JP4491003B2 - Inert gas injection / replacement equipment and inert gas injection / replacement method for ballast tank of liquid cargo ship - Google Patents

Description

  The present invention, in a ship that transports highly flammable liquid cargo, injects and holds an inert gas into a ballast tank formed on the double ship side wall and the double ship bottom, and a part or all of the inert gas is used as a new inert gas. The present invention relates to a replacement facility and method.

  In recent years, with the increase in automobile production overseas, the amount of plastic and polyurethane used has increased, and a large amount of propylene oxide, which is the raw material, has started to freight. "Liquid cargo ship").

  Here, the structure related to the cargo tank of the liquid cargo ship and the structure related to the ballast tank of the conventional liquid cargo ship will be outlined with reference to FIGS. 3 is a schematic vertical cross-sectional view of the liquid cargo ship, FIG. 4 is a schematic cross-sectional view of the liquid cargo ship, and FIG. 5 is a cross-sectional view taken along arrows VV in FIGS. 3 and 4. FIG. 6 is a perspective view of a ballast tank portion of a conventional liquid cargo ship. In FIGS. 3 and 4, the right side of the drawing is the bow and the left side of the drawing is the stern.

  The liquid cargo ship has a double ship side wall composed of a ship side skin 61 and a double ship side skin 63, and a double ship bottom composed of a ship bottom skin 65 and a double inner bottom plate 67. The space between the ship side wall and the double ship bottom includes a ship side bulkhead 69 installed on the ship side skin 61 and the double ship side skin 63, a ship bottom transverse partition wall 71 and a ship bottom installed on the ship bottom skin 65 and the double inner bottom plate 67. A plurality of ballast tanks 55, 55,... As shown in FIG. 4, the ballast tanks 55, 55,... Arranged on the port side are assigned tank numbers W8P, W7P,..., W1P in order from the stern side, and are arranged on the starboard. The ballast tanks 55, 55,..., Are assigned W8S, W7S,..., W1S and tank numbers in order from the stern side. Further, the cargo tank 55 is also arranged on both left and right sides of the ship center line symmetrically, and the cargo tanks 57, 57,... Arranged on the port side are C8P, C7P,.・ For the cargo tanks 57, 57, ... that are assigned C1P and tank number and are located on the starboard side, C8S, C7S, ..., C1S and tank numbers are assigned in order from the stern side. Between C7P and C7S and C6P and C6S, between C6P and C6S and C5P and C5S, between C5P and C5S and C4P and C4S, between C4P and C4S and C3P and C3S, C3P and C3S and C2P and Cofferdams 59, 59,... Are formed between the C2S.

  As shown in FIG. 5 or FIG. 6, the ballast tank 55 is a space having an L-shaped cross section in both the left and right sides, and its upper part is sealed by an upper deck 75, and the left and right sides are symmetrical with respect to the ship center line It is placed in the cage. An air vent 77 is provided in the upper deck 75 above the ballast tank 55.

There are specific liquid chemicals and general liquid chemicals in the liquid cargo on the liquid cargo ship, but the above-mentioned propylene oxide is highly volatile (boiling point: 34 ° C.) and flammable (flash point: −37 ° C. or lower). A liquid that is representative of a particular liquid chemical. When transporting a specific liquid chemical such as propylene oxide, it leaks into a ballast tank or cofferdam (coffer-dam) adjacent to the cargo tank in which the specific liquid chemical is loaded and mixes with air to explode. In order to prevent air-fuel mixture, an inert gas which is a nitrogen gas (N ₂ ) having a concentration of 98.5% is sealed.

  For example, when a specific liquid chemical is loaded into the four cargo tanks 57 of C5P, C5S, C6P, and C6S shown in FIG. And W6S) and two cofferdams 59 and 59 located on the bow side and the stern side are filled with inert gas.

