KR20240047494A - Fuel supply device that can use a variety of fuels - Google Patents

Abstract

The present invention not only provides a fuel supply device that can be used by combining fuels such as liquefied ammonia, liquefied petroleum gas, and methanol, but also provides a fuel supply device in which return fuel is not sent to the fuel tank, or the return fuel is not sent to the fuel tank. This solves the problem of providing a fuel supply device in which the sealing oil can be well separated from liquefied ammonia fuel and the like even when it contains sealing oil. The above problem is caused by a fuel supply line extending from the fuel tank 2 to the engine 1 and through which a fuel selected from liquefied ammonia, liquefied petroleum gas and methanol is stored in the engine 1 via the recovery tank 4 and the engine. (1) is provided with a fuel return line for returning part of the fuel to the recovery tank (4), and an oil removal and recovery device is installed in the recovery tank (4). .

Description

Fuel supply device that can use a variety of fuels

The present invention relates to a fuel supply device that can use various fuels. In particular, it can provide a fuel supply device that can use fuels such as liquefied ammonia, liquefied petroleum gas, and methanol, and can also use liquefied ammonia as a fuel. When, the return fuel is not sent to the fuel tank.

Conventionally, from the viewpoint of environmental regulations based on the prevention of global warming, liquefied ammonia (hereinafter referred to as “LNH 3 ” as necessary) which does not emit carbon dioxide during combustion, and liquefied petroleum gas (hereinafter referred to as “LNH ₃ ” as necessary) which does not emit SOx during combustion (hereinafter referred to as , fuels such as “LPG” and methanol are needed as needed, and the fuels are becoming more diverse.

Although some of the fuel can be returned to the fuel tank for flow rate adjustment and temperature adjustment, there is a risk that seal oil infiltrating from the fuel injecting valve may be mixed in the return line.

For this reason, depending on the combination with the fuel, there is a risk that the sealing oil will not mix and the filter or strainer for removing impurities such as particles may become clogged. Specifically, in the case of LPG, LPG and sealing oil are mixed in some cases, but in the case of LNH ₃ and the like, LNH ₃ and sealing oil are not mixed, so there is a problem of the above-mentioned clogging occurring.

In addition, when the fuel supply device is stopped, it is necessary to dispose of the fluid inside the device to the outside. However, since toxic ammonia is concerned about its adverse effects on the human body, the ammonia must be removed to protect the human body. We need to find a way.

As a detoxification method, methods such as scrubbers and combustion are generally known.

When using a scrubber, it is conceivable to store some of the treated water, but there is a problem in that the capacity of the tank increases depending on the amount of use.

For this, a method of discharging it overboard is needed. As for the discharge standard items at this time, the domestic river standards are applied, and ammonia nitrogen and oil are the standards.

For this reason, a removal device for ammonia nitrogen and oil is necessary, but if the removal device is attempted to be installed on board a ship, there is a problem that the amount to be treated increases depending on the installation situation.

For this purpose, a method of extruding nitrogen (nitrogen purge) is adopted to remove the liquefied ammonia gas remaining in the pipe after engine operation.

However, in the nitrogen purge extrusion method, if the discharge destination is at the top, supply pressure and flow rate for extrusion are required, and there is a problem that the removal equipment becomes large due to the relationship between flow rate and tower height.

Kjeld Aabo, Ammonia-fueled MAN B&W 2-Stroke Dual-fuel Engines, Journal of the Japanese Society of Marine Engineering, 2020, No. 56

Therefore, the object of the present invention is to provide a fuel supply device that can not only use fuels such as liquefied ammonia, liquefied petroleum gas, and methanol, but also to provide a fuel supply device in which return fuel is not sent to the fuel tank. .

In addition, another object of the present invention is to provide a fuel supply device that can properly separate sealing oil from liquefied ammonia fuel, etc., even if the return fuel contains sealing oil.

Additionally, other problems of the present invention will become clear from the following description.

The above problems are solved by the following inventions.

One.

to the engine,

a fuel supply line from a fuel tank storing one of liquefied ammonia, liquefied petroleum gas and methanol to the engine via a recovery tank;

a fuel return line that returns a portion of the fuel from the engine to the recovery tank;

A fuel supply device, characterized in that an oil removal and recovery device is installed in the recovery tank.

2.

