Molten salt heat storage and exchange system applied to gas generator set

Abstract

The utility model provides a fused salt heat storage and exchange system applied to a gas generator set. The fused salt heat storage and exchange system comprises a fuel pipeline, a combustion furnace and a waste heat furnace, wherein the combustion furnace and the waste heat furnace are sequentially arranged on the fuel pipeline in the fuel conveying direction; the low-temperature molten salt tank is connected with a heat exchange medium inlet of the waste heat furnace through a first medium pipeline; the mixed-temperature molten salt tank is connected with the heat exchange medium outlet of the waste heat furnace through a second medium pipeline and connected with the heat exchange medium inlet of the combustion furnace through a third medium pipeline; the high-temperature molten salt tank is connected with a heat exchange medium outlet of the combustion furnace through a fourth medium pipeline; and the salt dredging incoming pipe is connected to the inlet of the mixed-temperature molten salt tank and is suitable for conveying external dredging salt to the mixed-temperature molten salt tank. Through the arrangement of the multiple medium pipelines, the temperature mixing molten salt tank can be used for mixing the temperature of molten salt and can also be used for containing external salt dredging, an additional salt dredging tank does not need to be arranged, the structure is simplified, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of coal gas generator sets, and in particular to a molten salt heat storage and exchange system applied to coal gas generator sets. Background Art

[0002] Configuring energy storage for gas-fired power generation units is an effective way to improve the operational flexibility of gas-fired power generation units and give the units peak-shaving capabilities. Energy storage is divided into thermal energy storage, electrical energy storage, and hydrogen energy storage in terms of energy storage form, among which electrical energy storage also includes physical energy storage, electromagnetic energy storage, and electrochemical energy storage. Among various energy storage forms, electrical energy storage and thermal energy storage are widely used in gas-fired units. Among them, molten salt thermal energy storage has become the mainstream way to configure thermal energy storage for gas-fired units due to its low cost, high efficiency, and temperature range matching.

[0003] However, due to the inherent characteristics of the medium, molten salt still has two major difficulties when coupled with gas units. First, due to the high freezing point of the molten salt medium (binary molten salt is around 238°C, ternary molten salt is around 150°C), in order to prevent the molten salt from solidifying in the equipment and pipelines after the temperature drops, it is necessary to evacuate the molten salt to a centralized area when the system fails or shuts down. Therefore, a centralized molten salt evacuation equipment pipeline must be set up in the system, increasing the system cost; second, molten salt is currently only used in a small part of solar thermal power generation and some chemical industries, and its equipment is not standardized large equipment, there are few core equipment manufacturers, and the unit price of the equipment is high. These two factors lead to the current molten salt thermal energy storage system coupled with gas units. The design has a large redundancy, high cost, and large reduction potential. Therefore, how to configure the energy storage system to couple with the gas power generation system, optimize the system design to reduce the system cost, and improve the performance of the coupled energy storage system is an urgent problem to be solved. Utility Model Content

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defects of the molten salt thermal energy storage system coupled with the gas unit in the prior art, such as large design redundancy, high cost and poor performance, thereby providing a molten salt heat storage and exchange system applied to the gas generator set.

[0005] In order to solve the above problems, the utility model provides a molten salt storage and heat exchange system applied to a gas generator set, comprising: a fuel pipeline and a combustion furnace and a waste heat furnace arranged on the fuel pipeline in sequence according to the fuel delivery direction; a low-temperature molten salt tank, connected to the heat exchange medium inlet of the waste heat furnace through a first medium pipeline; a mixed temperature molten salt tank, connected to the heat exchange medium outlet of the waste heat furnace through a second medium pipeline, and connected to the heat exchange medium inlet of the combustion furnace through a third medium pipeline; a high-temperature molten salt tank, connected to the heat exchange medium outlet of the combustion furnace through a fourth medium pipeline; a salt distillation pipe, connected to the inlet of the mixed temperature molten salt tank, suitable for transporting external distilled salt to the mixed temperature molten salt tank.

[0006] Optionally, the salt diversion pipe includes a first salt diversion pipeline and a second salt diversion pipeline, the first salt diversion pipeline is connected between the salt diversion outlet of the combustion furnace and the inlet of the mixed temperature molten salt tank, and the second salt diversion pipeline is connected between the salt diversion outlet of the waste heat furnace and the inlet of the mixed temperature molten salt tank.

[0007] Optionally, the salt diversion pipeline includes a third salt diversion pipeline and a fourth salt diversion pipeline, the third salt diversion pipeline is connected between the heat release equipment and the mixed temperature molten salt tank, and the fourth salt diversion pipeline is connected between the salt transport pipeline and the mixed temperature molten salt tank.