  Techniques relating to the injection of inert gas into this type of ballast tank are disclosed in Japanese Patent Laid-Open Nos. 10-08295 and 06-298171. Japanese Patent Laid-Open No. 10-08295 discloses that “a double hull ballast tank supply / drain ventilation combined use piping device, in particular, a ventilation action using a ballast water pouring / exhausting pipe is sufficient in the ballast tank. As a means to solve this problem, "For ventilation of the ballast tank formed between the outer shell and the inner shell, it branches from the main pipe and extends along the horizontal partition wall." The branch pipe and the re-branch pipe from the branch pipe of the adjacent ballast tank are used. Specifically, the branch pipe is formed by the ship bottom bilge portion (the ship side skin 61 and the ship bottom skin 65 are formed). A structure branching from the main pipe arranged along the corners) and arranged one by one inside each ballast tank, and the re-branching pipe further branches from the branch pipe and opens into the adjacent ballast tank It has become.

  The object disclosed in Japanese Patent Laid-Open No. 06-298171 is to provide an inert gas injection facility for a ballast tank that can easily and reliably inject an inert gas throughout the entire ballast tank. As a solution to the above, "a facility for injecting inert gas into a ballast tank formed between a hull outer plate and a hull plate around a hold in a tanker provided with an inert gas supply pipe for supplying an inert gas into the hold, Inert gas supply piping and ballast water injection / drainage piping that injects and drains ballast water into the ballast tank via a bell mouth are connected by connecting piping, and an open / close valve is provided in the middle of this connecting piping. '' is there.

By the way, in the technique disclosed in Japanese Patent Laid-Open No. 10-081295, the main pipe disposed along the ship bottom bilge portion, which is an injection / drainage facility for the ballast tank, and the branch pipe branched from the main pipe for injecting the inert gas into the ballast tank In the technique disclosed in Japanese Patent Application Laid-Open No. 06-298171, ballast water is injected into the ballast tank by injecting the ballast water into the ballast tank via the bell mouth. This is done by connecting the inert gas supply pipe to the injection / drainage pipe, and all of these are additional equipment that connects the inert gas system to the injection / drainage equipment of the ballast tank, and the technology is limited to how the inert gas can be injected into the ballast tank. Is. If these prior arts are described generally, as shown in FIG. 6, an inert gas system connected to an inert gas generator is connected to a ballast water injection / drainage pipe 79, which is a ballast tank injection / drainage facility, and an inert gas is connected from the bottom of the ballast tank. If (N ₂ gas) is to be injected and inert gas is injected into the ballast tank, the air in the ballast tank is released from the air vent 77 to the atmosphere. The structure of the air vent 77 is not limited to the discharge and intake of air in the ballast tank, as shown in the sectional view of the VI section of FIG. 6, but when seawater enters from outside the ship, the float in the air vent 77 Floats up and blocks the intake and exhaust ports.
Japanese Patent Laid-Open No. 10-081295 Japanese Patent Laid-Open No. 06-298171

However, as described above, if the ballast tank adjacent to the cargo tank loaded with a specific liquid chemical having high flammability is not maintained at 98.5% or more of the N ₂ gas concentration, It is very dangerous if a specific liquid chemical leaks and enters the ballast tank and the specific liquid chemical vaporizes in the ballast tank and reaches the explosion limit. Therefore, the concentration of the inert gas in the ballast tank needs to be constantly managed, and such equipment is not considered in these prior arts. Also, there is no description or suggestion about the inert gas pressure in the ballast tank, and the inert gas is injected and filled for each ballast tank, so when the inert gas is poured and discharged, the inert gas is released into the atmosphere, The amount of inert gas used will inevitably increase.

  Therefore, in view of these prior arts, the present invention quickly replaces the air in the ballast tank with an inert gas having a predetermined concentration, and can reduce the amount of inert gas to be replaced. An object of the present invention is to provide an inert gas replacement facility for a tank and an inert gas replacement method for a ballast tank of a liquid cargo ship.