2. A fuel supply device according to claim 1, wherein the oil removal and recovery device includes a dam for improving separation of fuel and oil, and an instrument for determining the interface between fuel and oil.

3.

3. A fuel supply device according to claim 2, wherein the instrument is an electrostatic level switch or a density meter.

4.

The method according to any one of claims 1 to 3, wherein the fuel is introduced into a fuel return line that returns a part of the fuel from the engine to the recovery tank to separate it into vaporized ammonia gas, liquefied ammonia, and oil. Equipped with a gas-liquid separator,

A fuel supply device characterized by installing a removal device that generates ammonia water by introducing the vaporized ammonia gas and water separated by the gas-liquid separator.

5.

A fuel supply line that supplies one of liquefied ammonia, liquefied petroleum gas, and methanol to the engine includes a fuel tank, a low-pressure fuel pump, a first buffer tank, a high-pressure fuel pump, a heater, and a filter,

A recovery tank is provided in a fuel return line for returning part of the fuel from the engine,

Installing an oil removal and recovery device in the recovery tank,

A fuel supply device, characterized in that the fuel from which the oil has been removed is returned to the first buffer tank.

6.

The fuel supply device according to claim 5, comprising a drain tank for storing oil separated by the oil removal and recovery device.

7.

According to clause 6,

A fuel supply device, characterized in that a drain room including a drain tank for recovering remaining water is installed at a lower portion of the fuel supply room where the fuel supply line is formed.

According to the present invention, it is possible to provide a fuel supply device that can use fuels such as liquefied ammonia, liquefied petroleum gas, and methanol, as well as a fuel supply device in which return fuel is not sent to the fuel tank.

Furthermore, according to the present invention, even if the return fuel contains sealing oil, it is possible to provide a fuel supply device that can properly separate the sealing oil from liquefied ammonia fuel, etc.

[Figure 1] Flow chart showing one form of the fuel supply device of the present invention
[FIG. 2] A schematic cross-sectional view showing an example of a recovery tank applied to the fuel supply device of FIG. 1
[FIG. 3] A schematic diagram showing an example of a gas-liquid separator applied to the fuel supply device of FIG. 1
[Figure 4] Flow chart showing another form of the fuel supply device of the present invention

Hereinafter, modes for carrying out the present invention will be described based on the drawings.

A first form of the present invention will be described with reference to FIG. 1.

1 is a flowchart showing one form of a fuel supply device of the present invention.

In Figure 1, 1 is a marine engine, and fuel from the fuel tank 2 is supplied to the engine 1 through the drain tank 4. As the marine engine 1, an engine capable of supporting binary fuel is preferable. For example, an engine that can use dual fuel consisting of heavy oil and two types of fuel shown below can be exemplified.

Some of the engine fuels that the binary fuel can support may be any of fuels such as liquefied ammonia, liquefied petroleum gas (LPG), and methanol. Also, regarding liquefied petroleum gas, there are cases of butane rich and propane rich, but any main component can be used. This is because there are very few cases where LPG contains only butane components, and there are cases where it is not completely mixed with sealing oil. That is, if the degree of dissolution in the sealing oil changes only depending on the amount of propane contained in LPG, and the propane is not completely dissolved, the sealing oil can be separated by the oil removal and recovery device of the present invention.

Additionally, NH ₃ is polar and oil is non-polar, so they do not mix. Likewise, methanol is polar and does not mix with oil.

Depending on the production area, LPG mainly consists of propane LPG (propane rich LPG) and butane LPG (butane rich LPG). Ease of mixing with oil is not only generally evaluated based on polarity and non-polarity alone, but is also assumed to be related to the tilt effect and chain length disadvantages.

For long-chain alkanes with an even number of carbon atoms, when the number of carbon atoms is completely packed (solid crystal state), the molecular chain becomes a long “parallel cube” in the chain length direction, but for long-chain alkanes with an odd number of carbon atoms, one corner of the edge is missing, resulting in a corresponding packing. It falls out. Ease of packing indicates lipophilicity.

In other words, C ₃ H ₈ (propane) has the minimum number of carbon atoms, an odd number of 3, so it has a large fragmentation effect, is difficult to pack, and has the least oily heterogeneous properties among straight-chain alkanes. In contrast, C ₄ H ₁₀ (butane) has an even carbon number of 4, so packing is good.

