JP6940727B1 - Excess ammonia treatment equipment and treatment method - Google Patents

Abstract

Provided are a treatment apparatus and a treatment method for surplus ammonia that can effectively utilize surplus ammonia. The surplus ammonia treatment device in the marine diesel engine 23, which uses ammonia as a part of the fuel and is connected to the selective reduction catalyst unit 61, contains the waste liquid from the marine diesel engine and separates the oil and the ammonia component. 2 and a transport unit 6 for supplying the ammonia component separated in the separation container 2 to the selective reduction catalyst unit 61.

Description

The present invention relates to the treatment of excess ammonia.

Liquefied ammonia (LNH3) is used in marine diesel engines that use ammonia as part of their fuel. For safety reasons, it is necessary to reduce the pressure of liquefied ammonia and release it to the atmosphere when the engine is stopped or when the engine is stopped in an emergency. Ammonia has an effect on the human body and cannot be released into the atmosphere as it is. Therefore, it is necessary to remove ammonia with an abatement device.
On the other hand, in a diesel engine, a selective reduction catalyst unit is used in order to remove nitrogen oxides generated by combustion of a raw material typified by heavy oil. As a reducing agent material, a large amount of urea, ammonia, and an ammonia compound are required and are stored in a tank.

Japanese Patent Application Laid-Open No. 2020-515764 (hereinafter, “Patent Document 1”) discloses an exhaust control system and related methods for treating an exhaust gas flow. Patent Document 1 includes the use of an ammonia production system to provide ammonia to be injected into an exhaust gas stream as a reducing agent for a selective reduction catalyst.

The technique disclosed in Patent Document 1 requires that ammonium hydroxide, which is a raw material for producing ammonia, is stockpiled as a reducing agent for a selective reduction catalyst. The technique disclosed in Patent Document 1 does not effectively utilize excess ammonia generated from an engine or the like.

An object of the present invention is to provide a treatment apparatus and a treatment method for excess ammonia that can effectively utilize the surplus ammonia.

The first aspect of the present invention is
A device for treating excess ammonia in a marine diesel engine that uses ammonia as part of its fuel and is connected to a selective reduction catalyst unit.
A separation container that stores the waste liquid from the marine diesel engine and separates the oil and ammonia components.
A transport unit that supplies the ammonia component separated in the separation container to the selective reduction catalyst unit, and
It is a treatment device for excess ammonia having.

The second aspect of the present invention is
A method of treating excess ammonia in a marine diesel engine that uses ammonia as part of the fuel and is connected to a selective reduction catalyst unit.
Containing the waste liquid from the marine diesel engine,
The waste liquid is separated into an oil component and an ammonia component.
The separated ammonia component is supplied to the selective reduction catalyst unit.
This is a method for treating excess ammonia.

According to the surplus ammonia treatment apparatus and treatment method of the present invention, the surplus ammonia can be effectively used.

Schematic diagram of the surplus ammonia treatment unit of this embodiment Overall view of the surplus ammonia treatment unit when ammonia gas is supplied Overall view of the surplus ammonia treatment unit when ammonia water is supplied Overall system view when excess ammonia is supplied to the selective reduction catalyst unit Overall system view when excess ammonia is supplied to the selective reduction catalyst unit or to the fuel supply unit

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The various features shown in the embodiments shown below can be combined with each other.
First, the configuration of the surplus ammonia treatment unit of the present embodiment will be described.

FIG. 1 is a schematic view of the surplus ammonia treatment unit 1 of the present embodiment. The surplus ammonia treatment unit 1 has a separation container 2 and a transport unit 6. The separation container 2 may have a separation unit 3. Further, the extraction unit 4 may be attached to the separation container 2. The oil extracted in the separation container 2 is stored in the lower part of the separation container 2 and sent to the bilge tank 30, which will be described later. Therefore, it is desirable that the extraction unit 4 is installed above the separation container 2.

The separation container 2 stores the waste liquid from each unit of the marine diesel engine that uses ammonia as a part of the fuel. Specifically, as shown in FIGS. 4 and 5, the waste liquid from the fuel supply unit 21, the reducing agent supply unit 22 of the selective reduction catalyst, and the marine diesel engine unit 23 is housed in the separation container 2. Ammonia is supplied from the ammonia fuel tank 20 installed on the ship to the fuel supply unit 21, the reducing agent supply unit 22, and the marine diesel engine unit 23. Therefore, the waste liquid contains excess ammonia. When the separation container 2 uses the principle of specific gravity separation, it is desirable that the waste liquid flows in from the upper part of the separation container 2.
In FIGS. 4 and 5, the solid line arrow indicates the flow of the ammonia component, and the broken line arrow indicates the drain flow.

