Horizontal single-tank fused salt heat storage system

Abstract

The utility model relates to the technical field of fused salt heat storage, in particular to a horizontal single-tank fused salt heat storage system which comprises a fused salt single tank, a fused salt heater, a heat release heat exchanger, a fused salt pump and a fused salt sprayer. The molten salt single tank adopts a lower horizontal storage tank structure and a low-position arrangement design, so that the molten salt heater and the heat release heat exchanger are easier to realize high-position arrangement, meanwhile, the molten salt single tank has the function of a salt dredging tank, the system is simplified, and the occupied area and investment of the system are reduced. The molten salt heater and the heat release heat exchanger are connected in series, so that the molten salt heat storage system can run in a heat storage working condition, a heat release working condition and a working condition of storing and releasing at the same time, the requirement of 24-hour stable steam supply of a user is met, each device is always in a hot standby state, the operation control is simple, and the response speed is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of fused salt heat storage, in particular to horizontal single tank fused salt heat storage system. BACKGROUND

[0002] The traditional fused salt double-tank heat storage system adopts a design of separating cold and hot fused salts, and through the circulation heat exchange of the cold and hot fused salts between the cold tank and the hot tank, the technical risk is reduced and the stability of the whole heat storage system is improved. The fused salt double-tank heat storage system can usually support a larger energy storage scale, which is of great significance to meet the large-scale and long-time energy storage needs. However, the fused salt double-tank heat storage system needs additional equipment and pipelines to realize the separation and circulation of cold and hot fused salts, so the investment and operation cost is high, and the fused salt double-tank heat storage system involves more control logic and operation process, increasing the complexity and maintenance difficulty of the system. In addition, due to the need of two independent tanks, the fused salt double-tank heat storage system usually occupies a large area, which may be a challenge for places with limited space.

[0003] With the progress of energy storage technology, miniaturization and light weight have become important development directions of fused salt storage tanks. The fused salt single-tank system can better meet the needs of miniaturized applications and provide convenient and efficient energy storage solutions for distributed energy systems, mobile energy systems, etc.

[0004] At present, there are several technical routes for single-tank fused salt heat storage technology, among which the upper part of the inclined temperature layer fused salt single tank stores high-temperature fused salt and the lower part stores low-temperature fused salt. Since cold and hot fused salts are stored in one tank at the same time, the tank body is subjected to large thermal stress during storage and heat release, especially in the central inclined temperature layer area where the temperature gradient is the largest, causing the largest stress impact on the tank wall. In severe cases, it may cause leakage of fused salt, affecting the safe operation of the fused salt single tank. The heat storage and heat release conditions of the single-pump fused salt single-tank heat storage system can only be operated in time periods, which cannot meet the 24-hour steam supply demand of users, and the system includes a salt-removing tank and other equipment, which is complex to operate and occupies a large area. In combination with the steam supply demand of industries and businesses, it is an urgent problem to be solved to design a horizontal single-tank fused salt heat storage system to realize 24-hour stable steam supply. SUMMARY

[0005] The technical problem to be solved by the utility model is to provide a horizontal single-tank fused salt heat storage system, simplify the fused salt heat storage system, reduce the occupied area, and realize 24-hour stable steam supply.

[0006] In order to achieve the above object, the technical scheme of the utility model provides horizontal single tank molten salt heat storage system, including molten salt single tank, molten salt heater, heat releasing heat exchanger, molten salt pump, molten salt sprayer, the outlet of molten salt single tank is communicated with the inlet of molten salt heater through molten salt pump, the outlet of molten salt heater is communicated with the inlet of heat releasing heat exchanger, the outlet of heat releasing heat exchanger is communicated with the inlet of molten salt single tank. The molten salt single tank is horizontal storage tank, and the upper portion is inserted into molten salt pump and is provided with molten salt sprayer, and the molten salt flows to molten salt single tank through molten salt sprayer, the horizontal single tank molten salt heat storage system adopts high and low arrangement, and the molten salt single tank is arranged at low position, and the molten salt heater and heat releasing heat exchanger are arranged at high position.

[0007] Preferably, the position of the molten salt heater and heat releasing heat exchanger can be interchanged according to actual conditions.

[0008] Preferably, the molten salt single tank is a horizontal storage tank.

[0009] Preferably, the heat storage medium in the molten salt single tank is single molten salt or multi-element mixed molten salt.

[0010] Preferably, the heat source of the molten salt heater is valley electricity, new energy electricity, solar energy, high-temperature steam or high-temperature flue gas.

[0011] Preferably, the single tank molten salt heat storage system further comprises an electric heat tracing system, and electric heat tracing devices are provided on equipment, pipelines and valves.

