KR20190094906A - Manufacturing method of hydrate for storing natural gas and hydrogen - Google Patents

Abstract

The present invention relates to hydrates for storing natural gas and hydrogen. More specifically, a manufacturing method, by injecting a gas mixed with a natural gas composed of methane and ethane, and a gas composed of hydrogen so that hydrogen molecules can be collected in empty pores formed in a main molecule to perform as a thermodynamic stabilizer, can manufacture highly efficient hydrates in which two or at least three hydrogen molecules are collected in one empty pore. In addition, it is possible to use an existing natural gas transport and storage infrastructure as it is.

Description

Hydrate manufacturing method for storing natural gas and hydrogen {MANUFACTURING METHOD OF HYDRATE FOR STORING NATURAL GAS AND HYDROGEN}

The present invention relates to a hydrate manufacturing method, and more particularly, to a hydrate manufacturing method for storing natural gas and hydrogen capable of collecting and storing a mixed gas consisting of natural gas and hydrogen gas in the lattice structure of the pupil.

'Crusate hydrate', also called 'like ice material', is a kind of inclusion compound that can trap many small organic molecules and gas molecules in a unique lattice structure made of water.

In these hydrates, pure ice exhibits a specific crystal structure and no enclosed space exists, but when ice is mixed with other materials, the structure can be transformed into various forms under unique external environmental conditions, creating a new enclosed void space. This form is referred to as 'hydrate'.

Hydrates contain empty pupils that can store large amounts of gas, and have the potential to be an environmentally friendly energy storage medium and greenhouse gas solution because they can capture and store energy gases or greenhouse gases on a large scale.

High pressure conditions of about 220 MPa are required to form hydrogen hydrate by pressurizing hydrogen to pure water. When a small amount of organic matter (tetrahydrofuran, etc.) is added to pure water to hydrate, the hydrogen is sufficiently hydrated even at a pressure of about 10 MPa. Can be stored inside the grid.

However, organic molecules occupy a part of the pores in which hydrogen molecules formed in the hydrate can be stored, thereby reducing the hydrogen storage amount in the hydrate.

Thus, in the trade-off between the pressure needed to reliably store hydrogen in the hydrate lattice and the hydrogen storage capacity, it would be possible to solve this problem at once if several hydrogen molecules could be stored in one pupil in the presence of organic matter.

In order to solve this problem, in recent years, the results of controlling the concentration of organic molecules such as tetrahydrofuran, pyrrolidine, etc. to lower the hydrogen storage pressure and to store several hydrogen molecules in one pupil have been achieved. Due to the addition of high and liquid organic molecules, environmental problems remain a challenge.

Japanese Laid-Open Patent Publication No. 2012-236740 (2012.12.06.)

The technical problem to be achieved by the present invention is to reduce the pressure that hydrogen can be stored inside the hydrate using a mixed gas in the gas state and to store a plurality of hydrogen molecules in each of the empty pores formed in the lattice structure by the main molecule It is to provide a hydrate manufacturing method for storing gas and hydrogen.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

In order to achieve the above technical problem, the hydrate manufacturing method for storing natural gas and hydrogen according to the present invention is to put the ice powder consisting of the main molecule in a pressurized container and pressurized, the mixture of gaseous state composed of the object molecule in the ice powder Injecting a gas and the object molecules are collected and stored in the pupil formed by the main molecule.

In an embodiment of the present invention, the mixed gas may be a mixture of a natural gas consisting of methane and ethane and a gas consisting of hydrogen.

In an embodiment of the present invention, the methane and ethane may serve as a thermodynamic stabilizer such that a plurality of molecules of hydrogen are collected and stored in each of the empty pores formed by the main molecule.

In an embodiment of the present invention, the hydrogen may be trapped and stored in the empty cavity at a temperature of 263K or more and a pressure of 9Mpa or less through a thermodynamic stabilizer of methane and ethane.

In an embodiment of the present invention, the main molecule may be formed of a first lattice structure and a second lattice structure to be collected with the object molecules.

In an embodiment of the present invention, the first lattice structure may collect two hydrogen molecules, and the second lattice structure may be two hydrogen molecules or three or more hydrogen molecules.

In an embodiment of the present invention, the first lattice structure and the second lattice structure are adjusted in the size of the lattice structure through the collection with the object molecules, and through the dimension adjustment of the lattice structure, the plurality of hydrogen molecules and the collection It can be possible.

In order to achieve the above technical problem, a hydrate manufacturing method for storing natural gas and hydrogen provides an energy source based on the hydrate used as an energy source available to factories, homes or vehicles.