The present inventor experimentally confirmed that there is a difference in that liquefied C ₄ H ₁₀ is soluble in sealing oil and liquefied C ₃ H ₈ is not soluble in sealing oil.

From the above, the fact that the fuel stored in the fuel tank 2 of the present invention is any one of liquefied ammonia, liquefied petroleum gas, and methanol means that the fuel supply device of the present invention is particularly effective for fuels that do not dissolve in oil. , even fuels that dissolve in oil can be used, that is, any fuel such as liquefied ammonia, liquefied petroleum gas, and methanol can still be used simply by changing the fuel supplied to the fuel tank, expanding the range of options for fuel to be used. It is intended to be a highly versatile fuel supply device that can be used with a variety of fuels.

Hereinafter, a case where the fuel of this type is mainly liquefied ammonia will be described.

The fuel tank 2 is a low-pressure tank such as a full-ref tank or a semi-ref tank. When excess ammonia gas is generated, it is desirable to recover it and use it as a reducing agent in a denitrification device. A reliquefaction device 2A can be installed in the fuel tank 2. In the reliquefaction device 2A, ammonia gas discharged as a gas from the fuel tank 2 is introduced, pressurized to produce liquefied ammonia, and returned to the fuel tank. In addition, various ammonia gases, such as ammonia gas discharged from the gas-liquid separator 12 (12A, 12B) and ammonia gas obtained by nitrogen purge, are introduced into the reliquefaction device 2A and pressurized to generate liquefied ammonia and discharged from the fuel tank. You can also revert to (2).

The liquefied ammonia, which is the fuel charged in the fuel tank (2), is sent to the recovery tank (4) through the low-pressure pump (3), which is a low-pressure fuel pump. The discharge pressure of the low pressure pump (3) is preferably in the range of 1.8 to 2.0 MPaG (gauge pressure).

The fuel can be heated by the heater (3A) in the process of being sent to the recovery tank (4). Here, the reason for installing the heater 3A is that the fuel may be at a low temperature depending on the tank type.

In form 1, the liquefied ammonia comprises a fuel supply line from the fuel tank 2 through the recovery tank 4 to the engine 1, returning a portion of the fuel from the engine 1 to the recovery tank 4. Equipped with a fuel return line.

The fuel supply line from the recovery tank (4) to the engine (1) includes a high-pressure fuel pump (5), a heater (5A), a filter (7A) or filter (7B), and a fuel valve train (interface), SVT. (10) is provided.

The fuel in the recovery tank (4) is sent to the heater (5A) through the high pressure pump (5). The discharge pressure of the high pressure pump 5 is preferably in the range of 8.0 to 8.5 MPaG (gauge pressure). In this embodiment, the discharge pressure when LPG is used as the fuel is preferably in the range of 5.0 to 5.5 MPaG, and the discharge pressure when methanol is used as the fuel is preferably in the range of 1.0 to 1.5 MPaG.

Here, the heater 5A is installed as a spare in case temperature control is not possible with the heater 3A, and there is no need to install it if it can be controlled with the heater 3A.

Afterwards, the fuel is filtered through filter 7A or filter 7B. Here, the filter 7A and filter 7B are installed for the purpose of protecting the engine and valves.

The filter 7A and filter 7B can remove solids, rust, etc. contained in the fuel.

The fuel is filtered through filter 7A or filter 7B and then sent to engine 1 through SVT 10.

SVT (10) is a fuel valve train, and the auxiliary air flow (high pressure pump (5), heater 5A) that exists in the process of supplying the fuel in the recovery tank (4) to the engine (1) by the high pressure pump (5) , It is an interface between filters (7A, 7B)) and engine (1).

Nitrogen gas is supplied to the SVT 10 from the nitrogen supply device 10A. Although nitrogen gas is not shown, it is used for purging fuel in the engine 1, exhausting gas before maintenance, and testing airtightness after maintenance.

The fuel valve train is the interface between the auxiliary airflow and the engine 1 as described above, but its purpose is to safely isolate the engine 1 during shutdown or maintenance and to maintain the nitrogen supplied from the nitrogen supply device 10A. For example, purging of gas may be performed.

