A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system

Abstract

The invention discloses a double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system, which relates to the technical field of steam generation. The double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system comprises: a low-temperature molten salt tank; a high-temperature molten salt tank, wherein a flue gas-molten salt heat exchanger and an electric heater are provided between the low-temperature molten salt tank and the high-temperature molten salt tank. During off-peak electricity, the low-temperature molten salt in the low-temperature molten salt tank enters the flue gas-molten salt heat exchanger and exchanges heat with the boiler flue gas entering the flue gas-molten salt heat exchanger, and the formed high-temperature molten salt enters the high-temperature molten salt tank for storage; during off-peak electricity, the low-temperature molten salt in the low-temperature molten salt tank enters the electric heater for heating, and the formed high-temperature molten salt enters the high-temperature molten salt tank for storage; the double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system converts the low-temperature molten salt into high-temperature molten salt by utilizing the boiler flue gas to exchange heat with the low-temperature molten salt during off-peak electricity, and then the high-temperature molten salt is exchanged with water in the water heat exchange module, thereby forming steam.

Description

Technical Field

[0001] The present invention relates to the technical field of steam generation, and in particular to a double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system. Background Art

[0002] With the continued development of my country's economy and people's pursuit of material life, the total energy consumption will continue to increase in the future. Although my country's energy structure is constantly adjusting and energy efficiency is constantly improving, the use of non-renewable resources still occupies a major position in energy. Therefore, the rational use of waste heat resources has become an important measure to solve the problem of energy shortage.

[0003] Waste heat resources refer to the energy that can be recycled and reused under current conditions but has not yet been recycled. It is considered the fifth largest conventional energy source after coal, oil, natural gas and hydropower. These waste heat resources can be used for power generation, driving machinery, heating or cooling, etc., thus reducing the consumption of primary energy and reducing thermal pollution to the environment.

[0004] According to the source, waste heat resources can be divided into flue gas waste heat, cooling medium waste heat, waste steam and waste water waste heat, chemical reaction heat, high-temperature product and slag waste heat, as well as combustible waste gas and waste material waste heat.

[0005] At the same time, waste heat recovery is also of great significance in terms of energy conservation and environmental protection, and effectively promoting carbon peak and carbon neutrality. Among various waste heat resources, flue gas waste heat is the top priority.

[0006] Therefore, molten salt can be used to recover the waste heat in the flue gas. This recovery method generally uses a shell and tube heat exchanger for heat exchange. However, impurities in the flue gas will adhere to the outer surface of the tube inside the heat exchanger shell, resulting in a gradual decrease in heat exchange efficiency and difficulty in cleaning. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system, which solves the problem in the prior art that impurities in the flue gas will adhere to the outer surface of the tube inside the heat exchanger shell, resulting in a gradual decrease in heat exchange efficiency and difficulty in cleaning.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system, comprising:

[0009] Low temperature molten salt tank;

[0010] A high-temperature molten salt tank, wherein a flue gas-molten salt heat exchanger and an electric heater are provided between the low-temperature molten salt tank and the high-temperature molten salt tank. During off-peak hours, the low-temperature molten salt in the low-temperature molten salt tank enters the flue gas-molten salt heat exchanger and exchanges heat with the boiler flue gas entering the flue gas-molten salt heat exchanger, and the formed high-temperature molten salt enters the high-temperature molten salt tank for storage; during off-peak hours, the low-temperature molten salt in the low-temperature molten salt tank enters the electric heater for heating, and the formed high-temperature molten salt enters the high-temperature molten salt tank for storage;

[0011] Furthermore, the flue gas-molten salt heat exchanger comprises:

[0012] Heat exchange shell;

[0013] A heat exchange pipeline, wherein the heat exchange pipeline comprises a thick tube and a thin tube bundle fixed to the upper end of the thick tube, the low-temperature molten salt ascends from the lower end of the thick tube in the heat exchange pipeline, and the flue gas flows downward from the upper end of the heat exchange shell, so that the flue gas and the low-temperature molten salt exchange heat, and the thin tube bundle comprises a long vertical portion, a horizontal portion and a short vertical portion arranged in sequence from bottom to top, and the long vertical portion, the horizontal portion and the short vertical portion form a J-shaped structure, and the upper portion, the horizontal portion and the short vertical portion of the long vertical portion are exposed outside the upper end of the heat exchange shell;

[0014] A first pipe head, wherein the first pipe head is fixed to the upper end of the heat exchange shell by bolts, and the diameter of the first pipe head is larger than the heat exchange shell, and the upper part, the horizontal part and the short vertical part of the long vertical part are located in the first pipe head;

[0015] The boiler flue gas enters the heat exchange shell through the first pipe head, and impurities in the boiler flue gas adhere to the outer surfaces of the horizontal part and the short vertical part. The horizontal part and the short vertical part can be cleaned by removing the first pipe head.

