Floating body and ammonia decontamination method

Abstract

To provide a float capable of easily detoxifying ammonia while suppressing rise in cost and an ammonia detoxification method.SOLUTION: A float includes: a float body floating on sea water; an ammonia line provided in the float body circulating the ammonia water; an intake unit for taking in sea water inside the float body; a sea water introduction line for introducing the sea water taken in from the intake unit into the floating body; an electrolysis unit for generating sea water electrolyte containing sodium hypochlorite by performing electrolysis on the sea water introduced by the sea water introduction line; denitrifying reaction unit for having mixture of the ammonia water circulating in the ammonia line and the sea water electrolyte solution generated at the electrolysis unit react; and a discharge unit for discharging processed liquid after reaction at the denitrifying reaction unit into sea water surrounding the float body.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a floating body and a method for removing ammonia.

Background Art

[0002] In a floating body such as a ship, when ammonia is transported and supplied as fuel for a power generation plant or when ammonia is used as fuel for a main engine or the like, ammonia may leak in a compartment such as an equipment room that houses equipment for handling ammonia. When ammonia leakage occurs in such a compartment, it is assumed that the leaked ammonia vaporizes and leaks outside the compartment.

[0003] Patent Document 1 proposes a technique for preventing ammonia from leaking outside the compartment by providing a sealed duct communicating with the inside of the compartment, spraying water in this duct, absorbing ammonia in the water in the duct, and making the inside of the compartment negative pressure. In this Patent Document 1, the water that has absorbed ammonia is returned to the water tank and circulated to the water spray nozzles again, or discharged to other treatment facilities.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When attempting to remove ammonia by absorbing it into water as in Patent Document 1, the required amount of water increases as the amount of ammonia discharged increases. However, since the space within the floating body is limited, there may be cases where a storage location for a large amount of water that has absorbed ammonia cannot be secured. And the water that has absorbed ammonia may have an impact on the environment, so it cannot be directly discharged into the water around where the floating body floats. Therefore, it is desired to perform decontamination treatment on the water that has absorbed ammonia on the floating body.

[0006] As a method for decontaminating water that has absorbed ammonia, for example, a method of decomposing ammonia by using an oxidizing agent such as sulfuric acid or hydrochloric acid is known. However, such oxidizing agents may be difficult to obtain at ports of call or mooring locations, etc., and there is an issue that the cost may increase by using a large amount of oxidizing agent. The present disclosure has been made in view of the above circumstances, and provides a floating body and an ammonia decontamination method that can easily decontaminate ammonia while suppressing cost increases.

Means for Solving the Problems

[0007] In order to solve the above problems, the following configuration is adopted. The present disclosure One According to an aspect, the floating body includes a floating body main body that floats in seawater, an ammonia line provided within the floating body main body through which ammonia water flows, a water intake section that takes in the seawater within the floating body main body, a seawater introduction line that introduces the seawater taken in from the water intake section into the floating body main body, an electrolysis section that generates a seawater electrolytic solution containing sodium hypochlorite by subjecting the seawater introduced by the seawater introduction line to electrolysis, a denitrification reaction section that reacts a mixed solution of the ammonia water flowing through the ammonia line and the seawater electrolytic solution generated by the electrolysis section, and a discharge section that discharges the treated liquid after being reacted in the denitrification reaction section into the seawater around where the floating body main body floats. , the electrolysis unit includes the denitrification reaction unit, and the ammonia line supplies the aqueous ammonia to the electrolysis unit. It has. Furthermore, according to one aspect of the present disclosure, the floating body includes a floating body main body floating on seawater, an ammonia line provided in the floating body main body through which aqueous ammonia flows, a water intake unit that takes in the seawater into the floating body main body, a seawater introduction line that introduces the seawater taken in from the water intake unit into the floating body main body, an electrolysis unit that generates a seawater electrolysis solution containing sodium hypochlorite by electrolyzing the seawater introduced by the seawater introduction line, a denitrification reaction unit that reacts a mixed solution of the aqueous ammonia flowing through the ammonia line and the seawater electrolysis solution generated by the electrolysis unit, and a discharge unit that discharges the treated liquid after the reaction in the denitrification reaction unit into the seawater around the floating body main body, and includes a dilution line that merges a part of the seawater introduced into the floating body main body by the seawater introduction line into the treated liquid. Also, according to one aspect of the present disclosure, the floating body includes a floating body main body floating on seawater, an ammonia line provided in the floating body main body through which aqueous ammonia flows, a water intake unit that takes in the seawater into the floating body main body, a seawater introduction line that introduces the seawater taken in from the water intake unit into the floating body main body, an electrolysis unit that generates a seawater electrolysis solution containing sodium hypochlorite by electrolyzing the seawater introduced by the seawater introduction line, a denitrification reaction unit that reacts a mixed solution of the aqueous ammonia flowing through the ammonia line and the seawater electrolysis solution generated by the electrolysis unit, and a discharge unit that discharges the treated liquid after the reaction in the denitrification reaction unit into the seawater around the floating body main body, and includes a pH adjuster that adjusts the pH of the mixed solution in the denitrification reaction unit to the lower side.

[0008] According to an aspect of the present disclosure, One the ammonia removal method is an ammonia removal method for removing ammonia water from a floating body floating in seawater, including a generation step of taking in the seawater around the floating body and electrolyzing it to generate a seawater electrolytic solution containing sodium hypochlorite, and a denitrification reaction step of reacting the sodium hypochlorite in the seawater electrolytic solution with the ammonia in the ammonia water. view, in the denitrification reaction step, the pH of the mixed solution of the seawater electrolysis solution and the aqueous ammonia is lowered to a range where alkaline earth metals contained in the seawater do not precipitate. .

