A temperature control system suitable for liquefied fuel tanks

Abstract

This invention discloses a temperature control system suitable for liquefied fuel tanks. It is characterized by comprising: a cold source, which is the usable cold energy generated during the liquid-to-gas conversion of liquid fuel in the liquefied fuel tank or cold energy provided by electricity; a cooling branch, where the cold source and temperature control medium flow simultaneously into the cooling branch, and the cold source cools the temperature control medium; and a temperature control medium circulation pipeline, which allows the temperature control medium to circulate between the compartments surrounding the liquefied fuel tank and the cooling branch, thereby lowering the ambient temperature in the compartments surrounding the liquefied fuel tank and maintaining the external environment of the liquefied fuel tank located in the compartments surrounding the liquefied fuel tank at a lower temperature. This invention reduces the generation of evaporative gases, avoiding excessive waste of evaporative gases under low-load ship conditions; the system is simple, has low initial investment, occupies little space, and consumes little electricity.

Description

Technical Field

[0001] This invention relates to a temperature control system suitable for liquefied fuel tanks, belonging to the field of shipbuilding. Background Technology

[0002] As green, environmentally friendly, and low-carbon requirements gain increasing recognition, the shipping industry is increasingly inclined to adopt new fuels to replace traditional fuels with poorer environmental performance. Some new fuels, such as natural gas and ammonia, are gaseous at room temperature and require a significant amount of space on ships for storage. Therefore, these fuels must be cooled to a certain temperature to liquefy and maintained at a low temperature to reduce the generation and accumulation of vapors and prevent excessive pressure in the liquefied fuel tanks. Only in this way can the feasibility of using these gaseous fuels as marine fuels be established.

[0003] The initial liquefaction of gaseous fuels is usually completed by the fuel supplier. A major challenge in ship design and operation is reducing the generation and accumulation of vaporized gases. Existing technologies primarily employ the following methods:

[0004] 1) The vapors generated by heating the liquefied fuel tanks are transported to the ship's main engine and generators as fuel. However, when the ship is operating at low load, the main engine or generator requires less fuel, and the excess vapors can only be transported to the boiler for combustion, resulting in fuel waste, which is neither economical nor environmentally friendly.

[0005] 2) A reliquefaction unit is used to liquefy the vapors generated by heating the liquefied fuel tank. However, this method requires a large space, has a high initial investment, and consumes a lot of electricity during the liquefaction process.

[0006] Meanwhile, due to the extremely low temperature of liquid fuel, a leak in the liquefied fuel tank can cause excessively low temperatures around the tank, posing a risk of embrittlement and damage to the steel structure. To address this issue, the degree of temperature reduction caused by a fuel leak is typically calculated theoretically, and an appropriate grade of cryogenic steel is used. However, cryogenic steel is more expensive than conventional steel, resulting in higher initial investment. Furthermore, theoretically calculated cryogenic environments may not accurately assess the extreme low-temperature conditions during an actual leak, thus a certain risk of structural damage still exists. Summary of the Invention

[0007] The technical problem this invention aims to solve is that excessive evaporation gas generated by liquefied fuel due to heating by the surrounding environment is difficult to fully utilize, which can lead to increased tank pressure and fuel waste. To address the risk of steel structure embrittlement and damage when liquid fuel tanks leak, low-temperature steel of a corresponding grade is typically used, which increases the initial investment. Furthermore, there is still a certain risk of structural damage when liquid fuel tanks leak.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is to provide a temperature regulation system suitable for liquefied fuel tanks, characterized in that it includes:

[0009] The cold source is the usable cold energy generated during the conversion of liquid fuel in the liquefied fuel tank from liquid to gas or the cold energy provided by electricity.

[0010] In the cooling branch, the cold source and the temperature control medium flow into the cooling branch simultaneously, and the cold source cools the temperature control medium.

[0011] The temperature-controlled medium circulation pipeline allows the temperature-controlled medium to circulate between the compartments surrounding the liquefied fuel tank and the cooling branch lines. The cooled temperature-controlled medium lowers the ambient temperature in the compartments surrounding the liquefied fuel tank, thereby keeping the external environment of the liquefied fuel tank located in the compartments surrounding the liquefied fuel tank at a low temperature.

[0012] Preferably, the cold source is liquid fuel or cryogenic gaseous fuel.

[0013] Preferably, the cold source directly cools the temperature control medium.

[0014] Preferably, a cooler is provided in the cooling branch, and after the cold source and the temperature control medium flow into the cooler at the same time, the temperature control medium is directly cooled by the cold source.

[0015] Preferably, the cold source indirectly cools the temperature control medium.