According to an embodiment of the present invention, a method of preparing a hydrate for storing natural gas and hydrogen injects a mixture of natural gas composed of methane and ethane and a gas composed of hydrogen to collect hydrogen molecules in an empty cavity formed by the main molecule. Methane and ethane act as thermodynamic stabilizers so that two or three or more hydrogens can be collected and stored in one pupil, making it possible to manufacture hydrates with excellent storage efficiency and to use existing natural gas transportation and storage infrastructure. It can be effective.

The effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 illustrates various synthetic routes of the first lattice sI and the second lattice sII hydrates and corresponding object molecule distributions according to one embodiment of the invention.
Figure 2 is a table showing the composition of the feed gas and mixed gas hydrate for each sample according to an embodiment of the present invention.
3 shows a synchrotron XRD pattern of a mixed gas hydrate in accordance with one embodiment of the present invention.
4 shows an HH vibron region in the Raman spectrum in one embodiment of the invention.
5 shows an enlarged region of 24-36 ° of a synchrotron XRD pattern in accordance with another embodiment of the present invention.
6 shows the use of hydrogen-natural gas and dissociation of the synthesized hydrogen-natural gas and hydrates according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, coupled)" with another part, it is not only "directly connected" but also "indirectly connected" with another member in between. "Includes the case. In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. As used herein, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 illustrates various synthetic routes of first and second lattice hydrates and corresponding object molecule distributions according to one embodiment of the invention, and FIG. 2 shows each sample according to one embodiment of the invention. Figure 3 is a table showing the composition of the feed gas and the mixed hydrate, Figure 3 is a synchrotron XRD pattern of the mixed gas hydrate according to an embodiment of the present invention, Figure 4 is a HH in the Raman spectrum in one embodiment of the present invention A vibron region is shown, FIG. 5 shows an enlarged region of 24-36 ° of a synchrotron XRD pattern according to another embodiment of the invention, and FIG. 6 shows another region of the invention. The use of hydrogen-natural gas and dissociation of the synthesized hydrogen-natural gas and hydrates according to the examples is shown.

1 to 6, the hydrate manufacturing method for storing natural gas and hydrogen according to the present invention comprises the steps of putting the ice powder consisting of the main molecule in a pressurized container and pressurized, the gas state of the object powder in the ice powder And injecting a mixed gas and collecting and storing the object molecules in the pupil formed by the main molecule.

More specifically, the main molecule is composed of an ice powder (<200 μm) having a pupil lattice structure, and the object molecule is composed of a gaseous mixed gas and injected into the main molecule. In this case, the object molecules are collected and stored in a lattice structure of the pupil formed with the main molecules.

That is, the main molecule is a structure in which object molecules are physically trapped without chemical bonds in a three-dimensional lattice structure, and is composed of a crystalline compound, the main molecule is composed of water molecules, and the object molecules are gaseous mixed gas. It consists of.

In addition, the mixed gas is composed of a mixture of natural gas and hydrogen gas.

In more detail, the natural gas is a natural gas composed of methane and ethane, and the gas composed of hydrogen is mixed to form a mixed gas. Therefore, the methane, the ethane and the hydrogen gas are collected and stored in the empty pupil formed by the main molecule.

On the other hand, the methane and ethane serves as a thermodynamic stabilizer for the capture of hydrogen molecules.

More specifically, the mixed gas is composed of natural gas and hydrogen gas composed of methane and ethane, the mixed gas is collected and stored in the lattice structure of the empty pupil formed by the main molecule, wherein the methane and ethane is The hydrogen molecules promote the collection of the main molecules and molecules of the lattice structure of the empty pores. Therefore, a plurality of hydrogen molecules may be collected in each of the empty pores formed as the main molecule.

That is, a low temperature and a high pressure (220 MPa at 249 K) are required to capture the hydrogen molecules in the hollow pupil formed with the main molecule, but the bin formed by the main molecule at a relatively high temperature and a low pressure through the methane and ethane The hydrogen molecules can be collected in the pupil. Thus, methane and ethane are used as thermodynamic stabilizers for trapping the hydrogen molecules.

In addition, hydrogen molecules are collected at a predetermined temperature and pressure in a lattice structure of empty pores formed by the main molecule.

