JP2013249605A - Gas-hydrate collecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To collect a produced gas stably and efficiently while avoiding flame extinguishing by seawater and mixing of exhaust gas into the produced gas.SOLUTION: A gas-hydrate collecting system is located in a gas-hydrate layer H, and comprises: a combustion heater 120 for heating and melting gas-hydrate of the gas-hydrate layer; and a collecting pipeline 140 for collecting a produced gas produced from gas-hydrate by melting, and having one end as a collecting port 140a disposed near the combustion heater. The combustion heater includes: a combustion chamber 124 in which a fuel gas is burnt; an introduction part 122 through which the fuel gas is guided and having an injection nozzle 122b for injecting the fuel gas into the combustion chamber on one end side thereof; and a derivation part 126 which is a pipe housing at least the injection nozzle of the introduction part in its inside and through which exhaust gas after combustion in the combustion chamber flows. One end 126a of the derivation part on the side where the injection nozzle is positioned is sealed, and the combustion chamber is formed in the inside of one end side of the derivation part.

Description

  The present invention relates to a gas hydrate recovery device that recovers a product gas by heating a gas hydrate.

  Gas hydrate is a clathrate hydrate (hydrate) solid in which other molecules (gas) are incorporated into a cage structure of water molecules, and is buried in the seabed that satisfies conditions such as low temperature and high pressure. Has been. For example, methane hydrate incorporating methane molecules can be used as an alternative fuel to existing fuel if the contained methane can be recovered, and various recovery means have been proposed.

  Specifically, a technique has been proposed in which a combustion chamber is arranged in a well constructed in a methane hydrate layer, and fuel and an oxidant are supplied to the combustion chamber via piping and burned (for example, patents). Reference 1). In such a technique, methane hydrate is separated into water and methane gas by combustion heat, and the generated methane gas (generated gas) is recovered through a recovery pipe together with exhaust gas.

  There is also a system that heats the methane hydrate layer by pumping seawater with a pump installed at the submarine base, heating it with a heat exchanger, circulating the heated seawater through a pipe placed near the methane hydrate layer. It has been proposed (for example, Patent Document 2). In such a system, a product gas generated from methane hydrate is reformed by a reformer provided at a submarine base.

Japanese Patent No. 4727586 Japanese Patent Laid-Open No. 2004-321852

  However, in the technique of Patent Document 1 described above, exhaust gas is discharged from the open portion of the combustion chamber into the well, so that depending on the ocean current, seawater may enter the combustion chamber from the open portion. Thus, when seawater enters the combustion chamber, the risk of extinction increases. Further, since the product gas separated from the methane hydrate is recovered in a state in which the exhaust gas is mixed, the unit calorific value of the recovered gas is reduced.

  Further, in the technique of Patent Document 2 described above, since the reforming process of the generated gas is performed on the sea floor, it is difficult to operate and control the reformer on the sea floor. Also, the seawater is once heated by the combustion heat of the combustor, and the methane hydrate is heated by the pipe through which the warmed seawater flows. Therefore, the methane hydrate is heated directly by the combustor by the amount of seawater. However, the loss during heat transfer increases. In addition, piping for circulating seawater is easily corroded by seawater.

  In view of such problems, the present invention provides a gas hydrate recovery device that can avoid the flame extinguishing due to seawater and mix exhaust gas into the generated gas, and can recover the generated gas stably and efficiently. The purpose is to do.

  In order to solve the above problems, a gas hydrate recovery device of the present invention is located in a gas hydrate layer, a combustion heater for heating and melting the gas hydrate of the gas hydrate layer, and a melting from the gas hydrate. A recovery pipe having one end as a recovery port disposed in the vicinity of the combustion heater for recovering the generated gas generated by the combustion heater, the combustion heater having a combustion chamber in which the fuel gas is combusted, and a fuel gas being introduced. An exhaust pipe having a jet outlet for jetting fuel gas into the combustion chamber on one end side, and a pipe that accommodates at least the jet outlet of the inlet section inside the exhaust pipe after combustion in the combustion chamber An outlet portion through which the outlet is located. The outlet portion is sealed at one end on the side where the ejection port is located, and the combustion chamber is formed inside the one end side of the outlet portion.

