Combustion apparatus

Abstract

This invention relates to combustion equipment. The combustion equipment includes a combustion device, comprising a combustion space; a preheating device, in which fuel particles are fluidized to form solid fuel and gaseous fuel, the preheating device communicating with the combustion space via a first channel, wherein at least gaseous fuel enters the combustion space via the first channel; and a storage device receiving and storing at least a portion of solid fuel from the preheating device via a second channel, one end of the second channel communicating with the solid fuel outlet of the preheating device and the other end of the second channel communicating with the solid fuel inlet of the storage device, wherein: the storage device supplies solid fuel to the combustion space via a third channel, one end of the third channel communicating with the first solid fuel outlet of the storage device; and / or the storage device is adapted to supply solid fuel to the preheating device via a fourth channel, one end of the fourth channel communicating with the second solid fuel outlet of the storage device and the other end of the fourth channel communicating with the solid fuel return port of the preheating device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of fuel processing, and more particularly to a combustion device. Background Technology

[0002] my country's future power system will be based on new energy sources. However, the generation of renewable energy sources such as wind and solar power is random and intermittent, requiring coal-fired power units to undertake flexible peak-shaving tasks. Currently, the peak-shaving depth of coal-fired power units in my country is generally higher than 40%, while the speed is lower than 1.5% / min. Achieving a peak-shaving depth of 20% and a speed of 5% / min remains quite challenging.

[0003] In coal-fired industrial boilers (where the main product is generally heat), there is a pressing need for boilers to respond flexibly and quickly to changes in user load, and even to operate on a two-shift basis. Existing technologies also address the need for flexible load adjustments to the combustion unit.

[0004] Existing boiler operation modes are based on the boiler design load. They can participate in peak shaving or make rapid load adjustments within a certain range, but they have great limitations. When operating at low / ultra-low loads (below 25% of the design load, or even 3-6% of the design load), there are problems with the boiler's operational safety, economy, and reliability, and it is difficult to achieve rapid response to load changes. Summary of the Invention

[0005] To address at least one aspect of the aforementioned technical problems, this invention is proposed.

[0006] According to one aspect of an embodiment of the present invention, a combustion device is provided, comprising:

[0007] Combustion apparatus, including combustion space;

[0008] A preheating device, wherein fuel particles are adapted to be fluidized within the preheating device to form solid fuel and gaseous fuel, the preheating device being connected to the combustion space via a first channel, at least the gaseous fuel entering the combustion space via the first channel;

[0009] A storage device is adapted to receive and store at least a portion of solid fuel from a preheating device via a second channel, one end of which is connected to the solid fuel outlet of the preheating device, and the other end of which is connected to the solid fuel inlet of the storage device.

[0010] in:

[0011] The storage device is adapted to deliver solid fuel to the combustion space via a third channel, one end of which is connected to a first solid fuel outlet of the storage device; and / or

[0012] The storage device is adapted to deliver solid fuel to the preheating device via a fourth channel, one end of which is connected to the second solid fuel outlet of the storage device, and the other end of which is connected to the solid fuel return port of the preheating device. Attached Figure Description

[0013] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:

[0014] Figure 1 This is a schematic diagram of a combustion device according to an exemplary embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of a combustion device according to another exemplary embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of a storage device according to an exemplary embodiment of the present invention;

[0017] Figure 4 This is a schematic diagram of a combustion device according to another exemplary embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] This invention proposes a scheme for adjusting the heat load of combustion equipment by storing and releasing high-temperature solid fuel particles in a preheating device, which is particularly applicable to peak-shaving boilers. The combustion equipment may include: a preheating device for forming a high-temperature gas-solid mixture (including high-temperature gas fuel and high-temperature semi-coke); a combustion device, such as a boiler, defining a furnace for organizing the combustion of the fuel, including the high-temperature gas-solid mixture formed in the preheating device; and a storage device for storing the high-temperature semi-coke (a specific example of solid fuel) formed in the preheating device under specific operating conditions, and for discharging the high-temperature semi-coke into the furnace under specific operating conditions.

[0020] In this invention, a boiler absorbs heat generated from fuel combustion to produce high-temperature steam, which can be used for steam turbine power generation. The boiler and steam turbine are components of a generator set.