More specifically, the main molecule is a mixture of a natural gas consisting of methane (CH ₄ ) and ethane (C ₂ H ₆ ) and a gas consisting of hydrogen (H ₂ ), the hydrogen molecule is a temperature of more than 263K and less than 9Mpa At pressure, it is collected and stored in the empty pupil formed by the main molecule. At this time, the methane and ethane serve as a thermodynamic stabilizer in which the hydrogen molecules are trapped in the empty pores formed by the main molecule.

Therefore, the hydrogen molecules generally require a high pressure of 220Mpa or more to be trapped in the main molecule, but the methane and ethane act as a thermodynamic stabilizer, so that the hydrogen at a temperature of 263K or more and a pressure of 9Mpa or less without a separate organic matter A molecule may be collected with the main molecule to form a hydrate.

Meanwhile, the main molecules are formed in the first lattice structure and the second lattice structure and are collected with the object molecules.

More specifically, the ice powder is placed in a pressure vessel, pressurized at 263 K and 9 MPa, and the mixed gas is supplied to form the first lattice structure and the second lattice structure by the main molecules.

CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%)

CH ₄ (60.0 mol%) + C ₂ H ₆ (6.7 mol%) + H ₂ (33.3 mol%)

Therefore, it is possible to form a lattice structure in which a plurality of hydrogen is collected through the supply of methane, ethane and hydrogen gas.

In addition, the first lattice structure and the second lattice structure are two or three or more hydrogen molecules are collected.

In more detail, the first lattice structure collects two hydrogen molecules, and the second lattice structure collects two hydrogen molecules or three or more hydrogen molecules. Accordingly, when the object molecules are collected with the main molecules, the lattice structure is adjusted, and through the dimensional adjustment of the lattice structure, two hydrogen molecules are collected in the first lattice structure, and two hydrogen molecules in the second lattice structure. Or three or more hydrogen molecules are collected.

In addition, the hydrate may be prepared by a method of preparing a hydrate storing natural gas and hydrogen according to the present invention, and may be used as an energy source used in a factory, a headdress, or a vehicle using the prepared hydrate.

On the other hand, the method for producing a hydrate storing natural gas and hydrogen according to the present invention and the experimental example according to it will be described in detail.

Referring to FIG. 1, various synthesis paths and corresponding object molecules of the first lattice structure si and the second lattice structure sII of the cluster are illustrated.

The H ₂ , CH ₄ and C ₂ H ₆ molecules are represented by green, blue and red balls, respectively, and the notation below the hydrate structure indicates the synthetic route and corresponding hydrogen capture rate for each case.

'Ice-sII-sII (1S)': First, sII hydrate was formed and then H ₂ was 'alone' collected in a small cage (1S) through object molecular exchange.

Ice-SII (1S2S2L3L): sII hydrate was collected on was formed directly from the ice, at the same time one or two H ₂ molecules were collected in a small cage (1S2S), a large cage (2L3L) H ₂ molecule of the two or three.

Referring to FIG. 2, FIG. 2 shows a synchrotron XRD pattern of mixed gas hydrates. The object molecular composition of the hydrate samples synthesized via different routes was analyzed by gas chromatography and the results were shown using different feed gas compositions.

(a) CH ₄ (42.9 mol%) + C ₂ H ₆ (57.1 mol%),

(b) CH ₄ (32.5 mol%) + C ₂ H ₆ (56.5 mol%) + H ₂ (11.0 mol%),

(c) CH ₄ (37.2 mol%) + C ₂ H ₆ (41.7 mol%) + H ₂ (21.1 mol%),

(d) CH ₄ (69.4 mol%) + C ₂ H ₆ (30.6 mol%),

(e) CH ₄ (64.3 mol%) + C ₂ H ₆ (20.2 mol%) + H ₂ (15.5 mol%),

(f) Spatial group and lattice parameters of CH ₄ (60.4 mol%) + C ₂ H ₆ (17.2 mol%) + H ₂ (22.4 mol%).

n sI 하이드레이트 (자홍색), 큐빅 Fd

m sII 하이드레이트 (녹색) 및 육각형 P63 / mmc 얼음 (파란색)을 나타낸다.Red circle represents the observed XRD pattern, black solid line represents the calculated XRD pattern, tick mark, cubic Pm

n sI hydrate (magenta), cubic Fd

m sII hydrate (green) and hexagonal P63 / mmc ice (blue).

4 is the H-H vibron region in the Raman spectrum,

(a) hydrates of the first lattice structure (cases I and II) and

(b) hydrates of the second lattice structure (cases III and IV).

