CO2 Gas Hydrate Research Articles

Pore-level hydrate formation mechanisms using realistic rock structures in high-pressure silicon micromodels

We report pore-level visualization of CO2 and CH4 gas hydrate formation with dynamic growth patterns within a 2D porous silicon wafer micromodel with realistic pore shapes and sizes. Direct observation of pore-scale hydrate growth patterns at reservoir conditions provides an improved framework for fundamental studies of sediment-hosted gas hydrates. The growth pattern and formation rate are discussed with respect to wetting films, fluid distribution, and PT conditions for CH4 and CO2 hydrate. Hydrates appeared initially on the interface between gas spheres and thin water films coating the grain surface, followed by a continuous hydrate growth throughout the pore space. Redistribution of hydrate was observed over several hours at stable conditions. Furthermore, repeated hydrate formation occurred more rapidly and at higher temperatures than during primary formation. The understanding of pore-scale growth of sedimentary gas hydrate has great value in describing hydrates in a geological setting and toward production of a vast energy resource. It may also be a key feature in CO2 storage schemes.

Unexpected inhibition of CO2 gas hydrate formation in dilute TBAB solutions and the critical role of interfacial water structure

Gas hydrates formed under moderated conditions open up novel approaches to tackling issues related to energy supply, gas separation, and CO2 sequestration. Several additives such as tetra-n-butylammonium bromide (TBAB) have been empirically developed and used to promote gas hydrate formation. Here we report unexpected experimental results which show that TBAB inhibits CO2 gas hydrate formation when used at minuscule concentration. We also used spectroscopic techniques and molecular dynamics simulation to gain further insights and explain the experimental results. They have revealed the critical role of water alignment at the gas-water interface induced by surface adsorption of tetra-n-butylammonium cation (TBA+) which gives rise to the unexpected inhibition of dilute TBAB solution. The water perturbation by TBA+ in the bulk is attributed to the promotion effect of high TBAB concentration on gas hydrate formation. We explain our finding using the concept of activation energy of gas hydrate formation. Our results provide a step toward to mastering the control of gas hydrate formation.

Salinity Effect on the Equilibria and Kinetics of the Formation of CO2 and R-134a Gas Hydrates in Seawater

Gas hydrates are crystalline solids in which gas molecules (guests) are trapped in water cavities (hosts) that are composed of hydrogen-bonded water molecules. During the formation of gas hydrates in seawater, the equilibria and kinetics are then affected by salinity. In this study, the effects of salinity on the equilibria of CO2 and R134-a gas hydrates has been investigated by tracing the changes of operating temperature and pressure. Increasing the salinity by 1.75% led to a drop in the equilibrium temperature of about 2 oC for CO2 gas hydrate and 0.38 oC for R-134a gas hydrate at constant equilibrium pressure; in other words, there were rises in the equilibrium pressure of about 1 bar and 0.25 bar at constant equilibrium temperature, respectively. The kinetics of gas hydrate formation have also been investigated by time-resolved in-situ Raman spectroscopy; the results demonstrate that the increase of salinity delayed the formation of both CO2 and R134-a gas hydrates. Therefore, various ions in seawater can play roles of inhibitors for gas hydrate formation in terms of both equilibrium and kinetics.

Investigation of Hydrate-induced Ice Desalination (HIID) and its application to a pretreatment of reverse osmosis (RO) process

In this study, freeze desalination which utilizes CO2 gas hydrate itself as a refrigerant (referred to as Hydrate-induced Ice Desalination, HIID) was systematically investigated and evaluated as a pretreatment method for seawater reverse osmosis (RO) process. To the best of the authors' knowledge, the HIID is the first approach to use the hydrate dissociation energy to freeze seawater in an instant for desalination. The endothermic energy related to hydrate dissociation was the most dominant factor in the freezing of seawater. Using the HIID technique, the rejection of ions with 3.5wt% NaCl was about 67%. Increasing the concentration of salts enhanced rejection of component ions. However, humic acid organic rejection decreased due to agglomeration of organics in presence of salts. The HIID process showed similar levels of cation rejections-approximately 65% of seawater, except boron and potassium. The rejection of cations might be determined by the solubility of salts at various brine concentration. Using HIID as a pretreatment of seawater at 225psi, the RO process showed ~14 LMH and about 99% cation rejections except boron. This study shows that HIID can be utilized as a pretreatment of seawater desalination and further development might make HBID technology run on its own.