[0021] like Figure 1 As shown, under the condition that the generator unit does not need to participate in peak shaving, the pulverized coal is preheated by the fluidized bed preheating device 10 (in... Figure 1 In the example, after being processed by the preheating burner, preheated fuel is formed and enters the combustion space 30 of the furnace or combustion device for combustion. Figure 1 As shown, the combustion equipment also includes an insulated storage device 20 connected to the preheating device 10 and the boiler furnace, respectively, for storing high-temperature solid fuel generated by the preheating device or releasing high-temperature solid fuel into the furnace when needed. The high-temperature solid fuel is drawn from the particle enrichment area of ​​the preheating device and enters the storage device under gravity to achieve heat storage under reduced load conditions; the high-temperature solid fuel in the storage device can enter the furnace for combustion and heat release under increased load conditions by pneumatic conveying.

[0022] In a further embodiment, such as Figure 2 As shown, the preheating device 10 is a circulating fluidized bed structure including a riser, a cyclone separator, and a return feeder, and the particle enrichment area includes the bottom of the riser and the return feeder; or the preheating device 10 is a fluidized bed or a bubbling bed, and the particle enrichment area includes the bottom of the fluidized bed or the bubbling bed.

[0023] The particle enrichment zone of the preheating device 10 is equipped with a high-temperature solid fuel outlet, which is connected to the high-temperature solid fuel inlet of the storage device via a connecting pipeline. When the preheating device is a fluidized bed or a bubbling bed, the high-temperature solid fuel outlet is located in the dense phase zone of the fluidized bed or bubbling bed, above the air distribution device of the fluidized bed or bubbling bed and below the interface between the dilute phase zone and the dense phase zone.

[0024] In another embodiment, the preheating device 10 is a circulating fluidized bed structure. Figure 2 The particle enrichment zone includes the bottom of the riser and the return feeder. Therefore, the high-temperature solid fuel outlet can be located not only in the dense phase zone of the bed but also in the return feeder. As can be understood, the solid fuel outlet of the preheating unit can be located at one or both of the bottom of the riser and the return feeder.

[0025] Furthermore, in a fluidized bed / circulating fluidized bed equipped with an air distribution device, in one embodiment of the present invention, a solid fuel outlet for a preheating device is provided near the air distribution device in the bed height direction.

[0026] The high-temperature solid fuel outlet may also be equipped with a control valve (which may be a mechanical valve, such as a plate valve, mushroom valve, or impeller feed valve) to switch between normal combustion conditions and peak shaving conditions.

[0027] In one embodiment of the present invention, the high-temperature solid fuel inlet of the storage device 20 is located on the upper side or top of the storage device 20.

[0028] In one embodiment of the present invention, such as Figure 3 As shown, the storage device 20 includes a storage area 201 and a transport area 202. Figure 3 Under the control of valves (including pneumatic valves, mechanical valves, or gravity valves), the flow is unidirectional from the storage area to the conveying area.

[0029] In one embodiment of the storage device 20, the storage area is positioned higher than the transport area. There is a natural gravity difference between the storage area and the transport area for the high-temperature solid fuel. The potential energy difference formed by this gravity difference is used in conjunction with pneumatic transport to achieve a unidirectional flow of the high-temperature solid fuel to the transport area.

[0030] In one embodiment of the storage device 20, the storage area 201 is located above the conveying area 202 and is connected by a channel with a cross-section smaller than that of the storage area, and a valve (plate valve or mushroom valve) is installed on the channel. When the boiler reduces its load, the valve remains closed, and high-temperature solid fuel accumulates in the storage area; when the boiler needs to increase its load, the valve is opened, allowing the high-temperature solid fuel to fall into the conveying area under gravity, and the material is carried to the furnace for combustion under the pneumatic conveying action in the conveying area.

[0031] Nitrogen, CO2, or tail gas with an oxygen content of less than 5% are introduced into the storage device to provide an inert protective environment and prevent the high-temperature solid fuel from coming into contact with air and burning.

[0032] The pneumatic conveying inlet and outlet are located in the conveying area. Since the solid fuel flows unidirectionally from the storage area to the conveying area, the influence of the gas in the conveying area on the fuel in the storage area is avoided. The gas used for pneumatic conveying can be N2, CO2, or steam. When using steam, the steam can be drawn from the high-pressure steam of the boiler steam-water system. The steam itself has pressure and can be directly conveyed, resulting in a simple structure without the need for a pressurization device.

[0033] When the boiler needs to rapidly reduce its load, a portion of the hot solid fuel in the preheating burner is introduced into a sealed container, causing the burner load to decrease rapidly and thus achieving rapid boiler load reduction. When the boiler needs to rapidly increase its load, high-temperature solid fuel is introduced into the boiler via a pneumatic conveying device. Under the condition of air distribution, the high-temperature solid fuel burns rapidly in the furnace, achieving rapid boiler load increase. In another embodiment, such as... Figure 4 As shown, when the boiler is under increased load, the high-temperature solid fuel in the storage device can be sent to the preheating device through pneumatic conveying to supplement the heat in the preheating device and finally enter the furnace for combustion.

