JP4817606B2 - Gas hydrate regasifier - Google Patents

Description

  The present invention relates to a gas hydrate regasification apparatus.

  Gas hydrate is a hydrate that is stable as a solid formed by incorporating gas into the water molecules, and when the incorporated gas is methane, methane hydrate and natural gas (usually methane as the main component) Is called natural gas hydrate. Natural gas hydrate is stable under low temperature and high pressure, and becomes unstable under normal temperature and normal pressure. It is attracting attention as a natural gas resource.

  On the other hand, since gas hydrate can store a large amount of gas in its structure and can be transported and stored at -10 ° C. and atmospheric pressure, natural gas hydrate (NGH) is produced industrially. However, research is being conducted to use it as a means for transporting and storing natural gas instead of liquefied natural gas (LNG).

  When gas hydrate is used, generally, so-called regasification is performed in which gas hydrate and hot water as a heating medium are supplied into a gasification vessel, and the gas hydrate is thermally decomposed to extract gas. (For example, refer to Patent Document 1). According to this, the gas generated in the gasification vessel and the hot water are separated by guiding them to the gas-liquid separator, and the gas is taken out from the gas-liquid separator, and the hot water is extracted by the pump and heated and then gasified again. It is configured to return to the container.

Japanese Patent Laid-Open No. 2001-279281 (see FIG. 1, pages 2-4)

  However, according to the prior art described in Patent Document 1 described above, a gas-liquid separator is required in addition to the gasification vessel, and the gas hydrate and hot water are mixed while rotating the horizontal cylindrical gasification vessel. Since stirring is performed, there is a problem that the apparatus becomes complicated.

  Therefore, the gasification container is fixed, and the gas hydrate and hot water in the container are stirred, for example, with a stirrer, etc., and the gas is extracted from the top of the container, and the hot water is extracted from the bottom of the container with a circulating water pump and circulated. It is possible to make it.

  However, the circulating water containing many bubbles stirred by the stirrer may flow into the circulation pump and adversely affect the pump. Moreover, if a part of circulating water is extracted as produced water, many gases will be mixed in this produced water.

  The present invention stirs water into which gas hydrate has been charged by a stationary gasification vessel and gasifies the gas hydrate while circulating the water in the gasification vessel to remove gas bubbles mixed in the circulating water. The problem is to reduce.

In order to solve the above-described problems, a gas hydrate regasification apparatus according to the present invention supplies a gas hydrate and water to which a gas hydrate and water are supplied and a gas discharge port at the top, and water in the gasification vessel. A stirrer for stirring, a circulating water pump for extracting water from the outlet provided at the bottom of the gasification vessel and returning it to the upper portion of the gasification vessel, and returning water to the gasification vessel and / or the upper portion of the gasification vessel And a heater for heating the circulating water . A baffle plate is provided in the gasification container so as to face the outlet.

  According to this configuration, water and gas hydrate are stirred in the gasification vessel by the stirrer, whereby gasification is promoted and gas-liquid separation is promoted by agglomeration of gas bubbles. It can be taken out. In this case, if water containing many bubbles flows directly into the outlet when agitated, the bubbles will adversely affect the pump, but the flow that flows directly into the outlet can be blocked by a baffle plate. Can be reduced from flowing into the pump. Here, the stirrer can use a rotating blade for stirring water in the gasification vessel.

  Moreover, a heat exchanger can be used as a heater, This heat exchanger can be arrange | positioned in the gasification container or the discharge side flow path of a circulating water pump. The heat exchanger disposed in the gasification vessel can be configured such that the gasification vessel is formed in a vertical cylindrical shape and the cylindrical heat exchanger is provided concentrically on the body of the gasification vessel. In this case, the heat exchanger has a space formed by closing both ends of the inner cylinder and the outer cylinder with a closing plate, a plurality of heat transfer tubes are provided through the upper and lower closing plates, and a heat medium is provided in the space. The outflow inlet is communicated, and the rotary vane is arranged in the inner cylinder so that the circulating water in the inner cylinder can flow downward. According to this, it is possible to suppress that the downward flow caused by the stirrer collides with the upper surface of the baffle plate and is prevented from descending and directly flows into the outlet. In any case, it is preferable that the baffle is formed in a shade shape and is arranged with the protruding side facing downward.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a gas hydrate regasification apparatus of the present invention. As the gas hydrate used in the present embodiment, for example, natural gas hydrate or methane gas hydrate can be used. In the present embodiment, for example, water is used as the circulating water for heating the gas hydrate.

