CN118564374A - Heat exchange system of marine natural gas fuel and control method thereof - Google Patents

Abstract

The present application discloses a heat exchange system for marine natural gas fuel and a control method thereof, wherein the heat exchange system comprises a heat exchanger and at least one LNG fuel vaporizer, as well as a pump group device, a temperature control valve, and a first temperature sensor; the liquid outlet of the pump group device is connected to the coolant inlet of the heat exchanger through a first pipeline, the temperature control valve and the coolant outlet of the heat exchanger are connected through a second pipeline, the temperature control valve and the coolant inlet of the LNG fuel vaporizer are connected through a third pipeline, the coolant outlet of the LNG fuel vaporizer and the liquid inlet of the pump group device are connected through a fourth pipeline, the temperature control valve and the liquid inlet of the pump group device are connected through a fifth pipeline, and the first temperature sensor is connected to the gas outlet of the LNG fuel vaporizer; the heat exchange system can keep the gas outlet temperature of the LNG fuel vaporizer within a constant temperature range, thereby ensuring the stability of the operation of the main engine.

Description

Heat exchange system and control method of marine natural gas fuel

Technical Field

The present application relates to the field of marine fuel heat exchange equipment, and in particular to a marine natural gas fuel heat exchange system and a control method thereof.

Background Art

As a new type of ship energy, liquefied natural gas (LNG) has the advantages of low carbon, environmental protection, and economy. Natural gas fuel-powered ships use natural gas as the driving fuel, but the existing ship LNG fuel heat exchange system does not have the fuel temperature control function. The fuel temperature after LNG gasification fluctuates greatly, which can easily cause the use of ship natural gas engines to be unstable or even fail to shut down.

It can be seen that the existing technology still needs to be improved and enhanced.

Summary of the invention

In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a heat exchange system for marine natural gas fuel and a control method thereof, aiming to provide natural gas fuel with stable temperature to the natural gas fuel engine.

In order to achieve the above objectives, this application adopts the following technical solutions:

On the one hand, the present application discloses a heat exchange system for marine natural gas fuel, comprising:

a heat exchanger and at least one LNG fuel vaporizer;

A pump assembly device, wherein a liquid outlet of the pump assembly device is connected to a coolant inlet of the heat exchanger through a first pipeline;

A temperature control valve, wherein the temperature control valve is connected to the coolant outlet of the heat exchanger via a second pipeline, the temperature control valve is connected to the coolant inlet of the LNG fuel vaporizer via a third pipeline, a fourth pipeline is connected between the coolant outlet of the LNG fuel vaporizer and the liquid inlet end of the pump group equipment, and the temperature control valve is connected to the liquid inlet end of the pump group equipment via a fifth pipeline;

A first temperature sensor is connected to the gas outlet end of the LNG fuel vaporizer.

In some embodiments of the present application, the heat exchange system further includes:

a first stop valve, the first stop valve being connected to the first pipeline;

A pressure sensor is connected to the first pipeline and is arranged between the pump set equipment and the first stop valve.

In some embodiments of the present application, the heat exchange system further includes:

a second temperature sensor, the second temperature sensor being disposed at a coolant inlet end of the heat exchanger and connected to the first pipe;

A third temperature sensor is arranged at the coolant outlet of the heat exchanger and connected to the second pipeline.

In some embodiments of the present application, the heat exchange system further includes:

A flow meter is connected to the fourth pipeline and is used to detect the flow of the coolant in the fourth pipeline.

In some embodiments of the present application, the heat exchange system further includes:

A first stop check valve is connected to the fourth pipeline and is arranged downstream of the flow meter.

In some embodiments of the present application, a first air vent is provided on the fourth pipe, and the first air vent is provided at the highest point of the fourth pipe in the vertical direction;

The heat exchange system also includes:

An expansion water tank, wherein the expansion water tank is provided with a second air vent, a liquid filling port, a reflux port, a liquid outlet and a water replenishment port, the second air vent and the liquid filling port are arranged at the top of the expansion water tank, the reflux port is communicated with the gas phase space of the expansion water tank, and the reflux port is connected to the first air vent through a sixth pipe, the liquid outlet is connected to the liquid inlet end of the pump group equipment through a seventh pipe, and the water replenishment port is arranged at the upper part of the expansion water tank, and is configured to be able to replenish fresh water into the expansion water tank.