[0012] Preferably, the horizontal single tank molten salt heat storage system can operate heat storage condition, heat releasing condition and heat storage and releasing condition, and the specific operation process is as follows:

[0013] a, heat storage condition: the heat releasing heat exchanger is in a non-working state, the molten salt in the molten salt single tank is pumped out by the molten salt pump, flows into the molten salt heater, and then flows into the heat releasing heat exchanger after temperature rising, and then flows into the molten salt single tank; the molten salt is always heated, and the heat storage condition ends after being heated to a specified temperature.

[0014] b, heat releasing condition: the molten salt heater is in a non-working state, the molten salt in the molten salt single tank is pumped out by the molten salt pump, flows into the molten salt heater, and then flows into the heat releasing heat exchanger, and then flows into the molten salt single tank after temperature decreasing; the molten salt is always cooled, and the heat releasing condition ends after being cooled to a specified temperature.

[0015] c, heat storage and releasing condition: the molten salt in the molten salt single tank is pumped out by the molten salt pump, flows into the molten salt heater, and then flows into the heat releasing heat exchanger after temperature rising, and then flows into the molten salt single tank after temperature decreasing; the molten salt is first heated and then cooled in one cycle, if the degree of heating is stronger than the degree of cooling, the molten salt is in a circulating heating state; if the degree of heating is equal to the degree of cooling, the molten salt is in a temperature-invariant state.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] (1) In this utility model, the molten salt tank adopts a horizontal storage tank structure with a smaller height and a low-position arrangement, which makes it easier to realize the high-position arrangement of the molten salt heater and heat release heat exchanger. At the same time, the molten salt tank has the function of a salt discharge tank, which simplifies the system and reduces the system footprint and investment.

[0018] (2) This utility model, through the series design of molten salt heater and heat release heat exchanger, enables the molten salt heat storage system to operate in heat storage mode, heat release mode and simultaneous storage and release mode, so as to meet the user's demand for stable steam supply 24 hours a day. Moreover, each device is always in hot standby state, and the operation control is simple and the response speed is fast.

[0019] (3) By installing a molten salt sprayer on the molten salt tank, the present invention enables the hot and cold molten salts to be quickly and evenly mixed during the heat storage and heat release process, thus ensuring the safe operation of the molten salt tank. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a horizontal single-tank molten salt thermal storage system.

[0021] Reference numerals: 1. Molten salt tank; 2. Molten salt heater; 3. Heat exchanger; 4. Molten salt pump; 5. Molten salt sprayer. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] This utility model is a horizontal single-tank molten salt thermal storage system, such as Figure 1 As shown, it includes a molten salt tank 1, a molten salt heater 2, a heat release heat exchanger 3, a molten salt pump 4, and a molten salt sprayer 5. The outlet of the molten salt tank 1 is connected to the inlet of the molten salt heater 2 via the molten salt pump 4; the outlet of the molten salt heater 2 is connected to the inlet of the heat release heat exchanger 3; the outlet of the heat release heat exchanger 3 is connected to the inlet of the molten salt tank 1. The molten salt tank 1 is a horizontal storage tank, with the molten salt pump 4 inserted into its upper part and the molten salt sprayer 5 installed. Molten salt flows back into the molten salt tank 1 through the molten salt sprayer 5. The horizontal single-tank molten salt heat storage system adopts a high-low position arrangement, with the molten salt tank 1 located at the low position and the molten salt heater 2 and heat release heat exchanger 3 located at the high position. The horizontal single-tank molten salt heat storage system also includes an electric heat tracing system, with electric heat tracing devices installed on the equipment, pipelines, and valves.

[0024] As an optional embodiment, the positions of the molten salt heater 2 and the heat-releasing heat exchanger 3 can be interchanged according to actual conditions; the heat storage medium in the molten salt single tank 1 can be a single molten salt or a multi-element mixed molten salt; and the heat source of the molten salt heater 2 can be valley electricity, new energy electricity, solar energy, high-temperature steam or high-temperature flue gas.

[0025] In this embodiment, the molten salt is Hitec ternary salt (53% KNO3+40% NaNO2+7% NaNO3), the temperature range is 240-370°C, the energy source is valley electricity, and the external supply is 2.3 MPa, 220°C industrial steam. The horizontal single-tank molten salt heat storage system can flexibly switch between the heat storage working condition, the heat-releasing working condition and the heat storage and releasing working condition according to different energy requirements and power grid load conditions, so as to realize efficient energy management and supply. The specific operation processes of these working conditions are as follows:

[0026] Heat storage working condition: In this mode, the heat-releasing heat exchanger 3 does not work. The molten salt is pumped out from the molten salt single tank 1 by the molten salt pump 4, flows to the molten salt heater 2, the temperature is raised in the heater, then flows to the heat-releasing heat exchanger 3 (at this time the heat-releasing heat exchanger 3 does not work), and finally returns to the molten salt single tank 1. The molten salt is continuously heated in this process until the preset specified temperature (370°C) is reached, and the heat storage working condition is ended.

