KR20200051695A - Ship - Google Patents

Abstract

The vessel is not used as a fuel tank for storing LPG, a propulsion engine using LPG as fuel, a fuel supply line for supplying LPG from the fuel tank to the engine, a pump installed in the fuel supply line, and a fuel tank from the engine. A fuel recovery line for recovering LPG, a pressure regulating valve installed in the fuel recovery line, a control device for controlling the pump and the pressure regulating valve, and a pressure gauge for detecting the pressure of LPG supplied to the engine. , The relationship between the target opening of the pressure regulating valve and the fuel consumption of the engine is stored in advance, and the control device controls the pressure regulating valve so that the pressure detected by the pressure gauge becomes a set value, and at the same time, the opening of the pressure regulating valve is The pump is controlled to achieve a target opening degree corresponding to the actual fuel consumption.

Description

Ship

The present invention relates to a ship including a propulsion engine using LPG as fuel.

In a conventional ship, the fuel of the propulsion engine is generally fuel oil such as heavy oil or LNG (Liquefied Natural Gas). Recently, it has been proposed to use LPG (Liquefied Petroleum Gas) as a fuel for a propulsion engine.

For example, a patent document discloses a ship that supplies LPG in a liquid state from a fuel tank to a propulsion engine. When LPG is used as a fuel, sulfur oxide measures are unnecessary compared to fuel oil, and at the same time, there is an advantage that carbon dioxide emissions are small, and since the specific gravity is large compared to LNG, the fuel tank can be miniaturized.

Korean Patent Publication No. 2012-0113398

When LPG is used as fuel, it is considered that the fuel tank and the propulsion engine are connected by a fuel supply line and a fuel recovery line to circulate LPG between the fuel tank and the engine, and only the necessary amount is used in the engine.

However, when circulating LPG between the fuel tank and the engine as described above, it is preferable to supply the engine with a little more fuel than the engine consumes. To realize this, the flowmeter detects and detects the supply flow rate of the LPG to the engine (flow rate entering the engine through the fuel supply line) or the recovery flow rate from the engine (flow rate exiting the engine through the fuel recovery line). It is considered to control the pump installed in the fuel supply line so that the flow rate is a predetermined value corresponding to the fuel consumption of the engine.

In addition, in order to maintain the fuel supply pressure to the engine within the required range of the engine, it is necessary to detect the pressure of the LPG supplied to the engine with a pressure gauge, and to control the pressure regulating valve installed in the fuel recovery line so that the detected pressure becomes a set value Is considered.

However, when controlling the pump and the pressure regulating valve as described above, there is a possibility that the flow control and the pressure control may interfere.

Accordingly, an object of the present invention is to provide a vessel capable of stably controlling a pump installed in a fuel supply line and a pressure regulating valve installed in a fuel recovery line.

In order to solve the above problems, the inventors of the present invention, when the discharge flow rate of the pump is increased by a certain ratio than the fuel consumption amount of the engine, the tank return flow rate passing through the pressure regulating valve installed in the fuel recovery line becomes the constant ratio. Therefore, it has been found that it is possible to predetermine the target opening degree of the pressure regulating valve with respect to the fuel consumption of the engine in order to increase the discharge flow rate of the pump by a certain ratio than the fuel consumption of the engine. In other words, the target opening degree of the pressure regulating valve means that the discharge flow rate of the pump is increased by a certain percentage than the fuel consumption of the engine. The present invention has been made in this respect.

That is, the ship of the present invention, a fuel tank for storing LPG, a propulsion engine using LPG as fuel, a fuel supply line for supplying LPG to the engine from the fuel tank, and a pump installed in the fuel supply line , A fuel recovery line for recovering LPG that is not used as the fuel tank from the engine, a pressure regulating valve installed in the fuel recovery line, a control device for controlling the pump and the pressure regulating valve, and supplied to the engine A pressure gauge for detecting the pressure of the LPG is provided, and in the control device, a relationship between a target opening degree of the pressure regulating valve and a fuel consumption amount of the engine is stored in advance, and the pressure detected by the pressure gauge is set in the control device. At the same time as controlling the pressure regulating valve, the opening degree of the pressure regulating valve corresponds to the actual fuel consumption of the engine. It is characterized in that for controlling the pump so that the target opening degree.