(c) CH stretching mode in the Raman spectrum of the mixed sI hydrate consisting of CH ₄ (42.9 mol%) + C ₂ H ₆ (57.1 mol%) (black), CH ₄ (32.5 mol%) + C ₂ H ₆ (56.5 mol%) + H ₂ (11.0 mol%) (blue, case I) CH ₄ (37.2 mol%) + C ₂ H ₆ (41.7 mol%) + H ₂ (21.1 mol%) (red, Case II).

(d) The C-H stretching mode in the Raman spectrum of mixed sII hydrates is CH ₄ (69.4 mol%) + C ₂ H ₆ (30.6 mol%) (black), CH ₄ (64.3 mol%) + C ₂ H ₆ (20.2 mol%) + H ₂ (15.5 mol%) (blue, case III) and CH ₄ (60.4 mol%) + C ₂ H ₆ (17.2 mol%) + H ₂ (22.4 mol%) (red, case IV It is composed of

In addition, all spectra of (c) and (d) were normalized to the O-H stretching mode of the water framework for comparison.

FIG. 5 is an enlarged region of the synchrotron XRD pattern at 24.36 °, see FIG. 3 for a complete synchrotron XRD pattern.

(a) The capture of two H ₂ in a tight small cage of sI hydrate further expands the lattice.

(b) The capture of three or more H ₂ in a loose large cage of sII hydrate expands the lattice smaller.

Meanwhile, according to the present invention,

CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%),

CH ₄ (90.0 mol%) + C ₂ H ₆ (10.0 mol%),

CH ₄ (46.7 mol%) + C ₂ H ₆ (20.0 mol%) + H ₂ (33.3 mol%),

The composition of the gas mixture of CH ₄ (60.0 mol%) + C ₂ H ₆ (6.7 mol%) + H ₂ (33.3 mol%) is synthesized through the reactor with an ice powder composed of main molecules (<200 μm).

All samples examined the capture state of different object molecules in H ₂ loading order, detailed procedure is described below.

Before injecting H ₂ , a binary gas hydrate of CH ₄ and C ₂ H ₆ , which is a precursor skeleton, is synthesized by exposing the ice powder to a feed gas of a mixture of CH ₄ + C ₂ H ₆ and pressurizing the ice powder. It was placed in a vessel and pressurized to 263.15 K, 6 MPa with a gas mixture.

The reactor was then maintained for 3 days in a chilled water-ethanol circulator (RW-2025G, Jeio Tech Co., Ltd., South Korea) to obtain a fully converted CH ₄ + C ₂ H ₆ hydrate.

On the other hand, after confirming that the gas hydrate is free of ice phase through synchrotron X-ray diffraction (synchrontron XRD), all the samples are reloaded into the reactor, and the gas mixture of H ₂ is pressurized by pressing a gas mixture of H ₂ from 263.15 K to 9 MPa. To be loaded into the grid of:

Mixed gas hydrates formed from a mixture of CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%) consist of CH ₄ (46.0 mol%) + C ₂ H ₆ (20.0 mol%) + H ₂ (33.3 mol%) Repressurized. (Case I of FIG. 2),

In addition, the mixed gas hydrate formed from the mixture of CH ₄ (90.0 mol%) + C ₂ H ₆ (10.0 mol%) is CH ₄ (60.0 mol%) + C ₂ H ₆ (6.7 mol%) + H ₂ (33.3 mol% ) And repressurized. (Case III of Figure 2)

These compositions aimed to maintain the ratio of CH ₄ to C ₂ H ₆ at 7 to 3 and 9 to 1, respectively, and the reactor was quenched with liquid nitrogen to analyze mixed gas hydrates.

Meanwhile, a three-way mixture of CH ₄ + C ₂ H ₆ + H ₂ was used as the feed gas in the initial stage to form a mixed gas hydrate. Put ice powder into each pressure vessel and add CH ₄ (46.7 mol%) + C ₂ H ₆ (20.0 mol%) + H ₂ (33.3 mol%) (case II of Figure 2) and CH ₄ (60.0 mol%) + C Pressurized by supplying a mixed gas of ₂ H ₆ (6.7 mol%) + H ₂ (33.3 mol%) (case IV of Figure 2).

Finally, ice powder was exposed to a mixture of CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%) at 6 MPa and 263.15 K, forming a sI type gas hydrate for the first time. After confirming that the gas hydrate is free of ice phase, the feed gas is switched from CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%) to CH ₄ (60.0 mol%) + C ₂ H ₆ (6.7 mol%) + H ₂ (33.3 mol%), resulting in a structural transition from sI to sII hydrate.