In some embodiments of the present application, the heat exchange system further includes:

A liquid level meter is arranged in the expansion water tank.

In some embodiments of the present application, the heat exchanger is further provided with at least one water inlet and at least one water outlet, the water inlet is configured to be connected to the main engine cylinder jacket water outlet, the water outlet is configured to be connected to the main engine cylinder jacket water return port, and the direction of the main engine cylinder jacket water entering and exiting the heat exchanger is opposite to the direction of the coolant entering and exiting the heat exchanger.

In some embodiments of the present application, the heat exchanger is provided with two groups of heat exchange tubes, two water outlets and two water inlets, and both ends of each group of heat exchange tubes are connected to a water outlet and a water inlet respectively.

In some embodiments of the present application, the heat exchange system is configured with two LNG fuel vaporizers, the first end of the second pipeline is connected to the coolant outlet of the heat exchanger, the second end of the second pipeline forms a first branch and a second branch, and a temperature control valve is respectively connected to the first branch and the second branch.

In some embodiments of the present application, the temperature control valve is a three-way valve, including a first inlet, a first outlet and a second outlet, the first inlet is connected to the coolant outlet of the heat exchanger through the second pipe, the first outlet is connected to the coolant inlet of the LNG fuel vaporizer through the third pipe, and the second outlet is connected to the liquid inlet end of the pump group equipment through the fifth pipe.

In some embodiments of the present application, a second stop valve is provided between the first outlet and the coolant inlet of the LNG fuel vaporizer, and the second stop valve is connected to the third pipeline.

On the other hand, the present application further discloses a control method for a heat exchange system, the control method being applied to the heat exchange system as described above, the control method comprising:

When the first temperature sensor detects that the temperature of the gas outlet of the LNG fuel vaporizer is lower than 5° C., increasing the opening of the first outlet of the temperature control valve;

When the first temperature sensor detects that the temperature of the gas outlet of the LNG fuel vaporizer is higher than 25° C., the opening of the second outlet of the temperature control valve is increased.

In some embodiments of the present application, the control method includes:

When the first temperature sensor detects that the temperature at the outlet of the LNG fuel vaporizer is lower than 5°C, the first outlet of the temperature control valve is fully opened;

When the first temperature sensor detects that the temperature of the gas outlet of the LNG fuel vaporizer is higher than 25° C., the second outlet of the temperature control valve is opened by 90%.

Beneficial effects:

The present application provides a heat exchange system for marine natural gas fuel, which monitors the temperature of the natural gas fuel after gasification by arranging a first temperature sensor at the gas outlet end of the LNG fuel vaporizer, and arranging a pump group device at the coolant inlet end of the heat exchanger, and arranging a temperature control valve between the coolant outlet end of the heat exchanger and the LNG fuel vaporizer. The temperature control valve receives the gas outlet temperature feedback from the first temperature sensor, controls the flow of the coolant entering the LNG fuel vaporizer, adjusts the heat exchange effect between the coolant and the natural gas fuel, and keeps the temperature of the gasified natural gas fuel within a constant temperature range, thereby ensuring the stability of the main engine function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a heat exchange system for marine natural gas fuel provided in one embodiment of the present application.

Main component symbol description: 1. Heat exchanger; 101. Water inlet; 102. Water outlet; 103. Heat exchange tube; 2. LNG fuel vaporizer; 3. Pump group equipment; 4. Temperature control valve; 401. First inlet; 402. First outlet; 403. Second outlet; 5. First temperature sensor; 6. First stop valve; 7. Pressure sensor; 8. Second temperature sensor; 9. Third temperature sensor; 10. Flow meter; 11. First stop check valve; 12. First air vent; 13. Expansion water tank; 1301. Second air vent; 1302. Liquid filling port; 1303. Reflux port; 1304. Liquid outlet; 1305. Water replenishment port; 14. Liquid level gauge; 15. Second stop valve; 01. First pipeline; 02. Second pipeline; 021. First branch pipe; 022. Second branch pipe; 03. Third pipeline; 04. Fourth pipeline; 05. Fifth pipeline; 06. Sixth pipeline; 07. Seventh pipeline.

