Radiation type heat storage device and method for boiler

Abstract

The invention provides a boiler radiation type heat storage device which comprises a shell arranged at the top of a boiler, and at least part of the shell forms a light-transmitting radiation window; the thermochemical heat storage module is fixed in the shell; and the rotating mechanism is used for controlling the orientation of the radiation window or controlling the opening and closing of the radiation window. The thermochemical heat storage module is arranged in the shell and does not make contact with flue gas in the boiler, components in the flue gas can be prevented from making contact with heat storage materials in the thermochemical heat storage module, and it is guaranteed that the thermochemical heat storage module still has high heat storage performance after multiple times of circulation. The orientation of the radiation window is controlled through the rotating mechanism, or opening and closing of the radiation window are controlled through the rotating mechanism, so that when heat storage is needed, the radiation window is opened or faces the hearth to receive radiation heat, and when the thermochemical heat storage module releases heat, the radiation window is closed or rotated, absorption of the radiation heat of the hearth is reduced, and the heat is rapidly released into the boiler.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power generation, and in particular to a boiler radiation heat storage device and method. Background Art

[0002] In the existing technology, the total installed capacity of renewable energy such as wind power and photovoltaic power has continued to grow in recent years. However, the problem of mutual impact between renewable energy and thermal power energy has also been exposed. With the large-scale development of renewable energy, low-load operation and deep peak regulation of thermal power units have gradually become the norm. However, under low-load operation, the stable operation of boilers and the safe operation of equipment such as steam turbines and auxiliary machines will be affected. Therefore, by coupling coal-fired power generation and heat storage technology, a certain degree of "thermal and electric decoupling" can be achieved without affecting the heat supply. By using the principle of low storage and high generation, the time and space transfer of electric energy can be realized, and the flexible adjustment capacity of conventional thermal power units can be greatly improved, thereby increasing the absorption space of renewable energy. It is an effective way to resolve the contradiction between the development of thermal power and renewable energy.

[0003] At present, the main boiler heat storage peak regulation technologies include electric boiler solid heat storage technology, water storage energy storage technology, molten salt energy storage technology, etc. Among them, the electric boiler solid heat storage technology involves electric heat conversion, water storage energy storage and molten salt energy storage technologies use boiler extraction steam for heating, have many energy conversion stages, and the heat storage efficiency is not high.

[0004] In this regard, patent CN217402525U proposes a thermal power particle heat storage peak-shaving system, which uses the flue gas in the furnace to directly heat the particle heat storage medium in the heat absorption device, which can reduce the energy conversion level and improve the heat storage efficiency. However, in this thermal power particle peak-shaving heat storage system, the heat storage medium is located in the boiler and is directly washed by the flue gas. The impurities, sulfur and nitrogen compounds in the boiler flue gas may affect the structure and composition of the heat storage medium, especially for thermochemical heat storage particles, which will affect the reaction performance of thermochemical heat storage materials, resulting in low heat storage performance of the heat storage medium after multiple heat storage cycles. Summary of the invention

[0005] In view of the above problems, the present invention provides a boiler radiation heat storage device and method, which can avoid direct scouring of flue gas while ensuring the heat storage efficiency of the heat storage module.

[0006] On the one hand, the present invention provides a boiler radiation heat storage device, comprising: a shell arranged on the top of the boiler, the shell at least partially formed as a light-transmitting radiation window; a thermochemical heat storage module fixed in the shell; and a switching mechanism for switching the radiation window to directly face the furnace of the boiler or to be separated from the furnace of the boiler.

[0007] According to this technical solution, firstly, the thermochemical heat storage module is arranged in the shell and does not contact the flue gas inside the boiler, which can prevent the components in the flue gas from contacting the heat storage material in the thermochemical heat storage module, ensuring that the thermochemical heat storage module still has a high heat storage performance after multiple cycles.

[0008] Secondly, the shell is arranged on the top of the boiler, which reduces the scouring of the shell by the smoke in the boiler, and can directly absorb the radiant heat in the furnace below through the light-transmitting radiation window, with fewer energy conversion stages and high heat storage efficiency.