In order to achieve the above object, an inert gas injection / replacement facility for a ballast tank of a liquid cargo ship according to claim 1 of the present application is provided for a liquid cargo ship having a plurality of ballast tanks with a double ship side wall and a double ship bottom partitioned. in the inert gas injection and substitutions equipment ballast tanks, the inert gas feed pipe is on the upper deck of the open port opened to the atmosphere through the other opening and closing valve N ₂ gas generator or N ₂ generator is connected to one end of which is connected A first air pipe device that connects the ballast tank and the inert gas air supply pipe and injects the inert gas into the ballast tank, and a second air pipe that discharges the gas in the ballast tank from the ballast tank The first air pipe device has one end opened at the center of the bottom of the ballast tank and the other end penetrating the upper deck. The first air vent pipe to which the first pipe head fitting that extends upward and opens to the atmosphere via the first air vent valve is connected, the upper deck of the first air vent pipe, and the first An inert gas supply branch pipe branched from an intermediate part of the air release valve and connected to the inert gas supply pipe; the first air release valve of the first air release pipe; and a branch part of the inert gas supply branch pipe; The second air pipe device has one end opened at the upper part in the ballast tank and the other end at the upper deck. A second air vent pipe to which a second pipe head fitting penetrating and extending upward and opened to the atmosphere via a second air vent valve is connected; an upper deck of the second air vent pipe; and the second Branch from the middle of the air vent valve and connect to the inert gas feed pipe And a third pipe head fitting consisting of a pressure relief valve and a vacuum valve is connected to the tip of the air exhaust pipe, the upper part of the second air vent pipe and the second air vent valve. Each of the plurality of ballast tanks is provided with a connection port of a portable oximeter, the connection part of the inert gas air supply pipe of the first air pipe device and the second An inert gas opening / closing valve is inserted in the inert gas supply pipe between the inert gas supply pipe and the connecting portion of the air pipe device.
An inert gas injection / replacement facility for a ballast tank of a liquid cargo ship according to claim 2 of the present application is an inert gas injection / replacement facility for a ballast tank of a liquid cargo ship according to claim 1, wherein the pressure relief valve is When the pressure in the ballast tank becomes equal to or higher than a predetermined pressure, the valve is adjusted to “open”, and when the pressure in the ballast tank becomes lower than the predetermined pressure, the vacuum valve is adjusted to be “open”. It is characterized by that.
And the inert gas injection / replacement equipment for the ballast tank of the liquid cargo ship according to claim 3 of the present application is the inert gas injection / replacement equipment for the ballast tank of the liquid cargo ship according to claim 2, wherein the pressure relief valve is " The predetermined pressure at which “open” is approximately (external pressure + 0.014 MPa), and the predetermined pressure at which the vacuum valve is “open” is approximately (external pressure−0.0035 MPa).
Furthermore, the inert gas injection / replacement method for the ballast tank of the liquid cargo ship according to claim 4 of the present application is such that the inert gas is supplied to the ballast tank of the liquid cargo ship having a plurality of ballast tanks with a double ship side wall and a double ship bottom defined. In the method of injecting or replacing the inert gas already injected into the ballast tank, the ballast tank to be injected or replaced with the inert gas is arranged in order from the upstream side of the inert gas, the first ballast tank, When the ballast tank is a third ballast tank,..., The nth ballast tank, the inert gas supply pipe installed on the upper deck is connected to the first ballast tank via the air supply device. N ₂ gas having a predetermined concentration is injected into the first ballast tank, and the first ballast tank Gas is injected into the second ballast tank via an exhaust device connected to the first ballast tank, the inert gas air supply pipe and an air supply device connected to the second ballast tank, and the first ballast tank When the inside reaches a predetermined N ₂ gas concentration, the inert gas injection to the first ballast tank is stopped, and the second ballast tank is supplied to the second ballast tank via an air supply device connected to the second ballast tank. Inert gas having a concentration of 2 is injected, and the gas in the second ballast tank is connected to the second ballast tank, the inert gas air supply pipe, and the air supply device connected to the third ballast tank. The third ballast tank is injected into the third ballast tank, and thereafter, the same procedure is repeated until the first ballast tank, the second ballast tank, The n-th ballast tank is filled with N ₂ gas having a predetermined concentration.
Further, an inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 5 is an inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 4, wherein one end of the ballast tank is disposed in the ballast tank. A first air vent pipe that is open at the center of the bottom and has the other end extending through the upper deck and connected to a first pipe head fitting that opens into the atmosphere via the first air vent valve; An inert gas supply branch pipe branched from an intermediate portion between the upper deck of the first air release pipe and the first air release valve and connected to the inert gas supply pipe; and the first of the first air release pipe The air supply device comprising an air vent pipe branched from an intermediate portion between the air vent valve and the branch portion of the inert gas air supply branch pipe and opened to the upper portion in the ballast tank, and one end of the air vent device in the ballast tank Open to the other end A second air vent pipe that is connected to a second head fitting that extends through the upper deck and opens to the atmosphere via a second air vent valve; and an upper deck of the second air vent pipe; An air discharge pipe branched from an intermediate part of the second air vent valve and connected to the inert gas air supply pipe, and an intermediate part of an upper deck of the second air vent pipe and the second air vent valve And a pressure adjusting pipe to which a third pipe head fitting consisting of a pressure relief valve and a vacuum valve is connected at the tip, and the exhaust device comprising the first ballast tank, the second ballast tank, The ballast tank is characterized in that the nth ballast tank is filled with N ₂ gas having a predetermined concentration .
An inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 6 of the present application is the inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 4 or claim 5, wherein the N _2. The portable oximeter according to claim 1, wherein predetermined concentrations of the _two gases are installed in the first ballast tank, the second ballast tank, the third ballast tank,..., The nth ballast tank. The first ballast tank, the second ballast tank, the third ballast tank,..., The nth ballast tank, which is held at about 98.5% or more by a portable oximeter connected through a connection port. The inert gas pressure inside is maintained at approximately (external pressure−0.0035 MPa) to (external pressure + 0.014 MPa) by the third pipe head fitting according to claim 1. It is characterized by.