[0008] Optionally, a fifth medium pipeline is further included, one end of which is connected to the fourth medium pipeline to form a first node, and the other end of which is connected to the inlet of the mixed temperature molten salt tank.

[0009] Optionally, a first regulating valve is provided on the fourth medium pipeline between the first node and the high-temperature molten salt tank, and a second regulating valve is provided on the fifth medium pipeline.

[0010] Optionally, a first molten salt pump is provided on the first medium pipeline, and a second molten salt pump is provided on the third medium pipeline.

[0011] Optionally, the outlet of the high-temperature molten salt tank is connected to a heat release pipeline suitable for introducing heat exchange medium into a heat release device, and a third molten salt pump is arranged on the heat release pipeline.

[0012] Optionally, the low-temperature molten salt tank and the high-temperature molten salt tank are vertical vaulted tanks, and the mixed-temperature molten salt tank is a horizontal tank.

[0013] Optionally, a guide plate, a perforated plate or a stirrer is provided inside the mixed temperature molten salt tank.

[0014] The utility model has the following advantages:

[0015] The utility model is applied to the molten salt heat storage and exchange system of the coal-fired power generation unit. In the heat storage stage, the fuel pipeline transports the fuel to the combustion furnace, the combustion furnace burns the fuel to increase the temperature, and the high-temperature flue gas generated by the combustion enters the waste heat furnace along the fuel pipeline, and the temperature of the waste heat furnace increases. The heat exchange medium can be molten salt. The first medium pipeline transports the heat exchange medium in the low-temperature molten salt tank to the waste heat furnace for heat exchange. After the heat exchange, the heat exchange medium enters the mixed temperature molten salt tank through the second medium pipeline. The third medium pipeline transports the heat exchange medium in the mixed temperature molten salt tank to the combustion furnace for heat exchange. After the heat exchange, the heat exchange medium enters the high-temperature molten salt tank for storage through the fourth medium pipeline. During the heat storage process, the mixed temperature molten salt tank can mix the temperature of the molten salt after heat exchange with the waste heat furnace to avoid frequent fluctuations in the molten salt temperature affecting the subsequent heat exchange process.

[0016] The mixed temperature molten salt tank can also accommodate external dilute salt from dilute salt. The external dilute salt can directly enter the mixed temperature molten salt tank and mix with the molten salt in the mixed temperature molten salt tank. Since the original molten salt in the mixed temperature molten salt tank has a certain temperature, the external molten salt can be temperature mixed with the original molten salt, and then can be directly used for heat exchange with the combustion furnace and stored in the high-temperature molten salt tank. There is no need to set up a dilute salt tank and a transmission pipeline between the dilute salt tank and the low-temperature molten salt tank, which simplifies the structure and reduces costs.

[0017] In summary, the molten salt storage and heat exchange system provided by the utility model for coal-fired power generating units, through the setting of multiple medium pipelines, the mixed temperature molten salt tank can be used for both the temperature of the mixed molten salt and the accommodation of external salt dilution, and there is no need to set up an additional salt dilution tank, which simplifies the structure and reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The structural schematic diagram of the molten salt heat storage and exchange system applied to the coal-fired power generation unit in this embodiment is shown;

[0020] Description of reference numerals:

[0021] 10. Fuel pipeline; 11. Combustion furnace; 12. Waste heat furnace; 21. Low-temperature molten salt tank; 22. High-temperature molten salt tank; 23. Mixed-temperature molten salt tank; 31. First medium pipeline; 32. Second medium pipeline; 33. Third medium pipeline; 34. Fourth medium pipeline; 35. Fifth medium pipeline; 41. First salt-repelling pipeline; 42. Second salt-repelling pipeline; 43. Third salt-repelling pipeline; 44. Fourth salt-repelling pipeline; 51. First regulating valve; 52. Second regulating valve; 61. First molten salt pump; 62. Second molten salt pump; 63. Third molten salt pump; 71. Heat release pipeline. DETAILED DESCRIPTION

[0022] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 As shown, in this embodiment, a molten salt heat storage and exchange system applied to a gas power generation unit includes: a fuel pipeline 10, a combustion furnace 11, a waste heat furnace 12, a low-temperature molten salt tank 21, a high-temperature molten salt tank 22, and a mixed-temperature molten salt tank 23.

