This study was financially supported by the MH21 Research Consortium for Methane Hydrate Resources in Japan and the National Methane Hydrate Exploitation Program by the Ministry of Economy, Trade, and Industry. The authors would like to thank T. Maekawa and S. Goto for their assistance with the experiments.
Reprinted figures with permission from (Muraoka, M., Susuki, N., Yamaguchi, H., Tsuji, T., Yamamoto, Y., Energy Fuels, 29(3), 2015, 1345-1351., 2015, DOI: 10.1021/ef502350n). Copyright (2015) American Chemical Society.

Note: Please consult all relevant material safety data sheets as this study uses high-pressure flammable methane gas and a large high-pressure vessel. Wear a helmet, safety glasses, and safety boots. If the temperature control system stops, the pressure in the vessel increases with MH dissociation. To prevent accidents, the use of a safety valve system is strongly recommended to automatically release the methane gas to the atmosphere. The safety valve system can work without electrical power supply.
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<ol>
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Geol. 66 (Pt 2), 296 (2015).</li><li>Fujii, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Geological+setting+and+characterization+of+a+methane+hydrate+reservoir+distributed+at+the+first+offshore+production+test+site+on+the+Daini-Atsumi+Knoll+in+the+eastern+Nankai+Trough,+Japan.">Geological setting and characterization of a methane hydrate reservoir distributed at the first offshore production test site on the Daini-Atsumi Knoll in the eastern Nankai Trough, Japan.</a> Mar. Petrol. Geol. 66 (Pt 2), 310 (2015).</li><li>Mao, W. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+clusters+in+clathrate+hydrate.">Hydrogen clusters in clathrate hydrate.</a> Science. 297 (5590), 2247-2249 (2002).</li><li>Lee, S., Liang, L., Riestenberg, D., West, O. R., Tsouris, C., Adams, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CO2+hydrate+composite+for+ocean+carbon+sequestration.">CO2 hydrate composite for ocean carbon sequestration.</a> Environ. Sci. Technol. 37 (16), 3701-3708 (2003).</li><li>Muromachi, S., Ohmura, R., Takeya, S., Mori, H. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clathrate+Hydrates+for+Ozone+Preservation.">Clathrate Hydrates for Ozone Preservation.</a> J. Phys. Chem. B. 114, 11430-11435 (2010).</li><li>Waite, W. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+properties+of+hydrate-bearing+sediments.">Physical properties of hydrate-bearing sediments.</a> Rev. Geophys. 47 (4), (2009).</li><li>Muraoka, M., Susuki, N., Yamaguchi, H., Tsuji, T., Yamamoto, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+properties+of+a+supercooled+synthetic+sand-water-gas-methane+hydrate+sample.">Thermal properties of a supercooled synthetic sand-water-gas-methane hydrate sample.</a> Energy Fuels. 29 (3), 1345-1351 (2015).</li><li>Gustafsson, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+plane+source+techniques+for+thermal+conductivity+and+thermal+diffusivity+measurements+of+solid+materials.">Transient plane source techniques for thermal conductivity and thermal diffusivity measurements of solid materials.</a> Rev. Sci. 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Res. 109 (B1), (2004).</li><li>Huang, D., Fan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+and+modeling+thermal+conductivity+of+gas+hydrate-bearing+sand.">Measuring and modeling thermal conductivity of gas hydrate-bearing sand.</a> J. Geophys. Res. 110 (B1), (2005).</li></ol>

The authors have nothing to disclose.

The effect of the formation heat of MH on measurement was estimated. The formation heat of MH was estimated from products of change rate of Sh as shown in Figure 3b and the enthalpy of formation H = 52.9 kJ mol&#8722;1 for MH14. Consequently, the maximum temperature change was 0.00081 &#176;C sec&#8722;1. This was much lower than the temperature increase &#916;Tc of the TPS sensor between 1 &#176;C and 1.5 &#176;C during th...

