KR102710832B1 - Fuel gas supply system and ship including the same - Google Patents

Abstract

A gas supply system according to the present invention comprises: a storage tank provided on a hull and storing liquefied gas; a vaporizer heating the liquefied gas in the storage tank and supplying the heated gas to a demander; a PBU heating the liquefied gas in the storage tank and circulating the heated gas to the storage tank; a liquefied gas supply line delivering the liquefied gas in the storage tank to the vaporizer; and a vaporization gas supply line delivering vaporization gas in the storage tank to the vaporizer; wherein the vaporization gas supply line can join the liquefied gas supply line upstream of the vaporizer.

Description

Fuel gas supply system and ship including the same

The present invention relates to a gas supply system and a ship equipped with the same.

A ship is a means of transportation that sails the ocean carrying large quantities of minerals, crude oil, natural gas, or containers. It is made of steel and moves by the thrust generated by the rotation of a propeller while floating on the waterline due to buoyancy.

These ships generate thrust by driving engines or gas turbines, etc. The engines use oil fuel such as gasoline or diesel to move a piston, which rotates a crankshaft through the reciprocating motion of the piston, which then rotates a shaft connected to the crankshaft to drive a propeller, while gas turbines burn fuel with compressed air, generate electricity by rotating turbine blades through the temperature/pressure of the combustion air, and transmit power to the propeller.

In addition, the LNG fuel supply method, which uses LNG as fuel to drive engines and turbines and other demand sources on LNG carriers that transport liquefied natural gas, a type of liquefied gas, is being used. Since LNG is a clean fuel and its reserves are more abundant than oil, the method of using LNG as fuel on demand sources is being applied to ships other than LNG carriers.

When supplying LNG or LNG boil-off gas to a demand source such as an engine or turbine, the LNG or LNG boil-off gas must be heated or pressurized to meet the temperature and pressure required by the demand source, so a pressurizing means such as a compressor and a heating means such as a heater must be provided.

Meanwhile, a system for supplying liquefied natural gas to an engine is provided with a storage tank for pressurizing and storing liquefied natural gas. When boil-off gas is generated from the pressurized liquefied natural gas, the pressure inside the storage tank may increase until the maximum allowable pressure of the storage tank is reached. Therefore, in order to reduce the pressure of the storage tank, the boil-off gas must be discharged to the outside, or the discharged gas must be combusted through a gas burner. In this case, the operation and maintenance of the pressure of the storage tank may become complicated. On the other hand, when the liquefied natural gas is discharged to the outside from the storage tank, the pressure inside the storage tank may decrease and the liquefied natural gas may not be supplied to the vaporizer. Therefore, in order to maintain a constant pressure inside the storage tank, the liquefied natural gas stored in the storage tank must be vaporized and the vaporized liquefied natural gas must be circulated and injected into the storage tank.

In this way, in order to match the temperature and pressure conditions of the demand location with the temperature and pressure conditions of the storage tank, a pressurizing means and a heating means must be provided on the ship. However, as the number of pressurizing means and heating means provided on the ship decreases the space efficiency on the ship and the installation and operation costs of the fuel supply system increase, it is necessary to configure the system so that the pressurizing means and heating means are provided in small numbers.

The present invention has been created to solve the problems of the prior art as described above, and an object of the present invention is to provide a gas supply system that integrates lines for liquefied gas and liquefied gas vaporization gas and integrates a liquefied gas vaporizer and a liquefied gas vaporization gas heater.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those of ordinary skill in the art from the description below.

A gas supply system according to the present invention comprises: a storage tank provided on a hull and storing liquefied gas; a vaporizer heating the liquefied gas in the storage tank and supplying the heated gas to a demander; a PBU heating the liquefied gas in the storage tank and circulating the heated gas to the storage tank; a liquefied gas supply line delivering the liquefied gas in the storage tank to the vaporizer; and a vaporization gas supply line delivering vaporization gas in the storage tank to the vaporizer; wherein the vaporization gas supply line can join the liquefied gas supply line upstream of the vaporizer.

Specifically, it includes a PBU line for delivering liquefied gas from the storage tank to the PBU, and the liquefied gas supply line can be branched from the PBU line.

Specifically, it may include a block valve provided on the PBU line.

Specifically, it may include a pressure regulating valve provided downstream of the carburetor.

Specifically, it may include a blocking valve and a check valve provided on the evaporation gas supply line.

Specifically, it comprises a fruit heater for heating the fruit supplied to the vaporizer or the PBU,

A three-way valve may be included to branch the fruit line to pass through the fruit heater.

Specifically, the fruit heater can heat the fruit using steam, jacket cooling water, or electricity.

