JP2010201992A - Ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ship capable of securing high air tightness so as to prevent air from intruding into a cargo hold at a portion where a cargo handling device moves and the entire hatch portion of the cargo hold, and, in the worst case, capable of preventing formation of explosive atmosphere by intrusion of the air into a cargo handling section where the cargo handling device moves and the cargo hold in the ship equipped with the cargo hold for accommodating bulk solids generating combustible gas. <P>SOLUTION: The ship includes: a cargo handling facility moving on the cargo hold 3 in a hull longitudinal direction; and a fully closing cover 4 which has an airtight structure for covering the portion where the cargo handling device moves and the entire hatch portion of the cargo hold 3. The ship includes a first pipe arrangement 8 one end of which opens at a cargo handling section 6 in the fully closing cover 4, and the other end of which is connected to a gas pressure adjusting device 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ship for transporting solid cargoes that generate combustible gases such as natural gas hydrate (NGH) pellets.

  Recently, natural gas hydrate has attracted attention, and it has been studied to transport natural gas in the form of gas hydrate pellets in bulk.

  For example, as a gas hydrate transport ship that transports the gas hydrate cargo containing this gas while keeping it airtight, it is a box-shaped move that can move in the captain direction on a hold (cargo hold) arranged in the captain direction. There has been proposed a gas hydrate transport ship in which a house is provided, a cargo handling device is built therein, and the movable house is moved together with the cargo handling device to perform cargo handling (see, for example, Patent Document 1).

  In this gas hydrate transport ship, a sealing material is provided over the entire circumference of the moving house, and the gap between the moving house and the hull is sealed by this sealing material. In this configuration, a moving device for the moving house is required, and every time the moving house moves, the inside of the moving house is replaced with flammable gas from an inactive gas before moving for safety. In order to remove the air that has intruded during the movement, it is necessary to replenish the inert gas again, and after that, a new sealed state must be ensured.

  Further, when the gas hydrate pellets are transported, combustible gas is always generated by the decomposition of the gas hydrate. When this flammable gas is generated, the pressure in the compartment containing the flammable gas such as cargo hold increases, so the pressure in the cargo hold becomes too high from the aspect of protecting the cargo hold structure and the hull structure. It is necessary to control the gas pressure so that there is no.

  In addition, since an explosion atmosphere is formed when air enters the compartment containing flammable gas, the gas pressure in the cargo hold is maintained at a pressure higher than the atmospheric pressure outside the cargo hold. There is a need to.

  Usually, in an LNG ship or LPG ship that transports liquid cargo that generates flammable gas such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG), as shown in FIG. 6, from each cargo tank 21 of the ship 1X. Is connected to one main pipe 23, and the gas pressure inside the main pipe 23 is adjusted using the gas compressor 7, thereby adjusting the pressure of the entire cargo tank 21.

  However, when transporting solid cargo that generates flammable gas on a bulk carrier, LNG is included in the cargo handling compartment that covers the cargo handling device for handling solid bulk cargo. As with ships and LPG ships, it is necessary to adjust and control the pressure Pci inside the cargo hold, and also to adjust and control the internal pressure Pu as a separate section from the cargo hold. Further, from the viewpoint of preventing the formation of an explosion atmosphere, both the cargo hold and the cargo handling section must be maintained at a pressure higher than the atmospheric pressure.

  In this case, the cargo hold that stores the cargo that generates flammable gas and the cargo handling section that covers the handling equipment differ in the amount of flammable gas generated in each part. The pressure behavior is different. Therefore, it is necessary to control the gas pressure considering these things.

JP-A-2005-255014

  The present invention has been made in view of the above-described situation, and an object of the present invention is to provide a part in which a loading / unloading device moves and a cargo in a ship having a cargo hold for storing solid matter that generates flammable gas in a bulk state. Ensuring high airtightness that can prevent air from entering the cargo hold in all the hatch parts of the hold, and even in the unlikely event that air enters the cargo handling compartment and cargo hold where the loading equipment moves. An object of the present invention is to provide a ship that can prevent the formation of an explosion atmosphere.

  A further object is to simultaneously control each cargo hold and handling compartment at the same time with a single gas compressor when managing pressure in multiple compartments, including both cargo holds and cargo handling sections that cover cargo handling equipment. Thus, it is an object of the present invention to provide a ship that can rationalize control of gas pressure.

