KR20200047623A - Ship - Google Patents

Abstract

The vessel diverges from the fuel supply line supplying LPG to the engine from the fuel tank, the pump and shutoff valve installed in the fuel supply line, the fuel return line recovering LPG from the engine to the fuel tank, and the fuel supply line upstream of the shutoff valve. Bypass line connected to the fuel recovery line or fuel tank, a flow control valve installed in the bypass line, a pressure gauge to detect the supply pressure of LPG from the upstream side of the shut-off valve, a flow meter to detect the supply flow rate or recovery flow rate of LPG, and And a control device. Upon closing the shut-off valve, the control device controls the pump speed and / or flow control valve to maintain the supply pressure of the LPG detected by the pressure gauge at the required pressure required for the operation of the engine. When the shut-off valve is opened, the control device controls the pump speed and the flow rate control valve so that the flow rate detected by the flow meter becomes a predetermined value corresponding to the fuel consumption of the engine.

Description

Ship

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

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

For example, the vessel disclosed in the patent document is provided with a diesel storage tank for storing diesel oil and a deck tank for preserving LPG, and can selectively supply diesel or LPG as engine fuel for propulsion. . The deck tank is connected to the engine through a fuel transfer pipe, and a pump and a shut-off valve are installed in the fuel transfer pipe.

While using light oil, the pump stops and the shut-off valve is closed. When converting the fuel from diesel to LPG, the pump operates to open the shut-off valve, whereby the supply of LPG to the engine begins.

Korean Patent Publication No. 2012-0113398

In order to inject fuel in the engine, it is necessary to ensure that the fuel supply pressure to the engine is above a certain value. As described above, when the pump is operated in the step of starting supplying LPG, there is a possibility that the pressure of LPG in the fuel transfer pipe does not reach the pressure required by the engine, and thus the engine cannot be smoothly operated. Here, such a problem at the time of starting supply of LPG may occur in the same manner as in the engines using only LPG as fuel, as well as the binary fuel engine disclosed in the patent literature.

Accordingly, an object of the present invention is to provide a ship capable of smoothly driving a propulsion engine at the start of supply of LPG.

The ship according to an embodiment 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 installed in the fuel supply line A pump, a shutoff valve provided on the fuel supply line on the downstream side of the pump, a fuel recovery line for recovering LPG that is not used as the fuel tank from the engine, and the fuel supply line between the pump and the shutoff valve Branched from the bypass line connected to the fuel recovery line or the fuel tank, the flow control valve installed on the bypass line, and installed on the fuel supply line on the downstream side of the pump and the upstream side of the shutoff valve A pressure gauge that detects the pressure of LPG supplied from the pump, and LP flowing into the engine through the fuel line A flow meter for detecting the supply flow rate of G or LPG recovery flow rate from the engine through the fuel recovery line, and a control device for controlling the number of revolutions of the pump and the flow rate control valve, and closing the shutoff valve When the LPG is being stopped from being supplied to the engine, the control device controls the number of revolutions of the pump and / or the flow rate control valve to maintain the pressure of the LPG detected by the pressure gauge at a required pressure required to operate the engine. When the LPG is supplied to the engine by opening the shut-off valve, the control device is configured to rotate the pump so that the flow rate detected by the flowmeter is a predetermined value corresponding to the fuel consumption of the engine. The flow control valve is controlled.

According to the above configuration, since the bypass line is installed and the pump rotation speed and the flow rate control valve are controlled so that the flow rate of the LPG is adjusted in response to the fuel consumption, the oversupply of the LPG to the engine can be suppressed, and fuel recovery In a ship equipped with a line, excessive rise in temperature of the LPG in the fuel tank can be suppressed.

In addition, a pump and a flow control valve used for flow control during supply of LPG are used for regulating the LPG pressure in the fuel supply line when supply of LPG with the shutoff valve closed is stopped. Accordingly, the pump rotation speed and the flow rate control valve are used together for pressure control, and the LPG supply pressure is maintained at the required pressure required for the engine operation, so that the engine can be smoothly operated at the start of LPG supply.

