Patent Description:
This application claims the right of priority based on <CIT> and <CIT>.

A ship that is loaded with a combustible gas as fuel for ship propulsion or cargo is provided with a vent post for discharging the combustible gas to the atmosphere outside the ship. For example, PTL <NUM> discloses a configuration in which a combustible gas remaining in a pipe or the like of a gas engine that is driven by the combustible gas (gas fuel) is purged with a nitrogen gas or the like and released to the atmosphere through a vent post.

Incidentally, it is being considered to load ammonia as a gas fuel. There is a possibility that ammonia may not sufficiently diffuse even if it is purged with an inert gas and released to the atmosphere through a vent post. One of the reasons why ammonia is difficult to diffuse into the atmosphere in this manner is, for example, that ammonia more easily reacts with moisture in the air than other combustible gases such as a methane gas or a butane gas and reacts with moisture in the air to become mist-like (droplet-like) ammonia water and the specific gravity becomes larger than that of the atmosphere.

Further, since ammonia has high irritation to the mucous membranes of the human body, it is desirable to reduce the amount of ammonia released into the atmosphere as much as possible such that it does not come into contact with the human body.

The present disclosure has been made to solve the above problems, and has an object to provide a ship in which it is possible to reduce the amount of ammonia released into the atmosphere.

In order to solve the above problems, a ship according to the present disclosure includes a hull, an ammonia storage tank, an inert gas supply device, a vent pipe, and a treatment tank. The ammonia storage tank can store ammonia therein. The inert gas supply device supplies an inert gas to a circulation path for ammonia, which communicates with the ammonia storage tank. The vent pipe leads the ammonia in the circulation path together with the inert gas supplied by the inert gas supply device to the outside. The treatment tank is provided in the middle of the vent pipe. Water is stored in the treatment tank. The inert gas and the ammonia are introduced into the treatment tank from the vent pipe below a water surface of the water. Advantageous Effects of Invention.

According to the ship of the present disclosure, it is possible to reduce the amount of ammonia released into the atmosphere.

Hereinafter, a ship according to an embodiment of the present disclosure will be described with reference to <FIG>.

As shown in <FIG>, a ship <NUM> of the present embodiment includes a hull <NUM>, a superstructure <NUM>, an ammonia storage tank <NUM>, an inert gas supply device <NUM> (refer to <FIG>), a vent pipe <NUM> (refer to <FIG>), and a treatment tank <NUM>. The ship type of the ship <NUM> is not limited to a specific type. As the ship type of the ship <NUM>, for example, a liquefied gas carrier, a ferry, a RORO ship, a car carrier, a passenger ship, or the like can be exemplified.

The hull <NUM> has a pair of broadsides 5A and 5B and a ship bottom <NUM> that form an outer shell of the hull. The broadsides 5A and 5B include a pair of broadside outer plates forming the left and right broadsides. The ship bottom <NUM> includes a ship bottom outer plate that connects the broadsides 5A and 5B. The outer shell of the hull <NUM> is formed in a U shape in a cross section orthogonal to a bow-stern direction FA by the pair of broadsides 5A and 5B and the ship bottom <NUM>.

The hull <NUM> further includes an upper deck <NUM> that is a through deck which is disposed in the uppermost layer. The upper deck <NUM> that is exemplified in the present embodiment is also an exposed deck that is exposed to the outside. The superstructure <NUM> is formed on the upper deck <NUM>. An accommodation space and the like are provided in the superstructure <NUM>. For example, a cargo space (not shown) for loading cargo is provided in the hull <NUM> on the bow 3a side with respect to the superstructure <NUM> in the bow-stern direction FA and below the upper deck <NUM>.

Further, an internal combustion engine <NUM> is provided inside the hull <NUM>. The internal combustion engine <NUM> is used as a main engine for propelling the ship <NUM>, a generator for supplying electricity to the ship, and the like. In the embodiment of the present disclosure, the internal combustion engine <NUM> is operated by using ammonia stored in the ammonia storage tank <NUM> as fuel.

The ammonia storage tank <NUM> stores liquefied ammonia. The ammonia storage tank <NUM> of the present embodiment is provided in the hull <NUM>. A case where the ammonia storage tank <NUM> is disposed on the upper deck <NUM> on the stern 3b side with respect to the superstructure <NUM> in the bow-stern direction FA is exemplified.

The ammonia storage tank <NUM> and the internal combustion engine <NUM> are connected through a pipe system <NUM>. As shown in <FIG>, the pipe system <NUM> forms a circulation path R for ammonia, which communicates with the ammonia storage tank <NUM>. The pipe system <NUM> includes a supply pipe <NUM>, a return pipe <NUM>, and on/off valves <NUM> and <NUM>. The inert gas supply device <NUM> and a vent post <NUM> are connected to the pipe system <NUM>.