To analyze these mixed gas hydrate samples synthesized in different routes, spectroscopic analysis including cold synchrotron XRD, powder X-ray diffraction (PXRD) and dispersed Raman spectroscopy was used. In addition, gas chromatography (GC) analysis was performed to determine the composition of the object molecules in the mixed gas hydrate.

Looking at the results according to the present invention, it was confirmed that without the thermodynamic stabilizer, hydrogen molecules were trapped in the hydrate structure under the appropriate pressure and temperature conditions (ie 263K, P _H2 = 3MPa) with the help of CH ₄ and C ₂ H ₆ gas mixtures. did.

On the other hand, while the by the I H ₂ populations (Different H2 populations from pathway-dependent synthesis) difference from the path-dependent synthesis, a pure CH ₄ to form a first lattice structure (sI) hydrate, CH ₄ + C ₂ H ₆ two won mixture The use of may produce sI, second lattice structure (sII) or mixed sI and sII of various structures depending on the feed gas composition, pressure and temperature, depending on the feed gas composition, pressure and pressure.

That is, pure CH4 forms the first lattice (sI) hydrate, but the use of a binary mixture of CH ₄ + C ₂ H ₆ can produce various structures such as sI, second lattice (sII), or sI and sII. This structure can be created according to the feed gas composition, pressure and temperature of the mixed gas.

In this case, sI and sII hydrates have stoichiometric formulas of 6 (5 ¹² 6 ² ) 2 (5 ¹² ) 46H ₂ O and 8 (5 ¹² 6 ⁴ ) 16 (5 ¹² ) 136H ₂ O in the unit cell, respectively. Wherein C ₂ H ₆ is preferentially collected in 5 ¹² 6 ² and 5 ¹² 6 ⁴ cages, but CH ₄ can be collected in any type of cage. In addition, like CH ₄ , H ₂ can be stored in any type of cage, so it can be collected in various cages.

Meanwhile, a gaseous mixture of CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%) and CH ₄ (90.0 mol%) + C ₂ H ₆ (10.0 mol%) was used to form sI and sII hydrates, respectively. Selected as the feed gas, and although pure methane and ethane preferentially form sI hydrate, a hydrate is formed with a gaseous mixture of methane and ethane having a ethane composition in the range of 1 to 25 mol%.

Thus, depending on the formation conditions, it will be described below what structure is formed of sI and sII under specific experimental conditions.

For CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%) and CH ₄ (90.0 mol%) + C ₂ H ₆ (10.0 mol%) hydrates, the ethane composition on the hydrate was 57.1 mol% and It was found to be 30.6 mol%.

Considering the unit cell of hydrates of sI (6 (5 ¹² 6 ² ) 2 (5 ¹² ) 46H ₂ O) and sII (8 (5 ¹² 6 ⁴ ) 16 (5 ¹² ) 136H ₂ O), the result is CH ₄ versus The ratio of C ₂ H ₆ formed sI and sII hydrates at 7/3 and 9/1, respectively.

Even though ethane occupies large cages rather than small cages in each structure, the composition of enclosed ethane is 75.0 mol% (the fraction of six large cages), which is an ideal stoichiometric fraction due to the partial capture of methane in both large and small cages. Per unit cell of sI hydrate of 8 total cages) and 33.3 mol% (8 large cages / unit cell of sII hydrate of 24 total cages).

In addition, the prepared CH ₄ + C ₂ H ₆ hydrate was injected with H ₂ using a three-way gas mixture of CH ₄ + C ₂ H ₆ + H ₂ (cases I and III in Figure 2).

According to gas chromatography (GC) results, pressure and temperature conditions (9 MPa at 263.15 K) led to the capture of hydrogen in the pre-synthetic hydrate cage, with CH ₄ and C ₂ H ₆ being the feed gas (feed gas: CH ₄ ( 46.7 mol%) + C ₂ H ₆ (20 mol%) + H ₂ (33.3 mol%)) when still present at a ratio of 7/3 (case I), the H ₂ content (57.1 to 56.5) in the ethane composition hydrate medium mol%) is almost identical to the previous hydrate sample.

However, the increase in the amount of H _{2 in} the hydrate medium was about the same as the decrease in the amount of CH ₄ , which caused most hydrogen molecules to replace the methane captured in the 5 ¹² cage due to chemical differences.