The present invention has the following effects by the above configuration and method.
(1) In the first air pipe device connected to the inert gas air supply pipe installed on the upper deck, the inert gas air supply branch pipe connected to the inert gas air supply pipe is opened at the center of the bottom portion in the ballast tank. 1 and the air branch pipe that passes through the upper deck and opens to the upper part of the ballast tank, the inert gas supplied from the inert gas supply pipe is at the center of the bottom of the ballast tank and It is injected into the ballast tank from the upper part in the ballast tank. Therefore, the air in the ballast tank can be quickly replaced with an inert gas having a predetermined concentration without any spots.

(2) A first air pipe device and a second air pipe device are connected to an inert gas air supply pipe installed on the upper deck, and the inert gas air supply pipe of the first air pipe device and the second air pipe device. Since an inert gas on-off valve is inserted between each of the connecting parts, for example, in the first ballast tank, the second ballast tank, the third ballast tank,... By closing all the inert gas on-off valves placed opposite to each other, the first ballast tank, the second ballast tank, the third ballast tank,..., The nth ballast tank Since the air containing the inert gas in the first ballast tank, which is connected in series via the second air pipe device, is sent to the second ballast tank, the first ballast tank, The ballast tank 2, the third ballast tank,... Can use the inert gas more effectively than replacing the air in the nth ballast tank with the inert gas, and the amount of the inert gas to be replaced can be reduced. it can.

(3) The inert gas concentration in the ballast tank is about 98.5% or more due to the portable oximeter connected through the port of the portable oximeter installed in each ballast tank and the third pipe fitting. In addition, the inert gas pressure is maintained at approximately (atmospheric pressure−0.0035 MPa) to (atmospheric pressure + 0.014 MPa), so that pressure management is easy.

  Hereinafter, an embodiment according to the best mode for carrying out the present invention will be described with reference to FIGS. 1 and 2 and FIGS. 3 to 5 used in the description of [Background Art]. 1 is a partial cross-sectional view of a ballast tank parallel to the traveling direction of the ship using the inert gas replacement equipment for the ballast tank of the liquid cargo ship according to the embodiment, and FIG. 2 is a liquid cargo ship according to the embodiment. It is a fragmentary perspective view of the cargo tank which uses the inert gas substitution equipment of the ballast tank of.

