WO2021096049A1

WO2021096049A1 - Space-intensive lng fuel supply system for small ship

Info

Publication number: WO2021096049A1
Application number: PCT/KR2020/012412
Authority: WO
Inventors: 이윤혁; 김건웅; 이완태; 공태우; 김창수; 구병수
Original assignee: 주식회사 동화엔텍
Priority date: 2019-11-14
Filing date: 2020-09-15
Publication date: 2021-05-20
Also published as: KR102141086B1; JP7162380B2; KR102141086B9; CN113330244B; CN113330244A; JP2022517667A

Abstract

The objective of the present invention is to provide a space-intensive LNG fuel supply system for a small ship that is optimized for a fuel supply system of a small LNG-propelled ship and can satisfy all the conditions of stable fuel supply, operational convenience, and space intensiveness, so that a first free gas line and a second free gas line alongside an evaporation space of an LNG fuel tank can perform a buffer function.

Description

Space-intensive LNG fuel supply system for small ships

The present invention relates to a space-intensive LNG fuel supply system for a small ship, which is optimized for a small ship, especially among LNG fuel-propelled ships, and can concentrate the space occupied by the fuel supply system.

In the case of the LNG fuel supply system (FGSS) for small ships, gaseous natural gas is supplied to the engine after meeting a certain temperature and pressure required by the engine through a pump and heat exchanger to supply LNG as fuel. In other words, in the case of small ships, a pump pressurization method that supplies the required pressure to the engine by installing an LNG feed pump inside the LNG fuel tank to meet a certain pressure of natural gas to be supplied as fuel, and the LNG inside the tank without a pump After increasing to this required pressure, a method of supplying it to the engine through a heat exchanger was used.

And conventionally, the pressure line of the LNG fuel tank and the line that vaporizes and supplies the pressurized LNG to the engine are configured separately, and a line that can process boil off gas generated from the LNG fuel tank is configured separately. Therefore, when the pressure of the LNG fuel tank increases due to an increase in the amount of boil-off gas generated, it is released to the atmosphere.

In addition, in the case of small ships, it is composed of a non-pump type for the purpose of economy and convenience of operation, and a heat exchanger for pressure generation to generate the pressure of the LNG fuel tank and a heat exchanger for heating to meet the temperature required by the engine. Including the LNG fuel supply system. Here, heated ethylene glycol is used as a heat source of the heat exchanger, and cooling water flowing into the engine and circulating is used as a heat source for heating it.

The LNG fuel supply system for small ships must continuously supply natural gas at a constant pressure and temperature required by the engine despite the voyage in the wilderness and the sudden change in the engine's output.

Conventionally, when the engine's power changes rapidly, the pressure and temperature conditions required by the engine were not satisfied, and thus the engine efficiency was reduced and the situation was frequently switched to the diesel mode. This is because the proper pressure required for the engine is determined by the pressure of the LNG fuel tank, and the instantaneous pressure decreases at the same time as the flow rate of natural gas supplied to the engine increases when sailing in the wilderness or during rapid acceleration. At this time, to compensate for the lowered natural gas pressure, the internal pressure of the LNG fuel tank is pressurized to maintain the proper pressure, and the flow of natural gas due to the increase in the engine output compared to the time required to maintain the internal pressure of the LNG fuel tank. Because the pressure drop time of the LNG fuel tank according to the increase is faster, the engine efficiency decreases and the diesel mode is switched.

To prevent this, in recent years, LNG fuel supply systems have installed a buffer tank that can store a certain amount of natural gas at the front end of the engine to supply the natural gas in the butter tank corresponding to the engine's requirements to the engine. Is given.

However, due to the nature of the small ship, which has a large space limitation, there is a problem in that the above-described buffer tank is additionally disposed, so that additional space must be allocated. Therefore, it is necessary to develop a technology capable of improving the above-described buffer tank.

The present invention was conceived to solve the above problems, and is space-intensive for small ships capable of maximizing space utilization of small ships by dramatically reducing the space occupied by the conventional buffer tank while responding to bad weather voyages and sudden changes in engine output. Its purpose is to provide an LNG fuel supply system.

In addition, by integrating a line that vaporizes LNG and supplies it to the engine and a line that controls the pressure in the LNG fuel tank, the pressure of the LNG fuel tank can be constantly controlled and the pressure of the gas fuel supplied to the engine can be properly controlled. Its purpose is to provide a space-intensive LNG fuel supply system for small ships.

In addition, in the configuration in which the heat source for vaporization of natural gas supplied to the engine is supplied from the intermediate heat medium (ethylene glycol) of the engine jacket water, the variation of the flow rate and temperature change of the intermediate heat medium according to the change of the load of the engine It is largely generated, and in particular, an object thereof is to provide a space-intensive LNG fuel supply system for small ships capable of heating an intermediate heat medium to an appropriate temperature even when the engine load is low.