[0034] The storage capacity of the storage device 20 can be 0.5-3.0 times the amount of circulating material in the preheating device, and more specifically 0.5 to 1.0 times, thereby ensuring that the system can operate under a wide load.

[0035] Both the high-temperature solid fuel in the storage device and the gas-solid mixed fuel transported to the boiler furnace by the preheating device are thermal fuels. They are easy to ignite quickly and burn stably in the furnace. Moreover, the boiler furnace has at least two high-temperature fuel inlets, which is conducive to or can achieve an ultra-fast load increase rate of more than 5% of the rated load per minute.

[0036] use Figure 4 The combustion equipment shown enables, for example, a boiler's combustion device to operate stably under ultra-low loads (e.g., boiler set load 3-6%), thereby meeting the so-called two-shift operation requirements of the generator set. The two-shift system includes two states: normal operation under load and hot standby without load. It requires (a) rapid shutdown from normal operation under load to hot standby without load, and (b) rapid startup from hot standby without load to normal operation under load. In state (b), some or all of the solid fuel in the storage device is pneumatically conveyed into the preheating device 10.

[0037] The specific operation process is illustrated below:

[0038] (1) When the boiler is in normal operating condition with electrical load during the first shift, the boiler is operating at more than 25% of its rated load. The preheating device maintains oxygen-deficient oxidation conditions. At this time, there is no thermal fuel stored in the storage device, or it is in a small storage state. The preheating device continuously supplies fuel to the boiler.

[0039] (2) The second shift is when the boiler is not under electrical load but is in standby state with ultra-low heat load. When switching from the first shift to the second shift, most of the high-temperature solid fuel in the preheating device is quickly sent to the storage device in one go. At the same time, the coal feed rate of the preheating device is reduced, so that the interior of the preheating device becomes an oxidizing atmosphere. The coal is completely burned in the preheating device, and the high-temperature flue gas generated, about 3 to 6% of the rated load, is sent to the boiler in standby state to slow down the cooling rate of the boiler.

[0040] (3) When switching from the second shift to the first shift, by sending part or all of the high-temperature solid fuel in the storage device into the preheating device, the material concentration in the preheating device is increased, and the preheating device is switched to oxygen-deficient gasification conditions. The preheating device continuously supplies hot fuel to the boiler, which ignites rapidly in the furnace, and can achieve an ultra-fast load increase rate of more than 5% of the rated load per minute for the boiler.

[0041] (4) For large power plant boilers, in order to ensure the uniformity of combustion temperature in the large-scale furnace during rapid hot start-up and to avoid overheating of local heating surfaces, multiple preheating devices can be arranged at the same level of the furnace according to the type of boiler. These different numbers of preheating devices can operate synchronously during the rapid start-up and shutdown of the boiler. In one embodiment of a tangential pulverized coal boiler, four preheating devices will be arranged at a certain level of the furnace, so that each preheating device is in a hot standby state of about 1% (in this invention, about 1% is in the range of 0.5-1.5%) of the boiler's rated load during the second shift, and the entire boiler system is in a hot standby state of, for example, 4% of the rated load; in another embodiment of a swirl counter-current pulverized coal boiler, four, five, or six preheating devices will be arranged at a certain level of the furnace, so that each preheating device is in a hot standby state of about 1% of the boiler's rated load during the second shift, and the entire boiler system is in a hot standby state of, for example, 4%, 5%, or 6% of the rated load.

[0042] This type of boiler operates on two shifts. The system is simple and compact, and can quickly switch between normal operating conditions with load (25% and above) and hot standby conditions without power load (3% to 6% load). Moreover, this two-shift operation can be performed frequently, with low start-stop inertia.

[0043] Furthermore, when the boiler is operating at more than 25% of its rated load, the oxygen-deficient oxidation conditions in the preheating device are maintained, and solid fuel and gaseous fuel are supplied to the combustion space from the preheating device. In order to increase the load more quickly, if solid fuel is stored in the storage device 20, solid fuel can be supplied to the combustion space from the storage device.

[0044] use Figure 1 and Figure 3 The combustion device shown, combined with storing solid fuel from the preheating unit in a storage device and introducing the solid fuel in the storage device into the furnace as needed, can also effectively regulate the boiler's heat load.