  A fuel pipe that communicates with the introduction section and supplies fuel gas to the introduction section; and an exhaust pipe that communicates with the lead-out section and through which the exhaust gas guided from the lead-out section flows. It is located vertically above the chamber and may contain fuel piping and exhaust piping.

  The exhaust pipe may accommodate a part of the fuel pipe.

  A plurality of combustion heaters may be arranged, the fuel pipe may be branched and communicated with the introduction part of each combustion heater, and the exhaust pipe may be branched and communicated with each lead-out part of each combustion heater.

  The plurality of combustion heaters may have their tips arranged in parallel on a straight line perpendicular to the longitudinal direction.

  The plurality of combustion heaters may be arranged in parallel so that the respective tips are annular and equidistant.

  A separation unit that communicates with the other end of the recovery pipe and removes impurities from the product gas, and a delivery unit that sends a part of the product gas from which impurities are removed as fuel gas to the fuel pipe may be further provided.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to collect | recover generated gas stably and efficiently, avoiding the flame extinction by seawater, and mixing of the exhaust gas to generated gas.

It is a block diagram for demonstrating the gas hydrate collection | recovery apparatus in 1st Embodiment. It is a schematic sectional drawing for demonstrating the combustion heater in 1st Embodiment. It is a block diagram for demonstrating the gas hydrate collection | recovery apparatus in 2nd Embodiment. It is a schematic sectional drawing for demonstrating the some combustion heater in 2nd Embodiment. It is a conceptual diagram for demonstrating arrangement | positioning of a some combustion heater.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a block diagram for explaining a gas hydrate recovery apparatus 100 according to the first embodiment. In FIG. 1, the direction of the arrow indicates the gas flow. As shown in FIG. 1, the gas hydrate recovery device 100 includes a fuel pipe 110, a combustion heater 120, an exhaust pipe 130, a purification device 132, a recovery pipe 140, a separation unit 150, and a delivery unit 160. And a tank 170.

  The fuel pipe 110 communicates with an introduction portion described later of the combustion heater 120 and supplies fuel gas to the introduction portion. Specifically, in the fuel pipe 110, a pipe 112 through which fuel gas is guided and a pipe 114 through which oxidant gas such as air is led are individually arranged and communicated in the middle of supply, and both the fuel pipe 110 are connected to the fuel pipe 110. Gas is flowing in. Note that the fuel gas and the oxidant gas are mixed into the premixed gas in the pipe 112 and the communicating part of the pipe 114. The fuel pipe 110 guides this premixed gas to the combustion heater 120.

  The combustion heater 120 is located, for example, in the gas hydrate layer H in which the gas hydrate in the seawater O is deposited. The combustion heater 120 burns the fuel gas (premixed gas) supplied from the fuel pipe 110, and heats and melts the gas hydrate of the gas hydrate layer H by the combustion heat.

  In the present embodiment, methane hydrate will be described as an example of gas hydrate. However, the gas hydrate recovery apparatus 100 may recover substances contained in gas hydrate other than methane hydrate. Needless to say.

  The exhaust pipe 130 communicates with a later-described outlet portion of the combustion heater 120, and the exhaust gas after combustion led to the outlet portion flows. For example, the exhaust pipe 130 extends to the sea and guides the exhaust gas to the purification device 132. The purification device 132 purifies the exhaust gas and releases it to the atmosphere.

  The recovery pipe 140 is a pipe having a recovery port 140a as one end, and the other end communicates with a separation unit 150 provided on the sea. The recovery port 140a is located in the vicinity of the combustion heater 120, specifically, vertically above a combustion chamber described later of the combustion heater 120, and recovers a gas (generated gas) generated by melting from the gas hydrate.

  The product gas recovered by the recovery pipe 140 is mixed with impurities such as water molecules constituting the gas hydrate and water vapor evaporated from the seawater O. Therefore, the separation unit 150 communicates with the other end of the recovery pipe 140 and removes impurities from the generated gas guided by the recovery pipe 140.