[0009] Finally, by switching the switching mechanism, when heat storage is needed, the radiation window can be directly facing the furnace to receive radiant heat. When the thermochemical heat storage module releases heat, the radiation window is separated from the furnace to reduce the absorption of furnace radiant heat and quickly release heat into the boiler.

[0010] As a preferred technical solution of the present invention, the shell is formed as a light-proof shell with a radiation window, and the switching mechanism is a rotating mechanism that drives the shell to rotate.

[0011] According to the technical solution, when the rotating mechanism controls the shell to rotate to a position where the radiation window faces the furnace, the thermochemical heat storage module in the shell can receive the thermal radiation from the furnace through the light-transmitting radiation window to store heat; when the rotating mechanism controls the shell to rotate to a position where the radiation window faces away from the furnace, the opaque shell faces the furnace, blocking the radiant heat from the furnace, thereby reducing the absorption of the radiant heat from the furnace by the thermochemical heat storage module, while the thermochemical heat storage module releases heat.

[0012] As a preferred technical solution of the present invention, the switching mechanism is a rotatable light-proof plate covering the radiation window surface of the shell.

[0013] According to the technical solution, when the opaque plate covers the surface of the radiation window, the heat of the furnace is blocked by the opaque plate, and the thermochemical heat storage module in the shell releases heat to produce an oxidation reaction; when the opaque plate is rotated to be perpendicular to the surface of the radiation window, the radiation window directly faces the furnace, and the heat of the furnace can be directly transferred to the thermochemical heat storage module through the radiation window, and the thermochemical heat storage module absorbs heat to produce a reduction reaction.

[0014] As a preferred technical solution of the present invention, the shell is fixed to the top of the boiler, and the top surface of the boiler forms the upper wall surface or the lower wall surface of the shell.

[0015] According to the technical solution, fixing the shell directly to the top of the boiler can further reduce the scouring of the shell by the flue gas, and the installation structure of the boiler radiation heat storage device and the boiler is more compact.

[0016] As a preferred technical solution of the present invention, a grille is detachably provided in the shell, and the grille divides the shell into a plurality of compartments matching the shapes of the thermochemical heat storage modules.

[0017] According to the technical solution, the thermochemical heat storage modules can be individually placed in different compartments of the grid to avoid misalignment, accumulation, collision, etc. between the thermochemical heat storage modules. In addition, the detachable grid is also more conducive to the maintenance and replacement of thermochemical heat storage modules of various shapes.

[0018] As a preferred technical solution of the present invention, the boiler radiation heat storage device also includes an air pump arranged outside the boiler, which is connected to the shell through an air supply pipeline, and an air supply valve is arranged on the air supply pipeline.

[0019] According to the technical solution, the thermochemical heat storage module stores / releases heat through thermochemical reactions, and the thermochemical reaction process often requires the participation of gases such as oxygen and hydrogen. For example, for metal oxide thermochemical heat storage materials, when releasing heat, the metal oxide needs to undergo an oxidation reaction with oxygen. Therefore, by arranging an air pump outside the boiler, it is convenient to transport air into the shell, and the oxygen in the air can react with the thermochemical heat storage module to release heat.

[0020] As a preferred technical solution of the present invention, the boiler radiation heat storage device also includes: an air outlet pipe, one end of which is connected to the shell, and the other end is arranged in the top flue of the boiler, and an air outlet valve is arranged on the air outlet pipe.

[0021] According to the technical solution, when the thermochemical heat storage module undergoes an exothermic reaction, the air pump continuously introduces air into the shell. After the oxygen in the air reacts with the thermochemical heat storage module, the remaining oxygen-depleted air contacts the thermochemical heat storage module to form high-temperature air. The high-temperature air enters the top flue of the boiler through the air outlet pipe and releases heat into the boiler.

[0022] As a preferred technical solution of the present invention, the boiler radiation heat storage device also includes: a reflux pipe connecting the shell and the bottom of the boiler, and a gas delivery valve is arranged on the reflux pipe.