Gas hydrates are crystalline compounds that comprise cage structures of hydrogen-bonded water molecules containing guest molecules in the cage1. Large amounts of methane hydrates (MHs) in the ocean floor and permafrost regions are interesting future energy resources but may affect global climate conditions2.
In March 2013, the Japan Oil, Gas, and Metals National Corporation conducted the world&#39;s first offshore production test to extract gas from natural MH-bearing sediments in the eastern Nankai Trough using the &#34;depressurization method&#34; 3,4.
Gas hydrates can store gases such as methane1, hydrogen5, CO21,6, and ozone7. Hence, methane and hydrogen hydrates are studied as potential energy storage and transportation media. To reduce the CO2 emissions released into the atmosphere, CO2 sequestration using CO2 hydrates in deep-ocean sediments have been studied6. Ozone is currently used in water purification and food sterilization. Studies of ozone preservation technology have been conducted because it is chemically unstable7. The ozone concentration in hydrates is much higher than that in ozonized water or ice7.
To develop gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates. However, the thermal properties data and model studies of gas hydrate-bearing sediments are scarce8.
The &#34;depressurization method&#34; can be used to dissociate MH in the sediment pore space by decreasing the pore pressure below the hydrate stability. In this process, the sediment pore space components change from water and from MH to water, MH, and gas. The thermal properties&#39; measurement of the latter condition is difficult because the melting heat of MH may affect the measurements. To solve this problem, Muraoka et al. performed the thermal properties&#39; measurement at supercooled conditions during MH formation9.
With this video protocol, we explain the measuring method of supercooled synthetic sand-water-gas-MH sample.
Figure 1 shows the experimental setup for measuring the thermal properties of the artificial methane hydrate-bearing sediment. The setup is the same as shown in reference9. The system mainly comprises a high-pressure vessel, pressure and temperature control, and thermal properties of the measurement system. The high-pressure vessel is composed of cylindrical stainless steel with an internal diameter of 140 mm and a height of 140 mm; its inner volume with the dead volume removed is 2,110 cm3, and its pressure limit is 15 MPa. The transient plane source (TPS) technique is used to measure the thermal properties10. Nine TPS probes with individual radii of 2.001 mm are placed inside the vessel. The layout of the nine probes9 is shown in Figure 2 in reference9. The TPS probes are connected to the thermal properties&#39; analyzer with a cable and switched manually during the experiment. The details of the TPS sensor, connection diagram, and setup in the vessel are shown in Figures S1, 2, and 3 of the supporting information in reference9.
<img alt="Figure 1" src="/files/ftp_upload/53956/53956fig1.jpg" /> 
Figure 1: The experimental setup for measuring the thermal properties of the artificial methane hydrate-bearing sediment. The figure is modified from&#160;reference9. <a href="https://www.jove.com/files/ftp_upload/53956/53956fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The TPS method was used to measure the thermal properties of each sample. The method principles are described in reference10. In this method, the time-dependent temperature increase, &#916;Tave, is
<img alt="Equation 1" src="/files/ftp_upload/53956/53956eq1.jpg" />
where
<img alt="Equation 2" src="/files/ftp_upload/53956/53956eq2.jpg" />
In Equation 1, W0 is the output power from the sensor, r is the radius of the sensor probe, &#955; is the thermal conductivity of the sample, &#945; is the thermal diffusivity, and t is the time from the start of the power supply to the sensor probe. D(&#964;) is a dimensionless time dependent function. &#964; is given by (&#945;t/r)1/2. In Equation 2, m is the number of concentric rings of the TPS probe and I0 is a modified Bessel function. The thermal conductivity, thermal diffusivity, and specific heat of the sample are simultaneously determined by inversion analysis applied to the temperature increase as power is supplied to the sensor probe.