CO2 storage capacity in laboratory simulated depleted hydrocarbon reservoirs – Impact of salinity and additives

A number of depleted hydrocarbon reservoirs in Alberta, Canada provide an opportunity for enhanced CO2 storage density because the reservoir conditions favor CO2 gas hydrate crystal formation. A laboratory simulation study was conducted to study this process and assess the impact of injection method, presence of additives and salinity on the CO2 storage density. Results indicated constant flow rate followed by constant pressure CO2 injection enhanced CO2 hydrate formation compared to constant pressure gas injection. It was noted that 85 % of the original water in the reservoir formed CO2 hydrate after 24 h experiments and that figure rose to 90 % after a 120 h period. Certain amount of tapioca starch and Polyvinylpyrrolidone (PVP) added to the water prevented the hydrate formation in the earlier stage (delay of the onset of hydrate nucleation but subsequently more CO2 was stored as hydrate in the reservoir compared to the inhibitor-free systems. Hydrate formation in saline reservoirs was reduced compared to pure water conditions. The hydrate technology provides an improved CO2 storage density.

Experimental study and thermodynamic modeling of CO2 gas hydrate formation in presence of zinc oxide nanoparticles

The effect of synthesized zinc oxide (ZnO) nanoparticles was investigated on the kinetic and thermodynamic equilibrium conditions of CO2 hydrate formation. The amount of the gas consumption was measured and compared for the four sample fluids: pure water, aqueous solution of sodium dodecyl sulfate (SDS), water-based ZnO-nanofluid and water-based ZnO-nanofluid in the presence of SDS (0.001 mass fraction). The time of hydrate growth decreased and the amount of the storage gas enhanced in the presence of nanoparticles. Moreover, the nanoparticles size effect besides the CO2 solubility enhancement in ZnO-nanofluid led to the reduction of water activity, so that the equilibrium curve of hydrate formation was shifted to higher pressures. A new correlation for Henry’s law constant was obtained using CO2-solubility data in ZnO-nanofluid. Finally using this correlation, the water activity was calculated through the Chen–Guo approach to propose a thermodynamic method for prediction of the equilibrium hydrate formation conditions in the presence of the nanoparticles.

Investigation of the performance of low-dosage hydrate inhibitors combined with wax inhibitors for a mixed CH4-CO2 gas hydrate formation

Within the oil and gas industry, low-dosage hydrate inhibitors (LDHIs) are a proven technology to control hydrates. Besides hydrate inhibitors, wax inhibitors (WIs) are frequently injected to prevent wax buildup in the crude oil pipeline. However, little attention has been focused on the effect of wax inhibitors on the performance of LDHIs. In this study, performance tests of 3 LDHIs in the presence of wax inhibitors were carried out for a 67% CH4/33% CO2 gas hydrate formation. Using the isothermal cooling method at pressures of 9 MPa and temperatures of 4 °C (subcooling is 9 °C), the results showed that the induction time of CH4-CO2 gas hydrate formation with LDHI/WI was shorter than the system with only LDHI. During the growth period, when the concentration of the WIs was 1 mass%, the growth time of the system with LDHI/WI was prolonged. Taking the induction time and the growth time into consideration, it was found that WIs had a more negative impact on the kinetic hydrate inhibitor performance at low dosage. The effect of WIs at high concentration could be negligible.

Modeling nitrogen and methane with ethane and propane gas hydrates at low temperatures (173–290 K) with applications to Titan