Advantages of the Invention

[0009] According to the floating body and the ammonia removal method according to the present disclosure, ammonia can be easily removed while suppressing cost increase.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] [Embodiment] Hereinafter, a floating body and an ammonia removal method according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a side view of a floating body according to an embodiment of the present disclosure. (Configuration of the floating body) As shown in Fig. 1, the floating body 1 of this embodiment includes a floating body main body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, a piping system 20, a compartment 30, an ammonia recovery unit 60, a recovered ammonia water tank 70, and an ammonia decomposition device 80. Note that the floating body 1 of this embodiment will be described by taking a ship that can navigate by a main engine or the like as an example. The ship type of the floating body 1 is not limited to a specific ship type. Examples of the ship type of the floating body 1 include a liquefied gas carrier, a ferry, a RORO ship, an automobile carrier, a passenger ship, etc. In this embodiment, the case where the floating body 1 is a ship will be described, but the floating body 1 is not limited to a ship, and it may be an FSU (Floating Storage Unit), an FSRU (Floating Storage and Regasification Unit), etc. that cannot navigate by a main engine or the like.

[0012] The floating body main body 2 is formed to float in seawater. The floating body main body 2 has a pair of side plates 5A and 5B forming its outer shell and a bottom 6. The side plates 5A and 5B include a pair of side shell plates forming the left and right side plates respectively. The bottom 6 includes a bottom shell plate connecting these side plates 5A and 5B. By these pair of side plates 5A and 5B and the bottom 6, the outer shell of the floating body main body 2 forms a U shape in a cross section orthogonal to the fore-and-aft direction FA of the ship.

[0013] The floating body main body 2 further includes an upper deck 7 which is an all-through deck arranged at the uppermost layer. The upper structure 4 is formed on this upper deck 7. Living quarters and the like are provided in the upper structure 4. In the floating body 1 of this embodiment, for example, a cargo space (not shown) for loading cargo is provided on the bow 3a side in the fore-and-aft direction FA of the ship rather than the upper structure 4.

[0014] The combustion device 8 is a device that generates thermal energy by burning fuel, and is provided in the floating body main body 2 described above. Examples of the combustion device 8 include an internal combustion engine used for the main engine to propel the floating body 1, an internal combustion engine used for power generation equipment to supply electricity to the ship, a boiler that generates steam as a working fluid, etc. The combustion device 8 of this embodiment is also a heat generating device that generates heat by burning fuel.

[0015] The ammonia tank 10 is a tank for storing liquid ammonia (in other words, liquefied ammonia). This ammonia tank 10 is installed on the upper deck 7 on the stern 3b side of the superstructure 4. Note that the arrangement of the ammonia tank 10 is an example and is not limited to the upper deck 7 on the stern 3b side of the superstructure 4. The ammonia tank 10 of the present embodiment stores liquefied ammonia as fuel for the combustion device 8.

[0016] The piping system 20 connects the combustion device 8 and the ammonia tank 10 and is configured to be able to supply at least the ammonia stored in the ammonia tank 10 to the combustion device 8.

[0017] The compartment 30 is a compartment for housing ammonia-related equipment. The compartment 30 in the present embodiment is provided on the upper deck 7 on the bow 3a side of the superstructure 4. The above-described piping system 20 connects the combustion device 8 and the ammonia tank 10 via this compartment 30. Here, the ammonia-related equipment means all equipment for handling ammonia, and examples thereof include ammonia fuel equipment for handling ammonia and ammonia cargo equipment for handling ammonia as cargo. In the following description, the compartment 30 in which ammonia fuel equipment is housed will be described, but it may be a compartment 30 in which ammonia cargo equipment is housed.

[0018] (Configuration of Ammonia Recovery Section) The ammonia recovery unit 60 absorbs the ammonia to be recovered into water and recovers it as recovered ammonia water (aqueous ammonia). The ammonia recovery unit 60 of the present embodiment is disposed on the upper deck 7 on the stern 3b side of the ammonia tank 10. As the ammonia recovery unit 60, for example, a so-called scrubber that absorbs ammonia into water by injecting water into the gas containing ammonia can be used. Water (for example, fresh water) stored in a water tank (not shown) provided in the floating body main body 2 or water taken in from outside the floating body (for example, seawater, etc.) is supplied to the ammonia recovery unit 60. The ammonia recovered by the ammonia recovery unit 60 can be exemplified by, for example, ammonia leaked into the compartment 30 or ammonia discharged from the piping system 20 by fuel purge. Note that the ammonia recovery unit 60 may have any configuration as long as it can absorb ammonia into water and recover it as recovered ammonia water, and is not limited to the above configuration and arrangement.

[0019] The recovered ammonia water tank 70 stores the recovered ammonia water recovered by the ammonia recovery unit 60. The recovered ammonia water tank 70 in the present embodiment is disposed in the floating body main body 2 below the upper deck 7 where the ammonia recovery unit 60 is installed. The arrangement of the recovered ammonia water tank 70 is not limited to the above arrangement as long as it can recover the ammonia recovered by the ammonia recovery unit 60 as recovered ammonia water.

[0020] (Configuration of Ammonia Decomposing Device) FIG. 2 is a diagram showing a schematic configuration of an ammonia decomposing device in a floating body according to an embodiment of the present disclosure. As shown in FIG. 2, the ammonia decomposing device 80 is a device that decomposes and detoxifies ammonia contained in aqueous ammonia. The ammonia decomposing device 80 includes an ammonia line 81, a water intake section 82, a seawater introduction line 83, an electrolysis section 84, a line mixer 85, a denitrification reaction tank (denitrification reaction section) 86, a discharge section 87, an exhaust heat recovery section 88, and a dilution line 89.