  As shown in FIG. 1, a container 1 provided as a gasification tank is formed in, for example, a vertical cylindrical shape, and includes a crusher 2, a cylindrical heat exchanger 3 that is a heater, and a stirrer 7. It is prepared for.

  The crusher 2 includes a ridge 21 and a crushed blade 23 disposed in the ridge 21. The eaves 21 are formed of, for example, a mesh-shaped member (for example, 1 to 2 mm), and the crushing blade 23 is connected to a rotating shaft 25 that passes through the top of the container 1 and hangs down. The rotating shaft 25 is connected to a rotation driving device (not shown). A nozzle 27 is provided on the top of the container 1 above the jar 21, and a gas hydrate (for example, a particle size of 20 to 50 mm) is supplied from a supply device (not shown) to the jar 21.

  A nozzle 17 for supplying water is provided at the top of the container 1 above the bowl 21, and a water outlet 11 is provided at the bottom of the container 1. The outlet 11 is connected to the suction side of the circulating water pump 13, and the discharge side of the circulating water pump 13 is connected to the nozzle 17 via the auxiliary heat exchanger 15. For example, a hollow ring 18 concentric with the container 1 is connected to the tip of the nozzle 17, and a plurality of small holes are formed in the hollow ring 18. The plurality of small holes are formed so as to discharge the water 9 toward the inner wall of the container 1 and the bottle 21.

  The heat exchanger 3 has an inner cylinder 31 and an outer cylinder 33 that are arranged concentrically with the body portion of the container 1. The upper end of the inner cylinder 31 and the upper end of the outer cylinder 33, and the lower end of the inner cylinder 31 and the lower end of the outer cylinder 33 are connected by the closing plates 35 and 36 over the entire circumference, whereby the inner cylinder 31, the outer cylinder 33, and the closing plate are connected. A space 37 surrounded by 35 and 36 is formed. A plurality of heat transfer tubes 38 are provided between the inner cylinder 31 and the outer cylinder 33 so as to penetrate the blocking plates 35 and 36. In the space 37, the inlet 42 and the outlet 43 of the heat medium 40 are connected, and the heated heat medium 40 is circulated. In addition, although the outer cylinder 33 of the heat exchanger 3 was used as the body part of the container 1, the outer cylinder 33 and the body part of the container 1 can be formed of separate members.

  The stirrer 7 includes a rotating blade 44 connected to the tip of the rotating shaft 25 of the crushing blade 23, and the rotating blade 44 is disposed in the inner cylinder 31. The rotating shaft 25 is inserted through a through hole 24 formed in the bottom of the flange 21 and extends downward. Alternatively, the rotating shaft 25 may be formed of a double pipe, and the crushing blade 23 and the rotating blade 44 may be rotated separately.

  The bubble separation plate 45 (baffle) which is a baffle plate which is a characteristic part of the present embodiment is provided so as to face the outlet 11 which is an extraction part. The bubble separation plate 45 is formed in a shade shape smaller than the inner diameter of the bottom of the container 1 and is arranged with the protruding side facing downward.

  The operation of the gas hydrate regasification apparatus of this embodiment will be described. First, water 9 is stretched in the container 1 so that at least the heat exchanger 3 is submerged, the heat medium is passed through the heat exchanger 3 to heat the water 9, the rotating shaft 25 is rotated, and the crushing blade 23 and The rotary blade 44 is rotated. As a result, the gas hydrate introduced from the nozzle 27 is crushed by the crusher 2 and falls into the water 9, and the gas hydrate dropped into the water is heated in contact with the water 9 by so-called decomposition gasification. The gas is separated into water and gas bubbles (for example, a diameter of several tens to several μm) are generated. Water 9 is sent downward by a stirrer 7. This downward flow is reversed and rises at the bottom of the container 1 and flows through the heat transfer tube 38 and circulates. Thereby, the water 9 is heated and the heat required for gasification is supplied.