DETAILED DESCRIPTION

The present application provides a heat exchange system for marine natural gas fuel and a control method thereof. In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, and a specific orientation structure and operation, and therefore, cannot be understood as a limitation on the present application. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

Please refer to Figure 1. The present application provides a heat exchange system for marine natural gas fuel, including a heat exchanger 1, at least one LNG fuel vaporizer 2, a pump group device 3, a temperature control valve 4 and a first temperature sensor 5; the liquid outlet of the pump group device 3 is connected to the coolant inlet of the heat exchanger 1 through a first pipeline 01, so as to pressurize the coolant and input it into the heat exchanger 1, the temperature control valve 4 is connected to the coolant outlet of the heat exchanger 1 through a second pipeline 02, the temperature control valve 4 is connected to the coolant inlet of the LNG fuel vaporizer 2 through a third pipeline 03, a fourth pipeline 04 is connected between the coolant outlet of the LNG fuel vaporizer 2 and the liquid inlet of the pump group device 3, and the temperature control valve 4 is connected to the liquid inlet of the pump group device 3 through a fifth pipeline 05; the first temperature sensor 5 is connected to the gas outlet of the LNG fuel vaporizer 2.

In the above, the pump group equipment 3, the heat exchanger 1, the temperature control valve 4 and the LNG fuel vaporizer 2 are connected in sequence to form a first circulation loop; the pump group equipment 3, the heat exchanger 1 and the temperature control valve 4 are connected in sequence to form a second circulation loop. The exhaust end of the LNG fuel vaporizer 2 is connected to the host engine, and the coolant is heated in the heat exchanger 1 through the temperature control valve 4 and enters the LNG fuel vaporizer 2 to exchange heat with the LNG fuel or returns to the pump group equipment 3 and re-enters the heat exchanger 1.

The temperature control valve 4 is a three-way valve with two outlets. By controlling the opening of different outlets, the coolant can be distributed between the third pipeline 03 and the fifth pipeline 05, thereby adjusting the heat exchange effect between the coolant and the natural gas fuel. Specifically, the first temperature sensor 5 monitors the temperature of the natural gas discharged from the LNG fuel vaporizer 2, and feeds back the temperature information to the temperature control valve 4. The temperature control valve 4 adjusts the opening of the two outlets according to the received temperature information, so that the flow of the coolant entering the LNG fuel vaporizer 2 changes, thereby changing the heat exchange effect between the coolant and the natural gas fuel, so that the temperature of the natural gas fuel passing through the LNG fuel vaporizer 2 is stabilized at 5°C to 25°C, so as to ensure the stability of the fuel supply temperature of the marine main engine engine, so that the marine main engine can run stably. For example, when the first temperature sensor 5 detects that the temperature of the natural gas fuel discharged from the LNG fuel vaporizer 2 is lower than 5°C, the opening of the temperature control valve 4 connected to the heat exchanger 1 is fully opened, so that all the coolant enters the LNG fuel vaporizer 2 through the third pipeline 03, thereby increasing the temperature of the fuel. For another example, when the first temperature sensor 5 detects that the temperature of the natural gas fuel discharged from the LNG fuel vaporizer 2 is higher than 25°C, the opening of the temperature control valve 4 connected to the fifth pipeline 05 is opened by 90%, reducing the flow of the coolant entering the LNG fuel vaporizer 2, allowing more coolant to return from the fifth pipeline 05 to the pump group equipment 3, thereby lowering the temperature of the natural gas fuel.

In this embodiment, the coolant is an ethylene glycol solution. Ethylene glycol has a high boiling point and a low freezing point, can be mixed with water in any proportion, and the freezing point of the solution is different depending on the content of diethanol in the solution. In addition, ethylene glycol has a small volatilization loss and a long service life, and is an ideal coolant.