  In order to achieve the above object, the ship of the present invention is provided with a cargo handling facility that moves in the longitudinal direction of the hull in the ship having a cargo hold for bulking solid matter that generates flammable gas. A fully closed cover having an airtight structure is provided to cover the moving part of the cargo handling device and all the hatch parts of the cargo hold, one end being opened in the cargo handling section in the fully closed cover, and the other end of the gas pressure adjusting device being A connected first pipe is provided.

  According to this configuration, a fully closed cover having an airtight structure that covers a portion where the cargo handling device moves and all hatch portions of the cargo hold is provided, and a cargo handling section surrounded by the fully closed cover and the upper deck is provided. Since the hatch portion is configured not to be in direct contact with the atmosphere, the combustible gas generated in the cargo hold is not released directly into the atmosphere from the hatch portion. In this case, since the fully closed cover does not move, an excellent airtight structure can be easily obtained.

  In addition, the gas pressure Pu inside the cargo handling section can be adjusted and controlled by a gas pressure adjusting device such as a gas compressor connected to the first pipe so as to be larger than the atmospheric pressure Pa. Even when a problem occurs in the airtightness of the cover, the combustible gas inside the cargo handling section is released, so that it is possible to prevent air from entering the cargo handling section and forming an explosive atmosphere.

  When adjusting the gas pressures in both the cargo handling section and the cargo hold, a configuration as shown in FIG. 5 can be considered. That is, the branch pipe 31 from each cargo hold 3 of the ship 1B is connected to one main pipe 32, this main pipe 32 is connected to the first gas compressor 7A, and the auxiliary pipe 33 is provided in the cargo handling section 6. The sub-pipe 33 is connected to the second gas compressor 7B. However, this configuration requires two gas compressors that perform pressure control in different systems, and there is a problem that the pressure control becomes complicated.

  For this problem, in the above-mentioned ship, one end is opened inside the cargo hold, the other end is opened inside the cargo handling section, and a second pipe having a first valve is provided in each cargo hold. The second pipe is configured to be able to communicate with each of the previous cargo holds and the cargo handling section.

  With this configuration, the combustible gas is generated from the cargo in the cargo hold. Therefore, by opening the first valve provided in the second pipe, the gas in each cargo hold can be released into the cargo handling section. In addition, when the first valve provided in the second pipe is configured with an adjustment valve capable of adjusting the flow rate, and when the gas of each cargo hold is released into the cargo handling section while adjusting the flow rate and gas pressure, The gas pressure in each cargo hold can be controlled individually. By controlling the gas pressure in the cargo hold, the gas pressure in the cargo hold can be prevented from becoming too high.

  In this case, the cargo pressure and the cargo handling compartment are communicated by the second pipe, so that the gas pressure Pci inside the cargo hold (Pc1 to Pc6 in FIGS. 1 to 5) and the gas pressure Pu inside the cargo handling compartment are When completely communicated, it becomes substantially uniform. In addition, when the gas pressure Pci in the cargo hold is adjusted with the first valve provided in the second pipe, the gas pressure Pci in each cargo hold becomes equal to or higher than the gas pressure Pu in the cargo handling section. Since the gas pressure Pu in the cargo handling section can be adjusted and controlled to be higher than the atmospheric pressure Pa outside the cargo hold or the cargo handling section, as a result, Pci ≧ Pu> Pa can be satisfied.

  Therefore, when managing the pressure in a plurality of compartments including both the cargo hold and the cargo handling device covering the cargo handling device, each cargo hold and the cargo handling compartment can be controlled simultaneously with a single gas compressor. Pressure control can be streamlined.

  Further, in the above-described ship, a third pipe connected to the first pipe is provided, and a branch pipe is provided in the third pipe so that the respective cargo hold and the third pipe can communicate with each other. And a second valve on the cargo handling section side of the portion of the first pipe connected to the third pipe, a third valve on the third pipe, and a fourth valve on each branch pipe. Are provided and configured.

  According to this configuration, in the first pressure management method, the third valve and the fourth valve of each branch pipe are closed, and the second valve is opened, so that the gas pressure adjusting device performs the cargo handling section. Can be made higher than the atmospheric pressure Pa outside the cargo hold or cargo handling section. As a result, it is possible to satisfy Pci ≧ Pu> Pa.