  1 and 2, reference numeral 1 is an inert gas replacement facility for a ballast tank of a liquid cargo ship according to the embodiment, reference numeral 10 is a first air pipe device, reference numeral 11 is a first air vent pipe, and reference numeral 13 is a first Pipe fitting, reference numeral 15 is a first air vent valve, reference numeral 17 is an inert gas air supply branch pipe, reference numeral 19 is an air vent pipe, reference numeral 30 is a second air pipe device, reference numeral 31 is a second air vent pipe, Reference numeral 33 is a second pipe head fitting, reference numeral 35 is a second air vent valve, reference numeral 37 is an air exhaust pipe, reference numeral 39 is a pressure adjustment pipe, reference numeral 391 is a pressure adjustment horizontal pipe, reference numeral 393 is a pressure adjustment vertical pipe, Reference numeral 41 is a third pipe head fitting, reference numeral 411 is a pressure relief valve, reference numeral 413 is a vacuum valve, reference numeral 51 is an inert gas supply pipe, reference numeral 53 is an inert gas on-off valve, reference numeral 55 is a ballast tank, reference numeral 57 is a cargo tank, reference numeral 63 is double Side outside plate, reference numeral 67 is double the bottom plate, reference numeral 69 hull bulkhead, reference numeral 75 is the upper deck, numeral 79 is a ballast water Note drainpipe.

  First, the configuration of the inert gas replacement equipment for the ballast tank of the liquid cargo ship according to the embodiment will be described, and then the inert gas replacement method for the ballast tank of the liquid cargo ship according to the embodiment will be described.

  The configurations of the ballast tank 55, cargo tank 57, and coffer dam 59 of the liquid cargo ship in which the inert gas replacement facility 1 for the ballast tank of the liquid cargo ship is installed are as described in paragraph [0004], and thus the description thereof is omitted. In addition, the tank numbers assigned to the ballast tank 55 and the cargo tank 57 are used as they are in the following description.

The inert gas replacement equipment 1 for the ballast tank of the liquid cargo ship is connected to the inert gas air supply pipe 51 laid on the upper deck 75 and the ballast tanks 55, 55,. The first air pipe device 10 and the second air pipe device 30 which are connected to the ballast tanks 55, 55,... And the inert gas air supply pipe 51 on the bow side.
The inert gas air supply pipe 51 laid on the upper deck 75 is connected to an inert gas generator (not shown) at the stern side end and opened to the atmosphere at the bow side end via an on-off valve (not shown). An open port (not shown) is connected.

The first air pipe device 10 mainly includes a first air vent pipe 11 having one end opened at the center of the bottom of the ballast tank 55 and the other end penetrating through the upper deck 57 and the upper deck 57. An inert gas air supply branch pipe 17 branched from the upper first air exhaust pipe 11 and connected to the inert gas air supply pipe 51 and branched from the first air exhaust pipe 11 above the branch portion of the inert gas air supply branch pipe 17. The tip is constituted by an air branch pipe 19 that passes through the upper deck 57 and opens to the upper part in the ballast tank 55.
A first pipe head fitting 13 is connected to the upper end portion of the first air vent pipe 11 via a first air vent valve 15. The first pipe head fitting 13 is normally in an “open” state. When injecting ballast into the ballast tank 55, the air in the ballast tank 55 is released into the atmosphere and the ballast is discharged. In this case, outside air is taken into the ballast tank 55, so to speak, when the ballast tank 55 plays a role of venting air and seawater tries to enter from the first pipe head fitting 13, the first pipe head fitting. The float in 13 floats up and blocks the pipeline.

The second air pipe device 30 mainly includes a second air vent pipe 31 having one end opened at an upper part in the ballast tank 55 and the other end extending upward through the upper deck 57, and a second air vent pipe 31 on the upper deck 57. An air exhaust pipe 37 branched from the second air vent pipe 31 and connected to the inert gas air feed pipe 51, a pressure adjusting horizontal pipe 391 branched from the second air vent pipe 31 on the upper deck 57 and extending in the horizontal direction, and a pressure adjusted horizontal The pressure adjustment pipe 36 includes a pressure adjustment vertical pipe 393 extending in the vertical direction from the tip of the pipe 391.
A second pipe head fitting 33 is connected to the upper end portion of the second air vent pipe 31 via a second air vent valve 35. Since the configuration and operation of the second pipe head fitting 33 are the same as those of the first pipe head fitting 13, description thereof will be omitted.
A third pipe head fitting 41 is connected to the tip of the pressure adjustment pipe 36, that is, the upper end of the pressure adjustment vertical pipe 393, and the third pipe head fitting 41 is connected to the pressure relief valve 411 and the pressure relief valve 411. The vacuum valve 413 is configured. The pressure relief valve 411 is “open” when the pressure in the ballast tank 55 becomes (external pressure + 0.014 MPa) or more, and the vacuum valve 413 has the pressure in the ballast tank (external pressure−0.0035 MPa). It is adjusted to be “open” when: That is, the pressure in the ballast tank is adjusted to be (external air pressure−0.0035 MPa) to (external air pressure + 0.014 MPa).