[0021] The ammonia line 81 is provided inside the floating body main body 2. Recovered ammonia water (aqueous ammonia) flows through this ammonia line 81. The ammonia line 81 of the present embodiment is a pipe that guides the recovered ammonia water stored in the recovered ammonia water tank 70 described above to the electrolysis unit 84.

[0022] The water intake section 82 takes in seawater around the floating body main body 2 floating into the floating body main body 2. The water intake section 82 includes a water intake port 90, a seawater pump 91, and a marine organism adhesion prevention treatment device 92. The water intake port 90 opens below the light load waterline (not shown) of the outer plate of the floating body main body 2. That is, the water intake port 90 is always located below the sea surface. The seawater pump 91 sends out the seawater at the water intake port 90 into the floating body main body 2. The seawater sent out by the seawater pump 91 is respectively branched into the marine organism adhesion prevention treatment device 92 and the seawater introduction line 83.

[0023] The marine organism adhesion prevention treatment device 92 performs a treatment for preventing the adhesion of marine organisms to the taken-in seawater. Examples of the treatment for preventing the adhesion of marine organisms include electrolyzing seawater to generate sodium hypochlorite or generating copper ions, and adding these sodium hypochlorite and copper ions to the seawater taken in from the water intake port 90. By the treatment for preventing the adhesion of marine organisms by this marine organism adhesion prevention treatment device 92, it is possible to suppress the adhesion and blockage of marine organisms on the inner surface of the pipe through which seawater flows in the floating body main body 2 and the inner surface of the water intake port 90.

[0024] The seawater introduction line 83 introduces the seawater taken in by the water intake section 82 into the floating body main body 2. The seawater introduction line 83 of the present embodiment is a pipe that supplies seawater to at least the electrolysis unit 84. Here, the seawater introduction line 83 has a plurality of branch lines 93, and it is possible to supply seawater to facilities other than the ammonia decomposition device 80 through these branch lines 93. The seawater supplied to facilities other than the ammonia decomposition device 80 through these plurality of branch lines 93 is discharged from the discharge section 87 to the outside of the floating body main body 2 through the confluence line 94 and the dilution line 89 described later after being used as cooling water or the like.

[0025] In the middle of the above-described seawater introduction line 83, a waste heat recovery unit 88 is provided. The waste heat recovery unit 88 recovers the waste heat of the heat-generating equipment provided in the floating body main body 2. In the present embodiment, the waste heat of the combustion device 8 as the heat-generating equipment is recovered to heat the seawater flowing through the seawater introduction line 83. The cooling water (for example, fresh water) of the combustion device 8 and the seawater flowing through the seawater introduction line 83 are heat-exchanged. As a result, regardless of the seawater temperature at the water intake section 82, the temperature of the seawater flowing through the seawater introduction line 83 does not become 10°C or lower. In the present embodiment, a cooling water pump 102 is provided in the cooling water line 101 through which the cooling water of the combustion device 8 flows, and the cooling water circulates between the waste heat recovery unit 88 and the combustion device 8. Further, a cooling water branch line 103 for circulating the cooling water to other heat-generating equipment other than the combustion device 8 is also connected to the cooling water line 101, and the waste heat of other heat-generating equipment can also be recovered.

[0026] The electrolysis unit 84 generates a seawater electrolytic solution containing sodium hypochlorite by subjecting the seawater introduced into the floating body main body 2 through the seawater introduction line 83 to electrolysis. The electrolysis unit 84 of the present embodiment includes an electrolysis device 95, a storage tank 96, a circulation line 97, and a circulation pump 98.

[0027] The electrolysis device 95 electrolyzes seawater to generate a seawater electrolytic solution. Specifically, a positive electrode and a negative electrode (not shown) are arranged in seawater, and a voltage is applied between the positive electrode and the negative electrode to electrolyze the seawater. By this electrolysis, sodium hypochlorite is generated from the seawater. The seawater electrolytic solution electrolyzed by the electrolysis device 95 is introduced into the storage tank 96.

[0028] The storage tank 96 is capable of storing the seawater electrolytic solution generated by the electrolysis device 95. The storage tank 96 of the present embodiment is connected to the seawater introduction line 83, and in addition to the seawater electrolytic solution from the electrolysis device 95, seawater from the seawater introduction line 83 is injected.

[0029] The circulation line 97 circulates the seawater electrolytic solution between the electrolysis device 95 and the storage tank 96. That is, the circulation line 97 guides the seawater electrolytic solution stored in the storage tank 96 to the electrolysis device 95 and guides the seawater electrolytic solution electrolyzed by the electrolysis device 95 to the storage tank 96. The electrolysis section 84 of the present embodiment further includes an electrolytic solution line 99 for guiding the seawater electrolytic solution stored in the storage tank 96 to the line mixer 85. This electrolytic solution line 99 is branched and connected to the above-mentioned circulation line 97.

[0030] The circulation pump 98 is provided in the middle of the circulation line 97. The circulation pump 98 sends out the seawater electrolytic solution in the circulation line 97 toward the electrolysis device 95 and the line mixer 85. By driving this circulation pump 98, a part of the seawater electrolytic solution in the circulation line 97 circulates between the electrolysis device 95 and the storage tank 96, and the remaining part of the seawater electrolytic solution in the circulation line 97 is supplied to the line mixer 85 through the electrolytic solution line 99. A valve (not shown) whose opening can be adjusted from fully closed to fully open is provided in the middle of the electrolytic solution line 99, and it is possible to adjust the flow rate of the seawater electrolytic solution supplied to the line mixer 85.