In the present application, the heat exchanger 1 is fed with the main engine cylinder jacket water to exchange heat with the coolant, thereby effectively recycling the heat energy of the engine and improving the economy of the heat exchange system.

Furthermore, the heat exchange system further includes a first stop valve 6 and a pressure sensor 7; the first stop valve 6 is connected to the first pipeline 01, and the pressure sensor 7 is connected to the first pipeline 01 and is arranged between the pump group device 3 and the first stop valve 6. After being pressurized by the pump group device 3, the coolant enters the heat exchanger 1 through the first stop valve 6 for heat exchange and temperature increase. When the pressure sensor 7 detects that the pressure is too low, the pump group device 3 can be automatically started for pressurization.

Furthermore, the heat exchange system further includes a second temperature sensor 8 and a third temperature sensor 9; the second temperature sensor 8 is disposed at the coolant inlet end of the heat exchanger 1 and connected to the first pipeline 01; the third temperature sensor 9 is disposed at the coolant outlet end of the heat exchanger 1 and connected to the second pipeline 02. The second temperature sensor 8 is used to detect the temperature of the coolant entering the heat exchanger 1, and the third temperature sensor 9 is used to detect the temperature of the coolant discharged from the heat exchanger 1. The heat exchange effect of the heat exchanger 1 can be monitored in combination with the second temperature sensor 8 and the third temperature sensor 9 to ensure the heat exchange effect between the coolant and the LNG.

Furthermore, the heat exchange system also includes a flow meter 10, which is connected to the fourth pipeline 04 and is used to detect the flow of coolant in the fourth pipeline 04; during the operation of the heat exchange system, the flow meter 10 should always detect that there is coolant flowing in the fourth pipeline 04, that is, coolant is always entering the LNG fuel vaporizer 2 to prevent freezing and icing inside the LNG fuel vaporizer 2.

Furthermore, the heat exchange system also includes a first stop check valve 11 , which is connected to the fourth pipeline 04 and arranged downstream of the flow meter 10 ; it can prevent the coolant on the fourth pipeline 04 from flowing back to the LNG fuel vaporizer 2 .

Furthermore, the fourth pipe 04 is provided with a first air vent 12, which is provided at the highest point of the fourth pipe 04 in the vertical direction; the heat exchange system also includes an expansion water tank 13, which is provided at the highest position of the heat exchange system, and is used to load coolant and replenish the coolant to the heat exchange system. In addition, a gas phase space is formed at the upper part of the inner cavity of the expansion water tank 13, and a reflux port 1303 is provided on one side wall of the expansion water tank 13 corresponding to the gas phase space, and a second air vent 1301 is provided on the top of the expansion water tank 13, and the reflux port 1303 is connected to the first air vent 12 through the sixth pipe 06, and the air or other gas in the fourth pipe 04 is discharged into the gas phase space of the expansion water tank 13 through the first air vent 12 and the sixth pipe 06, and then discharged to the external environment through the second air vent 1301, so as to avoid the gas in the fourth pipe 04 affecting the flow and pressure control of the coolant.

The expansion water tank 13 is also provided with a liquid filling port 1302, a liquid outlet 1304 and a water replenishment port 1305. The liquid filling port 1302 is provided at the top of the expansion water tank 13 and is used to inject coolant into the expansion water tank 13. Preferably, a stop valve is also connected to the outside of the liquid filling port 1302. The stop valve is opened when liquid is added and is closed when liquid is not needed to prevent the coolant in the expansion water tank 13 from evaporating or leaking. The liquid outlet 1304 is provided at the bottom of the expansion water tank 13 and is connected to the liquid inlet of the pump group device 3 through the seventh pipeline 07. The seventh pipeline 07 is provided with a stop valve, which is opened when the pump group device 3 needs to replenish coolant and closed when coolant is not needed. The water replenishment port 1305 is arranged at the upper part of the expansion water tank 13, and is configured to replenish fresh water into the expansion water tank 13; during the operation of the heat exchange system, part of the water may evaporate, causing the content of solute and water in the coolant to change, thereby causing the change of the thermal conductivity of the coolant; replenishing fresh water into the expansion water tank 13 regularly or according to the frequency of use can maintain the concentration of the coolant within a stable range, thereby improving the stability of the air supply temperature of the LNG fuel vaporizer 2 to the main engine.