[0027] Heat-releasing working condition: In this mode, the molten salt heater 2 does not work. The molten salt is pumped out from the molten salt single tank 1 by the molten salt pump 4, the 370°C molten salt flows through the molten salt heater 2 (at this time the molten salt heater 2 does not work), the temperature does not change, then flows to the heat-releasing heat exchanger 3 to heat the feed water, and 2.3 MPa, 220°C industrial steam is supplied externally. After the molten salt releases heat in the heat exchanger, the temperature is lowered, and then returns to the molten salt single tank 1. The molten salt is continuously cooled in this cycle until the preset specified temperature (240°C) is reached, and the heat-releasing working condition is ended.

[0028] Heat storage and releasing working condition: This is the operation mode of the system when the power grid load is low, at this time the molten salt heater 2 and the heat-releasing heat exchanger 3 are started. The molten salt in the molten salt single tank 1 is pumped out by the molten salt pump 4, the 240°C molten salt is heated by flowing through the molten salt heater 2, then flows into the heat-releasing heat exchanger 3 to heat the feed water, and 2.3 MPa, 220°C industrial steam is supplied to the outside. In this embodiment, the heating degree of the molten salt is stronger than the cooling degree, the molten salt is in a circulating heating state, and the temperature of the molten salt in the molten salt single tank 1 will gradually rise. When the temperature of the molten salt rises to 370°C, the heat storage and releasing working condition is ended.

[0029] The horizontal single-tank molten salt heat storage system is simple in operation, high in safety and stability, the molten salt single tank 1 adopts a horizontal storage tank structure with a smaller height, and is arranged at a low position, so that the molten salt heater 2 and the heat-releasing heat exchanger 3 are more easily arranged at a high position, and the molten salt single tank 1 has the function of a salt-drawing tank, the system is simplified, and the land occupation and investment of the system are reduced; the molten salt heater 2 and the heat-releasing heat exchanger 3 are connected in series, so that the molten salt heat storage system can operate in a heat storage condition, a heat-releasing condition and a heat storage and releasing condition, the demand of 24h stable steam supply of a user is realized, each device is always in a hot standby state, operation control is simple, and response speed is fast; the molten salt spray 5 is arranged on the molten salt single tank 1, so that cold and hot molten salts can be quickly and uniformly mixed in the heat storage and heat-releasing process, and the safe operation of the molten salt single tank 1 is ensured.

[0030] Finally, it should be noted that: the above only for the preferred embodiments of the utility model have described, and do not limit the utility model, although the utility model has been described in detail with reference to the foregoing embodiments, for the person skilled in the art, it still can modify the technical scheme recorded in the foregoing each embodiment, or equivalent replacement to part of technical features, any modification, equivalent replacement, improvement etc. within the spirit and principles of the utility model, should be contained in the protection scope of the utility model.

Claims

1. A horizontal single-tank molten salt thermal storage system, characterized in that, The system includes a molten salt tank (1), a molten salt heater (2), a heat release heat exchanger (3), a molten salt pump (4), and a molten salt sprayer (5). The outlet of the molten salt tank (1) is connected to the inlet of the molten salt heater (2) through the molten salt pump (4). The outlet of the molten salt heater (2) is connected to the inlet of the heat release heat exchanger (3). The outlet of the heat release heat exchanger (3) is connected to the inlet of the molten salt tank (1). The molten salt tank (1) is a horizontal storage tank with the molten salt pump (4) inserted into its upper part and the molten salt sprayer (5) installed. Molten salt flows back to the molten salt tank through the molten salt sprayer (5). The horizontal single-tank molten salt heat storage system adopts a high-low position arrangement, with the molten salt tank (1) arranged at the low position and the molten salt heater (2) and the heat release heat exchanger (3) arranged at the high position.

2. The horizontal single-tank molten salt thermal storage system according to claim 1, characterized in that, The positions of the molten salt heater (2) and the heat release heat exchanger (3) can be interchanged according to the actual situation.

3. The horizontal single-tank molten salt thermal storage system according to claim 1, characterized in that, The molten salt tank (1) is a horizontal storage tank.

4. The horizontal single-tank molten salt thermal storage system according to claim 1, characterized in that, The heat storage medium in the molten salt tank (1) is a single molten salt or a multi-component mixed molten salt.

5. The horizontal single-tank molten salt thermal storage system according to claim 1, characterized in that, The heat source of the molten salt heater (2) is off-peak electricity, new energy electricity, solar energy, high-temperature steam or high-temperature flue gas.

6. The horizontal single-tank molten salt thermal storage system according to claim 1, characterized in that, The horizontal single-tank molten salt thermal storage system also includes an electric heat tracing system, with electric heat tracing devices installed on the equipment, pipelines, and valves.

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