  Note that the inert gas air supply pipe 51 between the connection portion of the first air pipe device 10 and the connection portion of the second air pipe device 30 is opposed to the respective ballast tanks 55, 55,. An inert gas on-off valve 53 is inserted. Each ballast tank 55, 55,... Is provided with a portable oximeter connection port (not shown).

Next, an inert gas replacement method for the ballast tank of the liquid cargo ship according to the embodiment will be described.
Here, among the cargo tanks 57 shown in FIG. 3, specific liquids are provided in eight cargo tanks 57 of the cargo tanks C3P, C4P, C5P, C6P on the port side and the cargo tanks C3S, C4S, C5S, C6S on the starboard side. An example of loading chemicals will be described.

  As described above, nitrogen gas (hereinafter referred to as “inert gas”) having a concentration of 98.5% as an inert gas must be sealed in the ballast tank 55 adjacent to the cargo tank 57 into which a specific liquid chemical is loaded. However, the inert gas replacement method for the ballast tank of the liquid cargo ship according to the embodiment is based on the following procedure. In the procedure described below, port side ballast tanks 55, 55,..., That is, W3P, W4P, W5P, W6P are taken as an example. In this case, the first ballast tank is W6P, The second ballast tank is W5P, the third ballast tank is W4P, and the fourth ballast tank is W3P.

(1) First, among the inert gas on-off valves 53, 53,... Inserted in the inert gas air supply pipe 51, the inert gas on-off valve 53 disposed in the first ballast tank (W6P) to the fourth ballast tank (W3P). The first air vent valve 15 of the first air pipe device 10 connected to the first ballast tank (W6P) to the fourth ballast tank (W3P), and the second air pipe The second air vent valve 35 of the device 30 is set to “closed”. By this operation, the inert gas generator (not shown) → the inert gas supply pipe 51 → the first air pipe device 10 → the first ballast tank (W6P) → the second air pipe device 30 → the inert gas supply pipe 51 → the first Air pipe device 10 → second ballast tank (W5P) → second air pipe device 30 → inert gas air supply pipe 51 → first air pipe device 10 → third ballast tank (W4P) → second air pipe device 30 → Inert gas air supply pipe 51 → first air pipe device 10 → fourth ballast tank (W3P) → second air pipe device 30 → inert gas air supply pipe 51 → open / close valve (not shown) → opening port (not shown) The inert gas air supply pipe line is formed.

(2) When the inert gas is supplied from the inert gas generator to the inert gas supply pipe 51, the inert gas enters the first ballast tank through the first air pipe device 10 connected to the first ballast tank (W6P). Inert gas is ejected from the center of the bottom of the first ballast tank by the first air vent pipe 11 and also from the upper part of the first ballast tank by the air branch pipe 19. . Then, the air in the first ballast tank containing the inert gas replaced by the inert gas passes through the second air pipe device 30 → the inert gas air supply pipe 51 → the first air pipe device 10 and passes through the second ballast tank. It is injected into (W5P).

(3) When the first ballast tank (W6P) is filled with the inert gas, the inert gas on-off valve 53 facing the first ballast tank is “open”, and the inert gas sent from the inert gas generator is Instead of being injected into the first ballast tank, it is injected directly into the second ballast tank (W5P). Thereafter, the second ballast tank (W5P) is filled with the inert gas by the same procedure as in (2) above. The concentration of N ₂ gas in the first ballast tank (W6P) is a portable oximeter (not shown) connected via a connection port of a portable oximeter installed in the first ballast tank. The inert gas pressure in the first ballast tank (W6P) is managed by the third pipe head fitting 41.
(4) Thereafter, the third ballast tank (W4P) and the fourth ballast tank (W3P) are similarly filled with the inert gas.
The starboard side ballast tanks 55, 55,... Are filled with an inert gas in the same procedure as the procedure (1) to the procedure (4).