The FREZCHEM model was primarily designed for cold temperatures (173–298K) and high pressures (1–1000bars). Nitrogen gas (95.0%) and methane gas (5.0%) are major gases on the surface of Titan. Recently, we added nitrogen and methane gas hydrates to FREZCHEM model on Titan; and nitrogen–methane gas hydrates formed on Titan at 178K. The other common but less abundant gases on Titan are ethane (C2H6) and propane (C3H8) that can also form gas hydrates with nitrogen and methane. The specific objectives of this study were to (1) add ethane and propane to gas hydrates, including mixtures with nitrogen, methane, and carbon dioxide, and (2) explore the potential roles of gas hydrates on Titan. At 273K, the Ln(gas hydrates) were 5.095 for N2, 3.217 for CH4, 2.327 for CO2, 1.288 for C2H6, and 0.281 for C3H8. At 173K, the Ln(gas hydrates) were −4.968 for N2, −6.102 for CH4, −7.803 for CO2, −5.125 for C2H6, and −5.512 for C3H8. Apparently C2H6 and C3H8 gas hydrates change less at lower temperatures than N2, CH4, and CO2 gas hydrates. In previous papers, we added three mixed CH4–CO2, N2–CH4, and N2–CO2 binary gas hydrates. In this paper, we added ethane and propane to include new binary gas hydrate mixtures of N2–C2H6, N2–C3H8, C2H6–C3H8, CH4–C2H6, CH4–C3H8, CO2–C2H6, and CO2–C3H8. Today, there are ten binary gas hydrates in the FREZCHEM model. In the text, how to cope with more than two species is described. Simulations from 273K to 173K used a surface Titan pressure of 1.467 bars with a major gas of nitrogen (94.24%), a minor gas of methane (5.65%), and extremely minor gases of ethane (0.0038%), and propane (0.000343%). Eventually at 178K, N2·6H2O formed with 0.17694mol, CH4·6H2O formed with 0.04101mol, C2H6·6H2O formed with 6.48e−6mol, and C3H8·6H2O formed with 9.36e−7mol. Based on the atmospheric conditions of Titan, the trace gases of ethane and propane led to low gas hydrate precipitations of ethane and propane with nitrogen and methane. However, the gas concentrations could be very different in an ocean of Titan that could be 50 to 175km beneath the surface where the temperatures may increase as high as 260K. Methane gas hydrates are likely dominant beneath the surface of Titan with some minor contributions from nitrogen, ethane, and propane. Below the surface of Titan in the ocean and icy shell, gas hydrates clearly depend on the gas concentrations of methane, nitrogen, ethane, and propane as well as temperature and pressure.

Fundamental Investigation of the Effects of Hydrophobic Fumed Silica on the Formation of Carbon Dioxide Gas Hydrates

Promoting the kinetics of CO2 hydrate formation using additives is of great importance in industrial applications of gas hydrates such as capture and storage of carbon dioxide. However, the mechanism of hydrate formation in the presence of solid particles is not well understood. This paper aims to gain a better understanding of the fundamental aspects of CO2 hydrates formation in the presence of hydrophobic silica nanoparticles. A novel mechanism for gas hydrate formation in the presence of hydrophobic particles was established from a series of well-designed experiments. Two types of particle stabilized systems, made by mixing hydrophobic silica nanoparticles and water, were tested: air-in-water foam and water-in-air powder (dry water). Gas consumption, CO2 conversion, induction time, and hydrate growth rate have been examined to establish the influence of particle hydrophobicity and concentration on hydrate formation kinetics. The results show that the promoting effect depends on the particle hydrophobicity and concentration. The most hydrophobic silica (dry water) enhances the kinetics of CO2 hydrate formation effectively. Cryogenic scanning electron microscopy, combined with energy-dispersive spectroscopy, was used to examine the morphology, microstructure, and pore characteristics of CO2 gas hydrates, as well as elemental composition of the samples. To provide further insight into the adsorption of gas molecules at the water/solid interface, surface potential of the hydrophobic fumed silica particles in aqueous system before and after exposing to N2 and CO2 gas was measured. These results, in combination with the result of our recent study on the structure of dry water, successfully provided further detailed information on how hydrophobic fumed silica promotes the formation of gas hydrates.

PVT parameters of fluid inclusions and the C, O, N, and Ar isotopic composition in a garnet lherzolite xenolith from the Oasis Jetty, East Antarctica