Each of the supply pipe <NUM> and the return pipe <NUM> connects the ammonia storage tank <NUM> and the internal combustion engine <NUM>. The supply pipe <NUM> supplies ammonia from the ammonia storage tank <NUM> to the internal combustion engine <NUM>. The return pipe <NUM> returns surplus ammonia remaining without being used as fuel in the internal combustion engine <NUM> to the ammonia storage tank <NUM>. The on/off valves <NUM> and <NUM> are provided in the supply pipe <NUM> and the return pipe <NUM>. The on/off valves <NUM> and <NUM> are always in an open state when the internal combustion engine <NUM> operates. The on/off valves <NUM> and <NUM> are in a closed state when the internal combustion engine <NUM> is stopped. The flow paths formed inside the supply pipe <NUM> and the return pipe <NUM> are blocked by closing the on/off valves <NUM> and <NUM>.

The inert gas supply device <NUM> supplies an inert gas to the circulation path R for ammonia, which communicates with the ammonia storage tank <NUM>. The inert gas supply device <NUM> supplies the inert gas to the pipe system <NUM> which is the circulation path R. The inert gas supply device <NUM> includes an inert gas supply unit <NUM>, an inert gas supply pipe <NUM>, and an inert gas supply valve <NUM>.

The inert gas supply unit <NUM> can supply an inert gas such as nitrogen (for example, an inert gas or the like) to the inert gas supply pipe <NUM>. The inert gas supply pipe <NUM> connects the inert gas supply unit <NUM> and the pipe system <NUM>. The inert gas supply pipe <NUM> is connected to a purge target region 20p of the pipe system <NUM>. The purge target region 20p is the side including the internal combustion engine <NUM> between the on/off valve <NUM> of the supply pipe <NUM> and the on/off valve <NUM> of the return pipe <NUM> in the pipe system <NUM>.

The inert gas supply valve <NUM> is provided in the inert gas supply pipe <NUM>. As shown in <FIG>, the inert gas supply valve <NUM> is in a closed state in normal times to cut off the supply of the inert gas from the inert gas supply unit <NUM> to the purge target region 20p of the pipe system <NUM>. In this state, the on/off valves <NUM> and <NUM> are in an open state to allow ammonia to be supplied from the ammonia storage tank <NUM> to the internal combustion engine <NUM> through the supply pipe <NUM> and surplus ammonia to be returned from the internal combustion engine <NUM> to the ammonia storage tank <NUM>.

As shown in <FIG>, when the internal combustion engine <NUM> is stopped for an emergency, for a long period of time, or the like, the inert gas supply valve <NUM> is changed from a closed state to an open state. In this state, the on/off valves <NUM> and <NUM> are in a closed state, and the supply pipe <NUM> and the return pipe <NUM> are blocked. That is, a state is created in which the supply of ammonia from the ammonia storage tank <NUM> to the internal combustion engine <NUM> is stopped. In this state, when the inert gas supply valve <NUM> is opened, the inert gas is supplied from the inert gas supply unit <NUM> to the purge target region 20p of the pipe system <NUM>. The inert gas supply device <NUM> supplies the inert gas to the purge target region 20p of the pipe system <NUM>, which is the circulation path R for ammonia, so that so-called purging to replace the ammonia in the purge target region 20p (the circulation path R) with the inert gas is performed.

The vent pipe <NUM> leads the ammonia in the circulation path R together with the inert gas that is supplied by the inert gas supply device <NUM> to the outside. One end of the vent pipe <NUM> is connected to the purge target region 20p as the circulation path R for ammonia, which communicates with the ammonia storage tank <NUM>. The other end of the vent pipe <NUM> is connected to the vent post <NUM>.

As shown in <FIG>, the vent post <NUM> is provided on the upper deck <NUM> of the hull <NUM>. The vent post <NUM> extends in an up-down direction Dv on the upper deck <NUM>. The vent post <NUM> has a tubular shape extending in the up-down direction Dv and is open at the top portion thereof. As shown in <FIG>, the other end of the vent pipe <NUM> described above is connected to a lower portion of the vent post <NUM>.

A purge on/off valve <NUM> is provided in the vent pipe <NUM>. As shown in <FIG>, the purge on/off valve <NUM> is in a closed state in normal times to block the flow path in the vent pipe <NUM>. As shown in <FIG>, when the internal combustion engine <NUM> is stopped for an emergency, for a long period of time, or the like, the purge on/off valve <NUM> is changed from a closed state to an open state. That is, the purge on/off valve <NUM> is opened and closed in conjunction with the inert gas supply valve <NUM>. The purge on/off valve <NUM> enters an open state in a case where the inert gas is supplied from the inert gas supply unit <NUM> to the purge target region 20p of the pipe system <NUM> by the inert gas supply device <NUM>. When the purge on/off valve <NUM> is in an open state, the ammonia in the purge target region 20p is sent from the purge target region 20p of the pipe system <NUM> into the vent pipe <NUM> together with the inert gas.

The treatment tank <NUM> is disposed on the way from one end of the vent pipe <NUM> to the other end. More specifically, the treatment tank <NUM> is disposed between the purge on/off valve <NUM> and the vent post <NUM>. As shown in <FIG>, the treatment tank <NUM> of the embodiment of the present disclosure is provided on the upper deck <NUM>, for example. The installation position of the treatment tank <NUM> is not limited at all, and it is sufficient if the treatment tank <NUM> is installed at an appropriate location on the hull <NUM>.