[0027] The fuel pipeline 10 and the combustion furnace 11 and the waste heat furnace 12 are arranged on the fuel pipeline 10 in sequence according to the fuel delivery direction. Figure 1 As shown, one end of the fuel pipeline 10 can be connected to the gas source of the gas generator set. In this embodiment, the gas generator set achieves the purpose of power generation by burning the gas generated in the ironmaking process. Part of the flue gas can be led out from the front end of the boiler of the coal-fired power unit to the combustion furnace 11 for combustion to achieve the purpose of peak load regulation. The gas can be one of blast furnace gas, coke oven gas, converter gas, natural gas, acetylene gas or any combination thereof, which can be determined according to actual conditions. The other end of the fuel pipeline 10 is connected to the flue gas treatment device of the original system, and the flue gas generated by the combustion of the gas can be introduced into the flue gas treatment device of the original system for treatment.

[0028] The low-temperature molten salt tank 21 is connected to the heat exchange medium inlet of the waste heat furnace 12 through the first medium pipeline 31. The mixed temperature molten salt tank 23 is connected to the heat exchange medium outlet of the waste heat furnace 12 through the second medium pipeline 32, and is connected to the heat exchange medium inlet of the combustion furnace 11 through the third medium pipeline 33. The high-temperature molten salt tank 22 is connected to the heat exchange medium outlet of the combustion furnace 11 through the fourth medium pipeline 34.

[0029] The salt distillation pipe is connected to the inlet of the mixed temperature molten salt tank 23 and is suitable for conveying external distilled salt to the mixed temperature molten salt tank 23 .

[0030] In the heat storage stage, the fuel pipeline 10 transports the fuel to the combustion furnace 11, and the combustion furnace 11 burns the fuel to increase the temperature. The high-temperature flue gas generated by the combustion enters the waste heat furnace 12 along the fuel pipeline 10, and the temperature of the waste heat furnace 12 increases. The heat exchange medium can be molten salt. The first medium pipeline 31 transports the heat exchange medium in the low-temperature molten salt tank 21 to the waste heat furnace 12 for heat exchange. After the heat exchange, the heat exchange medium enters the mixed temperature molten salt tank 23 through the second medium pipeline 32. The third medium pipeline 33 transports the heat exchange medium in the mixed temperature molten salt tank 23 to the combustion furnace 11 for heat exchange. After the heat exchange, the heat exchange medium enters the high-temperature molten salt tank 22 for storage through the fourth medium pipeline 34. During the heat storage process, the mixed temperature molten salt tank 23 can mix the molten salt after heat exchange with the waste heat furnace 12 to avoid frequent fluctuations in the molten salt temperature affecting the subsequent heat exchange process. In the present system, the temperature mixing of the molten salt can be achieved in the temperature mixing molten salt tank 23. The temperature mixing molten salt tank 23 has a certain volume, and the molten salt inside the tank can maintain a certain liquid level, which greatly reduces the temperature fluctuation after the molten salts of different temperatures are mixed.

[0031] The mixed temperature molten salt tank 23 can also accommodate external dilute salt from the dilute salt pipe. The external dilute salt can directly enter the mixed temperature molten salt tank 23 and mix with the molten salt in the mixed temperature molten salt tank 23. Since the original molten salt in the mixed temperature molten salt tank 23 has a certain temperature, the external dilute salt can be temperature mixed with the original molten salt, and then can be directly used for heat exchange with the combustion furnace 11 and stored in the high-temperature molten salt tank 22. There is no need to set up a dilute salt tank and a transportation pipeline between the dilute salt tank and the low-temperature molten salt tank 21, which simplifies the structure and reduces costs.

[0032] For example, external salt removal can come from external equipment and external pipelines. The external equipment can be all molten salt heat exchangers, and the external pipeline can be the pipeline between the molten salt heat exchanger and the mixed temperature molten salt tank 23.

[0033] In summary, the molten salt storage and heat exchange system provided by the utility model for coal-fired power generating units, through the setting of multiple medium pipelines, the mixed temperature molten salt tank 23 can be used for both the temperature of the mixed molten salt and the accommodation of external salt diversion, and there is no need to set up an additional salt diversion tank, which simplifies the structure and reduces the cost.

[0034] In addition, the molten salt pump installed on the first medium pipeline 31 of the low-temperature molten salt tank 21 of the system requires a smaller head and only needs to overcome the pressure drop of the waste heat furnace 12 and related pipelines, which can greatly reduce the power consumption of the system operation.

[0035] It should be noted that the salt drainage pipeline is generally started when the system is shut down or fails, and is used to introduce the molten salt in various equipment into the mixed temperature molten salt tank 23 for unified storage to prevent the molten salt from solidifying in the equipment or pipeline.

