Fuel supply system

Abstract

A fuel supply system according to the present invention comprises: a fuel tank in which fuel gas is stored, the fuel tank being capable of accommodating the boil-off gas of the fuel gas and purge gas that can be used for a purging operation; a fuel supply line for supplying fuel from the fuel tank to an engine; a purging gas generation part for generating purging gas suitable for use in the purging operation by using a mixed gas of the boil-off gas and the purge gas accommodated in the fuel tank; a purging line for purging the engine and a pipe with the purging gas generated by the purging gas generation part; and a recovery line connected to the purging line so that the purging gas used for the purging operation is recovered in the fuel tank.

Description

fuel supply system

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0129794, filed September 26, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a fuel supply system, and more particularly, to a fuel supply system that aims to solve the problems of toxic fuel gas emission and purge gas loss through closed-loop purging of purge gas.

[0004] In a typical fuel system, fuel used to power the engine remains in the engine or pipes. For example, if methanol is used as a fuel, it poses a fire and explosion risk if left in the engine or pipes due to its low flashpoint. For another example, if ammonia is used as a fuel, a leak can pose a toxic risk. Therefore, a fuel supply system must be installed to drain any fuel remaining in these engine systems.

[0005] Fig. 1 is a drawing of a conventional fuel supply system (1). Generally, the fuel supply system is configured to push out and discharge fuel remaining inside the engine and pipes using an inert gas such as nitrogen. Fuel in the fuel tank (4) is supplied to the engine (2) through the fuel supply line (8) and used for power generation. When the engine is stopped and purging operation is performed, purge gas is supplied through the purge gas supply line (6) to purge the engine (2) and the pipes. Note that during the purging operation, the fuel shut-off valve (7) is closed to prevent the purge gas from flowing into the fuel supply line (8). The purge gas used for the purging operation, together with the remaining fuel inside the engine and the pipes, flows into the fuel tank (4) through the fuel return line (3). Accordingly, the pressure inside the fuel tank (4) increases, and to prevent overpressure (e.g., 0.2 bar), the fuel gas and purge gas inside the fuel tank (4) are discharged to the atmosphere through the vent line (5).

[0006] Since the purge gas is exhausted and consumed, new purge gas must be resupplied through the purge gas supply line (6) for the next purging operation, which causes the problem of purge gas loss.

[0007] Accordingly, the present invention is intended to solve the problems of conventional fuel supply systems, and to provide a fuel supply system that forms a closed loop in which purge gas circulates within the fuel system, thereby preventing purge gas loss.

[0008] A fuel supply system according to one embodiment of the present invention comprises: a fuel tank in which fuel gas is stored; the fuel tank being capable of accommodating evaporation gas of the fuel gas and purge gas that can be used for purging work, and a fuel supply line for supplying fuel from the fuel tank to an engine; a purging gas generating unit for generating a purging gas suitable for use in a purging work using a mixed gas of the evaporation gas and the purge gas stored in the fuel tank; a purging line for purging an engine and a pipe with the purging gas generated in the purging gas generating unit; and a recovery line connected to the purging line for recovering the purging gas used in the purging work to the fuel tank.

[0009] According to one embodiment of the present invention, the purging line may include a supply valve for controlling the flow rate of the purging gas.

[0010] According to one embodiment of the present invention, the fuel tank may include a purge gas supply line connected to the fuel tank and supplying the purge gas.

[0011] According to one embodiment of the present invention, the fuel tank may include a vent line connected to the fuel tank to discharge the internal mixed gas of the fuel tank.

[0012] According to one embodiment of the present invention, the purging gas generating unit may include a compressor that compresses the mixed gas stored in the fuel tank; and a buffer tank provided at the rear end of the compressor that temporarily stores the mixed gas compressed by the compressor.

[0013] According to one embodiment of the present invention, the purging gas generating unit may include a compressor that compresses the mixed gas stored in the fuel tank; and a purging gas purifier provided at the rear end of the compressor that separates the evaporation gas from the compressed mixed gas.