Here, in the description of the present embodiment, the portion of the vent pipe <NUM> that is provided on the upstream side (the purge on/off valve <NUM> side) in the gas flow direction in the vent pipe <NUM> with respect to the treatment tank <NUM> is referred to as an upstream-side vent pipe 38A. Further, the portion of the vent pipe <NUM> that is provided on the downstream side (the vent post <NUM> side) in the gas flow direction in the vent pipe <NUM> with respect to the treatment tank <NUM> is referred to as a downstream-side vent pipe 38B. That is, the upstream-side vent pipe 38A is connected to the lower portion of the treatment tank <NUM>, and the downstream-side vent pipe 38B is connected to the upper portion of the treatment tank <NUM>.

As shown in <FIG>, water W is stored in the treatment tank <NUM>. The inert gas and an ammonia gas (hereinafter sometimes referred to as "ammonia-containing gas G") sent from the purge on/off valve <NUM> side through the upstream-side vent pipe 38A connected to the lower portion of the treatment tank <NUM> are introduced into a region below a water surface Wf of the treatment tank <NUM>. The upstream-side vent pipe 38A of the present embodiment extends downward within the treatment tank <NUM>. Then, the ammonia-containing gas G is introduced into the lower portion of the treatment tank <NUM> from the lower end of the upstream-side vent pipe 38A.

In the water W in the treatment tank <NUM>, the ammonia-containing gas G introduced from the upstream-side vent pipe 38A forms bubbles Gv, which float upward from below. At this time, the ammonia-containing gas G comes into contact with the water W in the treatment tank <NUM>. Since ammonia easily reacts with the water W, the ammonia becomes ammonia water due to the reaction with the water W, and easily dissolves in the water. On the other hand, the inert gas is difficult to dissolve in the water W, so that the inert gas rises in the state of the bubbles Gv and is released into atmosphere above the water surface Wf in the treatment tank <NUM>.

A porous member <NUM> is provided in the treatment tank <NUM>. The porous member <NUM> is provided below the water surface Wf of the water W stored in the treatment tank <NUM>. The porous member <NUM> has, for example, a flat plate shape and is provided along a plane intersecting (orthogonal to) the up-down direction Dv. A plurality of (a large number of) holes <NUM> are formed in the porous member <NUM>. For the porous member <NUM> as described above, for example, perforated metal, wire mesh, or the like can be used.

The size of each hole <NUM> is set smaller than the size of the initial bubble Gv sent into the water W in the treatment tank <NUM> from the upstream-side vent pipe 38A. For example, in a case where each hole <NUM> is a round hole, it is favorable if the diameter of each hole <NUM> is smaller than the bubble diameter (for example, the average bubble diameter) of the initial bubbles Gv sent into the water W of the treatment tank <NUM>. The bubbles Gv of the ammonia-containing gas G, which float upward from below in the water W of the treatment tank <NUM>, pass through the holes <NUM> of the porous member <NUM> formed as described above, thereby being made finer. The bubbles Gv of the ammonia-containing gas G are made finer, so that the contact area between the bubbles Gv of the ammonia-containing gas G and the water increases. In this way, the ammonia contained in the gas G reacts with the water W in the treatment tank <NUM> and easily dissolves in the water W.

In this way, a gas Gn that has passed through the water W in the treatment tank <NUM> from below to above the water surface Wf contains a large amount of inert gas. The gas Gn may contain ammonia that does not dissolve in the water W. The gas Gn over the water surface Wf of the treatment tank <NUM> is sent to the vent post <NUM> through the downstream-side vent pipe 38B. The vent post <NUM> releases the gas Gn introduced from below into the atmosphere through the opening at the top portion.

A water recovery tank <NUM> (refer to <FIG>) is connected to the treatment tank <NUM> through a recovery pipe <NUM>. The water recovery tank <NUM> is provided inside the hull <NUM>. A water recovery on/off valve <NUM> is provided in the recovery pipe <NUM>. When the water recovery on/off valve <NUM> is opened after the purge treatment is ended, water W2 is discharged from the treatment tank <NUM> through the recovery pipe <NUM> and recovered in the water recovery tank <NUM>. In the water recovery tank <NUM>, the stored water W2 may be subjected to treatment to reduce the concentration of ammonia, neutralization treatment, or the like, by using seawater or the like separately taken in from the outside.

In the ship <NUM> of the embodiment described above, when the inert gas is supplied from the inert gas supply device <NUM> to the circulation path R for ammonia, the ammonia in the circulation path R is extruded to the vent pipe <NUM> together with the inert gas. In this way, so-called purging, in which the ammonia in the circulation path R is replaced with the inert gas, can be performed. The ammonia-containing gas Gn extruded to the vent pipe <NUM> is introduced to below the water surface Wf of the water W stored in the treatment tank <NUM> from the vent pipe <NUM>. The ammonia-containing gas G forms the bubbles Gv in the water W in the treatment tank <NUM>, and the bubbles Gv float upward from below. At this time, the water W comes into contact with the ammonia-containing gas G. Since ammonia easily reacts with the water W, it becomes ammonia water due to the reaction with the water W and dissolves in the water W. In this way, the content of ammonia in the gas Gn that is led from the vent pipe <NUM> to the outside through the treatment tank <NUM> is reduced. In this way, it becomes possible to reduce the amount of ammonia released into the atmosphere.

