JP2002138289A - Manufacturing apparatus of natural gas hydrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively manufacture a natural gas hydrate with a high gas- liquid contact efficiency in a short time without necessitating a pump for circulating liquid or gas. SOLUTION: The manufacturing apparatus of a natural gas hydrate for manufacturing the natural gas hydrate by reacting natural gas with water in a pressure reaction vessel is provided with a natural gas passage 8 for passing through natural gas, extending in the direction of an agitating shaft, inside the agitating shaft 5 of a stirring apparatus 7 for stirring water 12 in the pressure reaction vessel 1, a natural gas inflow port 9 for causing natural gas to flow into the natural gas passage 8 at a position where the agitating shaft 5 contacts with natural gas, and a natural gas release port 11 for releasing natural gas in the natural gas passage 8 into water at the lower part of the agitating shaft 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a natural gas hydrate producing apparatus for producing natural gas hydrate by reacting natural gas with water.

[0002]

2. Description of the Related Art Natural gas hydrate requires less storage volume than natural gas stored as a gas and is safe from fires and the like. There have been proposed various techniques for producing natural gas hydrate by reacting water with water. FIG. 2 is a configuration diagram showing a conventional methane hydrate production apparatus disclosed in, for example, JP-A-11-130700. FIG.
As shown in the figure, in the conventional methane hydrate production apparatus, an aqueous phase L is transferred from an ascending flow chamber 33 to an upper chamber 34, a descending flow chamber 35, and an aqueous phase circulation pump 36 in a reaction vessel 32 having a partition plate 31. Circulated, methane is supplied from the methane inlet 37 to the ascending flow chamber 33 and reacted with water. This is a device that is collected in the hydrate collection tank 39.

[0003]

However, the above-mentioned conventional apparatus for producing natural gas hydrate has the following problems. Since natural gas hydrate generated by the reaction of natural gas being absorbed into water has a lower density than water, it floats near the liquid surface and forms a natural gas hydrate layer, so it follows the gas-liquid interface. To prevent natural gas from being absorbed into the water. Therefore, even after the natural gas hydrate layer is formed, it is necessary to circulate the liquid or gas in order to enhance the good gas-liquid contact efficiency, but the apparatus using the liquid or gas circulating pump is an apparatus. Is complicated and extra energy is consumed to drive the pump. The present invention has been made to solve the above-described problems of the prior art, and does not require a pump for circulating a liquid or a gas,
It is an object of the present invention to provide a natural gas hydrate production apparatus capable of realizing high gas-liquid contact efficiency.

[0004]

A natural gas hydrate producing apparatus according to the present invention is a natural gas hydrate producing apparatus for producing natural gas hydrate by reacting natural gas and water in a reaction vessel. A natural gas passage extending in the axial direction for passing natural gas is provided inside a stirring shaft of a stirrer for stirring water in the reaction vessel, and the natural gas passage is provided at a position where the natural gas passes through the stirring shaft. A natural gas inflow port for allowing natural gas to flow into the natural gas passage; and a natural gas discharge port for discharging natural gas in the natural gas passage into water at the lower end of the stirring shaft.

[0005] In the apparatus for producing a natural gas hydrate according to the present invention, the natural gas supplied to the reaction vessel flows from the natural gas inlet through a natural gas passage provided inside a stirring shaft of the stirrer, and flows into the natural gas hydrate. The natural gas is discharged into the water from a natural gas discharge port provided at the lower end of the gas passage, and a part of the released natural gas is reacted with water to form natural gas hydrate by being stirred by a stirrer. Float near to form a natural gas hydrate layer. Natural gas that has not reacted with water floats above the natural gas hydrate layer and, together with newly supplied natural gas, passes through the natural gas passage again from the natural gas inflow port to the natural gas passage. It is released into water together with the newly supplied natural gas from a natural gas discharge port provided at the lower end. As described above, the natural gas released into the water circulates along the flow of the newly supplied natural gas, so that the gas-liquid contacting efficiency is increased and the natural gas hydrate can be efficiently produced in a short time. Can be.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the apparatus for producing a natural gas hydrate of the present invention. The apparatus for producing a natural gas hydrate shown in FIG.
A gas introduction pipe 2 for introducing natural gas into the pressure-resistant reaction vessel 1 via a shut-off valve 2a;
a stirrer 7 comprising a water inlet pipe 3 introduced through a.a, a rotating shaft 4 rotated by a driving source (not shown), a stir shaft 5 rotated by the rotating shaft 4, and a stirring blade 6 attached to the stirring shaft 5. It is composed of

[0007] A natural gas passage 8 (indicated by a dotted line) extending in the axial direction through which natural gas passes is provided inside the stirring shaft 5 of the stirring device 7. A natural gas inlet 9 through which natural gas flows into the gas passage 8 is provided. Further, a horizontal member 10 orthogonal to the stirring shaft 5 is provided at a lower end portion of the stirring shaft 5, and a horizontal natural gas passage 10 a communicating with the natural gas passage 8 is provided inside the horizontal member 10. The horizontal member 10
A natural gas discharge port 11 for discharging natural gas in the horizontal natural gas passage 10a into water is provided at both ends of the natural gas passage 10a. The position of the natural gas discharge port 11 is such that the released natural gas rises and hits the tip of the stirring blade 6 in order to cause the natural gas to efficiently react with water.

