Marine fused salt energy storage system

Abstract

The invention provides a fused salt energy storage system for a ship. The fused salt energy storage system comprises a fused salt storage tank, fused salt, a heat exchanger and an energy management system, wherein the fused salt storage tank is filled with the fused salt; the heat exchanger is connected between the fused salt storage tank and a ship power system; the outer layer structure of the fused salt storage tank is made of anti-seismic composite materials, and the inner layer structure is made of high-temperature-resistant ceramic materials. The fused salt is a mixture of sodium nitrate and potassium nitrate; the energy management system monitors the temperature and flow velocity of the fused salt in real time through a sensor and automatically adjusts the flow velocity of the fused salt according to the temperature of the fused salt. According to the system, efficient heat energy storage and release are achieved through the high-temperature-resistant and anti-seismic fused salt storage tank and the efficient heat exchange system; molten salt formed by mixing sodium nitrate and potassium nitrate is adopted, energy can be stably stored for a long time, and the safety risk caused by temperature change is reduced; the system is provided with an energy management system and a safety monitoring system, so that the running state can be monitored and adjusted in real time, and the safety, reliability and energy efficiency of the ship in the sailing process are ensured.

Description

Technical Field

[0001] The invention relates to energy storage technology, in particular to a molten salt energy storage system. Background Art

[0002] Globally, ships are important means of transportation and cargo transport, and their energy efficiency and safety have attracted much attention. With the promotion of renewable energy, marine energy storage technology has gradually become the key to the development of the industry. However, existing energy storage solutions still have many shortcomings when adapting to the specific environment of ships.

[0003] First, traditional lithium-ion batteries do not perform well in the vibration environment of ships. The fluctuations in the marine environment and changes in wind force cause ships to constantly experience severe vibrations, which in turn affects the performance and safety of batteries. For example, lithium-ion batteries may experience internal short circuits or structural damage under high temperatures and severe vibrations, increasing the risk of fire and seriously threatening the safety of ships and crew members.

[0004] Secondly, although mechanical energy storage systems, such as flywheel energy storage, have certain advantages in efficiency, their sensitivity to the external environment and large size limit their use in ships. Flywheels run at high speeds, and any external shocks may cause them to lose control, which in turn poses a major safety hazard.

[0005] In addition, existing technologies need to be improved in terms of energy density and temperature adaptability. The performance of traditional batteries and mechanical systems decreases significantly in high or low temperature environments, which limits their application in extreme climates and cannot meet the needs of modern ships in changeable sea conditions.

[0006] As an emerging solution, molten salt energy storage technology has shown its unique advantages. The high melting point and thermal stability of molten salt enable it to maintain excellent performance at extreme temperatures and is not easily affected by shocks. Compared with traditional energy storage technologies, molten salt energy storage can not only achieve higher energy density, but also effectively reduce the risks caused by environmental changes.

[0007] Therefore, there is an urgent need for a new marine energy storage system that can ensure efficient energy storage and conversion while improving the safety of ships under various navigation conditions. The present invention aims to meet this demand and provide a safe, stable and efficient marine molten salt energy storage system. Summary of the invention

[0008] The purpose of the present invention is to provide a marine molten salt energy storage system to improve the safety, efficiency and reliability of ships in a shock environment.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a marine molten salt energy storage system, comprising a molten salt storage tank, molten salt filled in the molten salt storage tank, a heat exchanger arranged between the molten salt storage tank and the ship power system, and an energy management system; the outer layer structure of the molten salt storage tank adopts a seismic composite material, and the inner layer structure adopts a high-temperature resistant ceramic material; the molten salt is a mixture of sodium nitrate and potassium nitrate; the energy management system is configured to monitor the temperature and flow rate of the molten salt in real time through a sensor, and automatically adjust the flow rate of the molten salt.

[0010] The marine molten salt energy storage system comprises a salt outlet of a molten salt storage tank, a high-temperature molten salt pipeline, a high-temperature side of a heat exchanger, and a low-temperature molten salt pipeline, which are sequentially connected along a flow path of the molten salt to form a molten salt loop; the low-temperature side of the heat exchanger is connected to the ship power system.

[0011] The sensor includes at least one of a temperature sensor, a flow sensor, a current and voltage sensor, and a vibration sensor.

[0012] The marine molten salt energy storage system also includes a safety monitoring system and an emergency processing system; the safety monitoring system is configured to trigger an emergency cooling system when abnormal sensor data is detected; the emergency processing system includes a cooling pipe and a fault isolation device.