[0016] Furthermore, it also includes a water heat exchange module, which is connected to the high-temperature molten salt tank. The water heat exchange module is used to exchange heat between water and high-temperature molten salt to form water vapor, and allow the water vapor to enter the steam turbine to generate electricity.

[0017] Furthermore, it also includes a second tube sheet, wherein the second tube sheet includes:

[0018] A plate body, the plate body being located in the lower inner part of the first tube head, a tube bundle hole being provided in an area of ​​the plate body opposite to the short vertical portion, and a lower end of the short vertical portion being welded to the tube bundle hole;

[0019] The barrel portion is arranged below the outer edge of the plate body, a flange portion is arranged below the outer edge of the barrel portion, a large flange head of the shell is arranged at the upper end of the heat exchange shell, the flange portion, the large flange head of the shell and the first pipe head are connected by bolts, and a molten salt discharge pipe is arranged on one side below the large flange head of the shell;

[0020] The space above the plate body is a flue gas feeding space, and the space below the plate body is a molten salt discharging space. The high-temperature molten salt discharged from the short vertical portion enters the molten salt discharging space and then enters the high-temperature molten salt tank through the molten salt discharging pipe.

[0021] Furthermore, it also includes a first filter cartridge, wherein the first filter cartridge includes:

[0022] A mounting seat, the mounting seat being welded to a region on the upper surface of the second tube plate opposite to the short vertical portion, the short vertical portion being located inside the mounting seat;

[0023] The cylinder is located at the upper end of the mounting seat, and the cylinder is composed of a plurality of mounting frames arranged in a circular matrix, a filter screen is arranged in the mounting frame, and the lower end of the mounting frame is rotatably mounted on the mounting seat through a hinge seat;

[0024] A limiting ring, wherein a limiting hole is provided on the lower surface of the limiting ring, and a limiting column adapted to the limiting hole is provided at the upper end of the installation frame. When the limiting column is inserted into the limiting hole, the limiting ring is used to limit the rotation of the installation frame.

[0025] Furthermore, a docking port is provided on one side of the mounting seat, a branch pipe docking with the docking port is provided on the first pipe head, and a flue gas inlet pipe is provided between the plurality of branch pipes, so that the boiler flue gas enters the mounting seat through the flue gas inlet pipe, the branch pipe and the docking port in sequence, and impurities in the boiler flue gas adhere to the outer surface of the short vertical portion and the inner surface of the cylinder;

[0026] A filter layer is arranged above the cylinder, and the diameter of the filter layer is equal to the inner diameter of the first pipe head.

[0027] Furthermore, it also includes a second filter cartridge, which is located above the inner edge. A second clearance groove is opened in the area of ​​the lower part of the second filter cartridge opposite to the transverse part, and the lower end of the second clearance groove is an open end.

[0028] Furthermore, the second tube sheet further comprises a baffle ring, the baffle ring being located above the inner edge of the plate body, a first clearance groove being provided in the region of the upper end surface of the baffle ring opposite to the transverse portion, and the upper end of the first clearance groove being an open end;

[0029] The second filter cartridge is located in the baffle ring, and there is a gap between the second filter cartridge and the baffle ring;

[0030] The inner wall of the baffle ring is provided with a retaining edge capable of supporting the second filter cartridge.

[0031] Furthermore, a first tube sheet is provided at the lower end of the thick tube;

[0032] A second tube head is provided at the lower end of the heat exchange shell, and the heat exchange shell, the first tube sheet and the second tube head are fixedly connected by bolts;

[0033] A molten salt inlet pipe is provided on one side of the second pipe head, and low-temperature molten salt enters the second pipe head through the molten salt inlet pipe.

[0034] Furthermore, a smoke exhaust port is provided on a lower side of the heat exchange shell.

[0035] Furthermore, the water heat exchange module includes a three-stage heat exchanger and a water supply mechanism;

[0036] The high-temperature molten salt in the high-temperature molten salt tank can enter the three-stage heat exchanger, and the water in the water supply mechanism can enter the three-stage heat exchanger. The water and the high-temperature molten salt exchange heat in the three-stage heat exchanger to form water vapor.

[0037] The present invention has the following beneficial effects:

[0038] (1) The double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system converts low-temperature molten salt into high-temperature molten salt by using boiler flue gas to exchange heat with low-temperature molten salt during off-peak hours, or converts low-temperature molten salt into high-temperature molten salt through an electric heater during off-peak hours, and then exchanges heat between the high-temperature molten salt and water in a water heat exchange module to form steam for use in a steam turbine.