The separation container 2 separates the waste liquid into an oil component and an ammonia component. For example, when the principle of specific gravity separation is used, the waste liquid flowing into the separation container 2 is separated into an oil component and an ammonia component due to the difference in specific gravity. The separation container 2 may have a separation unit 3. The separation unit 3 separates the waste liquid flowing into the separation container 2 into an oil component and an ammonia component by using, for example, the principles of filter separation, cyclone separation, and centrifugation. The separated oil is supplied to the bilge tank 30. On the other hand, the separated ammonia component is supplied to the transport unit 6 via the extraction unit 4 and the storage unit 5 as shown in FIGS. 2 and 3.

As shown in FIGS. 2 and 3, the extraction unit 4 removes impurities that may be contained in the liquefied ammonia separated in the separation container 2. Therefore, when the separated ammonia component is ammonia gas, depending on the state of the waste liquid discharged from the marine diesel engine unit 23 or the like, the ammonia component is sent to the transport unit 6 without passing through the extraction unit 4 and the storage unit 5. May be supplied.
Further, as shown in FIG. 3, when the separated ammonia component is ammonia water, the ammonia component may be supplied to the storage unit 5 without passing through the extraction unit 4.

The extraction unit 4 mainly removes inorganic substances such as calcium compounds and metal pieces with a filter, but the removal method is not limited to the filter and the like. In particular, when a filter is used, a filter having a pitch of about 10 micrometers is preferable from the viewpoint of removal rate.

As shown in FIG. 2, the storage unit 5 stores liquefied ammonia supplied directly from the separation container 2 or via the extraction unit 4. When ammonia gas is supplied to the selective reduction catalyst unit 61 or the like, the vaporizer 8 is attached between the storage unit 5 and the transportation unit 6.

When ammonia gas is present as a gas phase in the upper part of the storage unit 5, the ammonia gas may be directly supplied to the selective reduction catalyst unit 61 by a blower without passing through the vaporizer 8.
On the other hand, when ammonia water is supplied to the selective reduction catalyst unit 61 or the like, water or a neutralizing agent is injected into the storage unit 5 from above, as shown in FIG. Further, a concentration adjusting unit 9 may be installed near the outlet of the storage unit 5 and connected to the transport unit 6 so that ammonia water having a predetermined concentration can be supplied.

As shown in FIG. 2, when supplying ammonia gas as a reducing agent, the transport unit 6 supplies the ammonia gas sent from the vaporizer 8 to the selective reduction catalyst unit 61.
On the other hand, as shown in FIG. 3, when supplying ammonia water as a reducing agent, the transport unit 6 supplies the ammonia water to the selective reduction catalyst unit 61. As shown in FIG. 5, the fuel may be supplied from the transport unit 6 to the pump unit 62 provided in the fuel supply unit 21 instead of the selective reduction catalyst unit 61. Further, the selective reduction catalyst unit 61 or the pump unit 62 can be selected as the supply destination from the transport unit 6, or a combination thereof may be selected.
The selective reduction catalyst unit 61 is directly or indirectly connected to the marine diesel engine unit 23.

As shown in FIG. 2, the oil content separated in the separation container 2 is supplied to the bilge tank 30. Since a small amount of liquefied ammonia is mixed and dissolved in the oil and impurities extracted in the extraction unit 4, it is similarly supplied to the bilge tank 30. Since the ammonia gas obtained from the bilge tank 30 cannot be released to the atmosphere as it is, the abatement device 7 is used. In order to release ammonia to the atmosphere, the abatement device 7 adjusts the ammonia gas to a concentration that does not affect the human body. For example, the abatement device 7 adjusts the ammonia concentration to about 25 PPM or less.

On the other hand, as shown in FIG. 3, when the ammonia water is supplied to the selective reduction catalyst unit 61, the abatement device 7 is unnecessary. At this time, the storage unit 5 temporarily stores the scrubber water. Ammonia is a highly toxic substance, but it is very soluble in water. Therefore, it is extremely unlikely that the ammonia gas volatilized from the liquefied ammonia will be mixed in the ammonia water supplied to the transport unit 6 via the storage unit 5. The method of allowing water to absorb ammonia gas is called scrubber. Scrubber is low cost and easy to operate.