[0016] Preferably, the cooling branch includes two coolers and a secondary cooling circulation pipeline connecting the two coolers. After the cold source and the temperature control medium flow into the cooling branch at the same time, the cold source flows into one of the two coolers, and the temperature control medium flows into the other of the two coolers, so that the cold source indirectly cools the temperature control medium through the secondary cooling circulation pipeline.

[0017] Preferably, the temperature control system further includes a heating branch, then:

[0018] The temperature control medium either flows into the cooling branch or into the heating branch; when the temperature control medium flows into the heating branch, the heating branch heats the temperature control medium.

[0019] Preferably, a terminal heat exchange device is provided in the compartments surrounding the liquefied fuel tank, and the temperature control medium, after being cooled or heated, cools or heats the liquefied fuel tank through the terminal heat exchange device.

[0020] Preferably, after the cooling branch is closed by the valve, the temperature control medium flows into the heating branch; after the heating branch is closed by the valve, the temperature control medium flows into the cooling branch.

[0021] Preferably, the temperature control system further includes a temperature monitoring device, which automatically controls the start and stop of the temperature control system based on the monitoring results of the temperature monitoring device; shuts down the cooling branch and turns on the heating branch or shuts down the heating branch and turns on the cooling branch, thereby realizing the automatic switching of the temperature control system between cooling mode and heating mode.

[0022] Since liquid fuel cannot be directly supplied to ship's main engines and generators, it needs to be heated and vaporized to form gaseous fuel. During this liquid-to-gas conversion, the fuel absorbs a significant amount of heat, thus possessing usable cold energy. This invention fully utilizes this cold energy for cooling the liquefied fuel tank, helping to maintain the tank at a low temperature, thereby reducing the generation and accumulation of vaporized gas, and saving the energy consumption required to heat the liquid fuel.

[0023] Meanwhile, while providing cooling for the liquefied fuel tank, the present invention can provide an additional heating mode by adding only a small amount of equipment, that is, to provide heating when the liquefied fuel tank leaks, thereby ensuring structural safety.

[0024] Furthermore, the insulation layer and adhesive of the liquefied fuel tank are designed for cryogenic environments. When the liquefied fuel tank is empty and the ambient temperature is high, it will adversely affect the insulation layer and adhesive. In cases where liquid or gaseous cryogenic fuel cannot provide a cooling source, electrical energy is used for refrigeration, and the system required by this invention is used to cool the environment surrounding the liquefied fuel tank.

[0025] In summary, this invention fully utilizes the heat absorption energy during the vaporization process of liquefied fuel, thereby reducing the ambient temperature around the liquefied fuel tank. Compared with the prior art, this invention mainly has the following beneficial effects:

[0026] 1) It reduces the generation of evaporative gases, thus avoiding the waste of excessive evaporative gases when the ship is under low load.

[0027] 2) Compared to reliquefaction systems, the system of the present invention is simpler, has lower initial investment, occupies less space, and consumes less electricity;

[0028] 3) Adding a heating branch to the cooling system can increase the heating function and make full use of most of the equipment in the original cooling system;

[0029] 4) The application of heating systems reduces the use of low-temperature steel;

[0030] 5) The cooling and heating functions can be switched and started / stopped in a timely manner based on the temperature monitoring results. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a single cooling system;

[0032] Figure 2 Schematic diagram of a single cooling system with an additional heat exchange cycle;

[0033] Figure 3 A schematic diagram of a dual cooling and heating system;

[0034] Figure 4 This is a schematic diagram of the temperature control system layout;

[0035] In the diagram: 1. Liquefied fuel tank; 2. Surrounding compartments of the liquefied fuel tank; 3. Terminal heat exchange device; 4. Cooler; 5. Cold source, which is liquid fuel or cryogenic gaseous fuel; 6. Temperature-controlled medium pipeline, containing a temperature-controlled medium preferably a low-temperature resistant liquid, such as an aqueous solution of ethylene glycol; 7. Temperature-controlled medium tank; 8. Temperature-controlled medium circulation pump; 9. Secondary cooling circulation pipeline; 10. Heating branch; 11. Heater; 12. Valve; 13. Temperature monitoring device. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0037] Figure 1 A temperature control system suitable for a liquefied fuel tank is shown, comprising a liquefied fuel tank 1, a compartment surrounding the liquefied fuel tank 2, a terminal heat exchange device 3, a cooler 4, a cold source 5, a temperature control medium pipeline 6 (containing a temperature control medium, preferably a low-temperature resistant liquid, such as an aqueous solution of ethylene glycol), a temperature control medium chamber 7, a temperature control medium circulation pump 8, and a secondary cooling circulation pipeline.