[0023] According to the technical solution, when the thermochemical heat storage module undergoes a reduction reaction to store heat, it will produce combustible / combustion-supporting gases such as oxygen, which can flow back to the bottom of the furnace through the reflux pipeline, replacing part of the burnt air, ensuring sufficient combustion and improving boiler efficiency.

[0024] As a preferred technical solution of the present invention, a heat-insulating layer is arranged outside the shell.

[0025] According to this technical solution, the insulation layer can reduce the heat loss of the thermochemical heat storage module inside the shell, while preventing the direct exposure of the thermochemical heat storage module to the high temperature environment inside the boiler, thereby improving safety.

[0026] The second aspect of the present invention also provides a boiler radiation heat storage method, comprising the following steps:

[0027] In the feeding step, the grille is opened and the thermochemical heat storage modules are arranged in compartments;

[0028] In the heat storage step, the radiation window is switched to directly face the furnace, and the heat radiation in the furnace enters the shell of the boiler radiation heat storage device through the radiation window. The thermochemical heat storage module built into the shell absorbs the heat radiation to generate a reduction reaction and release oxygen;

[0029] In the heat release step, air is introduced into the shell, the radiation window is switched to be separated from the furnace, and the thermochemical heat storage module undergoes an oxidation reaction to release heat energy;

[0030] During the material replacement step, open the grille and take out the old thermochemical heat storage module. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the overall structure of the boiler radiation heat storage device and the boiler in an embodiment of the present invention;

[0032] Figure 2 is a schematic structural diagram of a boiler radiation heat storage device in an embodiment of the present invention;

[0033] Figure 3 is a flow chart of a boiler radiation heat storage method in an embodiment of the present invention;

[0034] Figure 4 It is a structural schematic diagram of another boiler radiation heat storage device in an embodiment of the present invention.

[0035] Explanation of the reference numerals: 1-shell; 2-switching mechanism; 21-rotating mechanism; 22-opaque plate; 3-grid; 4-thermochemical heat storage module; 5-boiler; 6-furnace; 7-radiation window; 8-screen superheater; 9-flame folding angle; 10-boiler radiation heat storage device; 11-air outlet valve; 12-air pump; 13-air supply valve; 14-air outlet pipe; 15-gas delivery valve; 16-reflux pipe; 17-grid. DETAILED DESCRIPTION

[0036] 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.

[0037] Figure 1 Schematic diagram of the overall structure of a boiler radiation heat storage device 10 and a boiler 5 provided in this embodiment. Figure 1As shown, the present invention provides a boiler radiation type heat storage device 10 , which comprises: a shell 1 , a thermochemical heat storage module 4 and a rotating mechanism 2 .

[0038] The shell 1 forms a closed cavity on the top of the boiler 5, wherein the shell 1 may be an independent closed shell, or may be closed and enclosed in a manner that the top wall of the boiler 5 is used as the upper wall or lower wall of the shell 1. In particular, at least part of the surface of the shell 1 is formed as a light-transmitting radiation window 7. In some embodiments, the shell 1 is made of a high-temperature resistant, light-opaque material, and only a light-transmitting radiation window 7 is provided at the bottom of the shell 1 (the side facing the furnace 6). Preferably, the light-transmitting radiation window 7 on the shell 1 is made of transparent quartz glass, which has the characteristics of high heat resistance, high spectral transmittance, and will not be damaged by radiation, so that while isolating the flue gas, the heat radiation from the furnace 6 can pass through the quartz glass to reach the shell 1. In addition, the quartz glass also has a certain heat insulation function, which can prevent part of the heat from being lost.

[0039] Further preferably, an insulation layer (not shown) is also provided outside the shell 1, which can reduce the heat loss of the thermochemical heat storage module 4 inside the shell 1, while avoiding direct exposure of the thermochemical heat storage module 4 to the high temperature environment inside the boiler 5, thereby improving safety.