[0013] The cooling pipeline is connected to the high-temperature molten salt pipeline; when the sensor data is monitored to be abnormal, the emergency processing system is triggered, specifically including: when the temperature sensor monitors that the molten salt temperature exceeds the safety range, a signal is sent to simultaneously open the valves of the fault isolation device, the cooling pipeline and the pipeline where the coolant is located, and the pipeline where the heat exchanger is located is shut off, so that the coolant flows to cool the cooling pipeline to reduce the molten salt temperature.

[0014] The top of the molten salt storage tank is connected to an inert gas source through a regulating valve, so that the top of the cavity of the molten salt storage tank is filled with low-pressure inert gas; the inert gas source adjusts the gas pressure through the regulating valve, so that the inert gas pushes the molten salt out of the molten salt storage tank to the heat exchanger within a first preset time, and returns the molten salt to the molten salt storage tank through the low-temperature molten salt pipeline within a second preset time.

[0015] At least one side of at least one heat exchanger has a connecting pipe, and the connecting pipe is connected to the expansion pipe; the liquid level of the molten salt is located in the expansion pipe, and an exhaust pipe is provided on the top of the expansion pipe; the exhaust pipe is connected to an inert gas source through a valve; and the cooling pipe is connected between the two expansion pipes.

[0016] The molten salt storage tank has a feeding port, and the marine molten salt energy storage system is configured to adjust the ratio of sodium nitrate and potassium nitrate in the molten salt through the feeding port for different working modes to meet different working temperatures.

[0017] The marine molten salt energy storage system also includes a molten salt cooling pipeline which is arranged between the high-temperature molten salt pipeline and the low-temperature molten salt pipeline and can be switched between an open state and a closed state; and in standby mode, the marine molten salt energy storage system is configured to start a heater on the molten salt loop to heat the molten salt loop to prevent the molten salt loop from being blocked.

[0018] The marine molten salt energy storage system also includes an elastic support system arranged at the bottom of the molten salt storage tank.

[0019] The capacity of the molten salt storage tank is between 500 liters and 5000 liters; the heat exchanger adopts a multi-channel plate design; and the marine molten salt energy storage system adopts a modular design.

[0020] The marine molten salt energy storage system provided by the present invention realizes efficient thermal energy storage and release through a highly temperature-resistant and shock-resistant molten salt storage tank and an efficient heat exchange system. The system uses a molten salt material mixed with sodium nitrate and potassium nitrate, which has excellent thermal conductivity and high melting point, can stably store energy for a long time, and reduce safety risks caused by temperature changes. The system is equipped with an energy management system and a safety monitoring system, which can monitor and adjust the operating status in real time to ensure the safety, reliability and energy efficiency of the ship during navigation.

[0021] In addition, the molten salt storage tank adopts a double-layer design, combined with a modular installation and maintenance solution, which improves the applicability and ease of operation of the system. In addition, the emergency handling mechanism and fault isolation device are set up to enable rapid response and reduce potential dangers in abnormal situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a structural schematic diagram of a marine molten salt energy storage system according to an embodiment of the present invention;

[0023] Figure 2 It is a partial dimension diagram of a marine molten salt energy storage system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] like Figure 1 and Figure 2 The figure shows a marine molten salt energy storage system according to an embodiment of the present invention, which includes a molten salt storage tank 10, molten salt filled in the molten salt storage tank 10, a heat exchanger 20 (the tank on the right is a heat exchanger) arranged between the molten salt storage tank 10 and the ship power system, an energy management system, a safety monitoring system and an emergency handling system, an inert gas source 40 connected to the top of the molten salt storage tank 10, and an elastic support system 50 arranged at the bottom of the molten salt storage tank 10.

[0025] The energy management system is configured to monitor the temperature and flow rate of the molten salt in real time through sensors, and automatically adjust the flow rate of the molten salt according to the temperature of the molten salt. The safety monitoring system is configured to trigger the emergency cooling system to reduce the temperature of the molten salt when abnormal data from the sensor is detected (i.e., abnormal temperature, pressure or vibration of the molten salt). The emergency treatment system includes a cooling pipe 31 and a fault isolation device 32 to reduce the safety risk when the system fails. The energy management system and the safety monitoring system are both installed on the central control unit, so that the data of the sensor is transmitted to the central control unit wirelessly. The energy management system and the safety monitoring system on the central control unit analyze the data of all sensors to determine the operating status of the marine molten salt energy storage system.