As shown in FIG. 2, the vaporizer 8 is mounted between the storage unit 5 and the transport unit 6. However, in order to prevent stress corrosion cracking, it is preferable that the vaporizer 8 is attached immediately before the transport unit 6. As the heat source of the vaporizer 8, in addition to the heat generated by electricity, the heat of the cooling water or the exhaust gas of the marine diesel engine unit 23 can be used. As a result, the environmental compatibility is improved in combination with the surplus ammonia treatment unit 1.

As shown in FIG. 3, the concentration adjusting unit 9 is attached to the storage unit 5. The concentration adjusting unit 9 supplies ammonia water to the transport unit 6 at a predetermined concentration. Specifically, the density adjusting unit 9 is a density meter or a density meter. Preferably, the density adjusting unit 9 is a density meter that can be measured more easily than the density meter. It is more preferable to acquire the relationship between the measured value of the density meter and the concentration in advance. For example, when the value is 0.912 on the density meter in optical measurement, the concentration of aqueous ammonia is about 15%. The concentration of aqueous ammonia is about 40% at the maximum in the saturated state. When supplied to the selective reduction catalyst unit 61, it is preferable that the concentration of aqueous ammonia is high.

<First Embodiment>
FIG. 2 is an overall view of the surplus ammonia treatment unit when ammonia gas is supplied, which is one aspect of the present embodiment. The waste liquid discharged from the fuel supply unit 21, the reducing agent supply unit 22 of the selective reduction catalyst, and the marine diesel engine unit 23 shown in FIGS. 4 and 5 is housed in the separation container 2. The separation container 2 recovers liquefied ammonia, which is excess ammonia contained in the waste liquid.

When the separation container 2 uses the principle of specific gravity separation, the separated oil content is stored in the lower part of the separation container 2. On the other hand, the liquefied ammonia is stored in the upper part of the separation container 2. The oil stored in the lower part is supplied to the bilge tank 30. In addition, liquefied ammonia mixed in the oil and impurities extracted by the extraction unit 4 is also supplied to the bilge tank 30. The ammonia gas obtained from the bilge tank 30 is treated by the abatement device 7 and then released to the atmosphere.

The oil contained in the waste liquid is, for example, seal oil used for the fuel injection valve of the fuel supply unit 21 and the marine diesel engine unit 23. When liquefied petroleum gas is used as fuel, the propane gas molecule itself, which is the main component, has no polarity. Therefore, propane gas molecules can be mixed with the sealing oil and treated as fuel. However, when liquefied ammonia is used as fuel, the ammonia molecule itself has polarity. Therefore, ammonia molecules do not mix with the seal oil and are difficult to treat as fuel. Therefore, the oil component and the liquefied ammonia are separated in the separation container 2.

The liquefied ammonia separated in the separation container 2 is supplied to the storage unit 5 via the extraction unit 4 or directly. The extraction unit 4 removes impurities that may be contained in the liquefied ammonia. The impurities are mainly oils that are easily vaporized. When impurities are supplied to the selective reduction catalyst unit 61, oil adheres to the catalyst and the performance deteriorates. Therefore, it is desirable that the extraction unit 4 is installed in front of the storage unit 5 so that the oil component that could not be separated due to the specific gravity separation or the like in the separation container 2 can be removed. By removing impurities such as unnecessary oil, the efficiency of the selective reduction catalyst unit 61 is increased.

When sufficient time for specific gravity separation is secured in the separation container 2 or when the separation unit 3 uses the principle of centrifugation, the possibility that the obtained liquefied ammonia contains impurities is low. Therefore, the liquefied ammonia may be directly supplied from the separation container 2 to the storage unit 5 without passing through the extraction unit 4.

The liquefied ammonia supplied to the storage unit 5 is supplied to the transport unit 6 as ammonia gas by the vaporizer 8. Further, ammonia gas is supplied to the selective reduction catalyst unit 61 and used as a reducing agent. It should be noted that the reason why the selective reduction catalyst unit 61 is supplied as ammonia gas instead of the liquefied ammonia is that the temperature of the liquefied ammonia is considerably lower than the temperature at which the selective reduction catalyst unit 61 acts. It is efficient to gasify ammonia so that the catalytic action of the selective reduction catalyst unit 61 is enhanced. In addition, steam pressure eliminates the need for pumps and cooling, increasing the energy efficiency of the entire system.

The vaporizer 8 is preferably installed immediately before the transport unit 6 in order to prevent stress corrosion cracking of each engine, pipe, etc.
Further, as the heat source of the vaporizer 8, in addition to the heat generated by electricity, the cooling water of the marine diesel engine unit 23 and the heat of the exhaust gas of the marine diesel engine unit 23 can be used. This improves environmental harmony.