[0038] The cold source 5 uses liquid fuel or cryogenic gaseous fuel, and the temperature control medium in the temperature control medium pipeline 6 is cooled by the cooler 4. The temperature control medium circulates between the liquefied fuel tank surrounding compartment 2 and the cooler 4 via the temperature control medium circulation pump 8 and the temperature control medium pipeline 6. The temperature control medium cools the external environment of the liquefied fuel tank 1 in the surrounding compartment 2 through the terminal heat exchange device 3, keeping the external environment of the liquefied fuel tank 1 at a low temperature, thereby reducing the generation of fuel vapor. The temperature monitoring device 13 can monitor the external ambient temperature, determine the operating temperature range of the temperature regulation system, and automatically control the start and stop of the temperature regulation system based on the monitoring results of the temperature monitoring device.

[0039] When the liquefied fuel tank 1 is empty, the cold source 5 cannot directly provide cooling energy from liquid fuel or cryogenic gaseous fuel. At this time, it can provide cooling function through electricity to maintain a low temperature in the surrounding area of ​​the liquefied fuel tank 1 when it is empty, so as to prevent the high temperature environment from adversely affecting the insulation layer and its adhesive of the liquefied fuel tank 1.

[0040] Figure 2 Another illustrated temperature control system suitable for liquefied fuel tanks is shown in Figure 1 Based on the above, a secondary cooling circulation pipe 9 is added. The cold source 5 does not directly cool the temperature-controlled medium in the temperature-controlled medium pipe 6, but achieves indirect cooling through the secondary cooling circulation pipe 9 to prevent the temperature of the temperature-controlled medium from falling below its freezing point.

[0041] Figure 3 Another type of temperature control system suitable for liquefied fuel tanks is... Figure 1 Based on the existing structure, a heating branch 10, a heater 11, and a valve 12 are added. When the temperature monitoring device 13 detects that the ambient temperature around the liquefied fuel tank 2 is too low, it closes the cooling branch equipped with the cooler 4 by switching control valve 12, while simultaneously starting the heating branch 10. The heater 11 can be electrically heated or heated by marine hot steam to heat the temperature control medium, which is circulated by the temperature control medium circulation pump 8. The temperature control medium heats the external environment of the liquefied fuel tank 1 within the surrounding compartments 2 through the terminal heat exchange device 3, preventing the external ambient temperature of the liquefied fuel tank 1 from becoming too low, thereby preventing damage to the surrounding structure due to excessively low temperatures.

[0042] like Figure 4 As shown, for Figure 1 , Figure 2 or Figure 3 The temperature control system shown is preferably located above the liquefied fuel tank 1, considering the need to make full use of the ship's space.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A temperature regulating system suitable for use in a tank of liquefied fuel, characterized in that, The temperature regulating system comprises: a cold source, which is the available cold energy generated during the conversion of liquid fuel into gaseous fuel in the liquefied fuel tank or the cold energy provided by electric energy; a cooling branch, in which the cold source and the temperature control medium flow simultaneously, and the temperature control medium is indirectly cooled by the cold source; a temperature control medium circulation pipeline, which enables the temperature control medium to flow between the surrounding cabin of the liquefied fuel tank and the cooling branch, and the ambient temperature in the surrounding cabin of the liquefied fuel tank is reduced by the cooled temperature control medium, so that the external environment of the liquefied fuel tank in the surrounding cabin of the liquefied fuel tank is kept at a lower temperature, wherein the cooling branch comprises two coolers and a sub-cooling circulation pipeline connecting the two coolers, the cold source and the temperature control medium flow into one of the two coolers and the other of the two coolers respectively, so that the cold source indirectly cools the temperature control medium through the sub-cooling circulation pipeline; a heating branch, which uses electric energy or ship steam to heat the temperature control medium, and then: the temperature control medium flows into either the cooling branch or the heating branch, the temperature control medium is heated by the heating branch when the temperature control medium flows into the heating branch, the temperature control medium flows into the heating branch after the cooling branch is closed by a valve, and the temperature control medium flows into the cooling branch after the heating branch is closed by a valve; a temperature monitoring device, which automatically controls the start and stop of the temperature regulating system and the switching between the cooling mode and the heating mode of the temperature regulating system according to the monitoring results of the temperature monitoring device.

2. A temperature regulating system for a tank of liquefied fuel as defined in claim 1, wherein The cold source is liquid fuel or low-temperature gaseous fuel.

3. A temperature regulating system for a tank of liquefied fuel as defined in claim 1, wherein, A terminal heat exchange device is arranged in the surrounding cabin of the liquefied fuel tank, and the cooled or heated temperature control medium cools or heats the liquefied fuel tank through the terminal heat exchange device.

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