[0026] The marine molten salt energy storage system comprises a salt outlet 11 of a molten salt storage tank 10, a high-temperature molten salt pipeline 61, a high-temperature side of a heat exchanger 20, and a low-temperature molten salt pipeline 62, which are sequentially connected along a flow path of the molten salt to form a molten salt loop.

[0027] Among them, the molten salt loop is the core channel of energy transmission, which is responsible for transferring the heat in the molten salt storage tank 10 to the heat exchanger, and returning the cooled molten salt released by the heat exchanger 20 to the molten salt storage tank 10, forming a closed loop. In addition, the low temperature side of the heat exchanger 20 is connected to the ship power system, so that the ship power system (such as the thermoelectric conversion module) is heated by the heat exchanger 20 to drive the ship to work, which is used to generate electricity or drive the ship propulsion system.

[0028] In this embodiment, the ship power system includes a thermoelectric conversion module, and the thermoelectric material in the thermoelectric conversion module directly converts heat energy into electrical energy under the action of temperature difference. The cold end of the thermoelectric conversion module is kept at a low temperature by the ship power cooling system to ensure the efficiency of thermoelectric conversion. In order to further improve the efficiency of thermoelectric conversion, the heat exchanger 20 and the thermoelectric conversion module are closely combined to maximize heat transfer and power generation.

[0029] The top of the molten salt storage tank 10 is connected to the inert gas source 40 through a regulating valve, so that the top of the cavity of the molten salt storage tank 10 is filled with low-pressure inert gas. The inert gas source 40 adjusts the gas pressure through the regulating valve to push the molten salt from the salt outlet 11 of the molten salt storage tank 10 to be transported to the heat exchanger 20 via the high-temperature molten salt pipeline 61, and the gas pressure of the inert gas is used to adjust the flow rate of the molten salt entering the high-temperature molten salt pipeline 61, without the assistance of a mechanical pump, to ensure that the high-temperature molten salt flows smoothly to the inlet of the heat exchanger.

[0030] At least one side of at least one heat exchanger 20 has a connecting pipe, and the connecting pipe is connected to the expansion pipe 21. The liquid level of the molten salt is located in the expansion pipe 21, and an exhaust pipe 41 is provided on the top of the expansion pipe 21. The exhaust pipe 41 can be connected to the inert gas source 40 through a valve, so that the inert gas can be reused. In this embodiment, the number of the expansion pipes 21 is 2, and the high-temperature molten salt pipeline 61 is connected to one of the expansion pipes 21.

[0031] Subsequently, the molten salt flows into the high temperature side of the heat exchanger 20, exchanges heat with the ship power system (such as a thermoelectric conversion module), and after the molten salt releases heat in the heat exchanger 20, the temperature decreases, flows out of the heat exchanger 20 into the low temperature molten salt pipeline 62 and flows back to the molten salt storage tank 10. The gas pressure of the inert gas in the molten salt storage tank 10 is dynamically adjusted, so that the low temperature molten salt can smoothly return to the molten salt storage tank 10.

[0032] That is to say, the inert gas source adjusts the gas pressure through the regulating valve, so that the inert gas pushes the molten salt to leave the molten salt storage tank 10 through the high-temperature molten salt pipeline 61 within a first preset time, and allows the molten salt to return to the molten salt storage tank 10 through the low-temperature molten salt pipeline 62 within a second preset time.

[0033] The refluxed molten salt is heated again by the heating device in the molten salt storage tank 10, and enters the next cycle after reaching the set temperature. In this embodiment, the number of heat exchangers 20 is 3.

[0034] Therefore, when the ship is in a sailing state, under high load conditions (such as when the ship is sailing at full speed), the high-temperature molten salt in the molten salt loop flows through the heat exchanger, transferring a large amount of heat to the power system, and the power system uses the heat for thermoelectric power generation or other mechanical conversions.

[0035] When the ship is in sailing state, under low load conditions (such as when the ship is berthed), the flow and temperature of the molten salt circuit are reduced, and the power system only needs a small amount of heat to maintain the operation of auxiliary functions. The remaining heat can be stored in the molten salt storage tank for later use.