Furthermore, the heat exchange system also includes a liquid level meter 14, which is arranged in the expansion water tank 13 and is used to monitor the liquid level in the expansion water tank 13, so that the refrigerant can be replenished in time when the liquid level in the expansion water tank 13 is too low; and when replenishing the refrigerant, it is not excessively added, so that the liquid phase space and the gas phase space are maintained in the expansion water tank 13, and the reflux port 1303 corresponds to the gas phase space, ensuring that the heat exchange pipe 103 can exhaust gas into the gas phase space of the expansion water tank 13.

The heat exchanger 1 is also provided with at least one water inlet 101 and at least one water outlet 102. The water inlet 101 is configured to be connected to the main engine cylinder jacket water outlet 102, and the water outlet 102 is configured to be connected to the main engine cylinder jacket water return port. The direction in which the main engine cylinder jacket water enters and exits the heat exchanger 1 is opposite to the direction in which the coolant enters and exits the heat exchanger 1, thereby improving the heat exchange effect. In the present application, the heat exchanger 1 utilizes the main engine cylinder jacket water to exchange heat with the coolant to heat the coolant, thereby effectively recycling the heat energy of the engine and improving the economy and environmental performance of the heat exchange system.

In some embodiments, two groups of heat exchange tubes 103, two water outlets 102 and two water inlets 101 are provided on the heat exchanger 1, and the two ends of each group of heat exchange tubes 103 are respectively connected to a water outlet 102 and a water inlet 101, each water outlet 102 is connected to the return water port of the cylinder jacket water of a main engine, and each water inlet 101 is connected to the water outlet 102 of the cylinder jacket water of a main engine. In this way, the heat exchanger 1 makes full use of the thermal energy of the two main engines, and can basically meet the needs of heating the liquefied natural gas to an ideal temperature to supply gas to the main engine, thereby reducing energy loss.

The two groups of heat exchange tubes 103 on the heat exchanger 1 are parallel to each other and spaced apart on two axially opposite sides of the heat exchanger 1. The coolant passes through the shell side of the heat exchanger 1, and the engine jacket water passes through the tube side of the heat exchanger 1, so that the coolant can fully contact the pipes circulating the engine jacket water, thereby enhancing the heat exchange effect.

In some embodiments of the present application, the heat exchange system is equipped with two LNG fuel vaporizers 2, each LNG fuel vaporizer 2 supplies gas to a main engine, and liquefied natural gas is introduced from one end of the LNG fuel vaporizer 2, and after heat exchange with the coolant and temperature rise, it is gasified from liquid to gas, and discharged to the main engine from the other end of the LNG fuel vaporizer 2. Each LNG fuel vaporizer 2 is connected to the heat exchanger 1 and the pump group equipment 3 by pipelines, that is, the two LNG fuel vaporizers 2 are connected in parallel between the heat exchanger 1 and the pump group equipment 3. Specifically, the first end of the second pipeline 02 is connected to the coolant outlet of the heat exchanger 1, and the second end of the second pipeline 02 forms a first branch pipe 021 and a second branch pipe 022, and a temperature control valve 4 is connected to the first branch pipe 021 and the second branch pipe 022 respectively. The temperature control valve 4 connected to the first branch pipe 021 is connected to the coolant inlet of one of the LNG fuel vaporizers 2 through a third pipeline 03, and is connected to the pump group equipment 3 through a fifth pipeline 05. Similarly, the temperature control valve 4 connected to the second branch pipe 022 is also connected to the coolant inlet of another LNG fuel vaporizer 2 through a third pipeline 03, and is connected to the pump group equipment 3 through a fifth pipeline 05.