The ammonia gas obtained from the vaporizer 8 is preferably boosted to, for example, about 6 bar, more preferably about 7 bar, and even more preferably about 8 bar. Specifically, for example, it is 2,3,4,5,6,7,8,9,10,11,12 bar, even if it is within the range between any two of the numerical values exemplified here. good. As a result, it is not necessary to install a booster in the transport unit 6, and the apparatus configuration of the surplus ammonia treatment unit 1 can be simplified.

<Second embodiment>
Next, the second embodiment will be described. The description of the functions and configurations substantially the same as those of the first embodiment will be omitted.
FIG. 3 is an overall view of the surplus ammonia treatment unit when ammonia water is supplied, which is one aspect of the present embodiment. The functions and configurations of the separation container 2, the separation unit 3, and the extraction unit 4 are the same as those in the first embodiment.

The storage unit 5 stocks the separated ammonia component directly from the separation container 2 or via the extraction unit 4. By injecting water into the storage unit 5, the ammonia component becomes ammonia water. Similar to the first embodiment, ammonia water is supplied to the selective reduction catalyst unit 61 through the transport unit 6.
Liquefied ammonia can also cause stress corrosion cracking. By using ammonia water as the ammonia component to be introduced, the life of the entire selective reduction catalyst unit 61 can be extended, and the load on the abatement device 7 can be reduced.

It is more preferable that a neutralizing agent such as dilute sulfuric acid is injected into the storage unit 5. If there is liquefied ammonia that has not been supplied from the separation container 2 to the storage unit 5, it is necessary to pass it through the abatement device 7 in order to discharge the surplus ammonia to the atmosphere. By using the neutralizing agent in advance, the load on the abatement device 7 becomes lighter than when water is used.

It is more preferable that the storage unit 5 is provided with the concentration adjusting unit 9. The ammonia supplied from the transport unit 6 is a small part of the ammonia used in the selective reduction catalyst unit 61, and is used as an auxiliary. Therefore, if the concentration of ammonia water is constant, nitrogen oxides can be efficiently removed regardless of whether the engine is operating constantly or unsteadily. The higher the ammonia concentration in the concentration adjusting unit 9, the more preferable it is, but there is no restriction on the lower limit of the concentration.

Table 1 shows the results of a simulated test in a reactor conducted to investigate the relationship between the ammonia concentration in the concentration adjusting unit 9, the denitration rate in the selective reduction catalyst unit 61, and the leaked ammonia concentration before release to the atmosphere.
The ammonia water flow rate ratio shown in Table 1 is a value when the flow rate at an ammonia water concentration of 14 w% is 1, and the ammonia concentration with respect to the entire exhaust gas is a value adjusted to be about 500 PPM at the time of vaporization. be. This value is a flow rate adjusted so that the concentration is approximately 1: 1 with the total concentration of nitrogen oxides, or the amount of ammonia is slightly reduced.

As can be seen from Table 1, denitration proceeds efficiently without depending on the concentration of aqueous ammonia.

<Other Embodiments>
It is even more preferable that the storage unit 5 is a part of the abatement device 7. As mentioned above, ammonia cannot be released into the atmosphere as it is because it affects the human body. It is necessary to remove ammonia with the abatement device 7. As a detoxification method, there are a method of diluting ammonia with a gas such as nitrogen and a method of absorbing ammonia in water such as scrubber as described above.

In marine diesel engines, scrubbers are often used because they are inexpensive and easy to operate, but the space for installing water that has absorbed ammonia becomes a problem.
However, when supplying ammonia water to the selective reduction catalyst unit 61, by integrating the storage unit 5 and the abatement device 7, not only the space inside the ship can be effectively used, but also the problem of treated water can be solved.
In particular, it is a more preferable embodiment because denitration proceeds efficiently even if the concentration of aqueous ammonia is low.

The surplus ammonia obtained in the surplus ammonia treatment unit 1 of the first embodiment and the second embodiment is supplied to the selective reduction catalyst unit 61, but is supplied to the selective reduction catalyst unit 61 via the pump unit 62 as shown in FIG. It may be supplied to the fuel supply unit 21. Further, excess ammonia may be directly supplied to the marine diesel engine unit 23 via the pump unit 62.
By sending ammonia water to the fuel supply unit, fuel efficiency is improved and the concentration of nitrogen oxides in the exhaust gas is reduced.