  According to the above procedure, nitrogen gas having a concentration of 98.5% can be sealed in the eight ballast tanks 55 adjacent to the eight cargo tanks 57 in which a specific liquid chemical is loaded. By the inert gas replacement method of the ballast tank, the inert gas supplied from the inert gas air supply pipe is injected into the ballast tank from the center of the bottom of the ballast tank and from the top of the ballast tank. Since the inert gas at the concentration of the first ballast tank can be quickly replaced without air and the air containing the inert gas in the first ballast tank is sent to the second ballast tank, the first ballast tank, the second ballast tank , The third ballast tank,..., The air in the nth ballast tank is replaced with inert gas Makes better use of the remote inert gas, it is possible to reduce the amount of inert gas to replace.

FIG. 1 is a partial cross-sectional view of a ballast tank parallel to the traveling direction of a ship using an inert gas replacement facility for a ballast tank of a liquid cargo ship according to an embodiment. FIG. 2 is a partial perspective view of the cargo tank using the inert gas replacement equipment for the ballast tank of the liquid cargo ship according to the embodiment. FIG. 3 is a schematic vertical sectional view of a liquid cargo ship. FIG. 4 is a schematic plan view of a liquid cargo ship. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a perspective view of a ballast tank portion of a conventional liquid cargo ship.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inert gas replacement equipment of the ballast tank of the liquid cargo ship which concerns on an Example 10 1st air pipe apparatus 11 1st air vent pipe 13 1st pipe head fitting 15 1st air vent valve 17 Inert gas air supply branch pipe 19 Air Branch pipe 30 Second air pipe device 31 Second air vent pipe 33 Second pipe head fitting 35 Second air vent valve 37 Air exhaust pipe 39 Pressure adjusting pipe 41 Third pipe head fitting 411 Pressure relief valve 413 Vacuum valve 51 Inert gas supply pipe 53 Inert gas on-off valve 55 Ballast tank 75 Upper deck

Claims (6)