In the embodiment described above, the treatment tank <NUM> includes the porous member <NUM> having a plurality of holes <NUM> through which the bubbles Gv of the ammonia-containing gas G pass. In this way, the ammonia-containing gas G which floats upward from below in the state of the bubbles Gv below the water surface Wf of the water in the treatment tank <NUM> passes through the holes <NUM> of the porous member <NUM>, so that the bubbles Gv are made finer according to the size of the hole <NUM>. The bubbles Gv of the ammonia-containing gas G are made finer, so that the contact area between the bubbles Gv of the ammonia-containing gas G and the water increases. As a result, the ammonia reacts with the water W in the treatment tank <NUM> and easily dissolves in the water W. In this way, it is possible to more efficiently reduce the amount of ammonia released into the atmosphere.

In the embodiment described above, the water recovery tank <NUM> that stores the water W2 which is discharged from the treatment tank <NUM> is further provided. In this way, the water W2 in which ammonia is dissolved in the treatment tank <NUM> can be stored in the water recovery tank <NUM>. In the treatment tank <NUM>, for example, treatment to dilute the ammonia contained in the recovered water W2, neutralization treatment, or the like can also be performed.

Next, a second embodiment of the ship according to the invention will be described. In the second embodiment that is described below, since only the internal configuration of the treatment tank <NUM> is different from that of the first embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and overlapping description is omitted.

As shown in <FIG>, in the second embodiment, the treatment tank <NUM> is provided on the way from one end to the other end of the vent pipe <NUM>, as in the first embodiment. The treatment tank <NUM> stores the water W therein. The ammonia-containing gas G which is sent from the purge on/off valve <NUM> side through the upstream-side vent pipe 38A connected to the lower portion of the treatment tank <NUM> is introduced to below the water surface Wf of the treatment tank <NUM>. In the water W in the treatment tank <NUM>, the ammonia-containing gas G introduced from the upstream-side vent pipe 38A forms bubbles Gv, which float upward from below.

In the embodiment of the present disclosure, a partition plate <NUM> is provided inside the treatment tank <NUM>. The partition plate <NUM> is provided below the water surface Wf of the water W in the treatment tank <NUM>. In the embodiment of the present disclosure, for example, two partition plates <NUM> are provided with an interval in the up-down direction Dv. Each partition plate <NUM> is formed so as to follow a plane (for example, a horizontal plane) intersecting (orthogonal to) the up-down direction Dv. A partition plate 65A on one side is provided on a side surface <NUM> located on one side in the horizontal direction in the treatment tank <NUM>. The partition plate 65A is provided with a gap in the horizontal direction interposed between it and a side surface 60t located on the other side in the horizontal direction in the treatment tank <NUM>. A partition plate 65B on the other side is provided on the side surface 60t located on the other side in the horizontal direction in the treatment tank <NUM>. The partition plate 65B is provided with a gap in the horizontal direction interposed between it and the side surface <NUM> located on one side in the horizontal direction in the treatment tank <NUM>.

In the treatment tank <NUM> provided with the partition plate <NUM> as described above, when the bubbles Gv of the ammonia-containing gas G floating upward from below the water surface Wf hit against the partition plate <NUM>, the bubbles Gv move along the bottom surface of the partition plate <NUM>. Due to the two partition plates <NUM> provided in the treatment tank <NUM>, a path F of the flow of the bubbles Gv of the ammonia-containing gas G in the treatment tank <NUM> is curved in a zigzag manner.

In the ship <NUM> of the embodiment described above, the bubbles Gv of the ammonia-containing gas G floating upward from below in the treatment tank <NUM> hit against the partition plates <NUM>, so that the length of the path F of the flow of the bubble Gv of the ammonia-containing gas G in the treatment tank <NUM> increases. In this way, the contact time between the bubbles Gv of the ammonia-containing gas G and the water W increases. As a result, the ammonia reacts with the water W in the treatment tank <NUM> and easily dissolves in the water W. In this way, as in the first embodiment, it is possible to more efficiently reduce the amount of ammonia released into the atmosphere.

Next, a third embodiment of the ship according to the invention will be described. In the third embodiment that is described below, since only the configuration around the treatment tank <NUM> and the water recovery tank <NUM> is different from that of the first embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and overlapping description is omitted.

As shown in <FIG>, in the treatment tank <NUM> and the water recovery tank <NUM> of the ship <NUM> of the third embodiment, dilution water is introduced from the outside through a dilution water introduction system 80C. In the third embodiment, the dilution water introduction system 80C introduces seawater as the dilution water from the outside of the hull <NUM>. The dilution water introduction system 80C includes a pump <NUM> for sucking seawater from the outside of the hull <NUM>, and an on/off valve <NUM>. In the dilution water introduction system 80C, the on/off valve <NUM> is opened and the pump <NUM> is operated to introduce seawater and supply it to the treatment tank <NUM> and the water recovery tank <NUM>.