In order to simplify the setting of the pipeline, the fifth pipeline 05 connected to the two temperature control valves 4 is connected to the pump group equipment 3 after converging. Specifically, for the convenience of description, the two LNG fuel vaporizers 2 are respectively represented as the first LNG fuel vaporizer 2 and the second LNG fuel vaporizer 2, the temperature control valve 4 connected to the first LNG fuel vaporizer 2 is represented as the first temperature control valve 4, and the temperature control valve 4 connected to the second LNG fuel vaporizer 2 is represented as the second temperature control valve 4. After the fifth pipeline 05 connected to the second temperature control valve 4 is merged with the fourth pipeline 04 connected to the second LNG fuel vaporizer 2, the fourth pipeline 04 connected to the first LNG fuel vaporizer 2 is merged downstream of the first stop check valve 11, and then merged with the fifth pipeline 05 connected to the first temperature control valve 4 and connected to the pump group equipment 3. In this way, the second pipeline 02 can be divided into a corresponding number of branches according to the number of LNG fuel vaporizers 2 set, with flexible structure and high applicability.

Furthermore, a stop check valve is provided on the second pipe 02 to prevent the coolant from flowing back into the heat exchanger 1. The stop check valve is provided upstream of the first branch pipe 021 and the second branch pipe 022, so that multiple branches can be controlled simultaneously by one valve, simplifying the structure.

Furthermore, the temperature control valve 4 is a three-way valve, including a first inlet 401, a first outlet 402 and a second outlet 403. The first inlet 401 is connected to the coolant outlet of the heat exchanger 1 through the second pipe 02, the first outlet 402 is connected to the coolant inlet of the LNG fuel vaporizer 2 through the third pipe 03, and the second outlet 403 is connected to the liquid inlet end of the pump group equipment 3 through the fifth pipe 05; during the operation of the heat exchange system, by switching the opening of the first outlet 402 and the second outlet 403 of the temperature control valve 4, the flow rate of the coolant entering the LNG fuel vaporizer 2 can be controlled, and the heat exchange effect can be adjusted to stabilize the air supply temperature of the LNG fuel vaporizer 2 to the main engine.

Different LNG fuel vaporizers 2 are controlled by separate temperature control valves 4. The temperature control valves 4 on different branches obtain the temperature data of the first temperature sensor 5 connected to the corresponding LNG fuel vaporizer 2, thereby controlling the flow rate of the coolant in the branch individually, further improving the control accuracy of the heat exchange effect of the heat exchange system.

Furthermore, a second stop valve 15 is provided between the first outlet 402 and the coolant inlet of the LNG fuel vaporizer 2 . The second stop valve 15 is connected to the third pipeline 03 to control the circulation of the coolant on the third pipeline 03 .

The present application also discloses a control method for a heat exchange system, which is applied to the heat exchange system as described in any one of the above items. When the control method is executed, it specifically includes:

Refrigerant is injected into the expansion water tank 13 from the liquid filling port 1302 at the top of the expansion water tank 13. The refrigerant flows out from the liquid outlet 1304 at the bottom of the expansion water tank 13 and flows to the pump group device 3 through the seventh pipeline 07. The pump group device 3 pressurizes the refrigerant and then delivers the coolant to the heat exchanger 1. At the same time, the engine cylinder jacket water enters the heat exchanger 1 from the water inlet 101 of the heat exchanger 1 and exchanges heat with the coolant, so that the coolant is heated and heated. The coolant after heat exchange flows to the temperature control valve 4 through the second pipeline 02, and the flow of the coolant entering the third pipeline 03 and the fifth pipeline 05 is distributed through the temperature control valve 4. The coolant enters the LNG fuel vaporizer 2 through the third pipeline 03, and after heat exchange with the natural gas fuel, it flows back to the pump group device 3 through the fourth pipeline 04. The coolant entering the fifth pipeline 05 directly flows back to the pump group device 3, and the circulation flows in this way.