According to the above configuration, since the number of rotations of the pump as well as the opening of the pressure regulating valve can be adjusted based on the pressure gauge, the pump and the pressure regulating valve can be stably controlled.

The ship further includes a bypass line branched from the fuel supply line on the downstream side of the pump and connected to the fuel recovery line or the fuel tank, and a flow control valve installed on the bypass line, and the control The apparatus may control the flow rate control valve such that when the rotational speed of the pump reaches the lowest rotational speed, the opening degree of the pressure regulating valve is a target opening degree corresponding to the actual fuel consumption of the engine. According to this configuration, even when the number of revolutions of the pump reaches the lowest number of revolutions, it is possible to increase the flow rate of LPG to the engine by a certain percentage from the fuel consumption of the engine.

The fuel tank may store the LPG so that the temperature of the LPG changes following the atmospheric temperature. According to this structure, it is necessary to make the fuel tank a pressure vessel, and a means for maintaining LPG at a low temperature in the fuel tank may be required.

According to the present invention, it is possible to stably control the pump installed in the fuel supply line and the pressure regulating valve installed in the fuel recovery line.

1 is a schematic configuration diagram of a ship according to an embodiment of the present invention.
2 is a table showing the relationship between the fuel consumption of the engine and the target opening degree of the first pressure regulating valve.

1 shows a ship 1 according to an embodiment of the invention. The ship 1 includes a propulsion engine 11 using LPG as fuel, and a fuel tank 2 storing LPG. The main component of LPG may be propane (propane gas) or butane (butane gas).

According to this embodiment, the fuel tank 2 is composed of a relatively large volume storage tank 21 and a relatively small volume service tank 22. The storage tank 21 and the service tank 22 together are pressure vessels whose internal pressure is higher than atmospheric pressure. The storage tank 21 and the service tank 22 are connected to each other by a relay line 26.

LPG is introduced into the storage tank 21 through the fuel introduction line 23 from the LPG supply source. The LPG supply source may be a cargo tank mounted on the ship 1, an on-shore LPG supply facility or an LPG fuel supply line.

According to this embodiment, the storage tank 21 is not provided with a means (for example, a heat insulating material) for keeping LPG at a low temperature, and the temperature of the LPG in the storage tank 21 changes according to the atmospheric temperature. On the other hand, LPG introduced from the LPG source is often about -42 ° C when LPG is propane gas. Therefore, the fuel introduction line 23 is provided with a heater 24 for heating LPG to a temperature ranging from -5 ° C to atmospheric temperature, for example. However, a heater is installed in the LPG supply facility on the ground or the LPG fuel supply line, which is an LPG supply source, so that the heater 24 is unnecessary when the temperature of the LPG delivered to the ship 1 is -5 ° C or higher.

When the component of the base layer in the storage tank 21 is only PG vaporized, the pressure of the base layer in the storage tank 21 is the saturated vapor pressure of LPG. For example, when the temperature in the storage tank 21 is 25 ° C, the pressure (saturated vapor pressure) of the base layer in the storage tank 21 is about 0.9 MPa as a gauge pressure. Hereinafter, all indications of pressure are gauge pressures. Here, since the saturated vapor pressure of LPG is about 1.7 MPa at 50 ° C, the storage tank 21 is configured to withstand, for example, 1.8 MPa. For reference, the saturated vapor pressure of LPG is about 0.4 MPa at 0 ° C.

A pump 25 is installed inside the storage tank 21. The number of pumps 25 may be one or plural. The upstream end of the relay line 26 described above is connected to the pump 25. In addition, the downstream end of the relay line 26 is opened in the service tank 22. Then, the LPG is supplied from the storage tank 21 to the service tank 22 through the relay line 26 by the pump 25. However, the pump 25 may be provided in the middle of the relay line 26 from the outside of the storage tank 21.

Like the storage tank 21, the service tank 22 is not provided with means for keeping the LPG at a low temperature, and the temperature of the LPG in the service tank 22 changes according to the atmospheric temperature. When the component of the base layer in the service tank 22 is only the vaporized PG, the pressure of the base layer in the service tank 22 is the saturated vapor pressure of LPG.

When LPG is circulated between the engine 11 and the service tank 22 as described later, the temperature of the LPG in the service tank 22 may be higher than the atmospheric temperature. For example, when the temperature of LPG in the service tank 22 is 60 ° C, the pressure (saturated vapor pressure) of the base layer in the service tank 22 is about 2.1 MPa. Here, the service tank 22 is configured to withstand, for example, 2.2 MPa.