In a facility for injecting and replacing inert gas into a ballast tank of a liquid cargo ship having a double ship side wall and a double ship bottom and having a plurality of ballast tanks,
An inert gas air supply pipe with an N ₂ gas generator or N ₂ generator connected to one end and an open port that opens to the atmosphere via an on-off valve is laid on the upper deck,
A first air pipe device that connects the ballast tank and the inert gas air supply pipe and injects inert gas into the ballast tank, and a second air pipe device that discharges the gas in the ballast tank from the ballast tank are disposed. And
In the first air pipe device, one end is opened at the center of the bottom in the ballast tank, and the other end extends through the upper deck and opens into the atmosphere via the first vent valve. An inert gas feed branching from an intermediate portion between a first air vent pipe to which one pipe head fitting is connected, an upper deck of the first air vent pipe and the first air vent valve and connected to the inert gas air feed pipe An air branch pipe branched from an intermediate portion between an air branch pipe, the first air vent valve of the first air vent pipe, and a branch portion of the inert gas feed branch pipe and opened to an upper portion in the ballast tank And consists of
The second air pipe device has a second pipe head having one end opened in the upper part of the ballast tank and the other end extending upward through the upper deck and opened into the atmosphere through a second air vent valve. A second air vent pipe to which the metal fitting is connected, an air exhaust pipe branched from an intermediate portion between the upper deck of the second air vent pipe and the second air vent valve, and connected to the inert gas supply pipe; A pressure adjusting pipe branched from an intermediate portion between the upper deck of the second air vent pipe and the second air vent valve and connected to a third pipe head fitting consisting of a pressure relief valve and a vacuum valve at the tip; Consists of
Each of the plurality of ballast tanks is provided with a portable oximeter connection port,
An inert gas on-off valve is interposed in the inert gas supply pipe between the connection portion of the inert gas supply pipe of the first air pipe device and the connection portion of the inert gas supply pipe of the second air pipe device. Inert gas injection and replacement equipment for ballast tanks of liquid cargo ships.   The pressure relief valve becomes “open” when the pressure in the ballast tank becomes equal to or higher than a predetermined pressure, and the vacuum valve becomes “open” when the pressure in the ballast tank becomes lower than a predetermined pressure. The inert gas injection / replacement equipment for a ballast tank of a liquid cargo ship according to claim 1, wherein the inert gas injection / replacement equipment is for a liquid cargo ship.   The predetermined pressure at which the pressure relief valve is “open” is substantially (external pressure + 0.014 MPa), and the predetermined pressure at which the vacuum valve is “open” is substantially (external pressure−0.0035 MPa). The inert gas injection / replacement facility for a ballast tank of a liquid cargo ship according to claim 2. In the method of injecting inert gas into the ballast tank of a liquid cargo ship having a double ship side wall and a double ship bottom and having a plurality of ballast tanks, or replacing the inert gas already injected into the ballast tank, When the ballast tank to be injected or replaced with inert gas is the first ballast tank, second ballast tank, third ballast tank,..., Nth ballast tank in order from the upstream side of the inert gas. ,
With N ₂ gas having a predetermined concentration is injected into the first ballast tank through the air supply device to be connected from the inert gas feed pipe to be laid on the upper deck in the first ballast tank, wherein the first Gas in the ballast tank is injected into the second ballast tank through an exhaust device connected to the first ballast tank, the inert gas air supply pipe, and an air supply device connected to the second ballast tank,
When the inside of the first ballast tank reaches a predetermined N ₂ gas concentration, the inert gas injection to the first ballast tank is stopped, and the first ballast tank is connected to the second ballast tank through the air supply device connected to the second ballast tank. Inert gas having a predetermined concentration is injected into the second ballast tank, and the gas in the second ballast tank is supplied to the exhaust device connected to the second ballast tank, the inert gas supply pipe, and the third ballast tank. Injected into the third ballast tank through a connected air supply device,
Thereafter, the same procedure is repeated to fill the first ballast tank, the second ballast tank, the third ballast tank,..., The nth ballast tank with N ₂ gas having a predetermined concentration. Inert gas injection / replacement method for ballast tank of liquid cargo ship. One end is opened at the center of the bottom of the ballast tank, the other end extends upward through the upper deck, and a first head fitting that opens to the atmosphere through the first vent valve is connected. A first air vent pipe, an inert gas feed branch pipe branched from an intermediate portion between the upper plate of the first air vent pipe and the first air vent valve, and connected to the inert gas feed pipe; an air抜枝pipe which opens is branched from an intermediate portion of the branch portion between the first air disconnect valve of the air extubation the inert gas air branch pipe at an upper portion in the ballast tank, the air supply device and consisting of Second air having one end opened in the upper part of the ballast tank, the other end extending upward through the upper deck, and connected to a second head fitting that opens into the atmosphere via a second air vent valve. Exhaust pipe, upper deck of the second air vent pipe and the second air vent valve And an air discharge pipe branched from the middle portion of the gas supply pipe and connected to the inert gas air supply pipe, and a pressure relief at the tip portion branched from the middle section of the upper plate of the second air vent pipe and the second air vent valve. The first ballast tank, the second ballast tank, the third ballast tank,..., The first ballast tank, the third ballast tank ,. 5. The inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 4, wherein the n ballast tanks are filled with N ₂ gas having a predetermined concentration . The portable oxygen concentration according to claim 1, wherein the predetermined concentration of the N ₂ gas is set in the first ballast tank, the second ballast tank, the third ballast tank, ... the nth ballast tank. It is held at about 98.5% or more by a portable oximeter connected through the connection port of the meter, the first ballast tank, the second ballast tank, the third ballast tank,. The inert gas pressure in the ballast tank is maintained at approximately (external pressure-0.0035 MPa) to (external pressure + 0.014 MPa) by the third pipe head fitting according to claim 1. An inert gas injection / replacement method for a ballast tank of a liquid cargo ship according to claim 4 or claim 5.

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