In this form, a fuel return line is provided which returns a portion of the fuel from the engine 1 to the recovery tank 4. RVT 11, which is a fuel valve train (interface), is installed in the fuel return line from the engine 1 to the recovery tank 4, and a cooler 15 is installed in the system leading to the recovery tank 4.

In the engine 1, a part of the fuel is returned for flow rate control and temperature control, and at this time, sealing oil is included in a part of the fuel, is depressurized in the RVT 11, and passes through the cooler 15 to the recovery tank. Go back to (4). That is, in this form, fuel is circulated between the recovery tank 4 and the engine 1.

According to this form, the system is such that a part of the fuel returns to the recovery tank 4, and the recovery tank 4 becomes a tank that supplies fuel to the engine, so the fuel that supplies fuel to the recovery tank 4 Tank (2) will not be contaminated with sealing oil.

As shown in FIG. 2, in the recovery tank 4, the return fuel from the engine 1 and the liquefied ammonia sent from the fuel tank 2 are mixed.

In the recovery tank 4, an oil removal and recovery device is provided with a structure in which liquid ammonia and sealing oil are separated as shown.

That is, in the case of liquefied ammonia (NH ₃ ), since it does not mix with the sealing oil, the two layers separate. The presence of liquefied ammonia can be determined using a density meter or electrostatic level switch.

Since the density (ρ) of liquefied ammonia at 25°C is about 600 kg/m ³ and the density (ρ) of sealing oil is about 900 kg/m ³ , as shown in Figure 2, liquefied ammonia flows to the upper layer. It is separated and the sealing oil is separated into the lower layer.

Additionally, the density (ρ) of LPG (propane rich) at 25°C is about 500 kg/m ³ , and the density (ρ) of LPG (butane rich) at 25°C is about 578 kg/m ³ . The density (ρ) of methanol at 20°C is about 792 kg/m ³ . For this reason, the density (ρ) of the sealing oil is about 900 kg/m ³ , so when it does not completely dissolve with the oil, the fuel can be separated into an upper layer and the sealing oil into a lower layer, as shown in FIG. 2.

As shown in FIG. 2, the recovery tank 4 is provided with a back plate 40, and is configured so that only the liquefied ammonia in the upper layer is sent to the liquefied ammonia tank 41. The liquefied ammonia in the liquefied ammonia tank 41 is supplied as fuel toward the engine 1 by the high-pressure pump 5.

The sealing oil in the lower layer is removed by opening the drain valve 42 and stored in the drain tank 43. The drain valve 42 can control discharge by a signal from the sensor 44 that detects the liquid level of the sealing oil. By installing the sensor 44, the oil removal state can be confirmed and the sealing oil can be discharged efficiently. This sealing oil can also be reused in the present invention.

With this configuration, liquefied ammonia fuel from which the sealing oil has been separated and removed by the oil removal and recovery device can be supplied to the engine 1.

In this form, the sealing oil flowing in from the fuel return line can be efficiently separated from the fuel due to the presence of the above-mentioned back plate 40, so when the fuel from which the sealing oil has been separated is supplied back to the engine, a filter or strainer is used. Fuel circulation can be carried out efficiently without blocking.

In addition, as the sensor 44, a liquid level sensor capable of detecting the liquid level is exemplified, but it is not limited to this, and may be an instrument that can determine the interface between fuel and oil, such as a capacitive level switch or a density meter (sensor). is desirable. Thereby, the sealing oil can be discharged more efficiently.

In this form, at the time of starting and stopping the supply of liquefied ammonia gas, in order to purge the inside of the system, liquefied ammonia containing the gas remaining in the pipe and partially vaporized when the pressure is reduced is introduced into the gas-liquid separator 12 (12A, 12B). It can be separated into vaporized gas and liquid.

As the gas-liquid separator 12, a gas-liquid separator 12A and a gas-liquid separator 12B can be installed as shown in FIG. 1.

Ammonia gas discharged upward from the gas-liquid separators 12A and 12B is sent to the detoxification device 13.

The liquid remaining in the gas-liquid separator 12 is returned to the recovery tank 4 using a pump to recover liquefied ammonia. Additionally, nitrogen can be used to extrude the liquid.

The vaporized ammonia gas vaporized by the gas-liquid separator 12 is supplied with water from the removal device 13 and recovered as ammonia water. The recovered ammonia water can be used, for example, as a reducing agent in a denitrification device on board a ship.