In the above process, the pump set 3 is not always in working state. When the pressure sensor 7 at the outlet of the pump set 3 detects that the pressure of the coolant is not less than the set value, the pump set 3 can be turned off; when the pressure sensor 7 detects that the pressure of the coolant is less than the set value, the pump set 3 can be started. The first temperature sensor 5 connected to the outlet of the LNG fuel vaporizer 2 always monitors the gas supply temperature of the LNG fuel vaporizer 2, and feeds the data back to the temperature control valve 4, and adjusts the flow rate of the coolant entering the LNG fuel vaporizer 2 through the temperature control valve 4, so as to achieve the purpose of adjusting the outlet temperature of the LNG fuel vaporizer 2.

Specifically, when the first temperature sensor 5 detects that the temperature at the outlet of the LNG fuel vaporizer 2 is lower than 5°C, the opening of the first outlet 402 of the temperature control valve 4 is increased, and the flow rate of the coolant entering the LNG fuel vaporizer 2 is increased to improve the heat exchange effect between the coolant and the natural gas fuel, thereby increasing the outlet temperature of the LNG fuel vaporizer 2; when the first temperature sensor 5 detects that the temperature at the outlet of the LNG fuel vaporizer 2 is higher than 25°C, the opening of the first outlet 402 of the temperature control valve 4 is reduced, and the opening of the second outlet 403 is increased; more coolant passing through the temperature control valve 4 is refluxed to the pump group equipment 3 through the fifth pipeline 05, the flow rate entering the LNG fuel vaporizer 2 is reduced, and the heat exchange effect between the coolant and the natural gas fuel is reduced, thereby reducing the outlet temperature of the LNG fuel vaporizer 2; the outlet temperature of the LNG fuel vaporizer 2 is always maintained within the range of 5°C to 25°C, ensuring the stability of the air supply temperature of the LNG fuel vaporizer 2 to the main engine.

Preferably, when the first temperature sensor 5 detects that the temperature at the outlet end of the LNG fuel vaporizer 2 is lower than 5°C, the first outlet 402 of the temperature control valve 4 is fully opened to quickly heat up the natural gas fuel in the LNG fuel vaporizer 2; when the first temperature sensor 5 detects that the temperature at the outlet end of the LNG fuel vaporizer 2 is higher than 25°C, the second outlet 403 of the temperature control valve 4 is opened by 90%, which can not only quickly reduce the outlet temperature of the LNG fuel vaporizer 2, but also ensure that there is still coolant entering the LNG fuel vaporizer 2 to prevent the inside of the LNG fuel vaporizer 2 from freezing.

The second temperature sensor 8 and the third temperature sensor 9 also monitor the temperature of the coolant entering and exiting the heat exchanger 1 to ensure the stability of the heat exchange effect of the heat exchanger 1. The flow meter 10 always detects the flow of the coolant on the fourth pipeline 04 to ensure that there is always coolant flowing on the fourth pipeline 04, that is, there is always coolant entering the LNG fuel vaporizer 2 to prevent the LNG fuel vaporizer 2 from freezing and icing inside.

It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and application concept of the present application, and all these changes or substitutions should fall within the protection scope of the claims attached to the present application.

Claims (14)

1. A heat exchange system for a marine natural gas fuel, comprising:

A heat exchanger and at least one LNG fuel vaporizer;

The liquid outlet end of the pump set equipment is connected with the cooling liquid inlet of the heat exchanger through a first pipeline;

the temperature control valve is connected with a cooling liquid outlet of the heat exchanger through a second pipeline, the temperature control valve is connected with a cooling liquid inlet of the LNG fuel vaporizer through a third pipeline, a fourth pipeline is connected between the cooling liquid outlet of the LNG fuel vaporizer and a liquid inlet end of the pump set equipment, and the temperature control valve is connected with the liquid inlet end of the pump set equipment through a fifth pipeline;

And the first temperature sensor is connected with the air outlet end of the LNG fuel vaporizer.

2. The marine natural gas fuel heat exchange system of claim 1, further comprising:

the first stop valve is connected to the first pipeline;

the pressure sensor is connected to the first pipeline and is arranged between the pump set equipment and the first stop valve.