[0014] According to one embodiment of the present invention, the evaporated gas or liquid fuel separated from the purging gas purifier can be recovered to the fuel tank through a drain line.

[0015] According to one embodiment of the present invention, the purging gas purifier may include an absorption purifier using an absorbent; a wastewater tank storing the absorbent used in the absorption purifier; and a degassing device separating fuel absorbed from the absorbent in the wastewater tank.

[0016] According to one embodiment of the present invention, the purging gas purifier may include an adsorption-type purifier using an adsorbent; and an adsorption-type supply valve provided between the compressor and the adsorption-type purifier to control the supply pressure of the mixed gas to the adsorption-type purifier.

[0017] According to one embodiment of the present invention, the purging gas purifier may include a heat exchanger for cooling the mixed gas compressed in the compressor; and a gas-liquid separator provided at a rear end of the heat exchanger for separating liquid fuel and purging gas from the mixed gas.

[0018] According to one embodiment of the present invention, the purging gas purifier may further include a buffer tank provided at the rear end of the gas-liquid separator to temporarily store the purging gas separated in the gas-liquid separator.

[0019] According to one embodiment of the present invention, in the recovery line, residual fuel can be recovered together with the purging gas used in the purging operation.

[0020] According to one embodiment of the present invention, a pressure reducing valve for reducing the pressure of the purging gas used in the purging operation may be provided in the recovery line.

[0021] According to one embodiment of the present invention, the evaporation gas of the fuel gas may be methanol or ammonia, the purge gas may be nitrogen, and the purging gas may be a mixed gas of methanol or ammonia and nitrogen or nitrogen gas.

[0022] According to another embodiment of the present invention, a fuel supply system includes: a fuel tank in which fuel gas is stored; the fuel tank can accommodate evaporation gas of the fuel gas and a purge gas that can be used for purging work, and a fuel supply line for supplying fuel from the fuel tank to an engine; a purging gas generation unit that generates a purging gas suitable for use in a purging work using a mixed gas of the evaporation gas and the purge gas stored in the fuel tank; a drain line that recovers the evaporation gas or liquid fuel separated from the purging gas generation unit into the fuel tank; a purging line that purges an engine and a pipe with the purging gas generated from the purging gas generation unit; and a recovery line that is connected to the purging line and recovers the purging gas used in the purging work into the fuel tank.

[0023] According to the present invention, the purging operation can be performed without loss of the purge gas because the purge gas flows along a closed loop circulating inside the fuel system.

[0024] According to the present invention, since resupply of purge gas is unnecessary, the problem of the pressure inside the fuel tank becoming excessively high due to continuous supply of purge gas, and thus toxic fuel gas having to be frequently discharged together with the purge gas, can be solved.

[0025] Figure 1 is a drawing of a conventional fuel supply system.

[0026] Figure 2 illustrates a fuel supply system according to the present invention.

[0027] Figure 3 illustrates a fuel supply system according to a first embodiment of a gas generating unit for purging of the present invention.

[0028] Figure 4 illustrates a fuel supply system according to the second embodiment of the purging gas generating unit of the present invention.

[0029] Figure 5 illustrates a fuel supply system according to the second embodiment of the purging gas generating unit of the present invention.

[0030] Figure 6 illustrates a fuel supply system according to the second-third embodiment of the purging gas generating unit of the present invention.

[0031] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components are given the same reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, detailed descriptions of known components or functions will be omitted if they are deemed to hinder understanding of the embodiments of the present invention.

[0032] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of embodiments of the present invention. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0033] In this specification, the forward / backward, left / right, and up / down directions are referred to for convenience of explanation and may be orthogonal to each other. However, these directions are determined relative to the direction in which the gas cutting device is positioned, and the up / down direction does not necessarily mean the vertical direction.