Orthopyroxene, clinopyroxene, and olivine from a metasomatized mantle xenolith of garnet lherzolite in alkaline rocks at the Jetty Oasis, East Antarctica, contain numerous carbon dioxide-dominated composite melt-fluid and fluidized sulfide-silicate (±carbonate) inclusions. Although the maximum pressure under which the inclusions were captured by rock-forming minerals was evaluated at 13 kbar, its actual value should have been much higher, judging by the fact that the inclusions have lost part of their material (decrepitated) when the xenolith was brought to the surface. Two major fluid populations are distinguished. The fluids entrapped during the earlier episode have a more complicated composition. Dominated by CO2, these fluids contain much N2 (0.1–0.2 mole fractions), H2S, and perhaps, also H2O and are hosted by sulfide-silicate (±carbonate) inclusions produced by liquid immiscibility. As these inclusions evolved, they enriched in CO2 and depleted in H2S and N2. Although the concentrations of N2, H2S, and H2O were generally relatively low, these components played an important role in mantle metasomatism, as is reflected in the geochemistry of the derived magmas. The fluids of the younger episode (pressures lower than 7 kbar) are notably richer not only in CO2 but also in H2O (up to the appearance of inclusions with a liquid aqueous phase and the formation of CO2 gas hydrate when cooled in a cryometric stage by liquid N2). The effect of fluids on the mantle source in two discrete episodes is also confirmed by isotopic-geochemical data. Isotopic data on gases obtained immediately from fluid inclusions in minerals by the stepwise crushing technique provide evidence of the evolution of elemental and isotopic ratios of the gases in the course of the metasomatic processes. The high-pressure fluid inclusions of the earlier episode have low C/N2, C/Ar, and N2/Ar ratios, isotopically heavy N2, and somewhat elevated (to 530) 40Ar/36Ar ratios. The younger fluids typically have higher (by two to three orders of magnitude) C/N2 and C/Ar ratios, lower δ13C of CO2, and N2/Ar and 40Ar/36Ar ratios close to the atmospheric values. The nitrogen and argon isotopic compositions and elemental ratios suggest that the younger fluids could have been produced by two-component mixing in the mantle-atmosphere system. Comprehensive analysis of the data and in particular the 40Ar/36Ar ratios, which are atypical of the mantle, and an increase in the H2O concentration, suggests a subduction-related nature of the fluids.

Modeling nitrogen-gas, -liquid, -solid chemistries at low temperatures (173–298 K) with applications to Titan

Molecular diatomic nitrogen (henceforth, “nitrogen”) is a major gas on Venus, Earth, Mars, Titan, Triton, and Pluto; a major condensed liquid component on Titan; and major condensed ices on Triton and Pluto. Nitrogen also occurs as a component of air gas hydrates in Earth’s polar ice sheets. The Solar System’s nitrogen originally might have been produced by condensation of nitrogen ice in the outer Solar Nebula disk, or it might have first condensed as and then decomposed from nitrogen gas hydrate or ammonia. The specific objectives of this study were to add nitrogen into the FREZCHEM model (which already included ammonia) and explore some roles of nitrogen on planetary satellites, especially Titan, where nitrogen is a major atmospheric gas and a component of Titan’s hydrocarbon-rich lakes and rain. Nitrogen gases, aqueous phases, and gas hydrates were added to FREZCHEM. Nitrogen, methane, and carbon dioxide gas hydrates were parallel with respect to temperature, which allowed extensions to 173K, including for mixed N2–CH4 and N2–CO2 gas hydrates. Simulations from 273 to 173K used a surface Titan pressure of 1.467bars with a major mixing gas of nitrogen at 1.394bars (95%) and methane at 0.073bars (5%). These gas concentrations eventually led to formation of N2–CH4 gas hydrate at 178K, which suggests that these gas hydrates could be forming on the surface of Titan today (at 94K) and in sub-surfaces with higher temperatures. On Earth, air gas hydrates are common deep within polar ice sheets and are dominated by atmospheric N2/O2 gas compositions; and as a consequence, gas hydrates do not control, but are controlled by, atmospheric N2/O2 gas compositions. Given that Earth and Titan have similar atmospheric nitrogen (0.78 vs. 1.39bars) and icy environments, on neither body are gas hydrates likely the main source of atmospheric nitrogen; but rather, atmospheric gases are likely the source of minor amounts of nitrogen in gas hydrates on Earth and Titan.

CO2 hydrate formation and dissociation rates: Application to Mars

CO2 clathrate hydrate is a crystalline material composed of water cages around a CO2 molecule. CO2 gas hydrates are naturally occurring on Earth and are a likely phase on Mars as well as other cold planetary bodies. CO2 hydrates have minor effects on terrestrial atmospheric composition, but may be a major reservoir for greenhouse gases on Mars. In this study, CO2 hydrate formation and dissociation rates were measured experimentally on ultrapure and CO2 infused water ice (ice containing previously trapped CO2 gas bubbles). Overall, increasing pressure and temperature increased CO2 consumption rates, indicating enhanced hydrate formation rates. CO2 consumption and release rates both increased significantly in infused ice experiments as did the overall amount of CO2 consumed. CO2 bubbles formed during freezing of the infused ice likely provided more surface area for hydrate nucleation, increasing the rate of formation. Higher dissociation rates in infused ice experiments compared to ultrapure ice may be due to the higher concentration of hydrate originally formed in the bubble-filled samples. These results suggest that CO2 hydrate formation in natural, gas-rich ice occurs significantly faster than previously assumed. In addition, formation rates would be maximized and dissociation rates minimized at Mars equatorial conditions, perhaps leading to long-term storage of atmospheric CO2 in localized clathrate reservoirs.