[0031] According to the above-mentioned electrolysis section 84, by circulating the seawater electrolytic solution stored in the storage tank 96, it can be electrolyzed again by the electrolysis device 95. Therefore, it is possible to obtain a seawater electrolytic solution with a higher concentration of sodium hypochlorite than the seawater electrolytic solution electrolyzed only once by the electrolysis device 95. Although the case where the electrolytic solution line 99 is branched and connected to the circulation line 97 has been described, it is not limited to this configuration. For example, it may be connected to the storage tank 96 so as to guide the seawater electrolytic solution stored in the storage tank 96 to the line mixer 85 without passing through the circulation line 97. In this case, another pump for sending the seawater electrolytic solution to the line mixer 85 may be provided in the electrolytic solution line 99.

[0032] The line mixer 85 stirs a mixed solution of the seawater electrolytic solution generated by the electrolysis unit 84 and the recovered ammonia water supplied by the ammonia line 81. The mixed solution stirred by this line mixer 85 is introduced into the denitrification reaction tank 86.

[0033] The denitrification reaction tank 86 causes a reaction between the recovered ammonia water flowing through the ammonia line 81 and the seawater electrolytic solution generated in the electrolysis unit 84. More specifically, as shown in formula (1), the denitrification reaction tank 86 causes the ammonia (2NH 3 ) of the recovered ammonia water to react with the sodium hypochlorite (3NaClO) of the seawater electrolytic solution in an acidic environment to decompose into nitrogen (N 2 ), sodium chloride (3NaCl), and water (3H 2 O). That is, a denitrification reaction is carried out in the denitrification reaction tank 86. 2NH 3 + 3NaClO ⇒ N 2 + 3NaCl + 3H 2 O ···(1)

[0034] The nitrogen generated by the denitrification reaction in the denitrification reaction tank 86 is discharged into the atmosphere through, for example, a vent post (not shown) extending from the upper deck 7. On the other hand, the sodium chloride and water generated by the denitrification reaction in the denitrification reaction tank 86 are discharged to the discharge section 87 as treated liquid.

[0035] Here, in the denitrification reaction in the denitrification reaction tank 86, in order to lower the pH of the mixed water of the recovered ammonia water and the seawater electrolytic solution at the start of the reaction, an oxidizing agent such as sulfuric acid or hydrochloric acid is added to the mixed water. Therefore, a chemical solution tank 100 (pH adjuster) for adding the oxidizing agent may be connected to the above-described denitrification reaction tank 86. Note that, without connecting the chemical solution tank 100, for example, an operator may add the oxidizing agent to the denitrification reaction tank 86 using a tank held by hand. The pH value of the mixed water in the present embodiment is adjusted to a value below which alkaline earth metals contained in seawater do not precipitate. Here, examples of the alkaline earth metals contained in seawater include calcium (Ca) and magnesium (Mg). In the denitrification reaction in an example of the present embodiment under the above acidic environment, in an intermediate process, NH 2 Cl and NHCl 2 Two types of intermediates (chloramines), namely, are generated, and these NH 2 Cl and NHCl 2 react with each other to form nitrogen gas (N 2 ) and hydrochloric acid (3HCl). That is, since hydrochloric acid is generated, it becomes possible to continue the denitrification reaction under an acidic environment without additionally adding an oxidizing agent to the mixed water in the denitrification reaction tank 86.

[0036] The dilution line 89 merges a part of the seawater introduced into the floating body main body 2 through the seawater introduction line 83 with the treated liquid discharged from the denitrification reaction tank 86. That is, the treated liquid is diluted by the seawater merged by the dilution line 89. The seawater flowing through the dilution line 89 in the present embodiment is the seawater diverted from the above-described seawater introduction line 83 and the seawater diverted by the branch line 93 and supplied to other facilities other than the ammonia decomposition device 80 and used for cooling or the like.

[0037] The discharge section 87 discharges the treated liquid after the reaction in the denitrification reaction tank 86 into the seawater around the floating body main body 2 floating. The discharge section 87 in the present embodiment discharges the treated liquid diluted by the seawater flowing through the dilution line 89.

[0038] (Ammonia removal method) Next, the ammonia removal method in the embodiment of the present disclosure will be described. FIG. 3 is a flowchart showing the ammonia removal method in the embodiment of the present disclosure. As shown in FIG. 3, the ammonia removal method of this embodiment includes an exhaust heat recovery step S11, a generation step S12, and a denitrification reaction step S13.

[0039] In the exhaust heat recovery step S11, the exhaust heat of the equipment in the floating body main body 2 is recovered using the taken seawater. That is, in this embodiment, the seawater introduced into the floating body main body 2 by the above-described seawater introduction line 83 is heated by the exhaust heat recovery unit 88. In the generation step S12, the seawater whose temperature has been raised in the exhaust heat recovery step S11 is electrolyzed to generate a seawater electrolytic solution containing sodium hypochlorite. In this embodiment, the seawater electrolytic solution is generated by the above-described electrolysis unit 84, and the seawater electrolytic solution is circulated between the storage tank 96 and the electrolysis device 95 to increase the concentration of sodium hypochlorite.

[0040] In the denitrification reaction step S13, the sodium hypochlorite in the seawater electrolytic solution is reacted with the ammonia in the recovered ammonia water. Further, in this denitrification reaction step S13, the pH of the mixed solution of the seawater electrolytic solution and the ammonia water is lowered to a range where alkaline earth metals contained in the seawater do not precipitate. That is, in this embodiment, an oxidizing agent is added to the mixed solution in the above-described denitrification reaction tank 86 to adjust the pH value to a value suitable for the denitrification reaction, and the sodium hypochlorite and ammonia are reacted in the denitrification reaction tank 86. Then, in this embodiment, the treated liquid after the reaction in the denitrification reaction step S13 is diluted using the seawater introduced into the floating body main body 2 and discharged into the seawater around the floating body main body 2.