Further, either the selective reduction catalyst unit 61 or the pump unit 62 may be selected, or both may be used in combination. The amount ratio of excess ammonia when used in combination may be determined by the user in a timely manner.
Depending on the operating conditions of the engine, supplying either one will improve the fuel efficiency of ammonia as a whole. Moreover, by using both in combination, the efficiency is further improved.

Although various embodiments have been described above, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Excess ammonia treatment unit 2 Separation container 20 Ammonia fuel tank 21 Fuel supply unit 22 Reducing agent supply unit 23 Marine diesel engine unit 3 Separation unit 4 Extraction unit 5 Storage unit 6 Transportation unit 61 Selective reduction catalyst unit 62 Pump unit 7 Harm removal Device 8 Vaporizer 9 Concentration adjustment unit

Claims (21)

A device for treating excess ammonia in a marine diesel engine that uses ammonia as part of its fuel and is connected to a selective reduction catalyst unit.
A separation container that stores the waste liquid from the marine diesel engine and separates the oil and ammonia components.
A transport unit that supplies the ammonia component separated in the separation container to the selective reduction catalyst unit, and
Excess ammonia processing equipment with. The separation container has a separation portion that separates the waste liquid into the oil component and the ammonia component.
The device for treating excess ammonia according to claim 1. The separation unit separates the waste liquid into the oil component and the ammonia component by filter separation, cyclone separation, or centrifugation.
The device for treating excess ammonia according to claim 2. Further having an extraction unit for removing impurities contained in the ammonia component separated in the separation container.
The device for treating excess ammonia according to any one of claims 1 to 3. It further has a vaporizer that vaporizes the ammonia component separated in the separation container into ammonia gas.
The transport unit supplies the ammonia gas vaporized by the vaporizer to the selective reduction catalyst unit.
The device for treating excess ammonia according to any one of claims 1 to 4. Further having a storage unit for injecting water into the ammonia component separated in the separation container and storing it as ammonia water.
The transport unit supplies the ammonia water stored in the storage unit to the selective reduction catalyst unit.
The device for treating excess ammonia according to any one of claims 1 to 4. The storage unit injects a neutralizing agent into the ammonia component separated in the separation container and stores it as ammonia water.
The device for treating excess ammonia according to claim 6. The storage unit has a concentration adjusting unit that adjusts the concentration of the ammonia water.
The device for treating excess ammonia according to claim 6 or 7. It further has an abatement device that dilutes the ammonia component to a concentration that does not affect the human body.
The device for treating excess ammonia according to any one of claims 1 to 8. The storage unit has the abatement device.
The device for treating excess ammonia according to claim 9. The transport unit supplies the ammonia component separated in the separation container to the ammonia fuel supply unit.
The device for treating excess ammonia according to any one of claims 6 to 10. The transport unit can select the supply destination of the ammonia component separated in the separation container to either the selective reduction catalyst unit or the ammonia fuel supply unit.
The device for treating excess ammonia according to claim 11. A method of treating excess ammonia in a marine diesel engine that uses ammonia as part of the fuel and is connected to a selective reduction catalyst unit.
Containing the waste liquid from the marine diesel engine,
The waste liquid is separated into an oil component and an ammonia component.
The separated ammonia component is supplied to the selective reduction catalyst unit.
How to treat excess ammonia. Further, impurities contained in the separated ammonia component are removed.
The method for treating excess ammonia according to claim 13. Further, the separated ammonia component is vaporized into ammonia gas, and the separated ammonia component is vaporized.
The vaporized ammonia gas is supplied to the selective reduction catalyst unit.
The method for treating excess ammonia according to claim 13 or 14. Further, water is injected into the separated ammonia component and stored as ammonia water.
The stored ammonia water is supplied to the selective reduction catalyst unit.
The method for treating excess ammonia according to claim 13 or 14. Further, a neutralizing agent is injected into the separated ammonia component and stored as ammonia water.
The method for treating excess ammonia according to claim 16. Further, the concentration of the ammonia water is adjusted.
The method for treating excess ammonia according to claim 16 or 17. Further, the ammonia component is diluted to a concentration that does not affect the human body.
The method for treating excess ammonia according to any one of claims 16 to 18. Further, the separated ammonia component is supplied to the ammonia fuel supply unit.
The method for treating excess ammonia according to any one of claims 16 to 19. Further, the separated ammonia component is selectively supplied to either the selective reduction catalyst unit or the ammonia fuel supply unit.
The method for treating excess ammonia according to claim 20.

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