[0039] (2) The flue gas waste heat recovery and steam supply system of the double-tank molten salt heat storage boiler is equipped with a flue gas-molten salt heat exchanger, so that the low-temperature molten salt here flows upward from the lower end of the heat exchange pipeline in the heat exchange pipeline, and the flue gas flows downward from the upper end of the heat exchange shell, so that the flue gas and the low-temperature molten salt can exchange heat. Therefore, the reverse flow of molten salt and flue gas can achieve "preheating and preliminary heating of the lower section of the heat exchanger" and "heating and raising the temperature of the upper section of the heat exchanger". In the heat storage process of this design, whether it is the upper section or the lower section of the heat exchange shell, the temperature difference between the molten salt and the flue gas is within a small range, which can achieve the cascade of flue gas waste heat. The heat is stored stably and evenly, and the upper end of the thin tube bundle is set into a J-shaped structure so that a part of the thin tube bundle is exposed outside the heat exchange shell, and the upper part of the long vertical part, the horizontal part and the short vertical part are exposed outside the upper end of the heat exchange shell. Since the thin tube bundle is composed of a plurality of closely arranged thin tubes, the distance between two adjacent thin tubes is small, so that the horizontal part and the short vertical part of the thin tube bundle themselves act as filters to preliminarily filter impurities in the flue gas. Since the horizontal part and the short vertical part are exposed outside the heat exchange shell, they are easy to clean, and impurities adhering to the tube path are prevented from affecting the heat exchange of the pipeline.

[0040] (3) The double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system is configured into two sections through the heat exchange pipeline, one section is a thick tube, and the other section is a thin tube bundle. The thin tube bundle is fixed at the upper end of the thick tube. Therefore, when the low-temperature molten salt enters the heat exchange pipeline, it first enters the thick tube. Since the diameter of the thick tube is larger, the probability of the thick tube being completely blocked can be greatly reduced. In daily maintenance, the cycle of the heat exchange pipeline can be greatly shortened. In addition, due to the setting of the thin tube bundle, the heat exchange efficiency can be ensured.

[0041] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is the overall system diagram of the present invention;

[0043] Figure 2 This is an appearance diagram of the flue gas-molten salt heat exchanger of the present invention;

[0044] Figure 3 This is a schematic diagram of the internal structure of the flue gas-molten salt heat exchanger of the present invention;

[0045] Figure 4 For the present invention Figure 3 The main view;

[0046] Figure 5 It is a schematic diagram of the installation of a single set of heat exchange pipelines in a heat exchange shell of the present invention;

[0047] Figure 6 It is an assembly diagram of a single set of heat exchange pipelines and a plate body of the present invention;

[0048] Figure 7 It is a schematic diagram of the position of the second filter cartridge of the present invention;

[0049] Figure 8 is a schematic structural diagram of the second tube sheet of the present invention;

[0050] Fig. 9 It is a schematic diagram of the position of the first filter cartridge of the present invention;

[0051] Fig.10 It is a schematic structural diagram of the first filter cartridge of the present invention;

[0052] Fig.11 is an exploded view of the first filter cartridge of the present invention;

[0053] Fig.12 It is a structural schematic diagram of the cylinder of the present invention;

[0054] Fig.13 It is an expanded view of the first filter cartridge of the present invention;

[0055] Fig.14This is a bottom view of the limiting ring of the present invention;

[0056] Fig.15 It is a schematic diagram of the position of the filter layer of the present invention;

[0057] Fig.16 It is a diagram showing the coordination between the transverse portion and the embedded plate of the present invention;

[0058] Fig.17 It is an exploded view of the baffle ring and the second filter cartridge of the present invention.

[0059] In the figure, 100, low-temperature molten salt tank; 110, low-temperature molten salt pump; 200, flue gas-molten salt heat exchanger; 300, electric heater; 400, electrode boiler; 500, high-temperature molten salt tank; 600, three-stage heat exchanger; 800, steam turbine; 900, water supply mechanism; 910, deaerator; 920, water supply booster pump; 930, soft water storage tank; 940, water supply pump; 1, molten salt inlet pipe; 2, heat exchange pipeline; 21, thick pipe; 22, end; 23, thin tube bundle; 231, long vertical part; 232, horizontal part; 233, short vertical part; 3, first tube sheet; 4, embedded plate; 51, first tube head; 52, heat exchange shell ;521, large flange head of the shell;53, second pipe head;6, filter layer;7, second tube sheet;71, plate body;72, cylinder;73, flange;74, tube bundle hole;75, deflector ring;76, one clearance groove;77, retaining edge;8, first filter cartridge;81, cylinder body;811, filter screen;812, limiting column;813, hinged seat;814, mounting frame;82, limiting ring;821, limiting hole;83, mounting seat;9, second filter cartridge;91, second clearance groove;10, flue gas inlet pipe;101, branch pipe;11, flue gas exhaust port;12, docking port;13, bracket;14, molten salt discharge pipe. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0062] According to the following Figure 1-Figure 17 The invention describes a double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system provided in an embodiment of the present invention.