[0034] Referring to FIG. 1, a fuel supply system (100) according to an embodiment of the present invention will be described. The fuel supply system (100) includes a fuel tank (10) in which fuel gas is stored; the fuel tank (10) can accommodate evaporation gas of the fuel gas and purge gas that can be used in a purging operation, and a fuel supply line (340) for supplying fuel from the fuel tank (10) to an engine; a purging gas generating unit (200) for generating a purging gas suitable for use in a purging operation using the evaporation gas and purge gas stored in the fuel tank (10); a purging line (310) for purging an engine and pipes with the purging gas generated in the purging gas generating unit (200); and a recovery line (320) connected to the purging line (310) for recovering the purging gas used in the purging operation to the fuel tank (10).

[0035] Fuel gas can be used to encompass all gaseous fuels typically stored in a liquid state, such as liquefied petroleum gas (LPG), ethylene, ammonia, methanol, and hydrogen. For convenience, fuels that are no longer in a liquid state due to heating or pressurization can also be referred to as fuel gas. This also applies to evaporative gases.

[0036] The purge gas may be an inert gas such as nitrogen or argon, but is not limited thereto. Purging gas is used herein to distinguish it from purge gas. Purging gas is a gas actually used in the purging operation, and refers to gas generated in the purging gas generation unit (200) and flowing along the purging line (310). The purging gas may be a mixture of evaporation gas and purge gas, or may be pure purge gas. This may vary depending on the processing method of the purging gas generation unit (200) described later.

[0037] Fuel gas is stored in the fuel tank (10), and the evaporation gas of the fuel gas and the purge gas that can be used for purging can be accommodated together at the upper part of the fuel tank. A purge gas supply line (330) is connected to the fuel tank (10) to supply the purge gas to the fuel tank (10). This purge gas may be used to prevent a decrease in pressure within the fuel tank (10). A regulator (12) for controlling the flow rate of the purge gas may be provided in the purge gas supply line (330). When the amount of purge gas for maintaining the pressure of the fuel tank (10) is insufficient, the regulator (12) may be automatically opened to allow additional purge gas to be supplied through the purge gas supply line (330) to prevent structural damage to the fuel tank (10).

[0038] Since the purge system according to the present invention is characterized by forming a closed loop of purge gas, once the purge gas is supplied to the fuel tank (10) through the purge gas supply line (330), there is no need to re-supply the purge gas thereafter.

[0039] In addition, since resupply of purge gas is unnecessary, the problem of the pressure inside the fuel tank (10) becoming excessively high due to continuous supply of purge gas, and the need to frequently discharge toxic fuel gas (e.g., methanol or ammonia) together with the purge gas can be solved.

[0040] The purging gas generation unit (200) uses the mixed gas within the fuel tank (10) to generate purging gas suitable for use in purging operations. The liquefied fuel or separated evaporated gas from the purging gas generation unit (200) can be recovered to the fuel tank (10) via a drain line (350). The specific configuration thereof will be described in detail with reference to FIGS. 3 to 6.

[0041] The purging gas generated in the purging gas generating unit (200) is used to purge the interior of the engine and pipes. According to Fig. 2, the purging line (310) is illustrated as a line that passes from the pipe connected to the purging gas generating unit (200) to some pipes of the fuel supply line (340) and the interior of the engine (20), but it can be understood as a line that circulates equipment and pipes that require purging work. A supply valve (30) is provided in the purging line (310) to control the flow rate of the purging gas.

[0042] According to FIG. 2, a heat exchanger (16) and a fuel shutoff valve (18) are shown in the fuel supply line (340), but may be replaced with other configurations depending on the fuel system. A fuel drain line (332) for draining fuel when the engine is stopped may be provided in the fuel supply line (340).

[0043] A vent line (360) is connected to the fuel tank (10) and can discharge the internal mixed gas of the fuel tank (10). A relief valve (14) can be provided in the vent line (360), thereby preventing the pressure inside the fuel tank (10) from becoming excessive.