[0036] In addition, the marine molten salt energy storage system also includes a molten salt cooling pipeline that is located between the high-temperature molten salt pipeline 61 and the low-temperature molten salt pipeline 62 and can be switched between the open and closed states. The molten salt cooling pipeline is opened in the energy reserve mode (such as non-navigation state), and its purpose is to ensure that the molten salt forms a temperature difference that can form a cycle, and prevent the blockage caused by the molten salt not forming a cycle in the non-navigation state. In the energy reserve mode (such as non-navigation state), the molten salt circuit cuts off the connection with the power system and opens the molten salt cooling pipeline, so the molten salt no longer passes through the heat exchanger 20, but only flows and circulates along the molten salt storage tank 10, the high-temperature molten salt pipeline 61, the molten salt cooling pipeline, and the low-temperature molten salt pipeline 62 in sequence, reducing heat loss, while keeping the molten salt in a state suitable for reuse. It should be noted that the molten salt cooling pipeline for the flow of molten salt is located at the low-temperature molten salt pipeline 62, and the molten salt cooling pipeline is opened in the non-navigation state, and its purpose is to ensure that the molten salt forms a temperature difference that can form a cycle, and prevent the blockage caused by the molten salt not forming a cycle in the non-navigation state. The cooling pipe for the coolant to flow is 31 in the figure, which will be described in detail below.

[0037] The molten salt storage tank 10 is a double-layer structure, including an outer layer structure and an inner layer structure. The outer layer structure is made of composite materials and has excellent shock resistance and corrosion resistance; the inner layer structure is made of high-temperature resistant ceramic materials, and the surface of the inner layer structure is specially treated to enhance its thermal conductivity and avoid reaction between molten salt and the tank wall.

[0038] Among them, the outer layer structure adopts a seismic composite material with excellent seismic resistance and corrosion resistance. In this embodiment, the composite material of the outer layer structure needs to meet the following conditions to ensure the seismic resistance and corrosion resistance of the system: the outer layer material needs to have high strength and toughness, and can absorb and resist the vibration and impact of the ship under complex sea conditions (such as waves, shaking, and collisions). Therefore, the outer layer structure adopts a glass fiber reinforced composite material with good toughness and fatigue resistance, low cost, and suitable for large-scale use. In addition, the outer layer material needs to be able to resist the corrosion of salt spray, moisture, and acidic substances in seawater in the ship's operating environment for a long time. Therefore, the outer layer structure also adopts an epoxy resin-based composite material with excellent corrosion resistance, which can be used in combination with glass fiber or carbon fiber.

[0039] The material of the outer structure needs to have low thermal conductivity to reduce heat loss to the outside, while providing good insulation and protection. The thermal conductivity of the material of the outer structure is in the range of 0.05–0.5W / (m·K). Low thermal conductivity can effectively isolate the high temperature of the inner layer, prevent the outer structure from overheating, and reduce energy loss.

[0040] The inner layer structure is made of high temperature resistant ceramic material, and its surface is specially treated by coating a layer of graphene coating on the ceramic surface. Thus, by coating the graphene on the ceramic surface, the thermal conductivity can be greatly improved, while the oxidation resistance and corrosion resistance of the ceramic can be enhanced, and the molten salt can be prevented from reacting with the tank wall. The reasons and purposes for setting the inner layer structure mainly include the following points:

[0041] 1. Uniform temperature. In the molten salt storage tank, the high thermal conductivity inner layer material can help distribute heat quickly and evenly to avoid local overheating or overcooling. Its advantage is to reduce local thermal stress: avoid local high temperature causing thermal fatigue or cracks on the inner layer material. Improve the thermal efficiency of the system: ensure that the molten salt in the molten salt storage tank always maintains a uniform operating temperature.

[0042] 2. To optimize thermoelectric conversion, the molten salt storage tank needs to provide a stable high-temperature heat source to the thermoelectric module. The enhanced thermal conductivity of the inner layer can quickly respond to the thermal demand of the thermoelectric module, ensure that the temperature difference is always maintained within the optimal range, and improve the power generation efficiency of the thermoelectric module.

[0043] 3. Rapid heat transfer: The main task of the inner layer of the molten salt storage tank is to efficiently transfer the heat of the molten salt to the external heat exchanger or molten salt circuit. If the thermal conductivity of the inner layer material is insufficient, it will cause delayed heat transfer and reduce the overall efficiency of the system.

[0044] The material of the inner layer structure needs to have high thermal conductivity to quickly transfer heat and ensure temperature uniformity inside the tank. The thermal conductivity of the material of the inner layer structure ranges from 20-60W / (m·K). The operating temperature range of molten salt is generally between 200-600°C. The high thermal conductivity can ensure that the heat in the molten salt tank 10 can be quickly transferred to the heat exchanger or loop.

[0045] The capacity of the molten salt storage tank 10 is designed according to the type of ship and navigation requirements, and is usually between 500 liters and 5000 liters. The molten salt storage tank 10 adopts a cylindrical design, which helps to evenly distribute the pressure and reduce the force concentration under shock conditions. The interior of the molten salt storage tank 10 is also provided with an insulation layer for dividing the internal cavity of the molten salt storage tank 10 into multiple parts to prevent heat loss and reduce the impact of the external environment on the molten salt. The molten salt storage tank 10 is connected to the hull through an elastic support system, which can effectively absorb shocks and reduce the impact on the molten salt storage tank 10.