Next, a method for producing natural gas hydrate by using the apparatus for producing natural gas hydrate will be described. First, if necessary, a solid catalyst is put into the pressure-resistant reaction vessel 1 and sealed with the lid 1a. Then, the air in the pressure-resistant reaction vessel 1 is degassed by the gas introduction pipe 2, and the shut-off valve 2a is closed. Next, the closing valve 3a is opened, a predetermined amount of water 12 is introduced into the pressure-resistant reaction vessel 1 through the water introducing pipe 3, and the closing valve 3a is closed. Then, the shut-off valve 2a of the gas introduction pipe 2 is opened, and natural gas is introduced until the pressure of the natural gas in the pressure-resistant reaction vessel 1 reaches a predetermined pressure. Then, the stirring shaft 5 is rotated by the rotation shaft 4 of the stirring device 7, and the water 12 in the reaction vessel 1 is rotated.
Is stirred by the stirring blade 6. Water 1 by stirring blade 6
When the agitator 2 is agitated, a region of negative pressure is generated around the agitating blade 6, so that the natural gas accumulated in the portion above the water 12 flows through the natural gas inlet 9 provided on the agitating shaft 5 through the natural gas inlet 9. The natural gas discharge ports 1 provided at both ends of the horizontal member 10 through the passage 8 and the horizontal natural gas passage 10a of the horizontal member 10
1 is released into water 12.

When the temperature in the pressure-resistant reaction vessel 1 reaches a predetermined temperature by stirring, the natural gas comes into contact with the water 12 and reacts to generate a natural gas hydrate. When the natural gas hydrate is generated, the pressure in the pressure-resistant reaction vessel 1 decreases, so that natural gas is additionally introduced from the gas introduction pipe 2 as appropriate. In the apparatus for producing a natural gas hydrate of the present invention, natural gas is circulated in the water 12 in the pressure-resistant reaction vessel 1, so that the gas-liquid contact efficiency is increased and the natural gas hydrate is efficiently produced in a short time. Can be manufactured well. The natural gas used to produce the natural gas hydrate described above is 90-99.9% methane gas. The rotation speed of the rotating shaft 4 of the stirring device 7 is about 500 rpm, and the stirring shaft 5 is made of stainless steel. The pressure in the reaction vessel 1 is about 5 MPa, and the temperature is about 1 ° C. The solid catalyst is a porous solid substance such as silica gel, alumina, silica, alumina,
Titania, magnesia, zeolite, activated carbon and the like are used.

[0010]

EXAMPLES A 300 ml stainless steel reaction vessel was charged with 200 ml of pure water and cooled until the water in the reaction vessel reached 1 ° C. Next, after the air in the reaction vessel was sufficiently exhausted by a vacuum pump connected to the gas introduction pipe,
Natural gas composed of 99.8% of methane gas, 0.1% of ethane gas and 0.1% of nitrogen gas was introduced into the reaction vessel, and the pressure in the reaction vessel was increased to 5 MPa. Furthermore, a stainless steel stirring rod provided with a natural gas inlet, a natural gas passage, and a natural gas discharge port was rotated at 500 rpm to stir water in the reaction vessel.

By this operation, a natural gas hydrate composed of natural gas and water is generated, the natural gas in the reaction vessel is consumed, and the pressure in the reaction vessel decreases, so that the pressure in the reaction vessel is maintained at 5 MPa. As we did, we continued to supply natural gas. Then, the natural gas consumption rate was determined from the natural gas supply rate after the start of the natural gas hydrate generation reaction, and this consumption rate was used as the natural gas hydrate generation rate. As a result, the generation rate of natural gas hydrate under the above conditions was 24.5 ml / min. On the other hand, as a comparative example, a natural gas inlet, a natural gas passage and a conventional reaction vessel equipped with a stirring shaft without a natural gas discharge port were used to generate natural gas hydrate under the same operating conditions as described above, and the generation rate was increased. I asked. As a result, the production rate of natural gas hydrate in the comparative example was 7.8 ml / min, and it could be confirmed that the production rate of natural gas hydrate was significantly increased by the natural gas hydrate production apparatus of the present invention. Was.

[0012]

As described above, according to the present invention, the natural gas supplied to the reaction vessel passes from the natural gas inlet through the natural gas passage provided inside the stirring shaft of the stirrer, and flows into the lower end of the natural gas passage. The natural gas is released into the water from the natural gas discharge port provided in the section, and a part of the released natural gas reacts with water to become natural gas hydrate by being stirred by the stirrer, and floats near the liquid level. The natural gas that has not reacted with water forms a natural gas hydrate layer and floats above the natural gas hydrate layer, and flows again through the natural gas inlet from the natural gas inlet with the newly supplied natural gas. As a result, the natural gas discharged from the natural gas discharge port provided at the lower end of the natural gas passage is released into the water together with the newly supplied natural gas. Along To ring, gas-liquid contact efficiency is high, there is an effect that can be produced efficiently in a short period of time natural gas hydrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a natural gas hydrate production apparatus of the present invention.

FIG. 2 is a configuration diagram showing a conventional apparatus for producing a natural gas hydrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure-resistant reaction vessel 2 Gas introduction pipe 3 Water introduction pipe 4 Rotation axis 5 Stirring axis 6 Stirring blade 7 Stirring device 8 Natural gas passage 9 Natural gas inlet 11 Natural gas discharge port 12 Water

Claims (1)

[Claims] 1. A natural gas hydrate producing apparatus for producing natural gas hydrate by reacting natural gas and water in a reaction vessel, wherein a stirring shaft of a stirring apparatus for stirring water in the reaction vessel. A natural gas passage extending in the axial direction through which natural gas passes is provided inside, and a natural gas inlet for flowing natural gas into the natural gas passage is provided at a position of the stirring shaft in contact with the natural gas; An apparatus for producing natural gas hydrate, wherein a natural gas discharge port for discharging natural gas in the natural gas passage into water is provided at a lower end portion.