[0044] The recovery line (320) is connected to the purging line (310) and is a line that recovers the purging gas used in the purging operation to the fuel tank (10). In the recovery line (320), the remaining fuel can be recovered together with the purging gas used in the purging operation. Therefore, the purge gas flows along the fuel tank (10), the purging gas generator (200), the purging line (310), and the recovery line (320) and is recovered back to the fuel tank (10). This closed-loop flow of the purge gas is illustrated in Fig. 2. Since the purge gas flows along the closed loop, the purging operation can be performed without loss of the purge gas (through reuse). A pressure reducing valve (50) for reducing the pressure of the purging gas used in the purging operation can be provided in the recovery line (320).

[0045] <Example 1>

[0046] Fig. 3 illustrates a first embodiment of a gas generator (200) for purging. The gas generator (200) for purging may include a compressor (210) for compressing a mixed gas stored in a fuel tank; and a buffer tank (220) provided at the rear end of the compressor (210) for temporarily storing the mixed gas compressed by the compressor (210).

[0047] The compressor (210) compresses a mixture of evaporation gas and purge gas. The high-pressure mixed gas is used as a purging gas, flows along the purging line (310) and the recovery line (320), and can be returned to the fuel tank (10). The high-pressure mixed gas may contain some evaporation gas of the fuel gas, but if it is lower than the allowable standard (for example, 5% or less in the case of methanol), the purging operation can also be performed with the mixed gas containing the evaporation gas of the fuel gas.

[0048] The buffer tank (220) serves to temporarily store high-pressure purging gas. The amount of purging gas used for purging is small compared to the amount of the entire purge gas including the fuel tank (10), and therefore can be sufficiently accommodated in the buffer tank (220). The mass of purge gas that the fuel tank (10) can accommodate (for example, at least 440 kg) is more than four times the mass of purging gas used for a single purging (for example, at most 110 kg). Conventionally, the purging gas (for example, 110 kg) was supplied through the purge gas supply line (6) each time a purging operation was performed, but in the present embodiment, the purging gas is initially supplied to the fuel tank (10) once through the purge gas supply line (330), and then stored in the buffer tank (220), recovered to the fuel tank (10) after the purging operation, and the purge gas stored in the buffer tank (220) can be recycled. Figures such as 440 kg and 110 kg are examples and are not limiting.

[0049] Since the high-pressure purging gas is temporarily stored in the buffer tank (220), the capacity of the compressor (210) can be reduced. That is, the high-pressure purging gas is stored in advance in the buffer tank (220), and during the purging operation, the high-pressure purging gas is additionally generated in the compressor (210) and discharged together. Therefore, since the buffer tank (220) is provided, there is an advantage in that the pressure of the purging gas can be sufficiently maintained even if the capacity of the compressor is reduced.

[0050] When the compressor (210) is turned for a long time, the gas inside the fuel tank (10) is stored in large quantities in the buffer tank (220), so that the amount of gas inside the fuel tank (10) decreases, thereby reducing the pressure in the fuel tank (10). In addition, when the compressor (210) is turned for a short time, the gas inside the fuel tank (10) is stored in small quantities in the buffer tank (220), so that there is no significant change in the amount of gas inside the fuel tank (10), thereby allowing the pressure in the fuel tank (10) to be maintained. In this way, the pressure inside the fuel tank (10) can be controlled by controlling the use of the compressor (210).

[0051] <Example 2>

[0052] Figures 4 to 6 illustrate a second embodiment of a purging gas generator (200). The purging gas generator (200) includes a compressor (210) for compressing a mixed gas stored in a fuel tank (10); and a purging gas purifier (230) provided at the rear end of the compressor (210) for separating an evaporation gas from the compressed mixed gas. Since the evaporation gas is separated in the purging gas purifier (230), the purity of the purge gas can be increased, and the allowable standard for the purging gas (for example, 5% or less in the case of methanol) can be satisfied. The high-purity purging gas passes through the purging gas purifier (230) and flows along the purging line (310) and the recovery line (320) and is then recovered back into the fuel tank (10).

[0053] According to the specific purification method of the gas purifier (230) for purging, it is divided into Embodiment 2-1 (absorption type purifier), Embodiment 2-2 (adsorption type purifier), and Embodiment 2-3 (gas-liquid separator).