[0063] See also Figure 1 The embodiment of the present invention provides a double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system. The present invention mainly aims at recovering the waste heat of the boiler flue gas generated when the electrode boiler 400 is working, and the boiler flue gas temperature is not lower than 560°C.

[0064] The double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system comprises a low-temperature molten salt tank 100 and a high-temperature molten salt tank 500. The low-temperature molten salt tank 100 is used to store low-temperature molten salt. The temperature of the low-temperature molten salt is about 200°C. There is a flue gas-molten salt heat exchanger 200 and an electric heater 300 between the low-temperature molten salt tank 100 and the high-temperature molten salt tank 500. This is because there is a low-temperature molten salt heat storage stage. The low-temperature molten salt has two heat storage modes:

[0065] ① The boiler flue gas is used to store heat in low-temperature molten salt: during non-off-peak electricity season, the low-temperature molten salt in the low-temperature molten salt tank 100 can enter the flue gas-molten salt heat exchanger 200 through the low-temperature molten salt pump 110, and the boiler flue gas generated by the electrode boiler 400 also enters the flue gas-molten salt heat exchanger 200, so that the boiler flue gas can exchange heat with the low-temperature molten salt, thereby reducing the temperature of the boiler flue gas, and the low-temperature molten salt is heated to form high-temperature molten salt, which can then enter the high-temperature molten salt tank 500 for storage.

[0066] ② The electric heater 300 is used to store heat for low-temperature molten salt: during off-peak hours, the low-temperature molten salt in the low-temperature molten salt tank 100 enters the electric heater 300 for heating through the low-temperature molten salt pump 110, and the formed high-temperature molten salt enters the high-temperature molten salt tank 500 for storage.

[0067] The above two heat storage methods can convert low-temperature molten salt into high-temperature molten salt, and the high-temperature molten salt can release heat after conversion. Therefore, the present invention should also be provided with a water heat exchange module to release heat from the high-temperature molten salt. The water heat exchange module is connected to the high-temperature molten salt tank 500. The water heat exchange module is used to exchange heat between water and high-temperature molten salt to achieve the purpose of releasing heat from the high-temperature molten salt.

[0068] The specific water heat exchange module includes a three-stage heat exchanger 600 and a water supply mechanism 900. The high-temperature molten salt in the high-temperature molten salt tank 500 can enter the three-stage heat exchanger 600 through a high-temperature molten salt pump, and the water in the water supply mechanism 900 can enter the three-stage heat exchanger 600. The water and the high-temperature molten salt exchange heat in the three-stage heat exchanger 600 to form water vapor, and the water vapor enters the steam turbine 800 to generate electricity; the water supply mechanism 900 mentioned here should include a soft water storage tank 930, a deaerator 910, a feed water booster pump 920 and a feed water pump 940. The water in the soft water storage tank 930 can be pumped into the deaerator 910 for deoxygenation through the feed water pump 940, and the deoxygenated water enters the three-stage heat exchanger 600 through the feed water booster pump 920 to exchange heat with the high-temperature molten salt.

[0069] Combination Figure 2-Figure 6 As shown, the flue gas-molten salt heat exchanger 200 in the double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system provided by the present invention includes a heat exchange shell 52 and a heat exchange pipeline 2. Molten salt flows in the heat exchange pipeline 2, and boiler flue gas flows in the heat exchange shell 52, that is, the molten salt flows through the tube side and the flue gas flows through the shell side.

[0070] Specifically, the low-temperature molten salt here flows upward from the lower end of the heat exchange pipeline 2 in the heat exchange pipeline 2, and the flue gas flows downward from the upper end of the heat exchange shell 52, so that the flue gas and the low-temperature molten salt exchange heat. Therefore, the reverse flow of the molten salt and the flue gas can achieve "preheating and preliminary heating of the lower section of the heat exchanger" and "heating and increasing the temperature of the upper section of the heat exchanger". During the heat storage process of this design, whether it is the upper section or the lower section of the heat exchange shell 52, the temperature difference between the molten salt and the flue gas is within a small range, which can achieve the step-by-step utilization of the flue gas waste heat and stable and uniform heat storage.

[0071] Preferably, spaced baffles are further provided in the heat exchange shell 52 (this is a known technology and is not shown in the figure to ensure the clarity of the drawings).

[0072] Preferably, a bracket 13 for supporting the heat exchange shell 52 is also provided.