Along with this, other objects and advantages of the present invention will be described below, which is furthermore by means and combinations within the scope that can be easily deduced from the matters described in the claims of the present invention and the disclosure content of the embodiments thereof. It is added that it will be included in a wide range.

In order to achieve the above object, the space-intensive LNG fuel supply system for a small ship according to the present invention includes: a first free gas line guiding the gaseous fuel in the evaporation space above the LNG fuel tank to be supplied to a fuel consumer; A heater for heating gaseous fuel supplied from the first free gas line; A gas line for supplying gaseous fuel heated by the heater to a fuel consumer; A liquid line guiding the liquid fuel under the LNG fuel tank to be supplied to a fuel consumer; An evaporator for vaporizing liquid fuel supplied from the liquid line into gaseous fuel; And a second free gas line for joining the gaseous fuel supplied from the evaporator to the first free gas line, wherein the pipes on the first free gas line and the second free gas line have a cross-sectional area of the pipe on the gas line. The LNG fuel tank is formed relatively larger and maintains the same gas fuel pressure on the LNG fuel tank, the first free gas line, and the second free gas line, but relatively higher than the pressure on the gas line. It is characterized in that the first free gas line and the second free gas line together with the evaporation space of are capable of performing a buffer function.

Further, according to a preferred embodiment of the present invention, a pressure control valve is installed on the liquid line to keep the pressure of the fuel tank constant.

In addition, according to a preferred embodiment of the present invention, a pressure reducing valve for depressurizing gaseous fuel supplied to the heater is installed on the first free gas line, and a reverse flow of gaseous fuel passing through the heater is reduced in pressure at the front end of the pressure reducing valve. It characterized in that the check valve is installed to prevent the.

In addition, according to a preferred embodiment of the present invention, the heat source of the heat exchanger and the heater is supplied through a glycol supply line, the heat source is an intermediate heat medium heated by the jacket water of the fuel demand, and an electric heater on the glycol supply line It is characterized in that it is possible to maintain an appropriate temperature of the intermediate heat medium is installed.

As described above, according to the present invention, the following effects can be expected.

It is optimized for the fuel supply system of LNG-propelled small ships to satisfy both stable fuel supply, convenience of operation, and space intensive. Conventional buffer tanks can be excluded, and lines for LNG vaporization and pressure control are integrated. Through downsizing, the space occupied by the fuel supply system can be intensively utilized, and manufacturing costs are also reduced.

Along with this, other effects of the present invention are not only the matters described in the embodiments described above and the claims of the present invention, but also effects that can occur within the range that can be easily deduced from them, and the possibility of potential advantages contributing to industrial development. It is added that it will be covered by a wider range of people.

1 is a schematic configuration diagram of a space-intensive LNG fuel supply system for a small ship according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to the description, the advantages and features of the present invention and a method of achieving them will be apparent with reference to the embodiments described later in detail together with the accompanying drawings. In addition, terms used in the present specification are for explaining embodiments and are not intended to limit the present invention, and among these terms, the singular form includes the plural form unless specifically stated in the phrase, and a word indicating a direction in the description. It is to be noted that is for the purpose of understanding the explanation and can be changed according to the viewpoint.

The main technical idea of the present invention is that it is optimized for the fuel supply system of LNG-propelled small ships to satisfy both stable fuel supply, convenience of operation, and space intensive, and the conventional buffer tank can be excluded, and LNG vaporization and It is to provide a space-intensive LNG fuel supply system for small ships that can intensively utilize the space occupied by the fuel supply system through downsizing by integrating a line for pressure control.

A detailed description of a preferred embodiment according to the present invention for achieving this is as follows.

As shown in FIG. 1, the present invention provides a first free gas line 100, a heater 200, a gas line 300, a liquid line 400, an evaporator 500, and a second free gas line 600. It is made including.

The first free gas line 100 is a line that guides the supply of boil-off gas (BOG, hereinafter referred to as gaseous fuel) generated in the evaporation space above the LNG fuel tank to a fuel consumer such as a four-stroke dual fuel engine or a gas engine. to be. In addition, the heater 200 heats the gaseous fuel supplied from the first free gas line 100 to an appropriate temperature required by the fuel consumer, and the gas line 300 converts the gaseous fuel heated from the heater 200 to the fuel consumer. This is the supply line.

Subsequently, the liquid line 400 is a line guiding the LNG stored under the LNG fuel tank (hereinafter, referred to as liquid fuel) to be supplied to a fuel consumer. In addition, the evaporator 500 vaporizes the liquid fuel supplied from the liquid line 400 into gaseous fuel, and the second free gas line 600 converts the gaseous fuel supplied from the evaporator 500 into the first free gas line 100. It is a line that joins with.

In detail, the first free gas line 100, the heater 200, and the gas line 300 are lines for supplying gaseous fuel to the engine from the evaporation space of the LNG fuel tank, and the liquid line 400 and the evaporator 500 And the second free gas line 600 is connected to the first free gas line 100 to vaporize liquid fuel and supply it to the engine, and perform a buffer function through pressure control of the evaporation space and the line through which the gaseous fuel flows. It is the line that becomes.