When the upstream side of the confluence point of the bypass line is provided with a pressure regulating valve installed in the fuel recovery line, and when the shutoff valve is opened to supply LPG to the engine, the control device operates the pressure regulating valve to The pressure of LPG supplied to the engine may be controlled. According to this configuration, when supplying LPG, the pressure control of LPG supplied to the engine can be realized while using the flow control valve and the pump rotational speed for flow control.

According to the present invention, it is possible to provide a vessel capable of smoothly driving a propulsion engine at the start of supply of LPG.

1 is a schematic configuration diagram of a ship according to an embodiment.
2 is a schematic configuration diagram of a ship according to a modification.

Hereinafter, embodiments will be described with reference to the drawings. Throughout the drawings, the same reference numerals are assigned to the same or corresponding elements, and duplicate detailed descriptions are omitted.

The ship 1 shown in FIG. 1 is an LPG fuel propulsion vessel. The ship 1 includes a fuel tank 2 storing LPG and a propulsion engine 11 using LPG as fuel. 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 a fuel introduction line 23 from an LPG supply source. The LPG supply source may be a cargo tank mounted on the ship 1, an onshore 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 maintaining LPG at a low temperature, and the temperature of the LPG in the storage tank 21 changes according to the atmospheric temperature. The LPG introduced from the LPG source is often about -42 ° C when the main component is propane gas. Therefore, the fuel introduction line 23 is provided with a heater 24 for heating the 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 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 the 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 is connected to the pump 25. The downstream end of the relay line 26 is opening in the service tank 22. By the pump 25, LPG is supplied from the storage tank 21 to the service tank 22 via the relay line 26. 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 the 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. LPG is supplied from the service tank 22 to the engine 11 via 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. 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.

In the relay line 26, a heater 27 for heating the LPG supplied from the storage tank 21 to the service tank 22 is provided. The heater 33 heats the LPG to the required temperature of the engine 11 (for example, 45 ° C). When LPG is being supplied to the engine 11, LPG in an amount corresponding to the fuel consumption 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 is provided with a first pressure regulating valve 42, a shut-off valve 43, a cooler 44 and a second pressure regulating valve 45 in order from the upstream side. The cooler 44 cools the LPG to a predetermined temperature (eg, 40 ° C). Here, the cooler 44 may be omitted.

The fuel supply line 31 and the fuel recovery line 41 are connected by a first bypass line 51. The first bypass line 51 branches off from the fuel supply line 31 between the pump 32 and the shut-off valve 34, more specifically between the heater 33 and the shut-off valve 34, and shuts off It is connected to the fuel recovery line 41 between the valve 43 and the cooler 44. A flow control valve 52 is installed in the first bypass line 51.

Further, according to the present 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.

Pump 32, shut-off valves 34, 43, pressure regulating valves 42, 45 and flow control valves 52, 54 are controlled by 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).

The control device 6 is electrically connected to the first supply pressure gauge 72, the second supply pressure gauge 73, the recovery pressure gauge 74, and the flowmeter 81. The flow meter 81 is used for the control of the pump 32 and the flow control valve 52, especially LPG flow control when LPG is being supplied to the engine 11. The first supply pressure gauge 72 is used for control of the pump 32 and the flow rate control valve 52, particularly LPG pressure control when supply of LPG to the engine 11 is stopped. The second supply pressure gauge 73 is used for the control of the first pressure regulating valve 42, and the recovery pressure gauge 74 is used for the control of the second pressure regulating valve 45.

The flow meter 81 is installed in the fuel supply line 31 at the downstream side of the branching point with the first bypass line 51, and the supply flow rate of LPG flowing into the engine 11 through the fuel supply line 31 (Qi) is detected.