[0073] However, in actual practical use, the temperature of the low-temperature molten salt is relatively low, so there will be certain crystals therein, which may cause blockage in the feed port of the heat exchange pipeline 2. Therefore, the present invention arranges the heat exchange pipeline 2 into two sections, one section is a thick tube 21, and the other section is a thin tube bundle 23. The thin tube bundle 23 is fixed to the upper end of the thick tube 21 through the end 22, so that when the low-temperature molten salt enters the heat exchange pipeline 2, it first enters the thick tube 21. Since the diameter of the thick tube 21 is relatively large, the probability of the thick tube 21 being completely blocked can be greatly reduced. In daily maintenance, the cycle of the heat exchange pipeline 2 can be greatly shortened, and due to the arrangement of the thin tube bundle 23, the heat exchange efficiency can be ensured.

[0074] Preferably, the diameter of the largest circle formed by the thin tube bundles 23 is equal to the inner diameter of the thick tube 21 , so that the number of the thin tube bundles 23 can be maximized and the heat exchange efficiency can be improved.

[0075] Combination Figure 6 and Figure 7 As shown, since the boiler flue gas contains a large amount of impurities that are not completely burned, when the boiler flue gas flows in the heat exchange shell 52, the impurities in it will adhere to the outer surface of the thin tube bundle 23, making it difficult to clean. In order to solve this problem, it is designed here that a part of the thin tube bundle 23 is exposed outside the heat exchange shell 52, and the first pipe head 51 is used to seal the thin tube bundle 23 exposed outside the heat exchange shell 52. Specifically, the thin tube bundle 23 includes a long vertical portion 231, a horizontal portion 232 and a short vertical portion 233 which are arranged in sequence from bottom to top, and the long vertical portion 231, the horizontal portion 232 and the short vertical portion 233 form a J-shaped structure, the upper portion of the long vertical portion 231, the horizontal portion 232 and the short vertical portion 233 are exposed outside the upper end of the heat exchange shell 52, the first tube head 51 is fixed to the upper end of the heat exchange shell 52 by bolts, and the diameter of the first tube head 51 is larger than that of the heat exchange shell 52, and the long vertical portion 231, the horizontal portion 232 and the short vertical portion 233 are located inside the first tube head 51.

[0076] In this embodiment, the boiler flue gas enters the heat exchange shell 52 through the first pipe head 51, so the impurities in the boiler flue gas first adhere to the outer surfaces of the horizontal portion 232 and the short vertical portion 233. When it is necessary to clean the impurities, it is only necessary to remove the first pipe head 51, and the entire horizontal portion 232 and the short vertical portion 233 can be completely exposed, thereby facilitating the cleaning of the horizontal portion 232 and the short vertical portion 233.

[0077] Combination Figure 3 , Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, since the intake of boiler flue gas and the discharge of molten salt are both carried out in the first tube head 51, in order to avoid the mutual influence between the two, a second tube sheet 7 is also provided here, and the second tube sheet 7 includes a plate body 71, and the plate body 71 is located in the lower part of the first tube head 51. A tube bundle hole 74 is opened in the area opposite to the short vertical portion 233 on the plate body 71, and the lower end of the short vertical portion 233 is welded to the tube bundle hole 74. The space above the plate body 71 is the flue gas feeding space, and the space below the plate body 71 is the molten salt discharge space.

[0078] In order to achieve the sealing and fixation of the plate body 71, a cylinder portion 72 is also provided here. The cylinder portion 72 is arranged below the outer edge of the plate body 71. A flange portion 73 is provided below the outer edge of the cylinder portion 72. A large shell flange head 521 is provided at the upper end of the heat exchange shell 52. The flange portion 73, the large shell flange head 521 and the first pipe head 51 are connected by bolts. A molten salt discharge pipe 14 is provided on one side below the large shell flange head 521. The high-temperature molten salt discharged from the short vertical portion 233 enters the molten salt discharge space and then enters the high-temperature molten salt tank 500 for storage through the molten salt discharge pipe 14.

[0079] Combination Figure 7-Figure 12 As shown, in order to further ensure that the impurities can adhere to the outer surfaces of the horizontal portion 232 and the short vertical portion 233 after the boiler smoke enters the first pipe head 51, a first filter cartridge 8 is also provided here, and the first filter cartridge 8 includes a mounting seat 83 and a cylinder body 81. The mounting seat 83 is welded to the area on the upper surface of the second tube sheet 7 opposite to the short vertical portion 233, the short vertical portion 233 is located in the mounting seat 83, the cylinder body 81 is located at the upper end of the mounting seat 83, and the cylinder body 81 is composed of a plurality of mounting frames 814 arranged in a circular matrix, and a filter screen 811 is provided in the mounting frame 814. The mounting frame 81 The lower end of the filter 4 is rotatably mounted on the mounting seat 83 through a hinge seat 813. A docking port 12 is provided on one side of the mounting seat 83. A branch pipe 101 docking with the docking port 12 is provided on the first pipe head 51. A flue gas inlet pipe 10 is provided between the plurality of branch pipes 101. The boiler flue gas first enters the flue gas inlet pipe 10, and then enters the mounting seat 83 through the flue gas inlet pipe 10, the branch pipe 101 and the docking port 12 in sequence. Part of the impurities in the flue gas entering the mounting seat 83 adhere to the outer surfaces of the horizontal portion 232 and the short vertical portion 233, and the other part remains on the inner surface of the filter screen 811.