[0041] (Function and effect) According to the floating body 1 of the above embodiment, seawater taken in from the water intake part 82 is introduced into the floating body main body 2 floating in seawater through the seawater introduction line 83, and this seawater is electrolyzed by the electrolysis part 84 to generate a seawater electrolytic solution containing sodium hypochlorite. Further, a mixed solution of ammonia water flowing through the ammonia line 81 and the seawater electrolytic solution is reacted in the denitrification reaction tank 86, and the treated liquid after this reaction is discharged into the seawater around the floating body main body 2 by the discharge part 87. In the seawater electrolytic solution generated by electrolyzing seawater as described above, in addition to sodium chloride (NaCl) which is a raw material for sodium hypochlorite, transition metal ions which have the effect of increasing the denitrification reaction rate as a promoting oxidation catalyst (Fenton catalyst) such as iron and manganese are contained. Therefore, by decomposing the ammonia in the recovered ammonia water using the seawater electrolytic solution obtained by electrolyzing the taken-in seawater, ammonia can be decomposed more efficiently than when using sodium hypochlorite alone. Also, since it is not necessary to mount a large amount of strongly acidic chemical solution for decomposing ammonia inside the floating body main body 2, it is possible to suppress the enlargement of the floating body main body 2 and improve the safety of the workers. Furthermore, since it is not necessary to obtain sodium hypochlorite as an oxidizing agent at the port of call or mooring location, etc., the burden on the workers can be reduced. Therefore, it is possible to easily remove ammonia while suppressing cost increase.

[0042] According to the floating body 1 of the above embodiment, the waste heat of the combustion device 8 is recovered by heat-exchanging the seawater introduced into the floating body main body 2 through the seawater introduction line 83 and the cooling water of the combustion device 8 which is a heat-generating device. Then, the seawater heat-exchanged by this waste heat recovery part 88 is led to the electrolysis part 84 by the seawater introduction line 83. As a result, the temperature of the seawater taken in from the water intake section 82 can be increased. Therefore, even when the temperature of the seawater around the floating body 2 is low, it is possible to suppress a decrease in the production efficiency of sodium hypochlorite by the electrolysis section 84. Further, since waste heat is utilized, energy savings can be achieved as compared with the case of providing a dedicated heat source for increasing the temperature of the seawater. Furthermore, since the temperature of the seawater electrolytic solution can be increased, the temperature of the mixed solution in the denitrification reaction tank 86 rises, and the viscosity of the mixed solution can be decreased. Therefore, precipitation of hydroxides due to the reaction between alkaline earth metal ions and ammonia can be suppressed.

[0043] According to the floating body 1 of the above-described embodiment, further, the water intake section 82 includes an anti-fouling treatment device 92 for marine products, and the anti-fouling treatment device 92 performs an anti-fouling treatment on the seawater taken in thereby. Thereby, it is possible to suppress the blockage of the flow path for taking in seawater due to the attachment of marine products to the inner surface of the water intake port 90 or the inner surface of the seawater introduction line 83. Further, when the anti-fouling treatment device 92 for marine products is configured to prevent the attachment of marine products by sodium hypochlorite generated by electrolyzing seawater, the concentration of sodium hypochlorite for the purpose of preventing the attachment of marine products can be set. Therefore, it is possible to suppress the occurrence of corrosion in the pipes for circulating seawater, such as the seawater introduction line 83 and the branch line 93, due to sodium hypochlorite.

[0044] According to the floating body 1 of the above-described embodiment, the electrolysis section 84 circulates the seawater electrolytic solution generated by electrolyzing seawater by the electrolysis device 95 between a storage tank capable of storing the seawater electrolytic solution and the electrolysis device 95 by a circulation line and a circulation pump. As a result, the concentration of sodium hypochlorite contained in the seawater electrolytic solution can be increased as needed. Therefore, since it is possible to generate a seawater electrolytic solution containing sodium hypochlorite having a concentration corresponding to the ammonia concentration of the recovered ammonia water, it is possible to efficiently perform the denitrification reaction in the denitrification reaction tank 86.

[0045] According to the floating body 1 of the above-described embodiment, a mixer stirs a mixed solution of seawater electrolytic solution and recovered aqueous ammonia, and the stirred mixed solution is introduced into the denitrification reaction tank 86. Thereby, the reaction rate of the denitrification reaction in the denitrification reaction tank 86 can be increased.

[0046] According to the floating body 1 of the above-described embodiment, a part of the seawater introduced into the floating body main body 2 through the seawater introduction line 83 is joined to the treated liquid through the dilution line 89. Thereby, even when ammonia remains unintentionally in the treated liquid, the treated liquid can be diluted with the seawater in the dilution line 89 and then discharged. Therefore, even when ammonia remains unintentionally in the treated liquid, the influence on the surrounding environment can be reduced.

[0047] According to the floating body 1 of the above-described embodiment, the pH of the mixed solution stored in the denitrification reaction tank 86 can be adjusted to the lower side by the chemical liquid tank 100 which is a pH adjuster. Further, the pH of the mixed solution of the seawater electrolytic solution and the recovered aqueous ammonia is lowered to a range in which alkaline earth metal ions contained in the seawater do not react with ammonia and precipitate as hydroxides. For example, when the seawater electrolytic solution and the recovered aqueous ammonia are reacted in an alkaline environment, alkaline earth metal ions such as calcium and magnesium contained in the seawater may react with ammonia to generate hydroxide scale and block the piping. However, by adjusting the pH of the mixed solution stored in the denitrification reaction tank 86 to the lower side, the generation of such hydroxide scale can be suppressed.