Study on Pilot-Scale CO2 Separation from Flue Gas by the Hydrate Method

Technology of hydrate-based CO2 separation and capture is considered as a green and economical gas separation technology and is extensively studied. Most of the previous studies involving the aspects of thermodynamics and kinetics of the CO2 gas hydrate formation were carried out with small reactors, whereas few studies were carried out with pilot-scale equipments. In this paper, a pilot-scale CO2 separation from flue gas by the hydrate method is reported. By the equipment, we successfully realize CO2 separation from flue gas. By a two-stage hydrate separation process, the CO2 concentration can be enhanced to approximately 90.0% from 17.0%. The effects of the operating pressure and gas flow rate on CO2 recovery are also investigated by comparing and analyzing the data of the CO2 concentration, gas consumption, and CO2 recovery. The higher pressure results in the higher CO2 recovery, and there is an optimal ratio of the gas flow rate to the fluid flow rate for obtaining the highest gas consumption. The res...

Explicit pressure dependence of the Langmuir adsorption constant in the van der Waals–Platteeuw model for the equilibrium conditions of clathrate hydrates

In this work, we propose a new pressure- and temperature-dependent Langmuir adsorption constant for the modeling of the phase boundary of clathrate hydrates over a wide range of conditions. The proposed Langmuir adsorption constant is designed to produce a reduced free volume available to the encapsulated gas molecules as the pressure increases. We show that the combination of a cubic equation of state and the van der Waals–Platteeuw model with this new Langmuir model can be used to describe various types of three phase coexisting conditions of gas hydrates, from vapor–ice–hydrate equilibrium (VIHE) at low temperatures, to vapor–liquid–hydrate equilibrium (VLHE) at higher temperatures, and to liquid–liquid–hydrate equilibrium (LLHE) at high pressures, using a single set of parameters. The average relative deviations in the equilibrium pressure are found to be 4.57% for 12 pure gas hydrates over a large range of temperatures (148.8–323.9K) and pressures (5.35×102Pa to 8.27×108Pa). Furthermore, the retrograde behavior observed in CH4, CO2, C3H8, and i-C4H10 pure gas hydrate systems can all be successfully modeled by the change of free volume at high pressures. We believe that this method is useful for many gas hydrates related the multiple three-phase regions.

Study of CO<sub>2</sub> Hydrate Growth Process Based on Diffusion-Controlled Reaction

A one-dimensional mathematical model of mass transfer during CO2 gas hydrate film formation at the boundary between the gas and water is established by analyzing the process of the static system. According to the model, we can get the concentration distribution of free CO2 in the hydrate film along with the time, and the conversion rate of hydrate with time can also be obtained. The results calculated at specific experiment condition in the system are analyzed. It indicates that the conversion rate can reach about 85% after 10 hours under static condition with 3.5MPa pressure and 0.5°C temperature by pure water when the initial reaction liquid depth is 20 mm

Formation Kinetics of Structure I Clathrates of Methane and Ethane Using an in Situ Particle Size Analyzer

Experimental data on the kinetics of structure I (sI) clathrate formation were obtained for pure methane and pure ethane in a semi-batch stirred-tank reactor that is equipped with an in situ particle size analyzer. The particle size analyzer used is a Lasentec focused beam reflectance measurement (FBRM) probe capable of measuring particle chord lengths between 0.5 and 100 μm. Experiments were conducted at temperatures ranging from 274 to 282 K and with pressures ranging from 0.99 to 7.25 MPa. A novel procedure for cleaning the FBRM probe tip, which eliminated the need to remove the probe between runs, was developed. Experimental data on the pressure, temperature, and particle size distribution were analyzed using the approach of Clarke and Bishnoi (Clarke, M. A.; Bishnoi, P. R. Determination of the intrinsic kinetics of CO2 gas hydrate formation using in situ particle size analysis. Chem. Eng. Sci. 2005, 60, 695−709), with minor modifications, and intrinsic rate constants were obtained for methane and ethane in sI.