[0045] In the example above, a single preheating device is connected to a single first fuel inlet, but the invention is not limited thereto. A single preheating device can also be connected to multiple first fuel inlets, which is also within the scope of this invention. Correspondingly, when a single preheating device is connected to multiple first fuel inlets, the amount of fuel supplied through a single first fuel inlet can be used to control each first fuel inlet to be in a hot standby state of approximately 1% of the boiler's rated load during the second shift, which is also within the scope of this invention.

[0046] In this invention, Figure 1 , 2 and Figure 4In the combustion apparatus shown, the solid fuel in the storage device 20 needs to be transported to the combustion device 30. However, although not specifically shown, the invention is not limited to this. In another embodiment of the invention, a transport path for transporting solid fuel from the preheating device 10 to the storage device 20, and a return path for returning solid fuel from the storage device 20 to the preheating device 10 to increase the material concentration in the preheating device, can be provided only between the storage device 20 and the preheating device 10. Using the above scheme, the combustion load in the preheating device 10 can also be adjusted flexibly and quickly. It is understood that returning solid fuel from the storage device 20 to the preheating device 10 can also be achieved using a pneumatic transport method similar to that used for transporting solid fuel from the storage device 20 to the combustion device 30, which will not be elaborated here.

[0047] The return port of the solid fuel in the storage device 20 to the preheating device 10 can be the same as the fuel inlet of the existing preheating device, or another inlet at the same height, or a return port at another location.

[0048] In this invention, the boiler, as an example of a combustion device, includes a plurality of first combustion space inlets, which are arranged on the same level and / or in multiple layers; and the preheating device includes one preheating device that is simultaneously connected to the plurality of first combustion space inlets, or the preheating device includes a plurality of preheating devices, one or more of which are connected to one or more of the plurality of first combustion space inlets. Accordingly, based on the exemplary operation of the boiler described above, the boiler is a tangential pulverized coal boiler, and the plurality of first combustion space inlets includes four first combustion space inlets located at the same level in the furnace; or the boiler is a swirl-flow counter-current pulverized coal boiler, and the plurality of first combustion space inlets includes four, five, or six first combustion space inlets located at the same level in the furnace; or the boiler is a counter-current pulverized coal boiler, and the plurality of first combustion space inlets includes two first combustion space inlets located diagonally at the same level in the furnace.

[0049] In this invention, the interconnection between the preheating device, the storage device, and the combustion device is achieved through corresponding channels. These channels are used to transport gaseous fuel and / or solid fuel. Depending on the needs, the channels may or may not be equipped with valves to control the flow of fuel, both of which are within the protection scope of this invention.

[0050] In this invention, high temperature means a temperature above the ignition point of solid fuel, for example, above 650-750°C for ordinary pulverized coal, and above 350°C for biomass fuel.

[0051] It should be noted that, in this invention, each numerical range, except where explicitly stated not to include endpoint values, can be either an endpoint value or the median of each numerical range, and all of these are within the protection scope of this invention.

[0052] Based on the above, the present invention proposes the following technical solution:

[0053] 1. A combustion device, comprising:

[0054] Combustion apparatus, including combustion space;

[0055] A preheating device, wherein fuel particles are adapted to be fluidized within the preheating device to form solid fuel and gaseous fuel, the preheating device being connected to the combustion space via a first channel, at least the gaseous fuel entering the combustion space via the first channel;

[0056] A storage device is adapted to receive and store at least a portion of solid fuel from a preheating device via a second channel, one end of which is connected to the solid fuel outlet of the preheating device, and the other end of which is connected to the solid fuel inlet of the storage device.

[0057] in:

[0058] The storage device is adapted to deliver solid fuel to the combustion space via a third channel, one end of which is connected to a first solid fuel outlet of the storage device; and / or

[0059] The storage device is adapted to deliver solid fuel to the preheating device via a fourth channel, one end of which is connected to the second solid fuel outlet of the storage device, and the other end of which is connected to the solid fuel return port of the preheating device.

[0060] 2. The combustion device according to claim 1, wherein:

[0061] The solid fuel inlet of the storage device is located on the upper or top side of the storage device.

[0062] 3. The combustion device according to claim 2, wherein:

[0063] The solid fuel inlet of the storage device is lower than the solid fuel outlet of the preheating device.

[0064] 4. The combustion device according to claim 1, wherein:

[0065] The solid fuel outlet of the preheating unit is equipped with a first control valve to control the amount and rate at which solid fuel enters the storage unit.

[0066] 5. The combustion apparatus according to claim 1, wherein:

[0067] The storage device includes a storage section and a conveying section. The storage section is provided with a solid fuel inlet. A second control valve is provided between the storage section and the conveying section. The second control valve controls the unidirectional flow of solid fuel from the storage section to the conveying section.