The first supply pressure gauge 72 is provided on the fuel supply line 31 at the downstream side of the pump 32 (more specifically, the downstream side of the heater 33). The first supply pressure gauge 72 detects the pressure of LPG supplied from the pump 32. The second supply pressure gauge 73 is installed on the fuel supply line 31 on the downstream side of the shutoff valve 34 and detects the pressure of LPG supplied to the engine 11 through the shutoff valve 34.

The recovery pressure gauge 74 is installed in the fuel recovery line 41 between the shut-off valve 43 and the second pressure regulating valve 45. The recovery pressure gauge 74 detects the pressure of LPG after being depressurized by the first pressure regulating valve 42. According to this embodiment, the recovery pressure gauge 74 is located on the upstream side of the cooler 44, but may be located on the downstream side of the cooler 44.

Here, the engine 11 may be an engine using only LPG as fuel, or a binary fuel engine using LPG and fuel oil such as heavy oil or light oil as fuel. In the case of an engine using only LPG as fuel, the timing for starting to supply LPG to the engine 11 corresponds to the timing for starting the operation of the engine 11. The period in which supply of LPG to the engine 11 is stopped corresponds to a period in which the engine 11 is stopped. In the case of a binary fuel engine, at the timing of starting to supply LPG to the engine 11, the timing of starting the operation of the engine 11 and the engine 11 is running, but the fuel supplied to the engine 11 is converted from heavy oil to LPG. Timing for switching is included. The period during which supply of LPG to the engine 11 is stopped includes a period in which the engine 11 is stopped and a period in which the engine 11 is operating using fuel oil as fuel.

Regarding the shut-off valves 34 and 43, the control device 6 closes the shut-off valves 34 and 43 in a period in which supply of LPG to the engine 11 is stopped. During the period when LPG is supplied to the engine 11, the control device 6 opens the shut-off valves 34 and 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 It is purged with an inert gas.

When LPG is supplied to the engine 11, pressure control, flow rate control, and temperature management of the LPG are executed.

With respect to LPG flow control during LPG engine supply, the control device 6 determines that the supply flow rate Qi detected by the flowmeter 81 is a predetermined value V according to the fuel consumption amount Qe of the engine 11. ), The number of revolutions of the pump 32 is controlled. According to this embodiment, the predetermined value V is a value obtained by multiplying the fuel consumption amount Qe of the engine 11 by a coefficient C (V = Qe × C). For example, the coefficient C is generally 1.1 to 1.50. The coefficient C may be a fixed value set within such a numerical range, or may be variably set within such a numerical range.

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. You may determine the fuel consumption amount Qe of the engine 11 based on the value regarding the consumed fuel consumption amount.

When the rotational speed of the pump 32 is the lowest rotational speed as a result of the control of the rotational speed of the pump 32 based on the supply flow rate Qi detected by the flowmeter 81, the control device 6 is connected to the flowmeter 81. One of the flow control valves 52 and 54 is controlled so that the detected supply flow rate Qi becomes the above-described predetermined value V. Specifically, the control device 6 increases the opening degree of either of the flow control valves 52 and 54 as the fuel consumption amount Qe of the engine 11 decreases, thereby increasing the amount of LPG supplied to the engine 11. Decrease the flow rate.

Since the rotation speed of the pump 32 and the flow rate control valve 52 are controlled so that the flow rate of the LPG is adjusted according to the fuel consumption, it is possible to suppress the excessive supply of the LPG to the engine 11. When the LPG passes through the engine 11, the temperature of the LPG rises as heat flows from the engine 11. By providing the bypass lines 51 and 53, it is possible to suppress excessive rise of the temperature of the LPG in the fuel tank 2 (service tank 22) in the ship 1 equipped with the fuel recovery line 41. .

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 sets the pressure detected by the recovery pressure gauge 74 to be higher than the saturated vapor pressure at the expected maximum temperature. The second pressure regulating valve 45 is controlled to be a value (eg, 2.0 MPa).