Continuous Formation Process of CO2 Gas Hydrate via a Vortex and Impinging Stream Reactor

A continuous formation process of CO2 hydrate was investigated in a vortex and impinging stream reactor (VIR) of 1.76 L with the temperatures ranging from 274.46 to 275.86 K and the pressures ranging from 1.79 to 3.163 MPa. In the VIR, a high-gravity field can be generated, where both centrifugal and impinging forces can intensify the mass transfer in reactants. There are two distinct steps in the process. The first step is the unstable hydrate formation process. The next one is called the stable formation process, which presents the rapid and continuous formation of the CO2 gas hydrate. It is found that the formation rate of CO2 hydrate is up to 249.8 mol/h when the Higee factor β is 390.28.

PREDICTION OF CO2 FREEZE-OUT CONDITIONS AND CO2 HYDRATE FORMATION CONDITIONS WITH A SINGLE EQUATION OF STATE

A recent study by Eggeman and Chaffin (2005), which showed large discrepancies in CO2 freeze-out conditions as predicted by several commercial simulators, prompted a reexamination of using the TBS equation of state for phase equilibrium calculations involving solids. Salim and Trebble (1994) had previously presented a methodology for extending the Trebble-Bishnoi-Salim (TBS) equation of state (Salim, 1990) to calculations involving a solid phase. In this study, the CO2 freeze-out conditions in CO2/CH4 and CO2/C2H6 mixtures are calculated from the TBS equation of state, and it is shown that they provide a better data fit than the traditional Poynting correction method. Furthermore, since the use of an equation of state in SLE/SVE calculations does not require the explicit assumption of a pure solid phase, the model was assessed for its ability to correlate CO2 gas hydrate equilibrium conditions. Gas hydrates were simply treated as an impure solid phase, and it was seen that the predictions of gas hydrate equilibrium were in very good agreement with the experimental data. Computationally, the use of the TBS equation of state has the advantage, over the model of Yokozeki (2005), that it does not require a modifying factor (cb) in the repulsive term to handle the presence of hydrates; they are instead handled using a unique binary interaction parameter for the hydrate phase.

2355 炭酸ガスハイドレートの連続生成に関する研究

The new concept of CO2 separation of prior to combustion was proposed, that CO2 is separated from the H2-CO2 mixed gas produced by steam-reforming of hydrocarbon fuel by means of Gas Hydrate Separation (GHS) system. In order to demonstrate the reality of the GHS system, we conducted experiments of CO2 and CO2-He mixed gas hydrate formation. GH reaction is confirmed but not succeeded in continuous operation of gas formation system, so far.

氷の融点付近におけるＣＯ２ハイドレートの成長挙動 ガスハイドレートの生成・分解に関する実験的研究

The mining systems of methane hydrate reservoirs using CO2 hydrate are proposed, i.e. the artificial block system and the CH4-CO2 replacement system. In order to accomplish the concepts, it is necessary to understand the mechanism of formation kinetics of gas hydrates. There are few experimental data on the growth rate of CO2 hydrate, particularly in the temperature range below melting point of ice, and the mechanism has not been well understood.In this study, two types of experiments were carried out on formation kinetics of CO2 hydrate below melting point of ice, using Raman spectrometry and gas consumption method.Spectra of CO2 trapped in the hydrate cages were directly observed by Raman spectrometry. The result showed the amount of CO2 molecules increased with time, and increasing rates depend on the temperature and pressure conditions. From the experiment of gas consumption method, it was found that the growth rate of CO2 hydrate has two stages. It is indicated that the first stage of growth is rapid growth mode caused by quasi-liquid-layer or locally melted water by the latent heat, and then the latter stage is slower growth mode between gas and ice. In the temperature range of-5 ∼-1 °C, more than 40 % of total reaction gas was consumed in the first stage of growth. Considering that the reaction at the first stage is similar to that of H-LW-V system, an empirical equation was applied to the experimental results. Reaction coefficients in the first stage were estimated to determine the growth of CO2 gas hydrate. From these results, we address that proper use of the first stage growth of CO2 gas hydrate is important to develop the advanced mining systems for methane hydrate.