  In the second pressure management method, the first valve and the second valve are closed and the third valve is opened, so that the gas pressure adjusting device can adjust the gas pressure Pci of each cargo hold in the cargo handling section. It can be adjusted regardless of the gas pressure Pu. In this case, Pci> Pa can be achieved in a short time. In addition, when the fourth valve is composed of an adjustable valve capable of adjusting the flow rate and the gas in each cargo hold is sent to the gas pressure adjusting device while adjusting the flow rate and gas pressure, The gas pressure can be individually controlled.

  In addition, when the inside of the cargo handling section 6 that performs maintenance and repair of the cargo handling device is replaced with air, it is necessary to manage the pressure of the combustible gas pressure in the cargo hold 3 alone. This pressure management can be performed by the pressure management method.

  According to the ship of the present invention, a fully closed cover having an airtight structure that covers a portion where the cargo handling device moves and all hatch portions of the cargo hold and a cargo handling section surrounded by an upper deck are provided, and the hatch portion of the cargo hold is directly Since it is configured so as not to be in contact with the atmosphere, the combustible gas generated in the cargo hold is not released directly into the atmosphere from the hatch portion. In this case, since the fully closed cover does not move, an excellent airtight structure can be easily obtained.

  In addition, the gas pressure Pu such as a gas compressor connected to the first pipe can be controlled to be higher than the atmospheric pressure Pa by controlling the gas pressure Pu inside the cargo handling section. Even when a problem occurs in the airtightness of the cover, the combustible gas inside the cargo handling section is released, so that it is possible to prevent air from entering the cargo handling section and forming an explosive atmosphere.

  In addition, a second piping provided with a valve is provided in each cargo hold, and each cargo hold and the cargo handling compartment can be communicated with each other by using this second pipe, whereby the cargo handling compartment that covers the cargo hold and the cargo handling device. In the pressure management of a plurality of sections including both of the above, each cargo hold and the cargo handling section can be controlled simultaneously with a single gas compressor, so that the control of gas pressure can be rationalized.

It is the typical side sectional view showing the composition of the ship in the 1st embodiment concerning the present invention. It is the typical sectional side view which showed the structure of the ship in 2nd Embodiment which concerns on this invention. It is the typical sectional side view which showed the flow of the gas at the time of 1st control in the ship in 2nd Embodiment which concerns on this invention. It is the typical sectional side view which showed the gas flow at the time of 2nd control in the ship in 2nd Embodiment which concerns on this invention. It is a typical side sectional view showing the composition of the ship used as a reference of the present invention. It is the typical side sectional view showing piping for combustible gas in a moss type liquefied gas carrier ship (LNG ship).

  Hereinafter, a ship according to the present invention will be described with reference to the drawings. In addition, in drawing, the structure of a hull structure, a cargo hold structure, and each piping system is shown typically, and the actual arrangement structure is not shown.

  As shown in FIG. 1, a ship 1 according to a first embodiment of the present invention includes a cargo hold 3 in which a hull 2 stores solid matter that generates combustible gas such as natural gas hydrate (NGH) pellets. It is configured with. A cargo handling facility (not shown) that moves in the longitudinal direction of the hull is provided on the cargo hold 3, but a fully closed cover with an airtight structure that covers the part where the cargo handling device moves and all the hatch portions of the cargo hold 3. 4 is provided to form a cargo handling section 6 surrounded by the fully closed cover 4 and the upper deck 5. Since the fully closed cover 4 does not move, an excellent airtight structure can be easily obtained.

  Further, a first piping 8 is provided which has one end opened in the cargo handling section 6 in the fully closed cover 4 and the other end connected to a gas pressure adjusting device 7 such as a gas compressor and a gas processing device (not shown). Each cargo hold 3 is provided with a second pipe 9 having one end inside the cargo hold 3 and the other end opened inside the cargo handling section 6. The second pipe 9 is provided with a first valve (first valve) 9a. The second piping 9 is configured to allow communication between the cargo holds 3 and the cargo handling section 6.

  According to this configuration, since the cargo handling section 6 is provided and the hatch portion of the cargo hold 3 is not directly in contact with the atmosphere, the combustible gas generated in the cargo hold 3 is hardly released into the atmosphere.