<table border="0" cellpadding="0" cellspacing="0" width="1353">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">TPS thermal probe, Hot disk sensor</td>
			<td style="width:251px;">Hot Disk AB Co., Sweden</td>
			<td style="width:267px;">#7577</td>
			<td style="width:392px;">Kapton sensor type, sensor radius 2.001 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Hot disk thermal properties analyzer</td>
			<td>Hot Disk AB Co., Sweden</td>
			<td style="width:267px;">TPS 2500&#160;</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:444px;">Toyoura standard silica sand</td>
			<td style="width:251px;">Toyoura Keiseki Kogyo Co., Ltd., Japan</td>
			<td style="width:267px;">N/A</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:444px;">Methane gas ,99.9999%</td>
			<td style="width:251px;">Tokyo Gas Chemicals Co., Ltd., Japan</td>
			<td style="width:267px;">N/A</td>
			<td>Grade 6N, Volume 47L, Charging pressure 14.7MPa</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Water Purification System,Elix Advantage 3&#160;</td>
			<td style="width:251px;">Merck Millipore., U.S.</td>
			<td style="width:267px;">N/A</td>
			<td>5 M&#937; cm (at 25&#176;C) resistivity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Vibrating table, Vivratory packer</td>
			<td style="width:251px;">Sinfonia Technology Co. Ltd., Japan</td>
			<td style="width:267px;">VGP-60</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Chiller, Thermostatic Bath Circulator&#160;</td>
			<td style="width:251px;">THOMAS KAGAKU Co., Ltd., Japan</td>
			<td style="width:267px;">TRL-40SP</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Coorant, Aurora brine</td>
			<td style="width:251px;">Tokyo Fine Chemical Co.,Ltd., Japan</td>
			<td style="width:267px;">N/A</td>
			<td>ethylene glycol 71wt%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Temparature gage</td>
			<td style="width:251px;">Nitto Kouatsu., Japan</td>
			<td style="width:267px;">N/A</td>
			<td>Pt 100, sheath-type platinum resistance temperature detector</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:444px;">Pressure gage</td>
			<td style="width:251px;">Kyowa Electronic Instruments., Japan</td>
			<td style="width:267px;">PG-200 KU</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Data logger</td>
			<td style="width:251px;">KEYENCE., Japan</td>
			<td style="width:267px;">NR-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">Mass flow controller</td>
			<td style="width:251px;">OVAL Co., Japan</td>
			<td style="width:267px;">F-221S-A-11-11A</td>
			<td>Maximum flow 2000 Nml/M, maximum design pressure 19.6 MPa</td>
		</tr>
	</tbody>
</table>

protocol for measuring the thermal properties of a supercooled synthetic sand-water-gas-methane hydrate sample

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates.
The thermal properties' measurements of samples comprising sand, water, methane, and MH are difficult because the melting heat of MH may affect the measurements. To solve this problem, we performed thermal properties' measurements at supercooled conditions during MH formation. The measurement protocol, calculation method of the saturation change, and tips for thermal constants' analysis of the sample using transient plane source techniques are described here.
The effect of the formation heat of MH on measurement is very small because the gas hydrate formation rate is very slow. This measurement method can be applied to the thermal properties of the gas hydrate-water-guest gas system, which contains hydrogen, CO2, and ozone hydrates, because the characteristic low formation rate of gas hydrate is not unique to MH. The key point of this method is the low rate of phase transition of the target material. Hence, this method may be applied to other materials having low phase-transition rates.

Figure 2a shows the temperature profile that is not affected by MH melting. &#916;Tc is the temperature change due to thermal constants&#39; measurement. Figure 2b shows the temperature profile that is affected by MH melting. The profile in Figure 2b cannot be analyzed through Equations 1 and 2 because these equations are derived by assuming stable sample conditions.
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Watch this Scientific Journal Video about Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample at JoVE.com

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

We present a protocol for measuring the thermal properties of synthetic hydrate-bearing sediment samples comprising sand, water, methane, and methane hydrate.

Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future ...