Next, a preferred form of the gas-liquid separator will be described with reference to FIG. 3. The embodiment described below has the effect of reducing the energy to be recovered because the amount of reaction heat is different in the case of contacting water as ammonia gas and the case of contacting liquefied ammonia with water.

First, the gas-liquid separator 12 is filled with fresh water in advance. It is desirable to install a sensor to detect the liquid level in the gas-liquid separator 12. In the illustrated example, a level switch LS is provided as a high level sensor 120 and a low level sensor 121 . HH represents high level and LL represents low level.

The high level sensor 120 detects the HH level and opens the fresh water valve 122 in advance to enter the standby state to charge fresh water. It is desirable to adjust the amount of fresh water so that the volume of liquefied ammonia (LNH ₃ ) in the fuel supply device is dissolved in water. Additionally, the fresh water corresponding to the introduced ammonia gas (including some liquefied ammonia) can be set to an appropriate amount by adjusting the HH level of the liquid level sensor.

Next, the valve 123 shown in FIG. 3 is opened, and liquefied ammonia (LNH ₃ ) is supplied to the gas-liquid separator 12 to bring the liquefied ammonia into contact with water to make ammonia water.

Liquefied ammonia (LNH ₃ ) is supplied from the fuel return system via RVT (11) to recovery tank (4). Therefore, in the RVT 11, since the liquefied ammonia is depressurized and returned to the recovery tank 4, a part of it may be vaporized when the pressure is reduced, and the liquefied ammonia (LNH ₃ ) flowing into the gas-liquid separator 12 may be added. , including partially vaporized ammonia gas, which may result in liquefied ammonia.

Next, the state in which the liquefied ammonia (LNH ₃ ) has escaped is detected by, for example, a level switch (not shown) in the fuel supply device, a pressure gauge, etc., and then the ammonia water is transferred from the primary storage tank 125 through the pump 124. retrieve it The ammonia water recovered from the primary storage tank 125 can be used as fuel again by supplying it to the recovery tank 4 as shown in FIG. 3.

Next, the liquid level is extracted by the pump 124 until it reaches the LL level, and when the low level sensor 121 detects the LL level, the pump 124 is stopped. This completes the series of processes in the gas-liquid separator.

Again, open the fresh water valve 122, introduce fresh water, and push it in until the high level sensor 120 detects the HH level.

The ammonia gas separated above the liquid level from the gas-liquid separator 12 is sent to the removal device 13. Water is supplied from the detoxification device 13 to generate ammonia water.

The ammonia water discharged from the removal device 13 is sent to the SCR 16 and is treated and removed, such as being used as a reducing agent.

According to the device shown in FIG. 3 and the method of using the same, there is an effect that the removal device can be compactized. This is because the amount of ammonia to be removed with the detoxification device is reduced. Additionally, there is an effect of reducing the amount of reaction heat generated when ammonia and water come into contact.

Next, Embodiment 2 of the present invention will be described with reference to FIG. 4.

The fuel supply line in mode 2 is located on the A side of the broken line in FIG. 4 and is a fuel supply line that supplies any one of liquefied ammonia, liquefied petroleum gas, and methanol to the engine.

Hereinafter, equipment installed in the fuel supply line will be described.

The fuel tank 2 is filled with liquefied ammonia. Liquefied ammonia is supplied to the first buffer tank (20) by a low pressure pump (3).

The fuel supply line from the first buffer tank 20 to the engine 1 includes a high pressure pump 5, a heater 5A, a filter 7A or filter 7B, and a fuel valve train (interface), SVT 10. is provided.

Meanwhile, RVT 11, which is a fuel valve train (interface), is located on the B side of the broken line in FIG. 4 and is installed in the fuel return line from the engine 1 to the recovery tank 4. That is, the fuel return line that returns part of the fuel from the engine 1 is provided with a recovery tank 4.

In this mode 2, as in mode 1, an oil removal and recovery device is installed in the recovery tank 4.

Since the structure of this oil removal and recovery device is the same as that described in Embodiment 1, its description is omitted.

The oil (sealed oil) separated to the lower layer by the oil removal and recovery device of the recovery tank 4 is transferred to the drain tank 43 through the drain valve 42 and the transfer pump 45.