A vessel according to the present invention may be equipped with the gas supply system.

The gas supply system of the present invention has the following effects.

The gas supply system according to the present invention can minimize the installation cost of the system and improve space efficiency within a ship by integrating lines for liquefied gas and liquefied gas vaporization gas and integrating a vaporizer for liquefied gas vaporization gas and a heater for liquefied gas vaporization gas.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Figure 1 is a conceptual diagram illustrating a gas supply system according to one embodiment of the present invention.
Figure 2 is a conceptual diagram illustrating a gas supply system according to another embodiment of the present invention.
Figure 3 is a conceptual diagram showing a gas supply system according to another embodiment of the present invention.

The purpose, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings. In this specification, when adding reference numerals to components in each drawing, it should be noted that, as much as possible, the same components are given the same numerals even if they are shown in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, in this specification, liquefied gas may be used to mean all gaseous fuels that are generally stored in a liquid state, such as liquefied natural gas (LNG), liquefied petroleum gas (LPG), ethylene, ammonia, etc., and may refer to LNG (Liquefied Natural Gas) as an example, and cases where it is not in a liquid state due to heating or pressurization may also be conveniently expressed as liquefied gas. This can also be applied to boil-off gas.

Please note that below, high pressure (HP), low pressure (LP), high temperature, and low temperature are relative and do not represent absolute values.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. FIG. 1 is a conceptual diagram showing a gas supply system according to one embodiment of the present invention, and FIG. 2 is a conceptual diagram showing a gas supply system according to another embodiment of the present invention.

Figure 1 is a conceptual diagram showing a gas supply system (1) according to one embodiment of the present invention.

Referring to FIG. 1, a gas supply system (1) according to the present invention includes a storage tank (10), a vaporizer (20), a PBU (30), an engine (40), and a buffer tank (50), and can be used in a ship using a heterogeneous fuel engine or a floating structure such as an FPSO (Floating, Production, Storage and Offloading). Here, the heterogeneous fuel engine includes all engines using heterogeneous fuel regardless of the engine type, such as a low-pressure gas injection type or a high-pressure gas injection type.

The storage tank (10) stores liquefied gas at normal pressure inside and allows an increase in internal pressure due to the generation of evaporated gas, etc., and to this end, it may be formed of a material and structure that allows an increase in internal pressure, and may be formed of a material that can sufficiently withstand the extremely low temperature of the liquefied gas, and an insulation member may be installed to block heat loss and entry.

The storage tank (10) may be provided in multiple units, and the storage tanks (10) may be connected to each other through a pipe through which liquefied gas or evaporated gas may move. In order to minimize the risk of gas leakage by blocking contact with the outside, the storage tanks (10) and the pipe connecting the storage tanks (10) to each other may be surrounded by a tank connection part (not shown) that forms a gas-tight space. The pipe connecting the storage tanks (10) to each other is surrounded by a tank connection part (not shown), so that even if a double wall pipe is not applied, the risk of gas leakage in the gas supply system (1) can be minimized.

In general, in the case of a liquefied gas leak, a vaporizer (20), etc., is configured as a skid in order to prevent damage to the hull in the event of a liquefied gas leak in the liquefied gas pipe. The skid is placed in a fuel gas supply system (FGSS) room or a room that can replace it, and a drip tray (not shown) can be installed along the path along which the pipe is installed. In the present invention, the storage tank (10) and the pipe connecting the storage tank (10) to each other are surrounded by a tank connection part (not shown), thereby replacing the fuel supply system room and the drip tray, thereby simplifying the system.

The gas supply system (1) is provided with a vapor line (not shown) that connects the storage tanks (10) to each other so that the vaporized gas can move between the storage tanks (10), thereby preventing the pressure of a specific storage tank (10) from rapidly increasing or decreasing. Furthermore, the operation diversity of the storage tanks (10) can be secured by controlling one storage tank (10) to be 100% filled with liquefied gas, or by controlling two storage tanks (10) to be 50% filled with liquefied gas each.

The vaporizer (20) is a device that receives liquefied gas delivered to the PBU (30) through the liquefied gas supply line (L1) and vaporizes the liquefied gas, or receives boil-off gas (BOG) through the boil-off gas supply line (L2) and heats the boil-off gas so that the boil-off gas matches the temperature conditions of the engine (40). Upstream of the vaporizer (20), the boil-off gas supply line (L2) joins the liquefied gas supply line (L1) so that both the liquefied gas and the boil-off gas are supplied to the vaporizer (20), so that the vaporizer (20) can heat the liquefied gas and the boil-off gas.