[0080] When the first pipe head 51 is removed, the branch pipe 101 is essentially separated from the docking port 12. It should be noted that there is no mechanical connection between the docking port 12 and the branch pipe 101, and there is no need to strictly require sealing between the two. Even if a small amount of boiler flue gas entering the branch pipe 101 leaks from the position where it contacts the docking port 12, it will not affect the entry of most of the boiler flue gas into the docking port 12.

[0081] In addition, the reason why the mounting frame 814 is set to a hinged state is to facilitate cleaning of the short vertical portion 233. Specifically, during cleaning, the mounting frame 814 can be rotated to form a hinged state. Fig.13 In the state shown, the short vertical portion 233 is exposed to the outside of the cylinder 81, so that it is convenient to clean the short vertical portion 233.

[0082] In order to avoid that the cylinder 81 is still in the filtering state Fig.13In the state shown, a limiting ring 82 is also provided here, and a limiting hole 821 is provided on the lower surface of the limiting ring 82. A limiting column 812 adapted to the limiting hole 821 is provided on the upper end of the mounting frame 814. When the limiting column 812 is inserted into the limiting hole 821, the limiting ring 82 is used to limit the rotation of the mounting frame 814, so that the cylinder 81 is kept Fig.10 status.

[0083] Preferably, a filter layer 6 is provided above the cylinder 81, and the diameter of the filter layer 6 is equal to the inner diameter of the first pipe head 51, so that the boiler flue gas discharged from the cylinder 81 can be further filtered by the filter layer 6. Figure 4 and Fig.15 The filter layer 6 here is glass fiber cotton, and its outer arc surface is fixed on the inner wall of the first tube head 51. It is also provided with a through hole for accommodating the short vertical portion 233, and a crack is also provided in the area opposite to the horizontal portion 232 to facilitate the disassembly and assembly of the filter layer 6.

[0084] Combination Figure 3 , Figure 5 and Figure 7 As shown, in order to further prevent impurities in the boiler flue gas from entering the heat exchange shell 52, a second filter cartridge 9 is also provided here. The second filter cartridge 9 is located above the inner edge of the plate body 71, so that after the flue gas passes through the filter layer 6, it needs to pass through the second filter cartridge 9 to enter the heat exchange shell 52. The material of the second filter cartridge 9 is also glass fiber wool, but the glass fiber wool here should be provided with a skeleton to maintain the annular shape of the glass fiber wool; in order to facilitate the cleaning of the second filter cartridge 9 after disassembly, a second make way groove 91 is opened in the lower part of the second filter cartridge 9 and the area opposite to the cross part 232, and the lower end of the second make way groove 91 is an open end, and the second make way groove 91 is used to make way for the cross part 232.

[0085] When the second filter cartridge 9 needs to be cleaned, the second filter cartridge 9 only needs to be directly pulled out upwards.

[0086] In addition, if Figure 7 and Fig.16 As shown, an embedded plate 4 is also provided, which is essentially used to fill the second clearance groove 91 to prevent impurities from entering the heat exchange shell 52 through the second clearance groove 91. Preferably, a hole for the cross portion 232 to pass through is provided on the embedded plate 4.

[0087] Combination Figure 8 and Fig.17As shown, in order to prevent the boiler flue gas discharged from the cylinder 81 from directly passing through the second filter cylinder 9 without passing through the filter layer 6, the second tube plate 7 here also includes a deflection ring 75, which is located above the inner edge of the plate body 71, and a clearance groove 76 is provided in the area opposite to the transverse portion 232 on the upper end surface of the deflection ring 75, and the upper end of the clearance groove 76 is an open end. The second filter cylinder 9 is located in the deflection ring 75, and there is a gap between the second filter cylinder 9 and the deflection ring 75, so that the flue gas is blocked by the deflection ring 75, and can only pass through the filter layer 6 and then enter the gap, and then be filtered by the second filter cylinder 9.

[0088] It should be noted that the top of the deflector ring 75 and the second filter cartridge 9 are set to be flush with the inner wall of the top of the first tube head 51, so as to prevent the smoke from passing through the filter layer 6 and directly entering the inner side of the second filter cartridge 9, and then directly entering the heat exchange shell 52 from the inner edge of the plate body 71, resulting in the second filter cartridge 9 being unable to perform filtering.