[0036] like Figure 1 As shown, in this embodiment, the salt diversion pipe includes a first salt diversion pipe 41 and a second salt diversion pipe 42, the first salt diversion pipe 41 is connected between the salt diversion outlet of the combustion furnace 11 and the inlet of the mixed temperature molten salt tank 23, and the second salt diversion pipe 42 is connected between the salt diversion outlet of the waste heat furnace 12 and the inlet of the mixed temperature molten salt tank 23. The first salt diversion pipe 41 can divert the molten salt in the combustion furnace 11 to the mixed temperature molten salt tank 23 for storage, and the second salt diversion pipe 42 can divert the molten salt in the waste heat furnace 12 to the mixed temperature molten salt tank 23 for storage. The mixed temperature molten salt tank 23 can mix the molten salt from the combustion furnace 11 and the waste heat furnace 12, balance the temperature, and facilitate centralized processing.

[0037] In one implementation of the present embodiment, a manifold is provided between the first salt-repelling pipeline 41, the second salt-repelling pipeline 42 and the mixed-temperature molten salt tank 23, and the molten salt in the first salt-repelling pipeline 41 and the second salt-repelling pipeline 42 can enter the mixed-temperature molten salt tank 23 through the manifold, thereby reducing the number of inlets on the mixed-temperature molten salt tank 23.

[0038] like Figure 1 As shown, in this embodiment, the salt diversion pipe includes a third salt diversion pipeline 43 and a fourth salt diversion pipeline 44, the third salt diversion pipeline 43 is connected between the heat release device and the mixed temperature molten salt tank 23, and the fourth salt diversion pipeline 44 is connected between the salt delivery pipeline and the mixed temperature molten salt tank 23. The third salt diversion pipeline 43 can transport the molten salt in the heat release device to the mixed temperature molten salt tank 23, and the fourth salt diversion pipeline 44 can transport the molten salt in the salt delivery pipeline to the mixed temperature molten salt tank 23, so as to mix the temperature of the molten salt and facilitate subsequent centralized processing.

[0039] like Figure 1 As shown, in this embodiment, the molten salt heat storage and exchange system further includes a fifth medium pipeline 35, one end of which is connected to the fourth medium pipeline 34 to form a first node, and the other end is connected to the inlet of the mixed temperature molten salt tank 23. The fifth medium pipeline 35 can guide part of the high-temperature molten salt in the fourth medium pipeline 34 to the mixed temperature molten salt tank 23 to ensure that the molten salt in the mixed temperature molten salt tank 23 maintains a certain temperature and avoids the molten salt solidification phenomenon in the mixed temperature molten salt tank 23.

[0040] like Figure 1As shown, in this embodiment, a first regulating valve 51 is provided on the fourth medium pipeline 34 between the first node and the high-temperature molten salt tank 22, and a second regulating valve 52 is provided on the fifth medium pipeline 35. The first regulating valve 51 and the second regulating valve 52 can respectively regulate the molten salt flow rate entering the high-temperature molten salt tank 22 and the molten salt flow rate entering the mixed-temperature molten salt tank 23, so as to reasonably control the molten salt temperature in the mixed-temperature molten salt tank 23.

[0041] According to the working conditions, the molten salt in the low-temperature molten salt tank 21 needs to be mixed with the molten salt in the high-temperature molten salt tank 22 before entering the combustion furnace 11 for heat exchange. Since the mixed-temperature molten salt tank 23 is provided in this embodiment, the molten salt in the fourth medium pipeline 34 can be directly passed into the mixed-temperature molten salt tank 23 to achieve the purpose of mixing and increasing the temperature of the molten salt in the mixed-temperature molten salt tank 23. Compared with mixing molten salt in the pipeline, the mixed-temperature molten salt tank 23 can reduce the temperature fluctuation when the molten salt is mixed. The second molten salt pump 62 can be a short-axis molten salt pump, which reduces the cost. For example, the molten salt temperature can be mixed to above 450°C in the mixed-temperature molten salt tank, and the mixing temperature can also be specifically set according to the actual situation, which is not listed here one by one.

[0042] like Figure 1 As shown, in this embodiment, a first molten salt pump 61 is provided on the first medium pipeline 31, and a second molten salt pump 62 is provided on the third medium pipeline 33. The first molten salt pump 61 can pump the molten salt in the low-temperature molten salt tank 21 into the waste heat furnace 12 for heat exchange, and the second molten salt pump 62 can pump the molten salt in the mixed temperature molten salt tank 23 into the combustion furnace 11 for heat exchange.