  The gasification described above is activated by stirring and promotes the aggregation of gas bubbles. Large bubbles generated by the aggregation rise in water, are discharged from a nozzle 29 that is a gas discharge port provided at the top of the container, and are sent to a gas utilization device, a gas storage tank, or the like.

  On the other hand, the water 9 containing many bubbles stirred by the stirrer 7 flows toward the outlet 11, but since this flow is blocked by the bubble separator 45, the bubbles are prevented from flowing directly into the outlet 11. it can. Further, a part of this flow descends from the gap between the bubble separation plate 45 and the inner wall of the container 1, is extracted from the outlet 11, and is used for circulation. Part of this circulating water can be extracted as product water, and according to this, for example, the water level in the container 1 can be adjusted.

  Thus, according to this embodiment, it is possible to suppress the bubbles from being mixed into the water 9 drawn out from the outlet 11 by the bubble separator 45. In particular, when a stirrer 7 is provided in the container 1 to cause the water 9 in the container 1 to flow downward and stir, the flow by the stirrer 7 is directed to the outlet 11. Since it collides, it can suppress that a bubble flows in into the outlet 11. Further, since the bubble separating plate 45 is formed in a cap shape and arranged with the protruding side facing downward, the bubbles colliding with the upper surface of the bubble separating plate 45 are likely to rise, so that the bubbles are extracted from the outlet 11. It can further be suppressed that the water 9 is accompanied. As a result, it has been necessary to separate bubbles and water in the past. For example, the container has sufficient residence time, or a gas separation layer such as a gas-liquid separator is separately installed, or a special circulation is provided. It is preferable because facilities such as using a pump are unnecessary.

  In the present embodiment, the configuration in which the heat exchanger 3 and the auxiliary heat exchanger 15 are provided has been described. However, as shown in FIG. 2, a large-capacity heat exchanger 55 is provided in place of the auxiliary heat exchanger 15. By doing so, the heat exchanger 3 can be omitted. In FIG. 1, the auxiliary heat exchanger 15 can be omitted. As described above, the heat exchanger 3 and the auxiliary heat exchanger 15 are used as the heater, but a heater such as a known electric heater may be used instead.

  In the present embodiment, the cap-shaped bubble separation plate 45 is used as the baffle plate. However, the baffle plate may be any shape as long as it can suppress the flow of bubbles into the outlet 11 and may have various shapes such as a flat plate shape.

It is sectional drawing of the regasification apparatus of the gas hydrate of one Embodiment of this invention. It is sectional drawing which showed the modification of embodiment shown in FIG.

Explanation of symbols

1 container 2 crusher 3 heat exchanger 7 stirrer 9 water 11 outlet 13 circulating water pump 15 auxiliary heat exchanger 17, 27, 29 nozzle 45 bubble separation plate

Claims (5)

A gasification vessel supplied with gas hydrate and water and having a gas outlet at the top, a stirrer for stirring the water in the gasification vessel, and the water from an outlet provided at the bottom of the gasification vessel A circulating water pump that is extracted and returned to the upper part of the gasification container; and a heater that heats the water in the gasification container and / or the circulating water returned to the upper part of the gasification container. A gas hydrate regasification device comprising a baffle plate facing the outlet.   The gas hydrate regasification apparatus according to claim 1, wherein the stirrer is a rotary blade that stirs the water in the gasification vessel.   The heater is a heat exchanger that is provided in a discharge-side flow path of the circulating water pump and that heats the water that is extracted from the gasification vessel and returned to the gasification vessel. The gas hydrate regasification apparatus according to 1 or 2.   The gasification vessel is formed in a cylindrical vertical shape, and the heater is provided concentrically on the body of the gasification vessel, and a space is formed by closing both ends of the inner cylinder and the outer cylinder with a closing plate, A plurality of heat transfer tubes are provided through the upper and lower blocking plates, a heat medium outlet / inlet is communicated with the space, and the stirrer is disposed in the inner cylinder, and the water in the inner cylinder is discharged. 2. The gas hydrate regasification apparatus according to claim 1, wherein the gas hydrate regasification apparatus is a rotary blade that flows downward.   5. The gas hydrate regasification apparatus according to claim 1, wherein the baffle plate is formed in a cap shape and is disposed with a protruding side facing downward. 6.

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