3. The marine natural gas fuel heat exchange system of claim 1, further comprising:

The second temperature sensor is arranged at the cooling liquid inlet end of the heat exchanger and is connected to the first pipeline;

and the third temperature sensor is arranged at the cooling liquid outlet end of the heat exchanger and is connected to the second pipeline.

4. The marine natural gas fuel heat exchange system of claim 1, further comprising:

And the flowmeter is connected to the fourth pipeline and is used for detecting the flow of the cooling liquid in the fourth pipeline.

5. The marine natural gas fuel heat exchange system of claim 4 further comprising:

and the first stop check valve is connected to the fourth pipeline and is arranged at the downstream of the flowmeter.

6. The marine natural gas fuel heat exchange system of claim 1 wherein,

The fourth pipeline is provided with a first ventilation opening, and the first ventilation opening is arranged at the highest point of the fourth pipeline along the vertical direction;

the heat exchange system further comprises:

The expansion tank, be provided with second ventilative mouth, filling opening, return port, liquid outlet and moisturizing mouth on the expansion tank, the second ventilative mouth with the filling opening set up in the top of expansion tank, the return port with expansion tank's gaseous phase space intercommunication, just the return port with first ventilative mouth passes through sixth pipeline connection, the liquid outlet with pump package equipment's feed liquor end passes through seventh pipeline connection, the moisturizing mouth set up in expansion tank's upper portion is configured can be to make up fresh water in the expansion tank.

7. The marine natural gas fuel heat exchange system of claim 6 further comprising:

the liquid level meter is arranged in the expansion water tank.

8. The marine natural gas fuel heat exchange system of claim 1, wherein the heat exchanger is further provided with at least one water inlet and at least one water outlet, the water inlet is configured to be connected with a main engine cylinder liner water outlet, the water outlet is configured to be connected with a main engine cylinder liner water return water inlet, and the direction of inlet and outlet of main engine cylinder liner water into and from the heat exchanger is opposite to the direction of inlet and outlet of cooling liquid into and from the heat exchanger.

9. The marine natural gas fuel heat exchange system according to claim 8, wherein the heat exchanger is provided with two groups of heat exchange tubes, and two water outlets and two water inlets, and two ends of each group of heat exchange tubes are respectively connected with one water outlet and one water inlet.

10. The marine natural gas fuel heat exchange system as claimed in claim 1, wherein the heat exchange system is provided with two LNG fuel vaporizers, a first end of the second pipe is connected to the coolant outlet of the heat exchanger, a second end of the second pipe forms a first branch pipe and a second branch pipe, and one temperature control valve is connected to each of the first branch pipe and the second branch pipe.

11. The marine natural gas fuel heat exchange system of any one of claims 1 to 10, wherein the temperature control valve is a three-way valve comprising a first inlet, a first outlet and a second outlet, the first inlet being connected to the coolant outlet of the heat exchanger by the second conduit, the first outlet being connected to the coolant inlet of the LNG fuel vaporizer by the third conduit, the second outlet being connected to the liquid inlet of the pump stack apparatus by a fifth conduit.

12. The marine natural gas fuel heat exchange system of claim 11 wherein a second shut-off valve is disposed between the first outlet and the coolant inlet of the LNG fuel vaporizer, the second shut-off valve being connected to the third conduit.

13. A control method of a heat exchange system, applied to the heat exchange system according to claim 12, comprising:

When the first temperature sensor detects that the temperature of the air outlet end of the LNG fuel vaporizer is lower than 5 ℃, increasing the opening of the first outlet of the temperature control valve;

And when the first temperature sensor detects that the temperature of the air outlet end of the LNG fuel vaporizer is higher than 25 ℃, increasing the opening of the second outlet of the temperature control valve.

14. The control method of a heat exchange system according to claim 13, wherein the control method comprises:

When the first temperature sensor detects that the temperature of the air outlet end of the LNG fuel vaporizer is lower than 5 ℃, the first outlet of the temperature control valve is completely opened;

And when the first temperature sensor detects that the temperature of the air outlet end of the LNG fuel vaporizer is higher than 25 ℃, the second outlet of the temperature control valve is opened by 90%.