  In addition, since the combustible gas is generated from the cargo in the cargo hold 3, the gas in each cargo hold 3 is released into the cargo handling section 6 by opening the first valve 9a provided in the second pipe 9. be able to. Further, when the first valve 9a provided in the second pipe 9 is constituted by an adjustment valve capable of adjusting the flow rate, and when the gas of each cargo hold 3 is discharged into the cargo handling section 6 while adjusting the flow rate and the gas pressure. Thereby, the gas pressure Pci (in FIGS. 1 to 5, Pc1 to Pc6, i = 1, 2, 3, 4, 5, 6) of each cargo hold 3 can be individually controlled.

  By controlling the gas pressure Pci of the cargo hold 3, it is possible to prevent the gas pressure Pci inside the cargo hold 3 from becoming too high. In this case, the gas pressure Pci inside each cargo hold 3 is equal to or higher than the gas pressure Pu inside the cargo handling section 6.

  In addition, the pressure Pu detected by a pressure sensor (not shown) provided in the cargo handling section 6 is detected, and the gas pressure Pu in the cargo handling section 6 is detected by the gas pressure adjusting device 7 outside the cargo hold 3 or the cargo handling section 6. It can be higher than atmospheric pressure Pa. As a result, it is possible to satisfy Pci ≧ Pu> Pa. Thereby, even if a problem arises in the airtightness of the fully closed cover 4, combustible gas inside the cargo handling section 6 is released, so that air enters the cargo handling section 6 and forms an explosive atmosphere. Can be prevented.

  Therefore, in a ship equipped with a cargo hold 3 that stores solid matter that generates flammable gas in a bulked state, when managing pressure in a plurality of compartments 3 and 6 including both the cargo hold 3 and the cargo handling compartment 6 that covers the cargo handling device. The single gas compressor 7 can collectively control the cargo holds 3 and the cargo handling section 6 at the same time, and can rationalize the control of the gas pressures Pci and Pu. This eliminates the need for a complicated system as shown in FIG. 5 that independently manages the pressure of the plurality of compartments 3 and 6 containing the combustible gas in the cargo hold 3 and the cargo handling compartment 6.

  Next, a ship 1A according to a second embodiment shown in FIGS. 2 to 4 will be described. This ship 1A is obtained by further adding the following configuration to the ship 1 of the first embodiment.

  While providing the 3rd piping 10 connected to the 1st piping 8, the branch piping 11 is provided in each cargo hold 3 so that this 3rd piping 10 and each cargo hold 3 may be connected. The first pipe 8 is provided with a second valve (second valve) 8a. The position of this 2nd valve | bulb 8a is provided in the cargo handling division 6 side rather than the site | part 12 to which the 3rd piping 10 connects. Further, a third valve (third valve) 10 a is provided in the third pipe 10, and a fourth valve (fourth valve) 11 a is provided in each branch pipe 11.

  According to this configuration, the following two types of pressure management methods can be easily switched and performed.

  The first pressure management method is a method for managing pressure in the cargo hold 3 and the cargo handling section 6 at the same time. In this method, the third valve 10 a and the fourth valve 11 a of each branch pipe 11 are closed, the second valve 8 a is opened, and the gas pressure is adjusted by the gas pressure adjusting device 7. The gas pressure Pu is set higher than the atmospheric pressure Pa outside the cargo hold 3 and the cargo handling section 6. As a result, it is possible to satisfy Pci ≧ Pu> Pa.

  Further, when the first valve 9a is configured by an adjustment valve capable of adjusting the flow rate, and the gas of each cargo hold 3 is sent to the gas pressure adjusting device 7 while adjusting the flow rate and gas pressure, The gas pressure in the cargo hold 3 can be individually controlled.

  And the 2nd pressure management method is a method of pressure-controlling only the cargo hold 3. In this method, the first valve 9a and the second valve 8a are closed, and the third valve 10a is opened, so that the gas pressure adjusting device 7 can perform the cargo hold regardless of the gas pressure Pu in the cargo handling section 6. 3 gas pressure Pci is adjusted and controlled. In this case, the pressure inside the cargo hold 3 is detected and controlled so as to become a preset pressure. In order to prevent air from entering the cargo hold 3, the gas pressure Pci of the cargo hold 3 is set. The pressure is controlled so that Pci> Pa with respect to the atmospheric pressure Pa. In this method, since the large cargo handling section 6 is excluded from the pressure control object, Pci> Pa can be achieved in a very short time.