A pressure control valve that maintains a constant pressure of the LNG fuel tank by supplying liquid fuel at about -160°C from the LNG fuel tank to the liquid line 400 at its own head pressure, and installing the liquid fuel on the liquid line 400 It is supplied to the evaporator (500, PBU Vaporizer) at a constant pressure and flow rate while passing through (410, Pressure Control Valve). In addition, the liquid fuel is vaporized through the evaporator 500 to become a low-temperature gaseous fuel of about -130°C to 50°C, and is supplied to the second free gas line 600, thereby reaching the evaporation space of the LNG fuel tank and the gas line 300. Supply becomes possible.

At this time, the pressure of the low-temperature gas fuel on the first and second

free gas lines

100 and 600 is controlled to be equally maintained, but relatively higher than the gas fuel pressure on the gas line 300, The pipes on the 1 free gas line 100 and the second free gas line 600 are formed relatively larger than the cross-sectional area of the pipe on the gas line 300 to perform a buffer function together with an evaporation space.

In addition, the low-temperature gaseous fuel supplied through the first free gas line 100 is heated to an appropriate temperature through the heater 200 to meet the temperature required by the fuel consumer and supplied to the gas line 300.

Here, as described above, the low temperature gas fuel pressure in the evaporation space, the first free gas line 100 and the second free gas line 600 is the same, and is 1 bar to 1.5 bar than the pressure of the hot gas fuel on the gas line 300 It is controlled to maintain pressure as high as bar.

This sets the set value of the pressure sensor on the gas line 300 to be relatively smaller than the pressure on the evaporation space and the first free gas line 100 and the second free gas line 600, and the first free gas line 100 ) It can be achieved in a configuration to reduce the gaseous fuel supplied through the pressure reducing valve 110 installed at the end of the heater 200 direction. In addition, it is preferable that a check valve is installed at the front end of the pressure reducing valve 110 on the first free gas line 100 to prevent the gaseous fuel from flowing back through the heater 200 by reducing pressure.

Meanwhile, the heat source of the heater 200 and the evaporator 500 is supplied through the glycol supply line 700. The glycol supply line 700 applies ethylene glycol, which is an intermediate heat medium for fuel demands such as an engine, and the intermediate heat medium is heated by jacket water (coolant) in a glycol water heater on the glycol supply line 700.

Here, fluctuations in the flow rate and temperature change of the intermediate heat medium occur greatly according to the change in the load of the fuel demand. In particular, in consideration of the difficulty of maintaining an appropriate temperature for the intermediate heat medium even when the load of the engine is low, the glycol supply line 700 ), an electric heater 710 is installed between the glycol water heater and the evaporator 500 to maintain an appropriate temperature of the intermediate heat medium.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the technical field to which the present invention belongs can make various modifications, changes, and substitutions within the scope not departing from the essential characteristics of the present invention. will be. And, as described above, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is limited by these embodiments and the accompanying drawings. It does not become. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims

A first free gas line guiding the gaseous fuel in the evaporation space above the LNG fuel tank to be supplied to a fuel consumer;

A heater for heating gaseous fuel supplied from the first free gas line;

A gas line for supplying gaseous fuel heated by the heater to a fuel consumer;

A liquid line guiding the liquid fuel under the LNG fuel tank to be supplied to a fuel consumer;

An evaporator for vaporizing liquid fuel supplied from the liquid line into gaseous fuel; And,

Includes; a second free gas line for joining the gaseous fuel supplied from the evaporator to the first free gas line, and

The pipes on the first and second free gas lines are formed relatively larger than the cross-sectional area of the pipes on the gas line,

By maintaining the same gas fuel pressure on the LNG fuel tank, the first free gas line, and the second free gas line, but relatively higher than the pressure on the gas line,

A space-intensive LNG fuel supply system for a small ship, characterized in that the first free gas line and the second free gas line can perform a buffer function together with the evaporation space of the LNG fuel tank.
The method of claim 1,

On the liquid line,

A space-intensive LNG fuel supply system for a small ship, characterized in that a pressure control valve for maintaining a constant pressure in the fuel tank is installed.
The method of claim 1,

On the first free gas line,

A pressure reducing valve for depressurizing the gaseous fuel supplied to the heater is installed,

A space-intensive LNG fuel supply system for small ships, characterized in that a check valve is installed at a front end of the pressure reducing valve to prevent reverse flow of gaseous fuel that has been depressurized and passed through the heater.
The method of claim 1,

The heat source of the heat exchanger and the heater is supplied through a glycol supply line,

The heat source is an intermediate heat medium that is heated by the jacket water of the fuel consumer,

A space-intensive LNG fuel supply system for a small ship, characterized in that an electric heater is installed on the glycol supply line to maintain an appropriate temperature of the intermediate heat medium.