The overall goal of this procedure is to determine the thermal properties of a sample comprised of sand, water, methane gas, and methane hydrate. This lesson can help answer key questions in the gas production technology field such as gas production simulation natural methane hydrates. To begin, place the high-pressure vessel on the vibrating table.Pour 1.5 liters of pure water in a water bottle and 4, 000 grams of silica sand in a sand bottle. Accurately weigh the masses of sand and water in their respective bottles. Then pour 1 liter of pure water in the high-pressure vessel with an inner volume of 2, 110 cubic centimeters from a water bottle until the water fills half the inner vessel.Turn on the vibrating table to vibrate the entire vessel. Set the vibration rate to 50 hertz and the power supply to 220 watts. Remove the residual air in the drain line and centered metallic filter at the bottom of the vessel by vibrating the vessel.Pour 3, 300 grams of silica sand from a sand bottle into the vessel at a constant rate of approximately one gram per second using a funnel held near the water surface while the entire vessel is vibrated to ensure uniform packing. Stop the vibration when the water reaches the rim of the vessel. Place a ring as a temporary wall on the rim of the vessel to prevent water from spilling.Vibrate the vessel again as before, and when the sand reaches the rim of the vessel, turn off the vibration. Remove the excess pour water using the drain line and pour it back into the water bottle. Remove the temporary wall.Pack the sand by vibrating the vessel once or twice at 50 hertz and 300 watts per one second and add more sand if necessary. Weigh the mass of the sand and water in their respective bottles. Next, calculate the sand and water masses in the vessel from the mass differences in the sand and water bottles.In this experiment, the mass of sand in the vessel was 3, 385 grams, and the mass of water in the vessel was 823.6 grams. The mass of water in the vessel is denoted as w total. Cover the high-pressure vessel with a stainless steel lid and tighten the bolts of diagonally opposite pairs in sequence.Move the high-pressure vessel from the vibrating table to the table intended for the experiment. Cover the high-pressure vessel with a heat insulator for controlling the temperature. Then connect the high-pressure pipelines and the cooling water flowlines to the high-pressure vessel.Open the valves of the input and output gas pipelines. Ventilate 10 liters of methane at a rate of 800 milliliters per minute until no excess water discharges into the trap under atmospheric pressure. The sand discharge is prevented by a centered metallic filter fixed on the bottom of the vessel.The residual water remains on the sand's surface because the hydrophilic silica sand absorbs the water molecules. Weigh the mass of water in the trap w trap to determine the gas volume in the vessel. Determine the mass of residual water, w resi.In this case w resi is 360.6 grams and w trap is 463 grams. After closing the valve of the output gas line, inject methane to increase the pour pressure of methane in the vessel to approximately 12.1 megapascal at room temperature. Then, close the valve of the input gas line.Start recording the pressure and temperature in the vessel during the experiment using the data logger. Turn on the chiller for cooling the vessel from room temperature to 2.0 degrees Celsius by circulating the coolant. Let the coolant circulate from the chiller to the bottom of the vessel, from there to the lid of the vessel and finally back to the chiller.Set up the measurement parameters using transient plane source, or TPS, analyzer software and calculating the degree of supercooling as determined in the text protocol. The most critical step is performing sonar constant measuerment by keeping the temperature increase over the TPS sensor supercoolant. Simultaneously measure the thermal conductivity, thermal diffusivity, and volumetric specific heat using the TPS analyzer after the degree of supercooling is greater than two degrees Celsius.After each measurement, manually switch the cables between the TPS probes and the analyzer during the experiment. Collect data every three to five minutes. Repeat the measurements until the degree of supercooling reaches two degrees Celsius again.In this experiment, the degree of supercooling initially increases with time. After the degree of supercooling reaches the maximum value, it gradually decreases to zero degrees Celsius because the pressure decreases with the formation of MH.Shown here is a temperature profile not affected by methane hydrate melting, and a temperature profile affected by melting. Note that this profile cannot be analyzed by the TPS technique because the analysis equations assume stable sample conditions.The pressure, temperature, and degree of supercooling in the vessel as a function of time are shown. MH nucleates after the system has reached pressure and temperature equilibrium. The saturation of the sediment with MH, water, and methane gas as a function of time are shown here.The degree of saturation is calculated using the equation of the state of the gas. An example of the thermal constants measurements is shown here. The double headed arrows denote the data range used in the analysis.Analysis 1 is an example of an inappropriate range, and Analysis 2 is an example of an approriate range. The TPS inversion analysis results from each range are shown here. The deviation of the temperature data from the linear fit curve is shown.If the appropriate analysis range is selected, the difference temperature becomes small and approximately constant. Finally, thermal conductivity as a function of time, specific heat as a function of time, and thermal diffusivity as a function of time are shown.

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8.8K visualizações.  National Institute of Advanced Industrial Science and Technology (AIST). The overall goal of this procedure is to determine the thermal properties of a sample comprised of sand, water, methane gas, and methane hydrate. This lesson can help answer key questions in the gas production technology field such as gas production simulation natural methane hydrates. To begin, place the high-pressure vessel on the vibrating table.Pour 1.5 liters of pure water in a water bottle and 4, 000 grams of silica sand in a sand bottle. Accurately weigh the masses of sand and w...