The treatment tank <NUM> is provided with a water injection unit 68C. The water injection unit 68C injects water Wk supplied through the dilution water introduction system 80C in the form of a shower downward from above the water surface Wf of the water W in the treatment tank <NUM>.

The water recovery tank <NUM> is provided with a water supply unit 78C. The water supply unit 78C supplies the water Wk, which is supplied through the dilution water introduction system 80C, downward from above the water W2 stored in the water recovery tank <NUM>.

The water recovery tank <NUM> is connected to the treatment tank <NUM> through the recovery pipe <NUM>, as in the first embodiment. A case where the water recovery on/off valve <NUM> is not provided in the recovery pipe <NUM> of the second embodiment is exemplified. However, the water recovery on/off valve <NUM> may be provided in the same manner as in the first embodiment. The recovery pipe <NUM> of the second embodiment is a so-called overflow pipe, and moves surplus water W to the water recovery tank <NUM> by its own weight when the water surface Wf in the treatment tank <NUM> reaches a predetermined level or higher.

A discharge system 90C is connected to the water recovery tank <NUM>. The discharge system 90C discharges some of the water W2 stored in the water recovery tank <NUM>. The discharge system 90C discharges surplus water W2 from the water recovery tank <NUM> to the outside as the dilution water is introduced from the outside by the dilution water introduction system 80C. The discharge system 90C includes an overflow pipe <NUM>. A tip portion 91a of the overflow pipe <NUM> is open at a lower portion inside the water recovery tank <NUM>. The overflow pipe <NUM> extends upward from the tip portion 91a and has a pipe top portion 91t at a defined height. The pipe top portion 91t is a portion disposed at the highest position in the overflow pipe <NUM>. The overflow pipe <NUM> discharges the surplus water W2 when a water surface Wf2 in the water recovery tank <NUM> reaches a level equal to or higher than the pipe top portion 91t.

The discharge system 90C further includes a seawater supply unit <NUM>. The seawater supply unit <NUM> supplies seawater taken in from outside to the water W2 that is discharged from the water recovery tank <NUM> through the overflow pipe <NUM>. The seawater supply unit <NUM> merges, for example, seawater which is sent from a main cooling seawater pump (not shown) or the like, which takes in seawater from the outside of the hull <NUM> in order to cool various devices and the like provided within the hull <NUM>, with the water in the overflow pipe <NUM> and sends it to a discharge pipe <NUM>. In this way, the water W2 in the overflow pipe <NUM> is further diluted. An on/off valve <NUM> is provided in the discharge pipe <NUM>. The on/off valve <NUM> is opened, so that as necessary, some of the water W2 in the water recovery tank <NUM> can be diluted with seawater that is supplied from the seawater supply unit <NUM> and then discharged overboard from the discharge pipe <NUM>.

According to the configuration as described above, as in the first embodiment, it becomes possible to reduce the amount of ammonia released into the atmosphere by passing through the treatment tank <NUM>. Further, as in the first embodiment, the water recovery tank <NUM> for storing the water W2 that is discharged from the treatment tank <NUM> is further provided. In this way, the water W2 in which ammonia is dissolved in the treatment tank <NUM> can be stored in the water recovery tank <NUM>.

Further, the treatment tank <NUM> includes the water injection unit 68C. In the treatment tank <NUM>, ammonia that has not completely dissolved in the water W in the treatment tank <NUM> is released into atmosphere above the water surface Wf together with the inert gas. The water W injected from the water injection unit 68C comes into contact with the ammonia released into atmosphere above the water surface Wf, so that the ammonia recovery efficiency can be improved.

Further, the water W in which ammonia is dissolved is diluted with the dilution water (the water Wk) introduced from the outside through the dilution water introduction system 80C, so that the ammonia concentration of the water W that is discharged overboard can be lowered.

Further, the seawater supply unit <NUM> for supplying seawater taken in from the outside is provided in the discharge system 90C, so that the ammonia concentration of the water W that is discharged overboard from the discharge system 90C can be lowered by the seawater that is supplied from the seawater supply unit <NUM>.

In the third embodiment, the water injection unit 68C and the water supply unit 78C are provided. However, only one of the water injection unit 68C and the water supply unit 78C may be provided.

Next, a fourth embodiment of the ship according to the invention will be described. In the fourth embodiment that is described below, since only the configuration around the treatment tank <NUM> and the water recovery tank <NUM> is different from that of the first and third embodiments, the same portions as those in the first and third embodiments are denoted by the same reference numerals, and overlapping description is omitted.

As shown in <FIG>, the ship <NUM> of the present embodiment includes a circulation system <NUM>. The circulation system <NUM> circulates some of the water W2 stored in the water recovery tank <NUM> to the treatment tank <NUM>. The circulation system <NUM> includes a pump <NUM>. The pump <NUM> sends the water W2 in the water recovery tank <NUM> to treatment tank <NUM>.