  The sending unit 160 sends a part of the product gas from which impurities are removed as fuel gas to the fuel pipe 110 via the pipe 112 and accumulates the rest in the tank 170. As described above, the delivery unit 160 sends a part of the product gas to the fuel pipe 110 via the pipe 112, so that after the start of the production gas delivery process by the delivery unit 160, it is generated in the combustion heater 120. There is no need to supply fuel gas other than gas separately. Therefore, the purchase cost of the fuel gas and the transport cost of the fuel gas to the gas hydrate recovery device 100 can be reduced.

  Next, a specific structure of the combustion heater 120 will be described. FIG. 2 is a schematic cross-sectional view for explaining the combustion heater 120 in the first embodiment. As shown in FIG. 2, the combustion heater 120 includes an introduction part 122, a combustion chamber 124, and a lead-out part 126.

  The introduction part 122 is a pipe (inner pipe of a double pipe) through which the fuel gas is guided, and one end 122a on the downstream side of the flow of the fuel gas is closed, and the fuel gas is placed near the one end 122a in the combustion chamber. It has a spout 122 b that spouts to 124. A plurality of the jet ports 122b are provided at equal intervals in the circumferential direction of the introduction portion 122.

  The combustion chamber 124 includes a space in the vicinity of the jet port 122b sandwiched between the introduction part 122 and the lead-out part 126, and uses the outer peripheral surface of the introduction part 122 and the inner peripheral surface of the lead-out part 126 as wall surfaces. That is, the combustion chamber 124 is formed inside the outlet 126 on the one end 126a side where the jet port 122b is located.

  In the combustion chamber 124, the fuel gas ejected from the ejection port 122 b of the introduction part 122 to the combustion chamber 124 is ignited and combusted by an ignition device (not shown).

  At this time, in order to avoid backfire from the combustion chamber 124 to the introduction part 122, the length of the flow path of the fuel gas formed by the jet port 122b, that is, the thickness of the wall provided with the jet port 122b is determined by combustion. The diameter of the jet outlet 122b is determined so as to be larger than the extinction distance of the flame generated in the chamber 124.

  The lead-out part 126 is a pipe (outer pipe of a double pipe) that houses the introduction part 122 (at least the jet outlet 122b) inside, and the exhaust gas after burning in the combustion chamber 124 flows. The lead-out portion 126 is sealed at one end 126a.

  Therefore, all the exhaust gas after burning in the combustion chamber 124 flows through the outlet 126, and the heat of the exhaust gas is transferred to the fuel gas flowing through the inlet 122 with the wall of the inlet 122 interposed therebetween. The exhaust gas and the fuel gas are in a counterflow, and the heat of the exhaust gas is efficiently transferred to the fuel gas. Thus, the combustion heater 120 can preheat the premixed gas and increase the thermal efficiency.

  And the wall which comprises the derivation | leading-out part 126 is heated by the flame in the combustion chamber 124 formed in the inside, or the exhaust gas which flows through the inside, and the gas hydrate layer through the layer M in which seawater and produced gas are mixed. Dissipate heat to H. In this way, the combustion heater 120 heats and melts the gas hydrate of the gas hydrate layer H, and the product gas generated by the melting is mixed into the layer M, and then buoyant, from the recovery port 140a of the recovery pipe 140. Collected.

  Inside the recovery pipe 140, as shown in FIG. 2, a fuel pipe 110 and an exhaust pipe 130 are accommodated. With this configuration, if sufficient durability (rigidity, toughness, corrosion resistance, etc.) can be secured for the outline of the recovery pipe 140, the portion of the fuel pipe 110 or the exhaust pipe 130 that is accommodated in the recovery pipe 140 is Since it is protected by the recovery pipe 140, it can be manufactured with an inexpensive member that is not so high in rigidity, toughness, and corrosion resistance, and the cost can be reduced.

  As described above, in the gas hydrate recovery device 100 of the present embodiment, the combustion heater 120 has a sealed structure, so that there is no possibility that seawater O enters the combustion chamber 124. Further, since the exhaust gas is sent from the outlet 126 to the purification device 132 through the exhaust pipe 130, the gas hydrate recovery device 100 does not mix with the product gas, and the unit calorific value of the product gas is reduced. Can also be avoided.