[0054] <Example 2-1>

[0055] Referring to FIG. 4, the purging gas purifier (230) may include an absorption purifier (240) using an absorbent. For example, when the evaporated gas of the fuel gas is methanol or ammonia and the purge gas is nitrogen, the absorbent may be used to generate high-purity nitrogen gas. The absorbent used in the absorption purifier (240) is stored in the wastewater tank (242). To recover the absorbed fuel, a degassing device (244) that heats the absorbent in the wastewater tank (242) to separate the fuel may be used. In addition, the absorbent in the wastewater tank (242) may be supplied to the absorption purifier (240) using an absorbent pump (246). The separated evaporated gas may be recovered to the fuel tank (10) through a drain line (350). A drain valve (40) may be provided in the drain line (350).

[0056] The purging gas purifier (230) of the second embodiment may further include a buffer tank (264) provided at the rear end of the absorption purifier (240) to temporarily store the high-purity purging gas separated from the absorption purifier (240). Since the buffer tank (264) has the same function as the buffer tank (220) described above, its description is omitted.

[0057] <Example 2-2>

[0058] Referring to FIG. 5, the purging gas purifier (230) may include an adsorption purifier (250) utilizing an adsorbent. For example, when the evaporated gas of the fuel gas is methanol or ammonia and the purge gas is nitrogen, the adsorbent may be used to generate high-purity nitrogen gas. An adsorption supply valve (252) may be provided between the compressor (210) and the adsorption purifier (250) to control the supply pressure of the mixed gas to the adsorption purifier (250).

[0059] When the compressor (210) is operated, the adsorption supply valve (252) is opened, and the supply valve (30) and the drain valve (40) are closed, a high-pressure environment can be created inside the adsorption purifier (250). On the other hand, when the compressor (210) is stopped, the adsorption supply valve (252) is closed, and the supply valve (30) or the drain valve (40) is opened, a low-pressure environment can be created inside the adsorption purifier (250). When a low-pressure environment is created in this way, the evaporation gas can be desorbed from the adsorbent. The desorbed evaporation gas can be recovered to the fuel tank (10) through the drain line (350). A drain valve (40) can be provided in the drain line (350).

[0060] The purging gas purifier (230) of the second embodiment may further include a buffer tank (264) provided at the rear end of the adsorption purifier (250) to temporarily store the high-purity purging gas separated from the adsorption purifier (250). Since the buffer tank (264) has the same function as the buffer tank (220) described above, its description is omitted.

[0061] <Example 2-3>

[0062] Referring to FIG. 6, the purging gas purifier (230) may include a heat exchanger (262) for cooling the mixed gas compressed in the compressor (210); and a gas-liquid separator (260) provided at the rear end of the heat exchanger (262) for separating liquid fuel and purging gas from the mixed gas.

[0063] When the mixed gas is compressed in the compressor (210), a high-temperature and high-pressure mixed gas is formed, and when the high-temperature and high-pressure mixed gas is cooled in the heat exchanger (262), the mixed gas changes to a low-temperature and high-pressure state, and the evaporated gas is condensed into liquid fuel. The liquid fuel collects in the lower part of the gas-liquid separator (260), and the high-purity purge gas collects in the upper part of the gas-liquid separator (260), so that the liquid fuel and the purge gas are separated.

[0064] The purging gas purifier (230) of the second embodiment may further include a buffer tank (264) provided at the rear end of the gas-liquid separator (260) to temporarily store the high-purity purging gas separated from the gas-liquid separator (260). Since the buffer tank (264) has the same function as the buffer tank (220) described above, its description is omitted.

