Swapping Phenomenon Occurred in Hydrates

Investigation into gas production from natural gas hydrate: A review

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Product

Resources

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Replacement of CH₄ in Hydrate in Porous Sediments with Liquid CO₂ Injection

Multiscale Analysis on CH₄–CO₂ Swapping Phenomenon Occurred in Hydrates