In contrast, for binary hydrates originally produced by CH ₄ (90 mol%) + C ₂ H ₆ (10 mol%), CH ₄ (60 mol%) + C ₂ H ₆ (6.7 mol%) + It is replaced by a feed gas of H ₂ (33.3 mol%) and the amount of CH ₄ and C ₂ H ₆ is reduced during the capture of H ₂ in hydrate media. (Case III).

In addition, in cases II and IV of FIG. 2, the amount of hydrogen stored in the hydrate increased dramatically when the triple gas mixture of CH ₄ + C ₂ / H ₂ was in direct contact with the ice powder.

In the mixed gas (CH ₄ + C ₂ H ₆ + H ₂ ) hydrate samples synthesized directly from the ice powder, the hydrogen composition in the hydrate medium is 21.1 mol% and 22.4 mol%, and CH ₄ and C ₂ H ₆ are 7/3. And at a ratio of 9/1.

Thus, gas-phased molecules of methane and ethane serve as thermodynamic stabilizers for the hydrogen storage of hydrate media and are dependent on the amount of highly mixed pathways of hydrogen.

Three-phase (hydrate (H)-liquid water (L _W )-vapor (V)) of the CH ₄ + C ₂ H ₆ + H ₂ system P-T According to the equilibrium conditions, hydrogen in the lattice structure of the hydrate Is included, and this can be achieved under suitable pressure and temperature conditions (FIG. S1).

Phase equilibrium curve of CH ₄ + C ₂ H ₆ with a H ₂ has been moved to the unstable area than a CH ₄ + C ₂ H ₆ without a H ₂ than the light P for pure H ₂ hydrate - is present in the T region, The structure and object molecule distribution of the synthesized mixed hydrate through this will be described below.

Referring to FIG. 4, the strength of the CH stretching mode of ethane in the large cages 2884 and 2940 cm ⁻¹ and the CH stretching mode of methane in the large cage 2900 cm ⁻¹ and the small cage 2921 cm ⁻¹ The intensity of was reduced by adding hydrogen to the feed gas for the exchange reaction of the object molecules (black to blue solid line).

The amount of CH ₄ and C ₂ H ₆ contained in the mixed hydrate with twice the H ₂ concentration of the 5 ¹² cages decreased more when the H ₂ amount reached maximum (solid red line), which is consistent with the GC result. (FIG. 2).

In addition, the mixed hydrate (CH ₄ (60.0 mol%) + C ₂ H ₆ (6.7 mol%) + H ₂ (6.7 mol%)) is a gas phase mixture (CH ₄ (60.4 mol%) + C ₂ Synthesized directly with H ₆ (33.3 mol%) + H ₂ (33.3 mol%) and several H ₂ captures appear in the 5 ¹² and 5 ¹² 6 ⁴ cages of sII hydrate (red solid line in FIG. 4b).

According to the above results, the Raman peak from 4128 to 4142 cm ^-1 is trapped by two or three H ₂ molecules (2 L to 3 L) in a 5 ¹² 6 ⁴ cage, and the gaseous co of CH ₄ and C ₂ H ₆ -guest molecule results in two or three or more H ₂ absorption from the two H ₂ absorption and 5 ¹² 6 ⁴ cages in the cage ⁵¹² can adjust the size of the hydrate cage.

In general, two to four hydrogen clusters in a 5 ¹² 6 ⁴ cage are typically achieved under high pressures of H _{2 in} the range of 35 MPa to 58 MPa at low temperatures of about 240 K, but in the experiments according to the invention the total pressure of the system is 9 MPa at 263 K. The partial pressure of H ₂ resulted in the collection of several hydrogen molecules at 3 MPa, which was quite modest compared to the pressure required to form pure hydrogen hydrate (about 200 MPa).

In contrast, similar to the case of pre-synthesized hydrates (dashed line in FIG. 4A), 5 ¹² or more in mixed hydrates (CH ₄ (64.3 mol%) + C ₂ H ₆ (20.2 mol%) + H ₂ (15.5 mol%)). Several H ₂ captures were not observed in the 5 ¹² 6 ⁴ cages, which was the product of the object molecule exchange reaction in the pre-synthesized hydrate of sII (dashed line in FIG. 4b).

In FIG. 4D, the Raman signal intensity of the CH stretching mode of CH ₄ and C ₂ H ₆ is (60.4 mol%) + C ₂ H ₆ (17.2 mol%) + H ₂ (22.4 mol%) in CH ₄ sII hydrate medium. (Red solid line) and CH ₄ (64.3 mol%) + C ₂ H ₆ (20.2 mol%) + H ₂ (15.5 mol%) (blue solid line) are shown almost identically, and 5 ¹² and 5 ¹² 6 ⁴ Due to the large number of H ₂ captures in both cages, the amount of enclosed H ₂ increased but the change in CH ₄ and C ₂ H ₆ did not change significantly.