[0046] The heat exchanger 20 adopts a multi-channel plate heat exchanger to ensure that heat is quickly and efficiently transferred between the molten salt and the ship power system. The shape and size of each channel of the heat exchanger 20 are optimized with the goal of maximizing the heat exchange efficiency of the fluid flow.

[0047] The molten salt is a mixture of sodium nitrate and potassium nitrate, which has excellent thermal conductivity and chemical stability, and can store heat energy for a long time without phase change. The specific heat capacity of the molten salt is above 2.5 kJ / kg·K, ensuring that heat energy can be stably stored for a long time, and is suitable for long-distance navigation.

[0048] The energy management system is connected to a variety of sensors and is configured to monitor the temperature, flow rate and gas pressure of the molten salt in real time, and automatically adjust the temperature and flow rate of the molten salt in combination with the ship's operating mode and / or energy demand, thereby adjusting the heat exchange rate to ensure that the ship's power system operates within the required temperature range, thereby improving the thermoelectric conversion efficiency and stabilizing the output of electrical energy. The energy management system is installed on the central control unit and is equipped with an advanced microprocessor and software algorithm.

[0049] In this embodiment, the sensors connected to the energy management system include a temperature sensor T1, a flow sensor, and a current and voltage sensor, and the temperature of the molten salt is adjusted by a flow control valve.

[0050] Wherein, the temperature sensor T1 is set to monitor the temperature of the molten salt at various positions in real time. The temperature sensor T1 may include one or more, respectively arranged in the molten salt storage tank 10, the expansion tube 21, various positions in the cooling pipe 31, the inlet and outlet of each heat exchanger 20, etc. The flow sensor is set to monitor the flow rate or mass flow of the molten salt or coolant in real time. The flow sensor and the flow control valve can be set at the same position as the temperature sensor T1. The current and voltage sensors are set to monitor the output current and output voltage of the ship power system (i.e., the electric heating module) in real time.

[0051] Therefore, the temperature gradient inside the tank is monitored by temperature sensor T1, and the total heat stored in the tank is calculated by combining the mass and specific heat capacity of the molten salt:

[0052] Among them, Q total is the total heat stored; T min and T max are the lowest and highest temperatures of the molten salt in the storage tank; m is the mass of the molten salt; c is the specific heat capacity of the molten salt.

[0053] In the heat exchanger 20, the energy flow is calculated by the flow sensor and the temperature sensor T1 at the inlet and outlet of the heat exchanger 20: P flow =m·c·ΔT, where ΔT is the temperature difference between the inlet and outlet of the heat exchanger, P flow is the energy exchanged through the heat exchanger.

[0054] The output power of the ship power system is the product of the output current and the output voltage, and is related to the temperature difference and the heat of the molten salt. Therefore, the output power P of the ship power system iselec It can also be calculated based on the data from temperature sensor T1:

[0055] P elec =η TE ·P heat ,

[0056] Among them, P elec is the output electrical energy of the ship power system, η TE is the thermoelectric conversion efficiency (related to temperature difference); P heat is the input thermal power, which is usually equal to the energy exchanged through the heat exchanger.

[0057] The flow rate of molten salt is mainly regulated by the flow control valve installed in the molten salt circuit. The flow control valve can accurately adjust the valve opening according to the instructions of the central control unit, thereby controlling the flow rate of the molten salt in the pipeline. The temperature of the molten salt can also be indirectly controlled by adjusting its flow rate. For example, increasing the flow rate of the molten salt shortens the residence time of the fluid in the circuit, and reduces the heat absorbed or released per unit time, thereby reducing the temperature difference between the inlet and outlet.

[0058] Among them, when the ship is in a sailing state, the ship-borne molten salt energy storage system can optimize energy use according to the sailing mode, reduce energy consumption, and improve overall efficiency.

[0059] According to the ship's mission and operating status, it can be divided into the following typical navigation modes:

[0060] (1) Economic cruising mode, suitable for: ships sailing at a stable economic speed. Features: low power load and medium heat demand. The regulation strategy of the marine molten salt energy storage system is: the molten salt temperature is maintained at a medium level to avoid excessive energy loss. The heat in the storage tank is only used to maintain the basic heat output required by the power system, and the molten salt temperature is maintained at a medium level to avoid excessive energy loss.