  Furthermore, the gas hydrate recovery device 100 simply heats the gas hydrate layer H with the combustion heater 120 in the sea, does not require complicated control, and the combustion heater 120 has a simple structure. Therefore, the failure rate can be reduced and the maintainability can be improved. In addition, since the gas hydrate layer H is directly heated by the combustion heater 120, the gas hydrate recovery device 100 is configured to heat the seawater O and circulate the heated seawater O through a pipe for heating, for example. In comparison, heat loss is suppressed, and the risk of pipe corrosion can be suppressed.

(Second Embodiment)
In the above-described embodiment, the gas hydrate recovery device 100 including one combustion heater 120 has been described. However, the gas hydrate recovery device may include a plurality of combustion heaters 120. In the second embodiment, a gas hydrate recovery apparatus 200 including a plurality of combustion heaters 120 will be described.

  FIG. 3 is a block diagram for explaining a gas hydrate recovery apparatus 200 according to the second embodiment. The gas hydrate recovery device 200 includes a fuel pipe 210, a plurality of combustion heaters 120, an exhaust pipe 230, a purification device 132, a recovery pipe 140, a separation part 150, a delivery part 160, and a tank 170. Consists of including. Since the gas hydrate recovery apparatus 200 in the second embodiment differs from the gas hydrate recovery apparatus 100 in the first embodiment in the number of fuel pipes 210, exhaust pipes 230, and combustion heaters 120, here The description of the same configuration as the first embodiment is omitted, and only the number of fuel pipes 210, exhaust pipes 230, and combustion heaters 120 having different configurations will be described.

  FIG. 4 is a schematic cross-sectional view for explaining a plurality of combustion heaters 120 in the second embodiment, and FIG. 5 is a conceptual diagram for explaining the arrangement of the plurality of combustion heaters 120. In FIG. 5, the position of the combustion heater 120 in the VV line cross section of FIG. 4 is simplified and shown.

  As shown in FIGS. 4 and 5A, in the gas hydrate recovery apparatus 200, a plurality of combustion heaters 120 are arranged. Here, a case where two combustion heaters 120 are arranged will be described.

  The fuel pipe 210 branches and communicates with the introduction part 122 of each of the two combustion heaters 120, and the exhaust pipe 230 branches and communicates with the lead-out part 126 of each of the two combustion heaters 120.

  As described above, the gas hydrate recovery apparatus 200 can heat the gas hydrate layer H over a wide range and recover a larger amount of product gas by arranging the plurality of combustion heaters 120.

  By the way, since the recovery pipe 140 is in contact with the seawater O, the generated gas circulating inside is cooled by the seawater O through the recovery pipe 140. When the fuel pipe 210 is cooled by the cooled product gas, the fuel gas is cooled, and the thermal efficiency in the combustion heater 120 is lowered.

  Therefore, in the present embodiment, the exhaust pipe 230 accommodates a part of the fuel pipe 210 as shown in FIG. With this configuration, the gas hydrate recovery device 200 suppresses the cooling of the fuel pipe 210 by the seawater O by the exhaust pipe 230 and the exhaust gas flowing through the exhaust pipe 230. In addition, the gas hydrate recovery device 200 can preheat the premixed gas flowing through the fuel pipe 210 with the exhaust gas flowing through the exhaust pipe 230, and can improve the thermal efficiency in the combustion heater 120. Become.

  Moreover, in the gas hydrate recovery apparatus 200, as shown in FIG.5 (b), the three or more combustion heaters 120 may be arrange | positioned. When three or more combustion heaters 120 are arranged, as shown in FIG. 5B, the respective tips are arranged in parallel on a straight line perpendicular to the longitudinal direction. Thus, when the gas hydrate layer H is extended in the horizontal direction by the structure which arrange | positions the some combustion heater 120 on a straight line, the some combustion heater 120 is made into the gas hydrate layer H. The product gas can be efficiently recovered.