[0048] (First Modification Example of the Embodiment) FIG. 4 is a diagram corresponding to FIG. 2 in the first modification example of the embodiment of the present disclosure. In the floating body 1 of the above-described embodiment, the case where the exhaust heat of the combustion device 8 is recovered by exchanging heat between the cooling water of the combustion device 8 as a heat generating device and the seawater flowing through the seawater introduction line 83 by the exhaust heat recovery unit 88 has been described. However, the heat generating device is not limited to the combustion device 8 cooled by the cooling water.

[0049] As in the first modification example shown in FIG. 4, for example, when the floating body 1 has a heat generating device 108 that can be cooled by seawater, the cooling system 109 of the heat generating device 108 may be connected in the middle of the seawater introduction line 83, and the seawater in the seawater introduction line 83 may be circulated through this cooling system 109. In the first modification example of this embodiment, a seawater branch line 110 for supplying seawater to other heat generating devices (not shown) other than the heat generating device 108 is also connected to the seawater introduction line 83, and a case where the exhaust heat of other heat generating devices can also be recovered is illustrated.

[0050] By adopting the first modification example of this embodiment, when seawater passes through the cooling system 109 of the heat generating device 108, it will exchange heat with the heat generating device 108 and the temperature will rise. In the first modification example of this embodiment, the cooling system 109 of the heat generating device 108 constitutes the exhaust heat recovery part of the present disclosure.

[0051] (Second modification example of the embodiment) FIG. 5 is a diagram showing a schematic configuration of an ammonia decomposition apparatus in a second modification example of an embodiment of the present disclosure. In the floating body 1 of the above-described embodiment, the case where a mixed solution of the recovered ammonia water flowing through the ammonia line 81 and the seawater electrolytic solution generated in the electrolysis unit 84 is reacted in the denitrification reaction tank 86 has been described. However, the denitrification reaction part for reacting the mixed solution of the recovered ammonia water and the seawater electrolytic solution is not limited to the denitrification reaction tank 86.

[0052] For example, as in the second modification example shown in FIG. 5, the electrolysis unit 84 may be used as a denitrification reaction part for reacting a mixed solution of the recovered ammonia water and the seawater electrolytic solution, such as supplying the recovered ammonia water flowing through the ammonia line 81 to the storage tank 96. The treated liquid after the denitrification reaction in the electrolysis unit 84 of this second modification example is discharged to the discharge part 87 through the treated liquid discharge line 111. By configuring in this way, it becomes possible to omit the denitrification reaction tank 86 of the above embodiment, it becomes possible to reduce the number of parts, and the enlargement of the floating body 1 can be suppressed. Although the case where the recovered aqueous ammonia is reacted with sodium hypochlorite in the seawater electrolytic solution stored in the storage tank 96 has been exemplified, the location where the recovered aqueous ammonia and sodium hypochlorite are reacted in the second modification is not limited to the storage tank 96 as long as it is within the electrolysis unit 84. For example, the recovered aqueous ammonia may be supplied to the electrolysis device 95, and the recovered aqueous ammonia and sodium hypochlorite may be reacted within the electrolysis device 95.

[0053] <Other Embodiments> As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included. For example, in the above embodiment, the case where the floating body 1 is a ship that can navigate by a main machine or the like has been described. However, it is not limited to a ship as long as it is a floating body capable of storing ammonia.

[0054] In the above-described embodiment, the recovered aqueous ammonia obtained by recovering ammonia leaked into the compartment 30 or ammonia discharged when purging the piping system 20 has been exemplified as the aqueous ammonia. However, the aqueous ammonia is not limited to the above-described recovered aqueous ammonia, and any aqueous ammonia may be used as long as it is water in which ammonia is absorbed and present within the floating body main body 2.

[0055] Furthermore, in the above-described embodiment, the case where seawater is heated using the waste heat generated within the floating body main body 2 has been described. However, it is not limited to the case of using waste heat, and for example, seawater may be heated without using waste heat, such as by providing a dedicated heat source.

[0056] In the above-described embodiment, the case where the marine organism adhesion prevention treatment device 92 is provided has been described. However, the marine organism adhesion prevention treatment device 92 may be provided as necessary. For example, when the maintenance of the adhered marine organisms is easy, the marine organism adhesion prevention treatment device 92 may be omitted.

[0057] In the above-described embodiment, the case where the line mixer 85 for stirring the mixed solution of the seawater electrolytic solution and the aqueous ammonia solution is provided has been described. However, the line mixer 85 may be provided as necessary. For example, when there is no need to perform stirring, the line mixer 85 may be omitted.

[0058] Furthermore, in the above-described embodiment, the configuration in which the electrolysis unit 84 circulates the seawater electrolytic solution by the circulation line 97 and the circulation pump 98 and repeatedly performs electrolysis to increase the concentration of sodium hypochlorite has been exemplified. However, the configuration for increasing the concentration of sodium hypochlorite is not limited to the one that repeatedly performs electrolysis. For example, the concentration of sodium hypochlorite may be increased by other configurations different from the configuration that repeatedly performs electrolysis, such as increasing the applied voltage to increase the current (amount of NaClO generated).

[0059] Also, in the above-described embodiment, the case where the seawater that has been used in the floating body main body 2 is used to dilute the treated liquid has been described. However, the seawater for diluting the treated liquid is not limited to the seawater that has been used in the floating body main body 2. For example, the seawater taken in from the water intake 90 may be directly merged into the treated liquid.

[0060] <Appendix> The floating body 1 and the ammonia decontamination method described in the embodiment are understood as follows, for example.