[0043] The second molten salt pump 62 can be a short-axis molten salt pump. Continuing with the above example, according to the working conditions, the high-temperature molten salt tank 22 needs to be additionally provided with pipelines to transport molten salt and mix it with the molten salt in the low-temperature molten salt tank 21. In this embodiment, without changing the molten salt transportation pipeline of the low-temperature molten salt tank 21, the setting of additional pipelines on the high-temperature molten salt tank 22 is also omitted, and the setting of long-axis molten salt pumps is reduced, thereby reducing costs.

[0044] like Figure 1 As shown, in this embodiment, the outlet of the high-temperature molten salt tank 22 is connected to a heat release pipeline 71 suitable for introducing the heat exchange medium into the heat release equipment. The heat release pipeline 71 is provided with a third molten salt pump 63, and the third molten salt pump 63 can pump the molten salt in the high-temperature molten salt tank 22 into the heat release equipment.

[0045] like Figure 1 As shown, in this embodiment, the low-temperature molten salt tank 21 and the high-temperature molten salt tank 22 are vertical vaulted tanks, and the mixed-temperature molten salt tank 23 is a horizontal tank, which is conducive to mixing molten salt.

[0046] like Figure 1As shown, in this embodiment, a guide plate, a perforated plate and an agitator are provided inside the mixed temperature molten salt tank 23, which is beneficial to increase the flow of molten salt inside the mixed temperature molten salt tank 23 and promote temperature mixing.

[0047] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A molten salt heat storage and exchange system applied to a coal gas generator set, characterized in that: include: A fuel pipeline (10) and a combustion furnace (11) and a waste heat furnace (12) arranged in sequence on the fuel pipeline (10) according to a fuel delivery direction; A low-temperature molten salt tank (21) is connected to the heat exchange medium inlet of the waste heat furnace (12) via a first medium pipeline (31); The mixed temperature molten salt tank (23) is connected to the heat exchange medium outlet of the waste heat furnace (12) through the second medium pipeline (32), and is connected to the heat exchange medium inlet of the combustion furnace (11) through the third medium pipeline (33); The high-temperature molten salt tank (22) is connected to the heat exchange medium outlet of the combustion furnace (11) via a fourth medium pipeline (34); The salt distillation pipe is connected to the inlet of the mixed-temperature molten salt tank (23) and is suitable for conveying external distilled salt to the mixed-temperature molten salt tank (23).

2. The molten salt heat storage and exchange system according to claim 1, characterized in that: The salt diversion pipe comprises a first salt diversion pipe (41) and a second salt diversion pipe (42), wherein the first salt diversion pipe (41) is connected between the salt diversion outlet of the combustion furnace (11) and the inlet of the mixed temperature molten salt tank (23), and the second salt diversion pipe (42) is connected between the salt diversion outlet of the waste heat furnace (12) and the inlet of the mixed temperature molten salt tank (23).

3. The molten salt heat storage and exchange system according to claim 1, characterized in that: The salt-repelling pipe comprises a third salt-repelling pipe (43) and a fourth salt-repelling pipe (44), wherein the third salt-repelling pipe (43) is connected between the heat release device and the mixed-temperature molten salt tank (23), and the fourth salt-repelling pipe (44) is connected between the salt transport pipe and the mixed-temperature molten salt tank (23).

4. The molten salt heat storage and exchange system according to claim 1, characterized in that: It also includes a fifth medium pipeline (35), one end of which is connected to the fourth medium pipeline (34) to form a first node, and the other end of which is connected to the inlet of the mixed temperature molten salt tank (23).

5. The molten salt heat storage and exchange system according to claim 4, characterized in that: A first regulating valve (51) is provided on the fourth medium pipeline (34) between the first node and the high-temperature molten salt tank (22), and a second regulating valve (52) is provided on the fifth medium pipeline (35).

6. The molten salt heat storage and exchange system according to claim 1, characterized in that: The first medium pipeline (31) is provided with a first molten salt pump (61), and the third medium pipeline (33) is provided with a second molten salt pump (62).

7. The molten salt heat storage and exchange system according to claim 1, characterized in that: The outlet of the high-temperature molten salt tank (22) is connected to a heat release pipeline (71) suitable for introducing heat exchange medium into a heat release device, and a third molten salt pump (63) is arranged on the heat release pipeline (71).

8. The molten salt heat storage and exchange system according to claim 1, characterized in that: The low-temperature molten salt tank (21) and the high-temperature molten salt tank (22) are vertical vaulted storage tanks, and the mixed-temperature molten salt tank (23) is a horizontal storage tank.

9. The molten salt heat storage and exchange system according to claim 8, characterized in that: The mixed temperature molten salt tank (23) is provided with a guide plate, a perforated plate or a stirrer inside.

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