[0040] It should be noted that the shell 1 is arranged on the top of the boiler 5 does not specifically mean that the shell 1 is arranged in the upper internal area of ​​the boiler 5. The shell 1 is fixed on the top inside the boiler 5, or fixed on the top outside the boiler 5, for example, it is arranged on the top of the screen superheater 8, close to the furnace top, close to the flame folding angle 9, or suspended on the top outside the boiler 5, all belong to the protection scope of the present invention.

[0041] The thermochemical heat storage module 4 is disposed in the housing 1. The main heat storage material of the thermochemical heat storage module 4 can be metal oxides, metal hydrides, hydroxides, carbonates, etc., which are not limited here. Preferably, as Figure 2 and Figure 3 As shown, staggered grilles 3 are fixed in the housing 1, and the grilles 3 divide the housing 1 into a plurality of compartments matching the shapes of the thermochemical heat storage modules 4. The thermochemical heat storage modules 4 can be individually placed in different compartments of the grilles 3 to avoid misalignment, accumulation, collision, etc. between the thermochemical heat storage modules 4. In addition, the grilles 3 can be detachably fixed to the housing 1, for example, by snap fastening, slotting, or screwing, etc., so as to facilitate maintenance and replacement of thermochemical heat storage modules 4 of various shapes.

[0042] Switching mechanism ( Figure 1The radiation window 7 is switched to directly face the furnace 6 of the boiler 5 or to be separated from the furnace 6 of the boiler 5. The structures and control processes of the two switching mechanisms are described in detail below with reference to the accompanying drawings.

[0043] Figure 2 Schematic diagram of the structure of the boiler radiation heat storage device 10 in the embodiment of the present invention. Figure 2 As shown, the housing 1 is formed as a light-proof shell with a radiation window 7, and the switching mechanism 2 is a rotating mechanism 21 fixed to the housing 1. Figure 1 As shown, the rotating mechanism 21 includes a rotating motor and a rotating shaft, wherein ... Figure 1 and Figure 2 From the perspective of heat storage, the shell 1 is fixed at a position where the rotating axis is parallel to the top surface of the boiler 5, and the radiation window 7 is opened on the side of the shell 1 that is not connected to the rotating axis. When heat storage is required, the rotating mechanism 21 controls the shell 1 to rotate around the rotating axis to the position where the radiation window 7 is facing the furnace 6, and the thermochemical heat storage module 4 in the shell 1 can receive the thermal radiation of the furnace 6 through the radiation window 7 to store heat; when heat release is required, the rotating mechanism 2 controls the shell 1 to rotate around the rotating axis to the position where the radiation window 7 is facing away from the furnace 6, and the opaque shell 1 is facing the furnace 6, blocking the radiant heat of the furnace 6, thereby reducing the absorption of the radiant heat of the furnace 6 by the thermochemical heat storage module 4, and the thermochemical heat storage module 4 releases heat at the same time.

[0044] Specifically, Figure 3 Flow chart of the radiant heat storage method of boiler 5 in the embodiment of the present invention. Figure 3 As shown, first, the feeding step S1 is performed, the grille 3 of the boiler radiation type heat storage device 10 is opened, and the thermochemical heat storage modules 4 are placed in the compartments; then, the heat storage step S2 is performed, the rotating mechanism 21 drives the shell 1 to rotate until the radiation window 7 faces the furnace 6, and the heat radiation in the furnace 6 of the boiler 5 enters the shell 1 of the boiler radiation type heat storage device 10 through the radiation window 7, and the thermochemical heat storage module 4 built into the shell 1 absorbs the radiation heat to undergo a reduction reaction and release oxygen; then, the heat release step S3 is performed, air is transported into the shell 1, and the rotating mechanism 21 drives the shell 1 to rotate until the radiation window 7 faces away from the furnace 6, and the thermochemical heat storage module 4 undergoes an oxidation reaction and releases heat energy; after repeating the heat storage step S2 and the heat release step S3 for multiple cycles, the material replacement step S4 is finally performed, the grille 3 is opened, and the old thermochemical heat storage module 4 is taken out.