[0061] (2) High-load acceleration mode is applicable to: when the ship sets sail, needs to accelerate quickly, or cope with severe sea conditions. The regulation strategy of the marine molten salt energy storage system is: due to the high power load, it is necessary to increase the temperature of the molten salt storage tank to the highest working level to meet the demand for rapid release of heat energy. As a result, the heat in the storage tank is quickly transferred to the heat exchanger, providing an efficient heat source for the power system.

[0062] (3) Low-load idling mode is applicable when the ship is waiting at the port or traveling at a low speed. The regulation strategy of the marine molten salt energy storage system is: due to the low power load, the temperature of the molten salt storage tank is reduced to the minimum safe temperature to reduce heat loss. Thus, the minimum heat energy supply is maintained, which is only for the basic function operation of the ship.

[0063] (4) The standby or emergency mode is applicable when emergency auxiliary power is required in case of emergencies or equipment failures. The regulation strategy of the marine molten salt energy storage system is as follows: due to the rapid increase in energy demand, the system is required to respond quickly. Specifically, the temperature of the storage tank needs to be quickly heated to the operating temperature to ensure that heat energy can be output at any time; and part of the molten salt is preheated for standby to avoid excessive heating time in case of sudden demand.

[0064] (5) Standby mode is applicable to: when the ship is docked at the port or not in navigation. The adjustment strategy of the marine molten salt energy storage system is: since it is mainly used to maintain the operation of the basic power and safety systems of the ship, the energy demand is relatively low. Therefore, the molten salt maintains a low temperature state and only maintains the basic energy supply capacity. The heat in the storage tank is used to maintain the operation of the ship's power and safety systems. In addition, in standby mode, the marine molten salt energy storage system is also configured to start the heater on the molten salt loop to heat the molten salt loop to ensure a certain initial temperature to prevent the molten salt loop from being blocked. In this embodiment, the heater includes but is not limited to a storage tank heater, a feed pipe heater, a high-temperature molten salt pipe heater, an expansion tube heater, a heat exchanger inlet and outlet heater, and the like.

[0065] Therefore, combined with the temperature sensor T1 and the flow control valve, the marine molten salt energy storage system can adjust the heat exchange rate in real time to adapt to the different load and speed conditions of the ship. The marine molten salt energy storage system can also work in conjunction with other energy systems of the ship (such as diesel generators, wind power generation systems, etc.) to achieve optimal energy configuration and use.

[0066] In this embodiment, the molten salt storage tank 10 has a feed port 12. Therefore, for different working modes, the ratio of each component in the molten salt can be adjusted through the feed port to achieve adaptation to different temperatures and energy requirements. Specifically, by changing the ratio of sodium nitrate and potassium nitrate, different working temperatures can be met. The following examples are provided:

[0067] (1) Applicable scenarios for medium temperature scenarios (400-550℃) include: the ship is in economic cruising mode. Since the energy demand is relatively balanced in this mode, the ratio of sodium nitrate to potassium nitrate (i.e. NaNo3:KNo3) is 50:50 to 40:60. The characteristic is that the melting point is low, at 400-520℃, which is convenient for the rapid start-up of the energy storage system. At the eutectic ratio, the fluidity and thermal stability of the molten salt are good, which is suitable for medium temperature circulation.

[0068] (2) Suitable for high temperature scenarios (550-600℃) include: ships are in high load acceleration mode and have high power demand. Therefore, the ratio of sodium nitrate to potassium nitrate (i.e., NaNo3:KNo3) is 60:40 to 70:30. The characteristic is that the melting point is 530-580°, and the high melting point helps to improve the thermoelectric conversion efficiency. It is suitable for working conditions that require high temperature heating, such as high-efficiency thermoelectric power generation modules.

[0069] (3) Applicable scenarios for low temperature scenarios (200-350℃) include: the ship is in standby mode or low load idling mode, the energy demand is low, and the ratio of sodium nitrate to potassium nitrate (i.e. NaNo3:KNo3) is 40:60. The characteristic is that the melting point of molten salt is between 180-330℃, and the lower melting point reduces the energy demand of molten salt, which is suitable for maintaining heat storage in low temperature state and improving the system startup speed and energy utilization rate in low temperature environment.

[0070] In summary, the working mode of the marine molten salt energy storage system is shown in Table 1.

[0071] Table 1: Working mode of marine molten salt energy storage system

[0072] The safety monitoring system is installed on the central control unit, which is connected to a variety of sensors to form a closed-loop monitoring system. The sensors connected to the safety monitoring system include temperature sensors, pressure sensors and vibration sensors to ensure the safety of the system during operation.