  Moreover, as shown to FIG.5 (c)-(e), the some combustion heater 120 may be distribute | arranged in parallel so that each front-end | tip may become cyclic | annular and equidistantly spaced. In other words, it can be said that the combustion heaters 120 arranged at equal intervals in a ring are arranged at the apexes of the polygon. For example, if the combustion heater 120 is FIG. 5 (c), it is at the apex of the triangle, if it is FIG. 5 (d), it is at the apex of the square, and if it is FIG. If it is FIG.5 (f) at the vertex, it will distribute | arrange so that it may each be located in a hexagonal vertex.

  With this configuration, the gas hydrate recovery apparatus 200 can uniformly heat the gas hydrate layer H over a wide range, and can efficiently recover the generated gas.

  In the above-described embodiment, the case where the recovery pipe 140 accommodates the fuel pipes 110 and 210 and the exhaust pipes 130 and 230 has been described. However, the fuel pipes 110 and 210 and the exhaust pipes 130 and 230 are the recovery pipes. It may be arranged outside 140.

  Further, in the second embodiment described above, the configuration in which the exhaust pipe 230 accommodates a part of the fuel pipe 210 has been described, but the fuel pipe 210 may be arranged outside the exhaust pipe 230. Further, in the first embodiment described above, the exhaust pipe 130 may be configured to accommodate a part of the fuel pipe 110.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  INDUSTRIAL APPLICABILITY The present invention can be used for a gas hydrate recovery device that recovers a product gas by heating a gas hydrate.

DESCRIPTION OF SYMBOLS 100,200 ... Gas hydrate collection | recovery apparatus 110,210 ... Fuel piping 120 ... Combustion heater 122 ... Introduction part 122a ... End 122b ... Outlet 124 ... Combustion chamber 126 ... Outlet part 126a ... End 130, 230 ... Exhaust piping 140 ... Recovery pipe 150 ... separation part 160 ... delivery part H ... gas hydrate layer

Claims (7)

A combustion heater located in the gas hydrate layer for heating and melting the gas hydrate of the gas hydrate layer;
A recovery pipe for recovering a product gas generated by melting from the gas hydrate, and having a recovery port disposed near the combustion heater as one end;
With
The combustion heater is
A combustion chamber in which fuel gas burns;
A pipe through which the fuel gas is guided, and an introduction part having an ejection port for ejecting the fuel gas into the combustion chamber on one end side;
A pipe that accommodates at least the jet port of the introduction part therein, and a lead-out part through which exhaust gas after combustion in the combustion chamber flows;
With
The derivation unit includes:
One end on the side where the spout is located is sealed,
The combustion chamber is
A gas hydrate recovery device, wherein the gas hydrate recovery device is formed inside one end of the lead-out portion. A fuel pipe communicating with the introduction part and supplying the fuel gas to the introduction part;
An exhaust pipe that communicates with the lead-out portion and through which the exhaust gas led from the lead-out portion flows;
Further comprising
The recovery pipe is
The gas hydrate recovery device according to claim 1, wherein the recovery port is positioned vertically above the combustion chamber and houses the fuel pipe and the exhaust pipe.   The gas hydrate recovery device according to claim 2, wherein the exhaust pipe accommodates a part of the fuel pipe. A plurality of the combustion heaters are arranged,
The fuel pipe branches and communicates with the introduction part of each of the combustion heaters,
4. The gas hydrate recovery device according to claim 2, wherein the exhaust pipe branches and communicates with the lead-out portion of each of the combustion heaters.   5. The gas hydrate recovery device according to claim 4, wherein each of the plurality of combustion heaters has a tip arranged in parallel on a straight line perpendicular to the longitudinal direction.   The gas hydrate recovery device according to claim 4, wherein the plurality of combustion heaters are arranged in parallel so that respective tips are annular and equidistant. A separation unit that communicates with the other end of the recovery pipe and removes impurities from the generated gas;
A delivery unit for delivering a part of the product gas from which impurities have been removed to the fuel pipe as a fuel gas;
The gas hydrate recovery device according to any one of claims 1 to 6, further comprising:

Images