[0045] Figure 4 is a structural schematic diagram of another boiler radiation heat storage device 10 provided in this embodiment, such as Figure 4As shown, the shell 1 is fixed to the top of the boiler 5 , and the top surface of the boiler 5 forms the upper wall surface of the shell 1 . The switching mechanism 2 is an opaque plate 22 covering the surface of the radiation window 7. By switching the rotation state of the opaque plate 22, the radiation window 7 can be controlled to directly face the furnace 6 or to face the furnace 6 separated by the opaque plate 22, which can further improve the stability of the fixed structure between the boiler radiation heat storage device 10 and the boiler 5. Preferably, the outside of the shell is also formed as a grid 17 for fixing the opaque plate 22, so that the opaque plate can be rotated open on the surface of the radiation window 7. When the opaque plate 22 covers the surface of the radiation window 7, the radiation window 7 and the furnace 6 are separated, the heat of the furnace 6 is blocked by the opaque plate 22, and the thermochemical heat storage module 4 in the shell 1 releases heat to produce an oxidation reaction; when the opaque plate 22 rotates to be perpendicular to the surface of the radiation window 7, the radiation window 7 directly faces the furnace 6, and the heat of the furnace 6 can be directly transferred to the thermochemical heat storage module 4 through the radiation window 7, and the thermochemical heat storage module 4 absorbs heat to produce a reduction reaction.

[0046] Specifically, if Figure 3 As shown, first, the feeding step S1 is performed, the grille 3 of the boiler radiation type heat storage device 10 is opened, and the thermochemical heat storage module 4 is placed in the compartment; then, the heat storage step S2 is performed, the opaque plate 22 is rotated to a position perpendicular to the radiation window 7, so that the radiation window 7 can directly receive the heat radiation of the furnace 6 without blocking, and the heat radiation in the furnace 6 of the boiler 5 enters the shell 1 of the boiler radiation type heat storage device 10 through the radiation window 7, and the thermochemical heat storage module 4 built into the shell 1 absorbs the radiation heat to undergo a reduction reaction and release oxygen; then, the heat release step S3 is performed, air is transported into the shell 1, and the opaque plate 22 is rotated to a position covering the surface of the radiation window 7, so as to block the heat radiation in the furnace 6 of the boiler 5, and the thermochemical heat storage module 4 undergoes an oxidation reaction and releases heat energy; after repeating the heat storage step S2 and the heat release step S3 for multiple times, the material replacement step S4 is finally performed, the grille 3 is opened, and the old thermochemical heat storage module 4 is taken out.

[0047] In this embodiment, first, the thermochemical heat storage module 4 is arranged in the shell 1 and does not contact the flue gas inside the boiler 5, which can prevent the components in the flue gas from contacting the heat storage material in the thermochemical heat storage module 4, ensuring that the thermochemical heat storage module 4 still has a high heat storage performance after multiple cycles.

[0048] Secondly, the shell 1 is arranged on the top of the boiler 5, which reduces the scouring of the shell 1 by the smoke in the boiler 5, and can directly absorb the radiant heat in the furnace 6 below through the light-transmitting radiation window 7, with fewer energy conversion stages and high heat storage efficiency.

[0049] Finally, the radiation window is switched to directly face the furnace of the boiler or to be separated from the furnace of the boiler through the switching mechanism 2, so that when heat storage is needed, the radiation window 7 can directly face the furnace 6 to directly receive the radiant heat. When the thermochemical heat storage module 4 releases heat, the radiation window 7 is separated from the furnace 6 to reduce the absorption of the radiant heat from the furnace 6 and quickly release heat into the boiler 5.

[0050] It is worth mentioning that in a preferred embodiment of the present invention, the boiler radiation heat storage device 10 also includes: an air pump 12 arranged outside the boiler 5, which is connected to the shell 1 through an air supply pipeline, and an air supply valve 13 is provided on the air supply pipeline; an air outlet pipe 14, one end of which is connected to the shell 1, and the other end is arranged in the top flue of the boiler 5, and an air outlet valve 11 is provided on the air outlet pipe 14; and a return pipe 16, which is connected to the shell 1 and the bottom of the boiler 5, and a gas delivery valve 15 is provided on the return pipe 16.