The service tank 22 is connected to the propulsion engine 11 by a fuel supply line 31 and a fuel recovery line 41. That is, LPG is supplied from the service tank 22 to the engine 11 through the fuel supply line 31, and unused LPG is recovered from the engine 11 to the service tank 22 through the fuel recovery line 41. do. In other words, LPG is circulated through the fuel supply line 31 and the fuel recovery line 41 between the service tank 22 and the engine 11.

The upstream end of the fuel supply line 31 is connected to the lower part of the service tank 22. The downstream end of the fuel recovery line 41 is opening in the service tank 22.

The engine 11 is, for example, a diesel cycle or an auto cycle reciprocating engine. Although not shown, the engine 11 includes a main flow path connecting the downstream end of the fuel supply line 31 and the upstream end of the fuel recovery line 41, and a plurality of fuel injection valves connected to the main flow path in parallel with each other. do.

The fuel supply line 31 is provided with a pump 32, a heater 33, and a shut-off valve 34 in order from the upstream side. The heater 33 heats the LPG to the required temperature of the engine 11 (eg, 45 ° C).

In the above-mentioned relay line 26, a heater 27 for heating the LPG supplied from the storage tank 21 to the service tank 22 is provided. During the operation of the engine 11, LPG in an amount corresponding to the fuel consumption amount Qe of the engine 11 is supplied from the storage tank 21 to the service tank 22. The heater 27 is used when it is difficult to heat to the required temperature of the engine 11 with the heater 33 alone. Here, the heater 27 may be omitted.

The fuel recovery line 41 has a first pressure regulating valve 42 (corresponding to the pressure regulating valve of the present invention), a shut-off valve 43, a cooler 44 and a second pressure regulating valve 45 in order from the upstream side. Is installed. The cooler 44 cools the LPG to a predetermined temperature (eg, 40 ° C). Here, the cooler 44 may be omitted.

According to this embodiment, the fuel supply line 31 and the fuel recovery line 41 are connected by the first bypass line 51. The first bypass line 51 branches from the fuel supply line 31 between the heater 33 and the shut-off valve 34, and the fuel return line 41 between the shut-off valve 43 and the cooler 44. ). A flow control valve 52 is installed in the first bypass line 51.

Further, according to this embodiment, the second bypass line 53 is employed. The second bypass line 53 branches from the fuel supply line 31 between the pump 32 and the heater 33 and is connected to the service tank 22. A flow control valve 54 is installed in the second bypass line 53. However, either one of the first bypass line 51 and the second bypass line 53 may be omitted.

The aforementioned pump 32, shut-off valves 34, 43. The pressure regulating valves 42 and 45 and the flow control valves 52 and 54 are controlled by the control device 6. However, in FIG. 1, only some signal lines are depicted for simplification of the drawing. The control device 6 is, for example, a computer having a memory and a CPU such as ROM or RAM, and a program stored in the ROM is executed by the CPU. The control device 6 may be a single device or may be divided into a plurality of devices (for example, an engine control device and a fuel supply control device).

With regard to the shut-off valves 34 and 43, the control device 6 closes the shut-off valves 34 and 43 while the engine 11 is stopped, and the shut-off valve 34 during standby and operation of the engine 11 , 43). During the stoppage of the engine 11, the flow paths between the shut-off valves 34 and 43 (the downstream side portion of the fuel supply line 31, the main flow path of the engine 11 and the upstream side portion of the fuel recovery line 41) are Purge with inert gas

The control device 6 is electrically connected to the first pressure gauge 71 (corresponding to the pressure gauge of the present invention) and the second pressure gauge 72. The first pressure gauge 71 is used for the control of the pump 32, the flow control valves 52, 54 and the first pressure regulating valve 42, and the second pressure gauge 72 is of the second pressure regulating valve 45. Used for control. Hereinafter, for convenience of description, the control based on the second pressure regulating valve 45 will be described.

The second pressure gauge 72 is installed in the fuel recovery line 41 between the first pressure regulating valve 42 and the second pressure regulating valve 45, after being depressurized in the first pressure regulating valve 42. The pressure of LPG is detected. According to this embodiment, the second pressure gauge 72 is located between the shut-off valve 43 and the cooler 44, but may be located upstream of the shut-off valve 43 or downstream of the cooler 44.