[0073] The safety monitoring system is configured to trigger an emergency cooling system to reduce the temperature of the molten salt when abnormal data from the sensor is detected. The emergency handling system includes a cooling pipe and a fault isolation device 32 to reduce the safety risk when the system fails. Thus, the sensor data is transmitted to the safety monitoring system in real time to analyze and judge the operating status. Once an abnormality is detected, such as excessive temperature or excessive vibration, the system will start the cooling pipe 31 and the fault isolation device 32 to reduce the temperature of the molten salt. The cooling pipe 31 is connected between the two expansion pipes 21, and one end thereof is connected to the high-temperature molten salt pipe 61.

[0074] Among them, the temperature sensor connected to the safety monitoring system can be set inside the molten salt storage tank to monitor the temperature of the molten salt through the temperature sensor to ensure that the molten salt temperature does not exceed the preset safety range to prevent overheating from causing safety problems. The temperature sensor can be set at the cold end of the thermoelectric module to monitor the temperature of the cold end of the thermoelectric module to ensure that the temperature difference is maintained within a reasonable range to prevent damage to the thermoelectric material. The temperature sensor can also be set at the inlet and outlet of the heat exchanger to monitor the temperature change of the molten salt passing through the heat exchanger in real time to ensure that the heat exchange process is efficient and does not cause overheating.

[0075] The pressure sensor connected to the safety monitoring system can be used to measure the pressure inside the molten salt storage tank. Among them, the pressure in the molten salt storage tank is monitored by the pressure sensor to avoid excessive pressure caused by overheating of the molten salt, thereby avoiding risks such as explosion. In addition, the pressure sensor connected to the safety monitoring system can also be set at the inlet and outlet of the heat exchanger to obtain the pressure difference between the inlet and outlet of the heat exchanger: monitor the pressure difference at both ends of the heat exchanger to determine whether the fluid flow is normal, and prevent abnormal pressure due to blockage or failure.

[0076] Vibration data of the safety monitoring system: Vibration of storage tanks and heat exchangers: In the ship's shock environment, vibration sensors are used to monitor the vibration of storage tanks and heat exchangers to prevent the system from being affected by excessive vibration, resulting in structural damage or failure; they are also used to monitor the vibration of thermoelectric modules and their emergency treatment systems to ensure stable operation of the equipment during ship movement and prevent equipment damage due to excessive vibration.

[0077] As a result, the data collected by all sensors will be transmitted to the central control unit in real time via wireless or wired means. The energy management system and safety monitoring system on the central control unit will analyze the data and determine the operating status of the system.

[0078] The emergency handling system includes a cooling pipe 31 and a fault isolation device 32 to reduce the safety risk when the system fails.

[0079] The safety monitoring system is configured to trigger an emergency processing system, such as opening the cooling pipe 31, closing the fault isolation device 32 or alarming, when abnormal sensor data is detected (i.e., abnormal temperature, pressure or vibration of the molten salt), to ensure the safety of the ship and crew.

[0080] Among them, when the sensor data is monitored to be abnormal, the emergency processing system is triggered, specifically including: when the temperature sensor monitors that the molten salt temperature exceeds the safety range, a signal is sent to simultaneously open the valves of the fault isolation device 32, the cooling pipe 31 and the coolant pipe, and shut down the pipe where the normal heat exchanger 20 is located, that is, disconnecting the heat exchange between the molten salt and the ship's power system, allowing the coolant to flow to cool the cooling pipe 31, thereby quickly reducing the molten salt temperature to prevent accidents caused by overheating and excessive pressure.

[0081] In this embodiment, the coolant is water. When the system detects that the molten salt temperature is too high, the coolant will quickly flow into the low-temperature side of the heat exchanger on the cooling pipe 31 through the coolant pipe to contact the molten salt, and the molten salt is connected to the high-temperature side of the heat exchanger on the cooling pipe 31, so that the coolant absorbs and takes away the heat.

[0082] The fault isolation device 32 is used to isolate the molten salt storage tank from other parts of the molten salt circuit, and can quickly isolate the fault area in an emergency to reduce the impact of risks on the overall safety of the ship. In this embodiment, the fault isolation device 32 is an isolation valve, which is arranged on the high-temperature molten salt pipeline 61 and the low-temperature lava pipeline 62.

[0083] In addition, the marine molten salt energy storage system of the present invention also includes a touch screen, through which the crew can view the system status, adjust settings and perform fault diagnosis in real time.