[0051] Specifically, since the thermochemical heat storage module 4 stores / releases heat through a thermochemical reaction, and the thermochemical reaction process often requires the participation of gases such as oxygen and hydrogen, for example, for metal oxide thermochemical heat storage materials, when releasing heat, the metal oxide needs to undergo an oxidation reaction with oxygen. Therefore, by arranging an air pump 12 outside the boiler 5, when the metal oxide needs to release heat, the air supply valve 13 is opened, and the air pump 12 blows air into the shell 1, and the oxygen in the air can react with the thermochemical heat storage module 4 to release heat. After the reaction, the remaining oxygen-depleted air reacts with the thermochemical heat storage module 4. After contact with the thermal storage module 4, high-temperature air is formed. The outlet valve 11 is opened, and the high-temperature air enters the top flue of the boiler 5 through the outlet pipe 14 to release heat into the boiler 5. When storing heat, the thermochemical heat storage module 4 undergoes a reduction reaction (decomposition reaction) to produce combustible / combustible gases such as oxygen. For example, metal oxides produce oxygen when storing heat. Therefore, when the metal oxides store heat, the gas delivery valve 15 is opened, and oxygen flows back to the bottom of the furnace 6 through the reflux pipe 16 to replace part of the burnt air, thereby ensuring sufficient combustion and further improving the efficiency of the boiler 5.

[0052] So far, the technical solution of the present invention has been described in conjunction with the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to the above specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A boiler radiation heat storage device, characterized in that: include: A shell, arranged on the top of the boiler, wherein at least a part of the shell is formed as a light-transmitting radiation window; A thermochemical heat storage module is fixed in the housing; A switching mechanism switches the radiation window to directly face the furnace of the boiler or to be separated from the furnace of the boiler.

2. The boiler radiation heat storage device according to claim 1, characterized in that: The shell is formed as a light-proof shell with a radiation window, and the switching mechanism is a rotating mechanism for driving the shell to rotate.

3. The boiler radiation heat storage device according to claim 1, characterized in that: The switching mechanism is a rotatable light-proof plate, which covers the radiation window surface of the shell.

4. The boiler radiation heat storage device according to claim 3, characterized in that: The shell is fixed to the top of the boiler, and the top surface of the boiler is formed as the upper wall surface or the lower wall surface of the shell.

5. The boiler radiation heat storage device according to claim 1, characterized in that: A grid is detachably disposed in the shell, and the grid divides the shell into a plurality of compartments matching the shapes of the thermochemical heat storage modules.

6. The boiler radiation heat storage device according to claim 1, characterized in that: Also includes: An air pump is arranged outside the boiler and is connected to the shell through an air supply pipeline, and an air supply valve is arranged on the air supply pipeline.

7. The boiler radiation heat storage device according to claim 6, characterized in that: Also includes: An air outlet pipe has one end connected to the shell and the other end arranged in the top flue of the boiler. An air outlet valve is arranged on the air outlet pipe.

8. The boiler radiation heat storage device according to claim 1, characterized in that: Also includes: A reflux pipe is connected to the shell and the bottom of the boiler, and a gas delivery valve is arranged on the reflux pipe.

9. The boiler radiation heat storage device according to claim 1, characterized in that: A heat-insulating layer is arranged outside the shell.

10. A boiler radiation heat storage method, characterized in that: The steps include: In the feeding step, the grille is opened and the thermochemical heat storage modules are arranged in compartments; In the heat storage step, the radiation window is switched to directly face the furnace, and the heat radiation in the furnace enters the shell of the boiler radiation heat storage device through the radiation window, and the thermochemical heat storage module built into the shell absorbs the heat radiation to generate a reduction reaction and release oxygen; a heat release step, wherein air is introduced into the shell, the radiation window is switched to be separated from the furnace, and the thermochemical heat storage module undergoes an oxidation reaction to release heat energy; The material replacement step is to open the grid and take out the old thermochemical heat storage module.

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