A neutralization treatment unit <NUM> is provided in the circulation system <NUM>. The neutralization treatment unit <NUM> performs neutralization treatment on the water W2 sucked from the water recovery tank <NUM> by the pump <NUM>. The water W subjected to the neutralization treatment in the neutralization treatment unit <NUM> is supplied to the treatment tank <NUM> through the circulation system <NUM>. Here, as the neutralization treatment, neutralization treatment using dilute sulfuric acid can be exemplified. Further, the concentration of ammonia after the neutralization treatment may be <NUM> ppm or less and more preferably less than <NUM> ppm.

The circulation system <NUM> includes a bypass system <NUM> that bypasses the neutralization treatment unit <NUM>. The circulation system <NUM> includes a switching valve (not shown) that switches the flow of the water W2 between the neutralization treatment unit <NUM> and the bypass system <NUM>, and can select whether or not to perform the neutralization treatment in the neutralization treatment unit <NUM>. In the neutralization treatment unit <NUM>, the neutralization treatment may be performed through the water W only in a case where the concentration of ammonia in the water W detected by a sensor (not shown) exceeds an upper limit value determined in advance. Further, the neutralization treatment unit <NUM> may constantly perform neutralization treatment on the water W flowing through the circulation system <NUM>.

The treatment tank <NUM> of the ship <NUM> of the fourth embodiment includes a water injection unit 68D. The water injection unit 68D injects the water W in the form of a shower downward from above the water surface Wf of the water W in the treatment tank <NUM>. In the fourth embodiment, the water injection unit 68D injects the water W (W2) circulated from the water recovery tank <NUM> through the circulation system <NUM> into the treatment tank <NUM>.

Further, the water recovery tank <NUM> includes a dilution water introduction system 80D. The dilution water introduction system 80D supplies the dilution water introduced from the outside into the water recovery tank <NUM> as water Ws. The water recovery tank <NUM> is provided with a water supply unit 78D. The water supply unit 78D supplies the dilution water introduced from the outside through the dilution water introduction system 80D downward from the upper portion of the water recovery tank <NUM> as the water Ws. In the fourth embodiment, the dilution water introduction system 80D introduces fresh water from a fresh water tank (not shown) provided in the hull <NUM> and supplies it as the water Ws from the water supply unit 78D. In this way, the water W2 in the water recovery tank <NUM> is diluted with the water Ws, which is fresh water, and an increase in ammonia concentration is suppressed. In the fourth embodiment, the water W (W2) is circulated between the treatment tank <NUM> and the water recovery tank <NUM>, and fresh water is used for reasons such as rust prevention.

A discharge system 90D is connected to the neutralization treatment unit <NUM>. The discharge system 90D discharges the surplus water W2, which is generated when the dilution water (water Ws) is introduced from the outside by the dilution water introduction system 80D, from the water recovery tank <NUM> to the outside. The discharge system 90D discharges some of the water W2 stored in the water recovery tank <NUM> to the outside after the neutralization treatment in the neutralization treatment unit <NUM>. The discharge system 90D includes a delivery pipe <NUM> that delivers the water W2 neutralized in the neutralization treatment unit <NUM>.

The discharge system 90D further includes the seawater supply unit <NUM>. The seawater supply unit <NUM> supplies the seawater taken in from the outside to water W3 that is discharged from the neutralization treatment unit <NUM> through the delivery pipe <NUM>. The seawater supply unit <NUM> merges the seawater that is supplied from a main cooling seawater pump (not shown) or the like with the water in the delivery pipe <NUM> and sends it to the discharge pipe <NUM>. In this way, the water W3 in the delivery pipe <NUM> is diluted. An on/off valve <NUM> is provided in the discharge pipe <NUM>. The on/off valve <NUM> is opened, so that as necessary, some of the water W3 discharged from the neutralization treatment unit <NUM> can be diluted with the seawater that is supplied from the seawater supply unit <NUM> and then discharged overboard from the discharge pipe <NUM>.

According to the configuration as described above, as in the first embodiment, it becomes possible to reduce the amount of ammonia released into the atmosphere by passing through the treatment tank <NUM>. Further, the water recovery tank <NUM> for storing the water W2 that is discharged from the treatment tank <NUM> is further provided. In this way, the water W2 in which ammonia is dissolved in the treatment tank <NUM> can be stored in the water recovery tank <NUM>.

Further, the ship <NUM> includes the circulation system <NUM>. In this way, some of the water W2 recovered from the treatment tank <NUM> to the water recovery tank <NUM> is circulated to the treatment tank <NUM>, so that ammonia can be recovered using more water W in an ammonia recovery device as a whole.

Further, the ship <NUM> includes the neutralization treatment unit <NUM>. In this way, neutralization treatment is performed on the ammonia in the water W2 in the water recovery tank <NUM> by the neutralization treatment unit <NUM>, so that an increase in the ammonia concentration in the water W (W2) is suppressed. Further, in a case where the water W2 is discharged overboard, the water W3 whose ammonia concentration is lowered by the neutralization treatment can be discharged overboard.