[0084] The marine molten salt energy storage system of the present invention adopts a modular design, which is easy to install and disassemble. Each module is equipped with a standard interface to ensure compatibility with other systems on the ship. The system comes with a detailed maintenance manual to guide the crew to perform regular inspections and maintenance, including sensor calibration, pump lubrication, and tank cleaning.

[0085] Through the above specific implementation methods, the ship-borne molten salt energy storage system of the present invention not only has significant advantages in energy storage and conversion efficiency, but also ensures the safety and reliability of ships under various navigation conditions through intelligent monitoring and emergency mechanisms.

[0086] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A marine molten salt energy storage system, characterized in that: It includes a molten salt storage tank, molten salt filled in the molten salt storage tank, a heat exchanger connected between the molten salt storage tank and a ship power system, and an energy management system; The outer structure of the molten salt storage tank is made of earthquake-resistant composite materials, and the inner structure is made of high-temperature resistant ceramic materials; the molten salt is a mixture of sodium nitrate and potassium nitrate; the energy management system is configured to monitor the temperature and flow rate of the molten salt in real time through sensors, and automatically adjust the flow rate of the molten salt according to the temperature of the molten salt.

2. The marine molten salt energy storage system according to claim 1, characterized in that: The marine molten salt energy storage system comprises a salt outlet of a molten salt storage tank, a high-temperature molten salt pipeline, a high-temperature side of a heat exchanger, and a low-temperature molten salt pipeline, which are sequentially connected along a flow path of the molten salt to form a molten salt loop; The low temperature side of the heat exchanger is connected to the ship power system.

3. The marine molten salt energy storage system according to claim 2, characterized in that: The sensor includes at least one of a temperature sensor, a flow sensor, a current and voltage sensor, and a vibration sensor.

4. The marine molten salt energy storage system according to claim 1, characterized in that: It also includes a safety monitoring system and an emergency processing system; the safety monitoring system is configured to trigger the emergency cooling system when abnormal sensor data is detected; the emergency processing system includes a cooling pipeline and a fault isolation device.

5. The marine molten salt energy storage system according to claim 4, characterized in that: The cooling pipeline is connected to the high-temperature molten salt pipeline; When abnormal sensor data is detected, the emergency response system is triggered, specifically including: when the temperature sensor detects that the molten salt temperature exceeds the safety range, a signal is sent to simultaneously open the valves of the fault isolation device, the cooling pipe and the coolant pipe, and shut off the pipe where the heat exchanger is located, so that the coolant flows to cool the cooling pipe to reduce the molten salt temperature.

6. The marine molten salt energy storage system according to claim 5, characterized in that: The top of the molten salt storage tank is connected to an inert gas source through a regulating valve, so that the top of the cavity of the molten salt storage tank is filled with low-pressure inert gas; the inert gas source adjusts the gas pressure through the regulating valve, so that the inert gas pushes the molten salt out of the molten salt storage tank to the heat exchanger within a first preset time, and returns the molten salt to the molten salt storage tank through the low-temperature molten salt pipeline within a second preset time.

7. The marine molten salt energy storage system according to claim 6, characterized in that: At least one side of at least one heat exchanger has a connecting pipe, and the connecting pipe is connected to the expansion pipe; the liquid level of the molten salt is located in the expansion pipe, and an exhaust pipe is provided on the top of the expansion pipe; the exhaust pipe is connected to an inert gas source through a valve; and the cooling pipe is connected between the two expansion pipes.

8. The marine molten salt energy storage system according to claim 1, characterized in that: The molten salt storage tank has a feeding port, and the marine molten salt energy storage system is configured to adjust the ratio of sodium nitrate and potassium nitrate in the molten salt through the feeding port for different working modes to meet different working temperatures.

9. The marine molten salt energy storage system according to claim 2, characterized in that: The marine molten salt energy storage system also includes a molten salt cooling pipeline which is arranged between the high-temperature molten salt pipeline and the low-temperature molten salt pipeline and can be switched between an open state and a closed state; and in standby mode, the marine molten salt energy storage system is configured to start a heater on the molten salt loop to heat the molten salt loop to prevent the molten salt loop from being blocked.

10. The marine molten salt energy storage system according to claim 1, characterized in that: The marine molten salt energy storage system further comprises an elastic support system arranged at the bottom of the molten salt storage tank; and / or The capacity of the molten salt storage tank is between 500 liters and 5000 liters; and / or The heat exchanger adopts a multi-channel plate design; and / or The marine molten salt energy storage system adopts a modular design.

Images