[0065] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0066] [Explanation of symbols]

[0067] 100 Fuel Supply System

[0068] 10 fuel tanks 20 engines

[0069] 30 supply valve 40 drain valve

[0070] 200 Gas generation unit for purging

[0071] 210 compressor 220 buffer tank

[0072] 230 Purging gas purifier 240 Absorption purifier

[0073] 242 Wastewater tank 244 Degassing device

[0074] 246 Absorbent pump 250 Adsorption purifier

[0075] 252 Adsorption feed valve 260 Gas-liquid separator

[0076] 262 Heat exchanger 264 Buffer tank

[0077] 310 Purging Line 320 Recovery Line

[0078] 330 purge gas supply line

[0079] 332 Fuel Discharge Line

[0080] 340 Fuel supply line 350 Drain line

[0081] 360 vent line

Claims

1. Fuel tank where fuel gas is stored; The above fuel tank can accommodate evaporation gas of fuel gas and purge gas that can be used for purging operations, A fuel supply line for supplying fuel from the fuel tank to the engine; A purging gas generating unit that creates a purging gas suitable for use in purging operations by using a mixture of evaporation gas and purge gas contained in the fuel tank; A purging line for purging the engine and piping with the purging gas generated in the purging gas generating unit; and A fuel supply system including a recovery line connected to the purging line to recover purging gas used in the purging operation to the fuel tank.

2. In claim 1, A fuel supply system including a supply valve provided in the purging line to control the flow rate of the purging gas.

3. In claim 1, A fuel supply system including a purge gas supply line connected to the fuel tank and supplying the purge gas.

4. In claim 1, A fuel supply system connected to the fuel tank and including a vent line for discharging the internal mixed gas of the fuel tank.

5. In claim 1, The above purging gas generating unit is, a compressor that compresses the mixed gas stored in the fuel tank; and A fuel supply system including a buffer tank provided at the rear end of the compressor for temporarily storing the mixed gas compressed by the compressor.

6. In claim 1, The above purging gas generating unit is, a compressor that compresses the mixed gas stored in the fuel tank; and A fuel supply system including a purging gas purifier provided at the rear end of the compressor to separate the evaporated gas from the compressed mixed gas.

7. In claim 6, A fuel supply system in which the evaporated gas or liquid fuel separated from the purging gas purifier is returned to the fuel tank through a drain line.

8. In claim 6, The above purging gas purifier is, Absorption purifier using absorbent; A wastewater tank storing the absorbent used in the above absorption purifier; and A fuel supply system including a degassing device for separating fuel absorbed in an absorbent of the above wastewater tank.

9. In claim 8, The above purging gas purifier is, A fuel supply system further comprising a buffer tank provided at the rear end of the absorption purifier for temporarily storing purging gas purified in the absorption purifier.

10. In claim 6, The above purging gas purifier is, Adsorption purifier using an adsorbent; and A fuel supply system including an adsorption supply valve provided between the compressor and the adsorption purifier to control the supply pressure of the mixed gas to the adsorption purifier.

11. In claim 10, The above purging gas purifier is, A fuel supply system further comprising a buffer tank provided at the rear end of the above adsorption purifier for temporarily storing purging gas purified in the above adsorption purifier.

12. In claim 6, The above purging gas purifier is, A heat exchanger that cools the mixed gas compressed in the compressor; and A fuel supply system including a gas-liquid separator provided at the rear end of the heat exchanger to separate liquid fuel and purging gas from the mixed gas.

13. In claim 12, The above purging gas purifier is, A fuel supply system further comprising a buffer tank provided at the rear end of the gas-liquid separator for temporarily storing the purging gas separated from the gas-liquid separator.

14. In claim 1, A fuel supply system in which a pressure reducing valve for reducing the pressure of the purging gas used in the purging operation is provided in the recovery line.

15. Fuel tank where fuel gas is stored; The above fuel tank can accommodate evaporation gas of fuel gas and purge gas that can be used for purging operations, A fuel supply line for supplying fuel from the fuel tank to the engine; A purging gas generating unit that creates a purging gas suitable for use in purging operations by using a mixture of evaporation gas and purge gas contained in the fuel tank; A drain line for recovering the evaporated gas or liquid fuel separated from the purging gas generating unit to the fuel tank; A purging line for purging the engine and piping with the purging gas generated in the purging gas generating unit; and A fuel supply system including a recovery line connected to the purging line to recover purging gas used in the purging operation to the fuel tank.

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