[0089] Preferably, the inner wall of the deflector ring 75 is provided with a retaining edge 77 capable of supporting the second filter cartridge 9 .

[0090] Combination Figure 3 and Figure 4 As shown, the double-tank molten salt heat storage boiler flue gas waste heat recovery and steam supply system proposed by the present invention is provided with a first tube sheet 3 at the lower end of the thick tube 21, and a second tube head 53 is provided at the lower end of the heat exchange shell 52. The heat exchange shell 52, the first tube sheet 3 and the second tube head 53 are fixed by bolts. A molten salt inlet pipe 1 is provided on one side of the second tube head 53. The low-temperature molten salt enters the second tube head 53 through the molten salt inlet pipe 1, and then enters the thick tube 21 through the first tube sheet 3.

[0091] Preferably, a smoke exhaust port 11 is provided on a lower side of the heat exchange shell 52 , so that the boiler smoke in the heat exchange shell 52 is discharged through the smoke exhaust port 11 .

[0092] When in use (when working), the flow of molten salt: low-temperature molten salt enters the interior of the molten salt inlet pipe 1 from the low-temperature molten salt tank 100, then enters the second pipe head 53, then enters the thick pipe 21, and then flows upward through the thin tube bundle 23, finally reaches the bottom of the plate body 71, and is discharged from the molten salt discharge pipe 14.

[0093] Flow of boiler flue gas: The flue gas discharged from the electrode boiler 400 enters the mounting seat 83 and the cylinder 81 through the flue gas inlet pipe 10 and the docking port 12. The short vertical portion 233 in the cylinder 81 acts as a preliminary filter, causing impurities in the flue gas to adhere to the short vertical portion 233, and some impurities in the flue gas will also adhere to the inner surface of the cylinder 81 (in fact, in this process, the molten salt in the short vertical portion 233 is in a state of heat exchange with the flue gas). The flue gas then passes through the cylinder 81 and enters the first pipe head 51, and is filtered again by the filter layer 6. The filtered flue gas enters the gap between the second filter cartridge 9 and the deflector ring 75, and is filtered again by the second filter cartridge 9. The filtered flue gas enters the heat exchange shell 52 to exchange heat with the molten salt in the long vertical portion 231. The flue gas with a lowered temperature after heat exchange is discharged from the flue gas exhaust port 11.

[0094] When it is necessary to clean impurities, only the first pipe head 51 needs to be removed. At this time, the filter layer 6 is removed together with the first pipe head 51, and then the second filter cartridge 9 is pulled out to clean the horizontal portion 232 and the short vertical portion 233. During cleaning, the first filter cartridge 8 can be formed. Fig.13 The state shown in FIG. 2 makes the short vertical portion 233 fully exposed, making it convenient to clean the short vertical portion 233 .

[0095] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0096] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system, characterized in that: include: Low temperature molten salt tank (100); A high-temperature molten salt tank (500), wherein a flue gas-molten salt heat exchanger (200) and an electric heater (300) are provided between the low-temperature molten salt tank (100) and the high-temperature molten salt tank (500); during off-peak electricity, the low-temperature molten salt in the low-temperature molten salt tank (100) enters the flue gas-molten salt heat exchanger (200) and exchanges heat with the boiler flue gas entering the flue gas-molten salt heat exchanger (200), and the formed high-temperature molten salt enters the high-temperature molten salt tank (500) for storage; during off-peak electricity, the low-temperature molten salt in the low-temperature molten salt tank (100) enters the electric heater (300) for heating, and the formed high-temperature molten salt enters the high-temperature molten salt tank (500) for storage; The flue gas-molten salt heat exchanger (200) comprises: Heat exchange shell (52); A heat exchange pipeline (2), the heat exchange pipeline (2) comprising a thick tube (21) and a thin tube bundle (23) fixed to the upper end of the thick tube (21), low-temperature molten salt ascends from the lower end of the thick tube (21) in the heat exchange pipeline (2), flue gas flows downward from the upper end of the heat exchange shell (52), and the flue gas exchanges heat with the low-temperature molten salt, the thin tube bundle (23) comprising a long vertical portion (231), a horizontal portion (232), and a short vertical portion (233) arranged in sequence from bottom to top, and the long vertical portion (231), the horizontal portion (232), and the short vertical portion (233) form a J-shaped structure, and the upper portion of the long vertical portion (231), the horizontal portion (232), and the short vertical portion (233) are exposed outside the upper end of the heat exchange shell (52); a first pipe head (51), the first pipe head (51) being fixed to the upper end of the heat exchange shell (52) by means of bolts, and the diameter of the first pipe head (51) being larger than that of the heat exchange shell (52), and the upper part of the long vertical part (231), the horizontal part (232) and the short vertical part (233) being located inside the first pipe head (51); It also includes a water heat exchange module, which is connected to the high-temperature molten salt tank (500). The water heat exchange module can exchange heat between water and the high-temperature molten salt, so that the water forms water vapor, and the water vapor can enter the steam turbine (800) to generate electricity; It also includes a second tube sheet (7), wherein the second tube sheet (7) includes: a plate body (71), the plate body (71) being located at a lower portion inside the first tube head (51), a tube bundle hole (74) being provided in a region of the plate body (71) opposite to the short vertical portion (233), and a lower end of the short vertical portion (233) being welded to the tube bundle hole (74); a barrel portion (72), the barrel portion (72) being arranged below the outer edge of the plate body (71), a flange portion (73) being arranged below the outer edge of the barrel portion (72), a large shell flange head (521) being arranged at the upper end of the heat exchange shell (52), the flange portion (73), the large shell flange head (521) and the first pipe head (51) being connected by bolts, and a molten salt discharge pipe (14) being arranged on one side below the large shell flange head (521); The space above the plate body (71) is a flue gas feeding space, and the space below the plate body (71) is a molten salt discharge space. The high-temperature molten salt discharged from the short vertical portion (233) enters the molten salt discharge space and then enters the high-temperature molten salt tank (500) through the molten salt discharge pipe (14); A first tube sheet (3) is provided at the lower end of the thick tube (21); A second pipe head (53) is provided at the lower end of the heat exchange shell (52), and the heat exchange shell (52), the first tube sheet (3) and the second pipe head (53) are fixedly connected by bolts; A molten salt inlet pipe (1) is provided on one side of the second pipe head (53), and low-temperature molten salt enters the second pipe head (53) through the molten salt inlet pipe (1).

2. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to claim 1, characterized in that: It also includes a first filter cartridge (8), wherein the first filter cartridge (8) includes: A mounting seat (83), the mounting seat (83) being welded to a region of the upper surface of the second tube sheet (7) that is opposite to the short vertical portion (233), the short vertical portion (233) being located inside the mounting seat (83); A cylinder (81), the cylinder (81) being located at the upper end of the mounting seat (83), and the cylinder (81) being composed of a plurality of mounting frames (814) arranged in a circular matrix, a filter screen (811) being arranged in the mounting frame (814), and the lower end of the mounting frame (814) being rotatably mounted on the mounting seat (83) via a hinge seat (813); A limiting ring (82), wherein a limiting hole (821) is provided on the lower surface of the limiting ring (82), and a limiting column (812) adapted to the limiting hole (821) is provided on the upper end of the installation frame (814); when the limiting column (812) is inserted into the limiting hole (821), the limiting ring (82) is used to limit the rotation of the installation frame (814).

3. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to claim 2, characterized in that: A docking port (12) is provided on one side of the mounting seat (83); a branch pipe (101) docking with the docking port (12) is provided on the first pipe head (51); a flue gas inlet pipe (10) is provided between the plurality of groups of branch pipes (101); boiler flue gas enters the mounting seat (83) through the flue gas inlet pipe (10), the branch pipe (101) and the docking port (12) in sequence; A filter layer (6) is provided above the cylinder (81), and the diameter of the filter layer (6) is equal to the inner diameter of the first pipe head (51).

4. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to any one of claims 1 to 3, characterized in that: It also includes a second filter cartridge (9), the second filter cartridge (9) being located above the inner edge of the plate body (71), a second clearance groove (91) being provided in an area of ​​the lower part of the second filter cartridge (9) opposite to the transverse part (232), and the lower end of the second clearance groove (91) being an open end.

5. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to claim 4, characterized in that: The second tube plate (7) further comprises a baffle ring (75), the baffle ring (75) being located above the inner edge of the plate body (71), and a first clearance groove (76) being provided in an area of ​​the upper end surface of the baffle ring (75) opposite to the transverse portion (232), and the upper end of the first clearance groove (76) is an open end; The second filter cartridge (9) is located inside the baffle ring (75), and a gap is provided between the second filter cartridge (9) and the baffle ring (75); The inner wall of the baffle ring (75) is provided with a retaining edge (77) capable of supporting the second filter cartridge (9).

6. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to claim 1, characterized in that: A smoke exhaust port (11) is provided on a lower side of the heat exchange shell (52).

7. A double-tank molten salt heat storage boiler flue gas waste heat recovery steam supply system according to claim 1, characterized in that: The water heat exchange module comprises a three-stage heat exchanger (600) and a water supply mechanism (900); The high-temperature molten salt in the high-temperature molten salt tank (500) can enter the three-stage heat exchanger (600), and the water in the water supply mechanism (900) can enter the three-stage heat exchanger (600). The water and the high-temperature molten salt exchange heat in the three-stage heat exchanger (600) to form water vapor.

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