A shell-and-plate type heat exchanger utilizes the vortex effect, but if a shell-and-plate type heat exchanger is used to supply fuel to an engine, pressure fluctuations may occur in the vaporized fuel. Therefore, in the case of a carburetor (20) used before supplying fuel to an engine, a shell-and-tube type heat exchanger is used.

A PBU (pressure build-up unit, 30) is installed in a PBU line (L3) connected to a storage tank (10) and heats the liquefied gas stored in the storage tank (10) to vaporize the liquefied gas and return it to the storage tank (10). The PBU (30) can deliver the vaporized liquefied gas to the storage tank (10) and maintain it within a certain pressure range within the storage tank (10).

When liquefied gas is discharged to the outside from the storage tank (10), the pressure inside the storage tank (10) decreases, and as a result, the liquefied gas may not be supplied to the vaporizer (20). However, the PBU (30) vaporizes the liquefied gas and returns it to the storage tank (10), thereby preventing a decrease in the pressure inside the storage tank (10) and facilitating the supply of liquefied gas to the vaporizer (20).

In this way, the liquefied gas in the storage tank (10) can be transferred to the PBU (30) only by the water head pressure of the storage tank (10). When the PBU (30) heats the liquefied gas and transfers it to the storage tank (10) to pressurize the storage tank (10), the liquefied gas in the storage tank (10) can be supplied to the vaporizer (20), and the vaporized evaporated gas can be supplied to the engine (40) through the vaporizer (20).

If the PBU (30) is a shell & tube type, the single path type is expensive and has significantly poor maintainability, so it is often a two path type. If the path through which the liquefied gas is vaporized is a two-pass type, there is a possibility that a vapor pocket will occur, and since a vapor pocket may occur when the ship is heeled due to the U-shaped tube, in order to prevent the occurrence of a vapor pocket in the liquefied gas, it is preferable that the PBU (30) be a single-pass type shell & plate type heat exchanger in the gas supply system (1) of the present invention. Furthermore, the shell & plate type heat exchanger has a relatively compact design, making it easy to arrange in a ship and to secure the required water head.

The gas supply system (1) according to the present invention may be provided with a first block valve (60) on a liquefied gas supply line (L1), a second block valve (61) on a vaporized gas supply line (L2), and a third block valve (62) on a PBU line (L3). The block valves (60, 61, 62) are valves for blocking flow and may be butterfly valves, ball valves, or gate valves.

In particular, when the third block valve (62) is a valve that controls flow, such as a throttle valve, the differential pressure generated at the valve in the low flow area may become excessive, which may prevent the liquefied gas from flowing to the PBU (30). Therefore, it is preferable that the third block valve (62) be a flow-cutting valve. Instead of a flow-control valve, a flow-cutting valve is provided in front of the PBU (30) to control the flow in an on/off manner, thereby reducing the pressure loss in the pipe during operation of the PBU (30), thereby lowering the required head level of the PBU (30).

In addition, the gas supply system (1) according to the present invention may be provided with a pressure control valve (PCV; Fuel Gas Press Control Valve, 70) on the liquefied gas supply line (L1) in front of the vaporizer (20), or may be provided with a pressure control valve (70) on the engine line (L4) in the rear of the vaporizer (20).

In the case where a pressure regulating valve (70) is provided at the rear end of the vaporizer (20), since gaseous fuel passes through the pressure regulating valve (70), the pressure regulating valve (70) processes the gaseous fuel, and thus the pressure regulating valve (70) can be made smaller. Accordingly, compared to the case where the pressure regulating valve (70) is provided at the front end of the vaporizer (20), when the pressure regulating valve (70) is provided at the rear end of the vaporizer (20), the size of the pressure regulating valve (70) can be made smaller, which reduces equipment costs and increases space efficiency within the ship. Therefore, it is preferable that the pressure regulating valve (70) be provided at the rear end of the vaporizer (20).

In addition, the gas supply system (1) according to the present invention may be equipped with both a cutoff valve (80) and a check valve (81) on the evaporation gas supply line (L2). The flow of the evaporation gas supply line (L2) is controlled by the cutoff valve (80), and when the liquefied gas flows in the evaporation gas supply line (L2), the backflow of the liquefied gas can be prevented by the check valve (81). In addition, the liquefied gas supply line (L1) may also be equipped with a check valve (not shown), and the backflow of the liquefied gas can be prevented by the check valve.

In addition, the gas supply system (1) according to the present invention may be equipped with a fruit supply line (L5), and a 3-way valve (90), a fruit tank (100), a fruit pump (110), and a fruit heater (120) may be equipped on the fruit supply line (L5). The fruit (heat medium) moves along the fruit supply line (L5), and after the fruit is heated in the fruit heater (120), the liquefied gas or the evaporated gas may be heated in the vaporizer (20) and the PBU (30) via the vaporizer (20) and the PBU (30).