The temperature of LPG is slightly increased by passing LPG through the engine 11 (for example, 55 ° C). Therefore, in order to prevent the LPG decompressed at the first pressure regulating valve 42 from vaporizing, the control device 6 is configured such that the pressure detected by the second pressure gauge 72 is higher than the saturated vapor pressure at the expected maximum temperature. The second pressure regulating valve 45 is controlled to be a set value (for example, 2.0 MPa).

The first pressure gauge 71 is installed on the fuel supply line 31 on the downstream side of the pump 32, and detects the pressure of LPG supplied to the engine 11. According to this embodiment, the first pressure gauge 71 is located downstream of the shut-off valve 34, but may be located between the shut-off valve 34 and the heater 33 or upstream of the heater 33. .

The control device 6 is provided so that the pressure detected by the first pressure gauge 71 is set within the required range of the engine 11 (for example, 5.0 to 6.0 MPa when the engine 11 is a diesel cycle). 1 Control the pressure regulating valve (42).

As for the pump 32 and the flow rate control valve 52, the relationship between the target opening degree of the first pressure regulating valve 42 and the fuel consumption amount Qe of the engine 11 is shown in FIG. 2 in the control device 6. It is stored in advance as a table as shown. The target opening degree of the first pressure regulating valve 42 generally increases as the fuel consumption Qe of the engine 11 increases.

For example, the control device 6 may determine the fuel consumption amount Qe of the engine 11 based on the operation amount of the telegraph lever operated by the operator. Alternatively, when the control device 6 is divided into an engine control device that controls the engine 11 and a fuel supply control device that controls the pump 32 and various valves, the fuel supply control device is calculated by the engine control device. The fuel consumption amount Qe of the engine 11 may be determined based on the value relating to the fuel injection amount.

Then, the control device 6 controls the pump 32 such that the opening degree of the first pressure regulating valve 42 is the target opening degree corresponding to the actual fuel consumption Qe of the engine 11. That is, when the actual opening degree of the first pressure regulating valve 42 is smaller than the target opening degree, the number of revolutions of the pump 32 is increased to increase the fuel supply pressure and increase the opening degree of the first pressure regulating valve 42 do. Conversely, when the actual opening degree of the first pressure regulating valve 42 is larger than the target opening degree, the number of revolutions of the pump 32 is reduced in order to reduce the opening degree of the first pressure regulating valve 42 by lowering the fuel supply pressure.

For example, when the load of the engine 11 increases and the fuel consumption Qe of the engine 11 increases, the target opening degree of the first pressure regulating valve 42 increases, so that the control device 6 To increase the actual opening degree of the first pressure regulating valve 42 to the target opening degree, the rotation speed of the pump 32 is increased. Conversely, when the load of the engine 11 decreases and the fuel consumption Qe of the engine 11 decreases, since the target opening degree of the first pressure regulating valve 42 decreases, the control device 6 first pressure The number of revolutions of the pump 32 is reduced to reduce the actual opening degree of the regulating valve 42 to the target opening degree.

Here, the control device 6 keeps the flow rate control valve 52 all closed unless the rotational speed of the pump 32 reaches the minimum rotational speed. The minimum rotational speed of the pump 32 may be a fixed value, but is changed, for example, in response to the pressure of the base layer in the service tank 22 (the higher the pressure of the base layer in the service tank 22, the higher the pressure of the pump 32). It is desirable to lower the lowest rotational speed).

As a result of the control based on the target opening degree of the first pressure regulating valve 42, when the rotational speed of the pump 32 becomes the lowest rotational speed, the control device 6 opens the opening of the first pressure regulating valve 42 to the engine ( 11) One of the flow control valves 52 and 54 is controlled to be the target opening degree corresponding to the actual fuel consumption Qe. That is, when the actual opening degree of the first pressure regulating valve 42 is smaller than the target opening degree, any of the flow control valves 52 and 54 is increased to increase the opening of the first pressure regulating valve 42 by increasing the fuel supply pressure. The opening degree on one side is reduced. Conversely, when the actual opening degree of the first pressure regulating valve 42 is larger than the target opening degree, any one of the flow control valves 52 and 54 is used to lower the fuel supply pressure to reduce the opening degree of the first pressure regulating valve 42. The opening degree of one side is increased.