[0061] (1) According to the first aspect, the floating body 1 includes a floating body main body 2 that floats in seawater, an ammonia line 81 provided in the floating body main body 2 through which ammonia water flows, a water intake section 82 that takes in the seawater into the floating body main body 2, a seawater introduction line 83 that introduces the seawater taken in from the water intake section 82 into the floating body main body 2, an electrolysis section 84 that generates a seawater electrolysis solution containing sodium hypochlorite by performing electrolysis on the seawater introduced by the seawater introduction line 83, a denitrification reaction tank 86 that reacts a mixed solution of the ammonia water flowing through the ammonia line 81 and the seawater electrolysis solution generated in the electrolysis section 84, and a discharge section 87 that discharges the treated liquid after the reaction in the denitrification reaction tank 86 into the seawater around the floating body main body 2 where it floats. Examples of the floating body 1 include ships such as liquefied gas carriers, ferries, RORO ships, car carriers, and passenger ships, and floating units such as FSU (Floating Storage Unit) and FSRU (Floating Storage and Regasification Unit).

[0062] As a result, it is not necessary to carry a large amount of strongly acidic chemical solution for decomposing ammonia in the floating body main body 2, so that the enlargement of the floating body main body 2 can be suppressed and the safety of the workers can be improved. Therefore, it is possible to suppress the cost increase and easily remove ammonia.

[0063] (2) According to the second aspect, the floating body 1 is the floating body 1 in (1), and includes a heat generating device 8 provided in the floating body main body 2 that generates heat, and a waste heat recovery section 88 that recovers the waste heat of the heat generating device 8 by exchanging heat with the seawater introduced into the floating body main body 2 by the seawater introduction line 83. The seawater introduction line 83 guides the seawater whose temperature has risen by recovering waste heat in the waste heat recovery section 88 to the electrolysis section 84. Examples of the heat generating device 8 include combustion devices such as internal combustion engines and boilers.

[0064] Accordingly, even when the temperature of the seawater around the floating body main body 2 is low, it is possible to suppress a decrease in the production efficiency of sodium hypochlorite by the electrolysis unit 84.

[0065] (3) According to the third aspect, the floating body 1 is the floating body 1 of (1) or (2), and the water intake unit 82 includes a marine organism adhesion prevention treatment device 92 that performs a marine organism adhesion prevention treatment on the taken seawater. This can suppress the blockage of the flow path for taking in seawater due to marine organisms adhering to the inner surface of the water intake port 90 or the inner surface of the seawater introduction line 83.

[0066] (4) According to the fourth aspect, the floating body 1 is the floating body 1 of any one of (1) to (3), and the electrolysis unit 84 includes an electrolysis device 95 that electrolyzes the seawater to generate the seawater electrolytic solution, a storage tank 96 capable of storing the seawater electrolytic solution generated by the electrolysis device 95, a circulation line 97 that circulates the seawater electrolytic solution between the electrolysis device 95 and the storage tank 96, and a circulation pump 98 provided in the circulation line 97. This can increase the concentration of sodium hypochlorite contained in the seawater electrolytic solution as needed.

[0067] (5) According to the fifth aspect, the floating body 1 is the floating body 1 of any one of (1) to (4), and includes a line mixer 85 that stirs a mixture of the seawater electrolytic solution generated by the electrolysis unit 84 and the aqueous ammonia supplied by the ammonia line 81, and introduces the mixture stirred by the line mixer 85 into the denitrification reaction tank 86. This can increase the reaction rate of the denitrification reaction in the denitrification reaction tank 86.

[0068] (6) According to the sixth aspect, the floating body 1 is the floating body 1 of any one of (1) to (4), the electrolysis unit 84 includes the denitrification reaction unit, and the ammonia line 81 supplies the aqueous ammonia to the electrolysis unit 84. This makes it possible to suppress an increase in the number of components as compared with the case where the denitrification reaction section 86 is provided separately from the electrolysis section 84, and to suppress an increase in the size of the floating body 1.

[0069] (7) According to the seventh aspect, the floating body 1 is any one of the floating bodies 1 in (1) to (6), and includes a dilution line 89 that merges a part of the seawater introduced into the floating body main body 2 by the seawater introduction line 83 into the treated liquid. Thereby, the treated liquid can be diluted with the seawater in the dilution line 89 and then discharged.

[0070] (8) According to the eighth aspect, the floating body 1 is any one of the floating bodies 1 in (1) to (7), and includes a pH adjuster 100 that adjusts the pH of the mixed liquid in the denitrification reaction tank 86 to the lower side. As an example of the pH adjuster 100, a chemical liquid tank can be exemplified. Thereby, it is possible to suppress the generation of hydroxide scale due to the reaction between alkaline earth metal ions and ammonia contained in the seawater electrolytic solution.

[0071] (9) According to the ninth aspect, the ammonia detoxification method is an ammonia detoxification method for detoxifying ammonia water of the floating body 1 floating in seawater, and includes a generation step S12 of generating a seawater electrolytic solution containing sodium hypochlorite by taking in and electrolyzing the seawater around the floating body 1 where the floating body 1 floats, and a denitrification reaction step S13 of reacting the sodium hypochlorite in the seawater electrolytic solution with the ammonia in the ammonia water. Thereby, ammonia contained in the ammonia water of the floating body 1 can be decomposed and detoxified using sodium hypochlorite generated from seawater.

[0072] (10) According to the tenth aspect, the ammonia detoxification method is the ammonia detoxification method in (9), and includes a waste heat recovery step S11 of recovering waste heat of equipment in the floating body 1 using the taken-in seawater, and in the generation step S12, the seawater from which waste heat has been recovered by the waste heat recovery step S11 is electrolyzed. As a result, the seawater taken in by utilizing the waste heat of the facilities in the floating body 1 can be heated, so that the electrolysis of seawater in the production step S12 can be efficiently performed.