In the fruit heater (120) above, the fruit can be heated by steam, jacket cooling water (JCW, engine coolant), or electricity. The fruit heater (120) may be provided in multiples, and both a fruit heater (120) that heats the fruit using jacket cooling water and a fruit heater (120) that heats the fruit using electricity may be provided.

In addition, since the safety of the gas supply system (1) may be reduced when the temperature of the fruit is controlled by adjusting the load of the fruit heater (120), a three-way valve (90) that can control the temperature of the fruit in the fruit supply line (L5) by controlling the flow toward the fruit heater (120) according to the temperature of the fruit may be provided in the fruit supply line (L5). A fuel line (L6) may be branched from the three-way valve (90).

Figure 2 is a conceptual diagram illustrating a gas supply system according to another embodiment of the present invention.

The gas supply system (1) according to the present invention may be equipped with a buffer tank (50) at the rear end of the vaporizer (20). Since the buffer tank (50) has an empty space therein to accommodate the vaporized gas, it may reduce pressure fluctuations in the rear end line of the vaporizer (20). Of course, as shown in Fig. 1, the gas supply system (1) according to the present invention may be equipped with a buffer tank (50) at the front end of the vaporizer (20).

Figure 3 is a conceptual diagram showing a gas supply system according to another embodiment of the present invention.

Referring to FIG. 3, the gas supply system (1) according to the present invention has a fruit supply line (L5) branched into a vaporizer fruit line (L7) connected to a vaporizer (20) and a PBU fruit line (L8) connected to a PBU (30), so that the vaporizer fruit line (L7) and the PBU fruit line (L8) can be connected in parallel. Of course, as in FIG. 1, the gas supply system (1) can have the vaporizer fruit line (L7) and the PBU fruit line (L8) of FIG. 3 connected in series like the fruit supply line (L5) of FIG. 1.

In this way, the gas supply system (1) according to the present invention can minimize the installation cost of the system and improve the space efficiency within the ship by integrating the lines of liquefied natural gas and liquefied natural gas boil-off gas and integrating the vaporizer of the liquefied natural gas and the heater of the liquefied natural gas boil-off gas.

The present invention is not limited to the embodiments described above, and may include a combination of the above embodiments or a combination of at least one of the above embodiments and a known technology as another embodiment.

Although the present invention has been described above with reference to embodiments of the present invention, this is merely an example and does not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various combinations or modifications and applications not illustrated in the embodiments are possible without departing from the essential technical contents of the present embodiments. Accordingly, technical contents related to modifications and applications that can be easily derived from the embodiments of the present invention should be interpreted as being included in the present invention.

1: Gas supply system 10: Storage tank
20: Carburetor 30: PBU
40: Engine 50: Buffer Tank
60, 61, 62: Block valve 70: Pressure regulating valve
80: Shut-off valve 81: Check valve
90: 3 way valve 100: Fruit tank
110: Fruit pump 120: Fruit heater
L1: Liquefied gas supply line L2: Evaporated gas supply line
L3: PBU line L4: Engine line
L5: Fruit line L6: Oil line
L7: Carburetor fruit line L8: PBU fruit line

Claims (8)

A storage tank provided on the hull to store liquefied gas;
A vaporizer that heats the liquefied gas in the above storage tank and supplies it to the demand source;
PBU that heats the liquefied gas in the above storage tank and circulates it into the above storage tank;
A liquefied gas supply line that delivers the liquefied gas of the above storage tank to the above vaporizer; and
Including an evaporation gas supply line that transfers the evaporation gas of the above storage tank to the above vaporizer;
The above-mentioned evaporative gas supply line joins the above-mentioned liquefied gas supply line upstream of the above-mentioned vaporizer,
Including a PBU line for delivering liquefied gas from the above storage tank to the above PBU,
The above liquefied gas supply line branches off from the upstream of the PBU of the above PBU line,
A gas supply system including a carburetor and a fruit line passing through the PBU. delete In the first paragraph,
A gas supply system including a block valve provided on the above PBU line. In the first paragraph,
A gas supply system including a pressure regulating valve provided downstream of the above-mentioned vaporizer. In the first paragraph,
A gas supply system including a shut-off valve and a check valve provided on the above-mentioned evaporation gas supply line. In the first paragraph,
Including a fruit heater for heating the fruit supplied to the above vaporizer or the PBU,
A gas supply system comprising a three-way valve for branching the fruit line to bypass the fruit heater. In paragraph 6,
The above fruit heater is a gas supply system that heats the fruit using steam, jacket cooling water or electricity. A vessel equipped with a gas supply system according to any one of paragraphs 1, 3 to 7.

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