As described above, in the ship 1 according to the present embodiment, since the opening of the first pressure regulating valve 42 as well as the rotational speed of the pump 32 can be adjusted based on the first pressure gauge 71 , The pump 32 and the first pressure regulating valve 42 can be stably controlled.

(Modified example)

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.

For example, both the first bypass line 51 and the second bypass line 53 are omitted, and when the rotational speed of the pump 32 reaches the lowest rotational speed, a large amount of LPG passes through the engine 11. You may allow it. However, when at least one of the first bypass line 51 and the second bypass line 53 is formed, and the number of revolutions of the pump 32 reaches the lowest speed, the first bypass line 51 or the first 2 When the flow control valve 52 or 54 installed in the bypass line 53 is opened, the LPG supply flow rate to the engine 11 is maintained even when the rotational speed of the pump 32 reaches the lowest rotational speed. It can be increased by a certain percentage than the fuel consumption (Qe).

Alternatively, when the second bypass line 53 is provided, the LPG passing through the engine 11 may be temporarily increased when the rotational speed of the pump 32 reaches the lowest rotational speed. The LPG returned to the service tank 22 through the second bypass line 53 receives heat from the pump 32. Therefore, as described above, when the LPG passing through the engine 11 temporarily increases when the rotational speed of the pump 32 reaches the lowest rotational speed, it is transferred to the service tank 22 through the second bypass line 53. While the amount of conveyance decreases, the LPG passing through the engine 11 is cooled by the cooler 44, so that the temperature rise of the LPG in the service tank 22 can be suppressed. Specifically, when the rotation speed of the pump 32 reaches the lowest rotation speed, the control device 6 increases the target opening degree of the first pressure regulating valve 42. As described above, the target opening degree of the first pressure regulating valve 42 does not always need to increase as the fuel consumption Qe of the engine 11 increases, as shown in FIG. 2.

Further, in the above embodiment, the fuel tank 2 is composed of a storage tank 21 and a service tank 22, but the storage tank 21 is omitted, and the fuel tank 2 is only the service tank 22. It may be configured. That is, LPG may be introduced directly from the LPG supply source into the service tank 22. However, if the same configuration as in the above embodiment, the fuel tank 2 can be divided into a storage tank 21 for LPG introduction and a service tank 22 for LPG circulation.

Further, the fuel tank 2 does not necessarily need to be a pressure vessel, and a tank having an internal pressure equal to atmospheric pressure may be sufficient. In this case, a means for maintaining LPG in the fuel tank 2 at a low temperature is required. However, if the fuel tank 2 stores the LPG so that the temperature of the LPG changes by following the atmospheric temperature as in the above embodiment, it is necessary to make the fuel tank 2 a pressure vessel, so that the LPG in the fuel tank 2 It may require a means to maintain the low temperature.

1: Ship
11: engine
2: fuel tank
31: fuel supply line
32: Pump
41: fuel recovery line
43, 45: pressure regulating valve
51: bypass line
52: flow control valve
6: Control device
71 to 73: pressure gauge

Claims (3)

A fuel tank for storing LPG,
A propulsion engine using LPG as fuel,
A fuel supply line for supplying LPG to the engine from the fuel tank,
A pump installed in the fuel supply line,
A fuel recovery line for recovering unused LPG from the engine to the fuel tank;
A pressure regulating valve installed in the fuel recovery line,
A control device for controlling the pump and the pressure regulating valve,
It has a pressure gauge for detecting the pressure of the LPG supplied to the engine,
In the control device, the relationship between the target opening of the pressure regulating valve and the fuel consumption of the engine is stored in advance,
The control device is configured to control the pump so that the opening of the pressure regulating valve is a target opening corresponding to the actual fuel consumption of the engine while controlling the pressure regulating valve such that the pressure detected by the manometer is a set value. Ship characterized by.
According to claim 1,
A bypass line branched from the fuel supply line on the downstream side of the pump and connected to the fuel recovery line or the fuel tank,
Further provided with a flow control valve installed on the bypass line,
The control device, when the number of revolutions of the pump reaches the lowest number of revolutions, the vessel characterized in that the opening of the pressure regulating valve controls the flow rate control valve to a target opening corresponding to the actual fuel consumption of the engine .
The method according to claim 1 or 2,
The fuel tank is a vessel characterized in that to store the LPG so that the temperature of the LPG changes according to the atmospheric temperature.

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