[0073] (11) According to the eleventh aspect, the ammonia removal method is the ammonia removal method of (9) or (10). In the denitrification reaction step, the pH of the mixed solution of the seawater electrolytic solution and the aqueous ammonia is reduced to a range in which alkaline earth metal ions contained in the seawater do not react with the ammonia to precipitate as hydroxides. As a result, although there is a possibility that alkaline earth metal ions contained in seawater react with ammonia to generate hydroxide scale and block the piping, the generation of such hydroxide scale can be suppressed.

Explanation of Signs

[0074] 1... floating body 2... floating body main body 3a... bow 3b... stern 4... superstructure 5A, 5B... side 6... bottom of the ship 7... upper deck 8... combustion device 10... ammonia tank 20... piping system 30... compartment 60... ammonia recovery section 70... recovered aqueous ammonia tank 80... ammonia decomposition device 81... ammonia line 82... water intake section 83... seawater introduction line 84... electrolysis section 85... line mixer 86... denitrification reaction tank 87... discharge section 88... waste heat recovery section 89... dilution line 90... water intake port 91... seawater pump 92... marine product adhesion prevention treatment device 93... branch line 95... electrolysis device 96... storage tank 97... circulation line 98... circulation pump 99... electrolytic solution line 100... chemical liquid tank 101... cooling water line 102... cooling water pump 103... cooling water branch line 108... heat generating equipment 109... cooling system 110... seawater branch line 111... treated liquid discharge line

Claims

1. A floating body main body floating on seawater, an ammonia line provided in the floating body main body through which ammonia water flows, a water intake section provided in the floating body main body for taking in the seawater, a seawater introduction line for introducing the seawater taken in from the water intake section into the floating body main body, an electrolysis section for generating a seawater electrolytic solution containing sodium hypochlorite by subjecting the seawater introduced by the seawater introduction line to electrolysis, a denitrification reaction section for reacting a mixed solution of the ammonia water flowing through the ammonia line and the seawater electrolytic solution generated in the electrolysis section, a discharge section for discharging the treated liquid after being reacted in the denitrification reaction section into the seawater around the floating body main body, comprising, the electrolysis section includes the denitrification reaction section, the ammonia line supplies the ammonia water to the electrolysis section Floating body.

2. A floating body main body floating on seawater, an ammonia line provided in the floating body main body through which ammonia water flows, a water intake section provided in the floating body main body for taking in the seawater, a seawater introduction line for introducing the seawater taken in from the water intake section into the floating body main body, an electrolysis section for generating a seawater electrolytic solution containing sodium hypochlorite by subjecting the seawater introduced by the seawater introduction line to electrolysis, a denitrification reaction section for reacting a mixed solution of the ammonia water flowing through the ammonia line and the seawater electrolytic solution generated in the electrolysis section, a discharge section for discharging the treated liquid after being reacted in the denitrification reaction section into the seawater around the floating body main body, comprising, a dilution line for merging a part of the seawater introduced into the floating body main body by the seawater introduction line into the treated liquid Floating body.

3. A floating body main body floating on seawater, an ammonia line provided in the floating body main body through which ammonia water flows, a water intake section provided in the floating body main body for taking in the seawater, a seawater introduction line for introducing the seawater taken in from the water intake section into the floating body main body, an electrolysis section for generating a seawater electrolytic solution containing sodium hypochlorite by subjecting the seawater introduced by the seawater introduction line to electrolysis, a denitrification reaction section for reacting a mixed solution of the ammonia water flowing through the ammonia line and the seawater electrolytic solution generated in the electrolysis section, a discharge section for discharging the treated liquid after being reacted in the denitrification reaction section into the seawater around the floating body main body, comprising, It is provided with a temperature adjuster for adjusting the temperature of the mixed liquid in the denitrification reaction section to the lower side. Floating body.

4. A heating device provided in the floating body main body and generating heat, A waste heat recovery section for recovering the waste heat of the heating device by heat-exchanging with the seawater introduced into the floating body main body through the seawater introduction line, Comprising The seawater introduction line Leads the seawater whose temperature has risen by recovering waste heat in the waste heat recovery section to the electrolysis section The floating body according to any one of claims 1 to 3.

5. The water intake section Is provided with a marine organism adhesion prevention treatment device for performing an adhesion prevention treatment of marine organisms on the taken seawater The floating body according to any one of claims 1 to 4.

6. The electrolysis section An electrolysis device for electrolyzing the seawater to generate the seawater electrolytic solution, A storage tank capable of storing the seawater electrolytic solution generated by the electrolysis device, A circulation line for circulating the seawater electrolytic solution between the electrolysis device and the storage tank, A circulation pump provided in the circulation line, Comprising The floating body according to any one of claims 1 to 5.

7. It is provided with a line mixer for stirring the mixed liquid of the seawater electrolytic solution generated by the electrolysis section and the aqueous ammonia supplied by the ammonia line, The mixed liquid stirred by the line mixer is introduced into the denitrification reaction section The floating body according to any one of claims 1 to 6.

8. An ammonia decontamination method for decontaminating aqueous ammonia of a floating body floating on seawater, A generation step of generating a seawater electrolytic solution containing sodium hypochlorite by taking in and electrolyzing the seawater around the floating body of the floating body, A denitrification reaction step of reacting sodium hypochlorite in the seawater electrolytic solution with ammonia in the aqueous ammonia, Including In the denitrification reaction step, The temperature of the mixed liquid of the seawater electrolytic solution and the aqueous ammonia is lowered to a range where alkaline earth metals contained in the seawater do not precipitate. Ammonia decontamination method.

9. Including a waste heat recovery step of recovering the waste heat of the equipment in the floating body using the taken seawater, In the generation step, The seawater whose waste heat has been recovered in the waste heat recovery step is electrolyzed. The ammonia decontamination method according to claim 8.

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