On the other hand, when looking at the structural conversion from sI to sII, as shown in Fig. 1, when hydrogen is initially present in a feed gas having a coguest molecule of methane and ethane, the finely ground ice particles simultaneously contain methane, ethane and hydrogen. It is transformed into the receiving hydrate structure (cases II and IV).

During the formation of hydrates, methane and ethane with two 5 ^{12 64} Cage hydrate cage to allow for two or three H ₂ absorption in the H allows the _second collection, and sII hydrate in ⁵¹² cages sI hydrate at the same time adjust Can be.

Conversely, when preforming the sI and sII hydrate structures without hydrogen in the cage, if hydrogen is continuously added to the feed gas while maintaining the CH ₄ / C ₂ H ₆ ratio, then a number of H ₂ captures are pre-synthesized sI and sII It could not be achieved in both hydrates (cases I and III), and only H ₂ was collected alone in 5 ¹² cages as a result of the exchange reaction of the object molecules.

On the other hand, since the unit cell of sII hydrate has a larger cage (5 ¹² 6 ⁴ ) and a smaller cage (5 ¹² ) than sI hydrate, the newly formed 5 ¹² and 5 of sII hydrate during the structural transition from sI to sII hydrate. ¹² 6 ⁴ H ₂ can be captured twice in the cage.

Therefore, the feed gas composition (FIG. S2) can be altered to assess the possibility of several H ₂ captures and look at the structural transition from pre-synthesized sI to sII hydrate.

After forming the sI hydrate under a feed gas of CH ₄ (70.0 mol%) + C ₂ H ₆ (30.0 mol%), the feed gas was changed for spectroscopic analysis (FIG. S2).

In addition, the presynthesized hydrate samples (FIG. 3A) had very low amounts of ice impurities, but the PXRD pattern formed all sII hydrates as a result of the structural transition from sI hydrates rather than the remaining hexagonal ice powder (FIG. S3). ).

According to the invention, a small number of methane and ethane molecules surrounded by sII hydrate can be replaced with each other or with small hydrogen molecules. Thus, the Raman strength of ethane in large cages decreased during the reaction time. However, the Raman intensity of methane in a small cage remained constant for three weeks. That is, most of the hydrogen molecules were preferentially trapped in newly synthesized small cages of sII hydrates during structural transitions.

On the other hand, the lattice parameters calculated using the Le Bail fitting method are: sI for a = 11.933 (92) 는 is CH ₄ (42.9 mol%) + C ₂ H ₆ (57.1 mol%) hydrate and And sII for a = 17.139 (08) Å is mixed with CH ₄ (69.4 mol%) + C ₂ H ₆ (30.6 mol%) hydrate.

sI hydrate is more include C ₂ H ₆ molecules because it has a larger molecular size than _{CH 4 CH 4 (42.9 mol%} ) + C 2 lattice parameter of the H ₆ (57.1 mol%) hydrate is 93 K (a = Significantly larger than the lattice parameter of pure CH ₄ hydrate measured at 11.820 (41) iii).

In the same vein, the lattice parameter of CH ₄ (69.4 mol%) + C ₂ H ₆ (30.6 mol%) hydrate is the lattice of CH ₄ (82.0 mol%) + C ₂ H ₆ (18.0 mol%) measured at 90 K. Slightly larger than the parameter. Thus, storing molecular clusters of H ₂ instead of CH ₄ and C ₂ H ₆ involves a change in lattice parameters.

FIG. 5 shows an enlarged region from 24 to 36 ° of the synchrotron XRD pattern of sI and sII hydrates, respectively.

Figure 5a shows the peak shift to the left of the synchrotron XRD pattern shows a larger lattice parameter (increased 0.471%) as the amount of H ₂ contained in the cage ⁵¹² increases to twice the absorption of H _2.

The exact lattice parameters are a = 11.935 (19) for mixed CH ₄ (37.2 mol%) + C ₂ H ₆ (41.7 mol%) + H ₂ (21.1 mol%) hydrate (case II), mixed CH ₄ (32.5 mol%) + C ₂ H ₆ (56.5 mol%) + H ₂ (11.0 mol%) hydrate (case I) for a = 11.879 (15) ms.

Therefore, two H ₂ capture rates in tight 5 ¹² cages with the help of CH ₄ and C ₂ H ₆ can lead to significant cage expansion in the sI hydrate.