Regarding the LPG pressure control when the LPG is supplied to the engine, the control device 6 ensures that the pressure detected by the second supply pressure gauge 73 is the required pressure of the engine 11 (eg, 5.0 to 6.0 MPa). The first pressure regulating valve 42 is controlled. The required pressure is a pressure required to properly inject fuel and further to smoothly operate the engine 11.

Even when supply of LPG to the engine 11 is stopped, pressure control of the LPG is performed. However, this pressure control is not always performed during the LPG supply stoppage. In binary fuel engines, for example, while using light oil. At this time, in preparation for starting supply of LPG to the engine 11, the LPG may be filled in the main flow path for the LPG engine. In engines using only LPG as fuel, it is performed, for example, during a waiting period. Here, in an engine using only LPG as fuel, purging with an inert gas may be performed during the waiting period.

Regarding the pressure control of the LPG in a period in which the shut-off valves 34 and 43 are closed and the supply of LPG is stopped, the control device 6 operates the pump 32 and at the same time the flow control valve 52 and / or flow rate The control valve 54 is opened. Accordingly, LPG in the storage tank 21 is returned to the storage tank 21 without going through the engine 11 through the fuel supply line 31, the first bypass line 51 and the fuel recovery line 41. Goes. And / or, LPG in the storage tank 21 is returned to the storage tank 21 without going through the engine 11 via the fuel supply line 31 and the second bypass line 53. The control device 6 is configured to maintain the supply pressure of LPG detected by the first supply pressure gauge 72 at a required pressure (for example, 5.0 to 6.0 MPa), and the rotational speed and flow rate control valve of the pump 32 ( 52, 54). Here, the first supply pressure gauge 72 is installed on the fuel supply line 31 at the downstream side of the pump 32 and the upstream side of the shutoff valve 34, and the branch point of the first bypass line 51 is likewise. Since it is arranged on the upstream side of the shut-off valve 34, it is possible to detect the pressure of LPG refluxed.

As an example, the rotational speed of the pump 32 is maintained at the lowest rotational speed, and the flow rate control valve 52 increases the opening degree when the detected pressure exceeds the required pressure, and opens the opening when the detected pressure is below the required pressure. Make it small.

In a situation in which such pressure control is executed, when the shut-off valves 34 and 43 are switched from the closed state to the open state, the supply pressure of LPG at the upstream side of the shut-off valve 34 initially reaches the required pressure. . Therefore, after that, only the step-up of the downstream side (especially between the shut-off valves 34 and 43) of the shut-off valve 34 is necessary, and the shut-off valves 34 and 43 are opened to promptly return to the engine 11 Can stabilize the supply pressure. When the pressure is stable, it can be switched to the operation using the LPG, so the operation using the LPG can be started smoothly and quickly.

The rotational speed of the pump 32 and the opening degree of the flow control valves 52 and 54 are used for pressure control when LPG is not supplied, and used for flow control when LPG is supplied. Since the control device 6 controls the pressure supplied to the engine 11 by operating the first pressure regulating valve 42, the number of revolutions of the flow control valves 52, 54 and the pump 32 is used to control the flow. While using, control of the supply pressure can also be realized simultaneously.

(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, as shown in FIG. 2, a flow meter 81 is installed in the fuel recovery line 41 on the upstream side of the shut-off valve 43, and flows out of the engine 11 through the fuel recovery line 41. The recovered flow rate Qo of the LPG to be used may be detected. That is, the control device 6, the pump 32 and the flow rate, so that the recovery flow rate (Qo) detected by the flow meter 81 is a predetermined value (V ') corresponding to the fuel consumption (Qe) of the engine 11 The control valve 52 may be controlled. In this case, the predetermined value V 'is, for example, a value obtained by multiplying the fuel consumption Qe of the engine 11 by a coefficient C of 0.1 to 0.50 in general.