  Further, when the fourth valve 11a is constituted by an adjustment valve capable of adjusting the flow rate, and the gas of each cargo hold 3 is sent to the gas pressure adjusting device 7 while adjusting the flow rate and the gas pressure, The gas pressure in the cargo hold 3 can be individually controlled.

  This second pressure management method is used in the following cases. Since there is a solid cargo that generates flammable gas in the cargo hold 3, when servicing and repairing the cargo handling device, the combustible gas only inside the cargo handling section 6 containing the cargo handling device is replaced with air. It is necessary to enable a person to enter the cargo handling section 6. In this case, it is necessary to manage the pressure of the combustible gas only in the cargo hold 3. However, by switching the valve operation of the valves 8a, 9a, 10a, and 11a, the conventional LNG ship and LPG ship can be easily used. In the same manner as the pressure management of the cargo tanks, it is possible to perform pressure management that enables individual pressure control of the plurality of cargo holds 3.

  Therefore, according to the ships 1 and 1A described above, the cargo handling section 6 is formed by providing the fully closed cover 5 having an airtight structure that covers the portion where the cargo handling device moves and all the hatch portions of the cargo hold 3. This increases the amount of combustible gas generated in the cargo hold 3 into the atmosphere and prevents air from entering the cargo handling section 6 and the cargo hold 3.

  Further, the gas pressure adjusting device 7 such as a gas compressor connected to the first pipe 8 can control the gas pressure Pu inside the cargo handling section 6 so that it can be made larger than the atmospheric pressure Pa. Even when a problem occurs in the airtightness of the fully closed cover 4, it is possible to prevent air from entering the cargo hold 3 or the cargo handling section 6 to form an explosion atmosphere.

  Furthermore, when managing the pressure in the plurality of compartments 3 and 6 including both the cargo hold 3 and the cargo handling compartment 6 covering the cargo handling device, each cargo hold 3 and the cargo handling compartment 6 are simultaneously collected by one gas compressor 7. Therefore, the control of the gas pressures Pci and Pu can be rationalized.

  As described above, the ship of the present invention can improve the airtightness of the cargo hold and the cargo handling section, and the gas pressure of each cargo hold and the cargo handling section can be collectively increased from the atmospheric pressure with one gas compressor. Therefore, even if a problem occurs in the airtightness of the fully closed cover, it is possible to prevent air from entering the cargo hold or the cargo handling section to form an explosion atmosphere. Therefore, it can utilize as a ship which conveys the solid substance which generate | occur | produces combustible gas, such as NGH hydrate, in a bulk state.

DESCRIPTION OF SYMBOLS 1,1A Ship 3 Cargo hold 4 Fully closed cover 5 Upper deck 6 Cargo handling section 7 Gas pressure regulator 8 1st piping 8a 2nd valve 9 2nd piping 9a 1st valve 10 3rd piping 10a 3rd valve 11 Branch piping 11a 4th valve Pci Gas pressure in cargo hold Pu Gas pressure in cargo handling area Pa Atmospheric pressure

Claims (3)

  In a ship equipped with a cargo hold for bulking solid matter that generates flammable gas, a cargo handling facility is provided that moves in the longitudinal direction of the hull on the cargo hold, and a part where the load handling device moves and all of the cargo hold A fully closed cover having an airtight structure is provided to cover the hatch portion, and a first pipe having one end opened in the cargo handling section in the fully closed cover and the other end connected to the gas pressure adjusting device is provided. Ship.   One end is opened inside the cargo hold, the other end is opened inside the cargo handling section, and a second pipe having a first valve is provided in each cargo hold. The ship according to claim 1, wherein the ship can be communicated with a cargo handling section.   A third pipe connected to the first pipe is provided, a branch pipe is provided in the third pipe, and the branch pipe is configured so that the cargo holds and the third pipe can communicate with each other. A second valve is provided on the cargo handling section side of the part to which the third pipe of the pipe is connected, a third valve is provided on the third pipe, and a fourth valve is provided on each branch pipe. The ship according to claim 1 or 2.

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