FIG. 5B shows a small peak shift (0.041% increase) caused by multiple H ₂ molecules, with the correct lattice parameters being mixed CH ₄ (60.4 mol%) + C ₂ H ₆ (17.2 mol%) + H ₂ ( 22.4 mol%) CH ₄ (64.3 mol%) + C ₂ H ₆ (20.2 mol%) + H ₂ (15.5 mol%) hydrate (case III) mixed with a = 17.155 (83) for hydrate (case IV) For a = 17.148 (44).

The calculated parameter was higher than that of pure H ₂ hydrate with several H ₂ captures in the small or large cage (a = 17.047 ms) of the reported lattice parameter THF hydrate (a = 17.130 ms). Therefore, the inclusion of the most extreme molecules in the gas phase of methane and ethane allows the hydrate cage dimensions to be adjusted to provide larger cage sizes for several H ₂ captures in sII hydrates.

As a result, the present invention can capture hydrogen in the hydrides of the clathrate compounds by trapping gaseous co-guest species of natural gas (mainly CH ₄ + C ₂ H ₆ ) instead of liquid organic promoters.

Three different approaches to forming the mixed CH ₄ + C ₂ H ₆ + H ₂ hydrates above can accommodate hydrogen molecules in water cages at appropriate pressure and temperature conditions (total pressure at 263.15K). 9 MPa, the partial pressure of H ₂ is about 3 MPa).

When the hydrogen molecule take part in formation of the hydrate lattice, CH ₄ and C ₂ H ₆ is two H ₂ ⁵¹² of the collector and sII hydrate in ⁵¹² cages sI hydrate by adjusting the hydrate cage dimensions and one 5 ^{12 64} Cage Two and three or more H ₂ captures are possible at.

In addition, the lattice parameters of the mixed hydrates are highly dependent on the synthesis route, even with the same feed gas composition, and the expanded lattice of the adjusted hydrates can increase the total hydrogen storage through the capture of two or three H ² per cage. .

On the other hand, the present invention can be applied not only to energy efficient gas storage materials but also to smart platforms utilizing hydrogen natural gas mixtures such as Hythane®, HCNG (hydrogen and CNG mixtures).

Thus, by designing the synthesis route of the mixed gas hydrate, it can be used as a new alternative energy source with the target hydrogen content.

Referring to FIG. 6, (a) shows a process of hydrogen-natural gas production and supply, (b) shows artificially synthesized hydrogen-natural gas hydrate, and (c) shows hydrogen without chemicals- Dissociation of hydrogen-natural gas hydrate in liquid water releasing a natural gas mixture is shown.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is represented by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.

Claims (8)

Putting the ice powder composed of the main molecule into a pressurized container and pressurizing it;
Injecting a gaseous mixed gas composed of object molecules into the ice powder; And
Collecting and storing the object molecules in the pupil formed by the main molecule;
Hydrate manufacturing method for storing natural gas and hydrogen comprising a. The method of claim 1, wherein the mixed gas is a hydrate manufacturing method for storing natural gas and hydrogen, characterized in that a mixture of a natural gas consisting of methane and ethane and a gas consisting of hydrogen. The method of claim 2, wherein the methane and ethane to store the natural gas and hydrogen, characterized in that to act as a thermodynamic stabilizer to collect and store a plurality of molecules of hydrogen in each of the empty pores formed by the main molecule Hydrate manufacturing method. 4. The hydrate manufacturing method of claim 3, wherein the hydrogen is collected and stored in the empty pupil at a temperature of 263 K or higher and a pressure of 9 Mpa or lower through a thermodynamic stabilizer of the methane and ethane. Way. 5. The method of claim 4, wherein the main molecule is formed of a first lattice structure and a second lattice structure so as to be collected with the object molecules. 6. The hydrate of claim 5, wherein the first lattice structure collects two hydrogen molecules, and the second lattice structure collects two hydrogen molecules or three or more hydrogen molecules. Manufacturing method. The method of claim 6, wherein the first lattice structure and the second lattice structure is the size of the lattice structure is adjusted through the collection with the object molecules, and through the dimensioning of the lattice structure, it is possible to collect a plurality of hydrogen molecules Hydrate manufacturing method for storing natural gas and hydrogen, characterized in that. An hydrate-based energy source according to claim 1, wherein the hydrate manufacturing method for storing natural gas and hydrogen is used as an energy source available for use in factories, homes or vehicles.

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