Further, the predetermined values (V, V ') do not always have to be constant, and the control device 6 increases the predetermined values (V, V') when the number of revolutions of the pump 32 reaches the lowest number of revolutions. You may want to For example, in the configuration shown in Fig. 1, the predetermined value V may be increased to a flow rate within a range from 1.1 x Qe to 11.0 x Qe. Alternatively, in the configuration shown in Fig. 2, the predetermined value V 'may be increased to a flow rate within a range from 0.1 x Qe to 10.0 x Qe.

When the rotational speed of the pump 32 reaches the minimum rotational speed, the predetermined values V and V 'are constant, and when the flow control valve 54 provided in the second bypass line 53 is opened, The surplus obtained by subtracting predetermined values (V, V ') from the discharge flow rate (Q) of the pump (32) is conveyed to the service tank (22) through the second bypass line (53). Since the surplus is receiving heat from the pump 32, the temperature of the LPG in the service tank 22 rises. On the other hand, when a predetermined value (V, V ') is increased when the rotational speed of the pump 32 reaches the minimum rotational speed, LPG conveyed to the service tank 22 through the second bypass line 53 is reduced. I can do it. On the other hand, LPG passing through the engine 11 also increases by increasing the predetermined values V and V ', but such an increase is cooled by the cooler 44 installed in the fuel recovery line 41. Therefore, the temperature rise of LPG in the service tank 22 can be suppressed.

In addition, as shown in FIG. 2, the second supply pressure gauge 73 may be omitted. In this case, the first pressure regulating valve 42 is controlled using the detection pressure of the first supply pressure gauge 72.

Further, in the above embodiment, in the control of the pressure when the supply of LPG is stopped, the rotation speed of the pump 32 is controlled to a constant value of the lowest rotation speed, but the rotation speed of the pump 32 is controlled to a constant value different from that. It may be, or may be variably set in response to the temperature or the pressure of the base layer in the fuel tank 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.

1: ship 2: fuel tank
6: control unit 11: propulsion engine
31: fuel supply line 32: pump
34: shut-off valve 41: fuel return line
42: first pressure regulating valve 43: shut-off valve
51: first bypass line 52: flow control valve
53: second bypass line 54: flow control valve
72: first supply pressure gauge 81: flow meter
Qe: Fuel consumption Qi: Influent flow
Qo: Flux flow

Claims (2)

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,
A shut-off valve installed on the fuel supply line on the downstream side of the pump,
A fuel recovery line for recovering unused LPG from the engine to the fuel tank;
A bypass line branched from the fuel supply line between the pump and the shut-off valve and connected to the fuel recovery line or the fuel tank,
A flow control valve installed in the bypass line,
A pressure gauge installed on the fuel supply line at the downstream side of the pump and the upstream side of the shutoff valve to detect the pressure of LPG supplied from the pump;
A flow meter configured to detect a supply flow rate of LPG flowing into the engine through the fuel line or an LPG recovery flow rate from the engine through the fuel recovery line;
It is provided with a control device for controlling the number of revolutions of the pump and the flow control valve,
When the supply of LPG to the engine is stopped by closing the shut-off valve, the control unit rotates the pump so as to maintain the pressure of LPG detected by the pressure gauge at a required pressure required to operate the engine. And controlling one or more of the flow control valves,
When the LPG is supplied to the engine by opening the shut-off valve, the control device controls the number of revolutions of the pump and the flow rate control valve so that the flow rate detected by the flowmeter becomes a predetermined value corresponding to the fuel consumption of the engine. Vessel characterized in that to control.
According to claim 1,
A pressure regulating valve installed in the fuel recovery line at an upstream side of the confluence point of the bypass line,
When the LPG is supplied to the engine by opening the shut-off valve, the control device controls the pressure of the LPG supplied to the engine by operating the pressure regulating valve.

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