The second buffer tank 22 functions as a primary storage tank for liquefied ammonia when the inner pipe of the double piping as a leakage countermeasure in case of pipe damage in the engine room is damaged. In a normal state, air flows from the RVT 11 to the second buffer tank 22. However, when an abnormality such as damage to a pipe occurs, the fuel (liquefied ammonia, etc.) in the engine 1 can be recovered from the RVT 11 by installing the second buffer tank 22. Additionally, ammonia water, which is the fuel in the engine 1, may be supplied to the SCR 16 as a reducing agent through the second buffer tank 22. As a result, the reducing agent can be supplied to the SCR 16 without going through a detoxification device (not shown), and as a result, the detoxification device can be made more compact and the release of ammonia gas into the atmosphere can be suppressed.

In the recovery tank 4 shown in FIG. 4, the liquefied ammonia fuel in the liquefied ammonia tank 41 is sent to the first buffer tank 20 by the pump 24. In this case, it is desirable to install a check valve (not shown) between the pump 24 and the first buffer tank 20 to prevent liquid flow from the first buffer tank 20 toward the recovery tank 4. .

Additionally, the ammonia gas in which the liquefied ammonia in the recovery tank 4 has vaporized can be sent to a detoxification device (not shown), and ammonia water can be sent to the SCR 16 as a reducing agent through the detoxification device.

In this form, a drain room consisting of a second buffer tank 22 and/or a drain tank 43 for recovering remaining water can be installed at the lower part of the fuel supply chamber where the fuel supply line is formed. By installing it at the bottom in this way, the amount of nitrogen supplied into the fuel supply device can be reduced by dropping the liquid under its own weight, and the removal device can be made compact.

In addition, ammonia gas generated from the fuel tank 2, recovery tank 4, etc. is processed by generating ammonia water by a detoxification device (not shown) and sending it to the SCR 16 to be used as a reducing agent in the SCR 16. ·It is removed.

1: engine
2: Fuel tank
2A: Reliquefaction device
3: Low pressure pump
3A: Heater
4: Recovery tank
40: board
41: Liquefied ammonia tank
42: Drain valve
43: Drain tank
44: sensor
45: transfer pump
5: High pressure pump
5A: Heater
6: Parallel
7A: Filter
7B: Filter
10A: Nitrogen supply device
12: Gas-liquid separator
12A: Gas-liquid separator
12B: Gas-liquid separator
120: high level sensor
121: low level sensor
122: Fresh water valve
123: valve
124: pump
125: Primary storage tank
13: Removal device
15: cooler
16:SCR
20: first buffer tank
22: second buffer tank
24: transfer pump

Claims (7)

a fuel supply line to the engine from a fuel tank storing one of liquefied ammonia, liquefied petroleum gas and methanol to the engine via a recovery tank;
a fuel return line that returns a portion of the fuel from the engine to the recovery tank;
A fuel supply device, characterized in that an oil removal and recovery device is installed in the recovery tank. The fuel supply device according to claim 1, wherein the oil removal and recovery device includes a beam for improving separation of fuel and oil, and an instrument for determining the interface between fuel and oil. 3. A fuel supply device according to claim 2, wherein the instrument is a capacitive level switch or a density meter. The method according to any one of claims 1 to 3, wherein the fuel is introduced into a fuel return line that returns a part of the fuel from the engine to the recovery tank to separate it into vaporized ammonia gas, liquefied ammonia, and oil. Equipped with a gas-liquid separator,
A fuel supply device characterized by installing a removal device that generates ammonia water by introducing the vaporized ammonia gas and water separated by the gas-liquid separator. A fuel supply line that supplies one of liquefied ammonia, liquefied petroleum gas, and methanol to the engine is provided with a fuel tank, a low-pressure fuel pump, a first buffer tank, a high-pressure fuel pump, a heater, and a filter,
A recovery tank is provided in the fuel return line for returning a portion of the fuel from the engine,
By installing an oil removal and recovery device in the recovery tank,
A fuel supply device, characterized in that the fuel from which the oil has been removed is returned to the first buffer tank. The fuel supply device according to claim 5, further comprising a drain tank for storing oil separated by the oil removal and recovery device. The fuel supply device according to claim 6, wherein a drain room including a drain tank for recovering remaining water is installed at a lower portion of the fuel supply room where the fuel supply line is formed.