Further, the water W in which ammonia is dissolved is diluted with the dilution water (water Ws) introduced from the outside by the dilution water introduction system 80D, so that an increase in ammonia concentration in the water W (W2) circulating between the water recovery tank <NUM> and the treatment tank <NUM> is suppressed. Further, the ammonia concentration in the water W3 discharged overboard can be lowered.

Further, the treatment tank <NUM> includes the water injection unit 68D. In this way, the water W injected from the water injection unit 68D comes into contact with the ammonia released into atmosphere above the water surface Wf, so that the ammonia recovery efficiency is enhanced.

Further, the seawater supply unit <NUM> is provided in the discharge system 90D, so that the ammonia concentration of the water W which is discharged overboard from the discharge system 90D can be lowered by the seawater which is supplied from the seawater supply unit <NUM>.

The embodiments of the present disclosure have been described in detail above with reference to the drawings. However, the specific configurations are not limited to these embodiments and also include design changes and the like within a scope which does not depart from the gist of the present disclosure.

In the first embodiment described above, the platelike porous member <NUM> is provided. However, a member of any shape may be used as long as the bubbles Gv pass through it, so that the bubbles Gv are made finer. For the porous member, for example, a sponge-like porous member or the like having a large number of holes can be adopted. Further, the hole <NUM> is not limited to a circular shape. For example, the hole <NUM> may be an elongated hole, a polygonal hole, a slit-shaped hole, or the like.

Further, in each of the embodiments described above, the ammonia in the purge target region 20p is introduced into the treatment tank <NUM> by the inert gas supply device <NUM>. However, the ammonia may be introduced into the treatment tank <NUM> from a pipe in another appropriate portion as long as it is the circulation path R for ammonia, which communicates with the ammonia storage tank.

Further, in the embodiments described above, the internal combustion engine <NUM> is shown as a device that is driven by the ammonia that is supplied from the ammonia storage tank. However, the use of the internal combustion engine <NUM> is not limited at all. Further, the device is not limited to the internal combustion engine <NUM>, and may be a boiler or the like as long as it is driven by ammonia.

Further, the ammonia storage tank is provided on the stern 3b side with respect to the superstructure <NUM>. However, there is no limitation thereto. For example, the ammonia storage tank may be provided on the upper deck <NUM> on the bow 3a side with respect to the superstructure <NUM>. Furthermore, the ammonia storage tank may be provided not only on the upper deck <NUM> but also inside the hull <NUM> below the upper deck <NUM>.

In addition, the ammonia that is introduced into the treatment tank <NUM> is not limited to the ammonia that is stored in the ammonia storage tank storing fuel for propelling the ship <NUM> and may be ammonia that is stored in a tank for cargo that is carried by the ship <NUM>.

The ship <NUM> described in each of the embodiments is understood as follows, for example.

In the ship <NUM>, when the inert gas is supplied from the inert gas supply device <NUM> to the ammonia circulation path R, the ammonia in the circulation path R is extruded to the vent pipe <NUM> together with the inert gas. In this way, so-called purging, in which the ammonia in the circulation path R is replaced with the inert gas, can be performed. The ammonia-containing gas Gn extruded to the vent pipe <NUM> is introduced to below the water surface Wf of the water W stored in the treatment tank <NUM> from the vent pipe <NUM>. The ammonia-containing gas G forms the bubbles Gv in the water W in the treatment tank <NUM> and floats upward from below. At this time, the water W comes into contact with the ammonia-containing gas G. Ammonia easily reacts with the water W2, so that it becomes ammonia water due to the reaction with the water W and dissolves in the water. In this way, the content of ammonia in the gas Gn that is led from the vent pipe <NUM> to the outside through the treatment tank <NUM> is reduced. On the other hand, nitrogen is difficult to dissolve in the water W, floats in the state of the bubbles Gv, and is released into atmosphere above the water surface Wf. In this way, it becomes possible to reduce the amount of ammonia released into the atmosphere.

(<NUM>) In a ship <NUM> according to a second aspect, in the ship <NUM> of the above (<NUM>), the treatment tank <NUM> is provided with the porous member <NUM> that is provided below the water surface Wf of the water W and has a plurality of holes <NUM> through which the bubbles Gv of the inert gas and the ammonia which float upward from below in the water W pass.

In this way, the ammonia-containing gas G which floats upward from below in the state of the bubbles Gv below the water surface Wf of the water in the treatment tank <NUM> passes through the holes <NUM> of the porous member <NUM>, so that the bubbles Gv are made finer according to the diameter of the hole <NUM>. The bubbles Gv of the ammonia-containing gas G are made finer, so that the contact area between the bubbles Gv of the ammonia-containing gas G and the water increases. As a result, the ammonia reacts with the water W in the treatment tank <NUM> and easily dissolves in the water W. In this way, it is possible to more efficiently reduce the amount of ammonia released into the atmosphere.

(<NUM>) In a ship <NUM> according to a third aspect, in the ship <NUM> of the above (<NUM>) or (<NUM>), the treatment tank <NUM> is provided with the partition plate <NUM> that is provided along a plane intersecting the up-down direction Dv below the water surface Wf of the water W.

In this way, when the bubbles Gv of the ammonia-containing gas G floating upward from below in the treatment tank <NUM> hit against the partition plates <NUM>, the bubbles Gv flow along the partition plate <NUM>. In this way, the length of the path F of the flow of the bubbles Gv of the ammonia-containing gas G in the treatment tank <NUM> increases. In this way, the contact time between the bubbles Gv of the ammonia-containing gas G and the water W increases. As a result, the ammonia reacts with the water W in the treatment tank <NUM> and easily dissolves in the water W. In this way, it is possible to more efficiently reduce the amount of ammonia released into the atmosphere.

(<NUM>) In a ship <NUM> according to a fourth aspect, the ship <NUM> of any one of the above (<NUM>) to (<NUM>) further includes the water recovery tank <NUM> provided in the hull <NUM> to store the water W2 that is discharged from the treatment tank <NUM>.

In this way, the water W2 in which ammonia is dissolved in the treatment tank <NUM> can be stored in the water recovery tank <NUM>. In the treatment tank <NUM>, for example, treatment to dilute the ammonia contained in the recovered water W2, neutralization treatment, or the like can also be performed.

(<NUM>) In a ship <NUM> according to a fifth aspect, the ship <NUM> of the above (<NUM>) further includes the circulation system <NUM> that circulates some of the water W2 stored in the water recovery tank <NUM> to the treatment tank <NUM>.

In this way, some of the water W2 recovered from the treatment tank <NUM> to the water recovery tank <NUM> is circulated to the treatment tank <NUM>, so that ammonia can be recovered by using more water W as a whole.

(<NUM>) In a ship <NUM> according to a sixth aspect, in the ship <NUM> of the above (<NUM>) or (<NUM>), the treatment tank <NUM> includes the water injection unit 68C or 68D that injects the water W or Wk downward from above the water surface Wf of the water W.

In the treatment tank <NUM>, ammonia that has not completely dissolved in the water W in the treatment tank <NUM> is released into atmosphere above the water surface Wf together with the inert gas. The water W or Wk injected by the water injection unit 68C or 68D comes into contact with the ammonia released into atmosphere above the water surface Wf, so that the ammonia recovery efficiency in the treatment tank <NUM> is enhanced.

(<NUM>) In a ship <NUM> according to a seventh aspect, the ship <NUM> of any one of the above (<NUM>) to (<NUM>) further includes the neutralization treatment unit <NUM> that performs neutralization treatment on the water W2 in the water recovery tank <NUM>.

In this way, neutralization treatment is performed on the ammonia in the water W2 in the water recovery tank <NUM> by the neutralization treatment unit <NUM>, so that an increase in ammonia concentration in the water W or W2 is suppressed. Further, in a case where the water W2 is discharged overboard, the water W2 whose ammonia concentration is lowered by the neutralization treatment can be discharged overboard.

(<NUM>) In a ship <NUM> according to an eighth aspect, the ship <NUM> of any one of the above (<NUM>) to (<NUM>) further includes: the dilution water introduction system 80C or 80D that introduces dilution water from the outside into at least one of the treatment tank <NUM> and the water recovery tank <NUM>; and the discharge system 90C or 90D that discharges some of the water W2 stored in the water recovery tank <NUM>.

In this way, in a case where the water W2 is discharged overboard from the discharge systems 90C or 90D, the water W2 in which the ammonia is dissolved is diluted with the dilution water introduced from the outside by the dilution water introduction systems 80C or 80D, so that the ammonia concentration of the water W2 which is discharged can be lowered. Further, in a case where some of the water W2 in the water recovery tank <NUM> is circulated to the treatment tank <NUM> by the circulation system <NUM>, an increase in ammonia concentration in the water W (W2) that circulates between the water recovery tank <NUM> and the treatment tank <NUM> is suppressed.

(<NUM>) In a ship <NUM> according to a ninth aspect, the ship <NUM> of the above (<NUM>) further includes the seawater supply unit <NUM> that supplies seawater taken in from the outside to the discharge system 90C or 90D.

In this way, the ammonia concentration of the water W2 that is discharged overboard from the discharge system 90C or 90D can be lowered by the seawater that is supplied from the seawater supply unit <NUM>.

Claim 1:
A ship (<NUM>) comprising:
a hull (<NUM>); and
an ammonia storage tank (<NUM>) capable of storing ammonia therein;
an inert gas supply device (<NUM>) that supplies an inert gas to a circulation path (R) for the ammonia, which communicates with the ammonia storage tank (<NUM>);
a vent pipe (<NUM>) that leads the ammonia in the circulation path (R) together with the inert gas supplied by the inert gas supply device (<NUM>) to an outside; and
a treatment tank (<NUM>) which is provided in a middle of the vent pipe (<NUM>) and stores water (W) therein, and into which the inert gas and the ammonia are introduced from the vent pipe (<NUM>) below a water surface (Wf) of the water (W).