[0068] 6. The combustion apparatus according to claim 5, wherein:

[0069] The second control valve includes a pneumatic valve, a mechanical valve, or a gravity valve.

[0070] 7. The combustion device according to claim 5, wherein:

[0071] The storage section is positioned higher than the delivery section so as to utilize at least gravitational potential energy to deliver solid fuel to the delivery section.

[0072] 8. The combustion apparatus according to 7, wherein:

[0073] The storage section is located above the conveying section and is connected to the conveying section through a connecting channel with a cross-sectional area smaller than that of the storage section. The second control valve is provided on the connecting channel.

[0074] 9. The combustion apparatus according to 8, wherein:

[0075] The second control valve is a plate valve or a mushroom valve.

[0076] 10. The combustion apparatus according to claim 5, wherein:

[0077] The conveying unit includes a pneumatic conveying inlet, through which conveying gas enters. The conveying gas, carrying the solid fuel, is adapted to enter the combustion space from the first solid fuel outlet via the third channel, or the conveying gas, carrying the solid fuel, is adapted to enter the solid fuel return port from the second solid fuel outlet via the fourth channel.

[0078] 11. The combustion apparatus according to 10, wherein:

[0079] The transported gas includes nitrogen, carbon dioxide, or pressurized steam from a combustion device.

[0080] 12. The combustion apparatus according to claim 1, wherein:

[0081] The storage device is provided with an inert gas inlet, through which inert gas is suitable for entering the storage device.

[0082] 13. The combustion apparatus according to 12, wherein:

[0083] The inert gas includes nitrogen, carbon dioxide, or flue gas from the combustion device with an oxygen content of less than 5%.

[0084] 14. The combustion apparatus according to claim 1, wherein:

[0085] The wall of the storage device is an insulation layer, or the wall of the storage device is a water-cooled wall or an air-cooled wall.

[0086] 15. The combustion apparatus according to claim 1, wherein:

[0087] The solid fuel storage capacity of the storage device is set to 0.5-3.0 times the amount of circulating material in the preheating device, and further to 0.5-1.0 times.

[0088] 16. The combustion apparatus according to any one of 1-15, wherein:

[0089] The solid fuel outlet of the preheating unit is located in the fuel particle enrichment area of ​​the preheating unit.

[0090] 17. The combustion apparatus according to 16, wherein:

[0091] The preheating device is a circulating fluidized bed comprising a riser, a separator, and a return feeder. The solid fuel outlet of the preheating device is located on the lower or bottom side of the riser, or at the return feeder. Furthermore, the air distribution device is arranged close to the riser.

[0092] The preheating device includes a fluidized bed or a bubbling bed. The solid fuel outlet of the preheating device is located above the air distribution device of the fluidized bed or bubbling bed and below the interface between the dilute phase zone and the dense phase zone. Furthermore, it is arranged close to the air distribution device.

[0093] 18. The combustion apparatus according to any one of 1-17, wherein:

[0094] The combustion device is a boiler, and the combustion space is a furnace; and / or

[0095] The preheating device is a fluidized bed, a bubbling bed, or a circulating fluidized bed.

[0096] 19. The combustion apparatus according to 18, wherein:

[0097] The combustion space is provided with at least one first combustion space inlet communicating with the first channel, and at least one second combustion space inlet communicating with the third channel.

[0098] 20. The combustion apparatus according to 18, wherein:

[0099] The combustion device is a boiler, the combustion space is a furnace, and the preheating device includes multiple preheating devices arranged around the furnace.

[0100] 21. The combustion device according to claim 20, wherein:

[0101] The boiler includes multiple first combustion space inlets, which are arranged on the same floor and / or multiple layers; and

[0102] The preheating device includes a preheating device that is simultaneously connected to the plurality of first combustion space inlets, or the preheating device includes a plurality of preheating devices, one or more of which are connected to one or more of the plurality of first combustion space inlets.

[0103] 22. The combustion device according to claim 21, wherein:

[0104] The boiler is a tangentially circular pulverized coal boiler, and the plurality of first combustion space inlets include four first combustion space inlets located at the same elevation in the furnace; or

[0105] The boiler is a swirl-flow counter-current pulverized coal boiler, and the plurality of first combustion space inlets include 4, 5, or 6 first combustion space inlets located at the same elevation in the furnace; or

[0106] The boiler is a counter-coil pulverized coal boiler, and the plurality of first combustion space inlets include two first combustion space inlets diagonally arranged at the same level in the furnace.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A combustion device for peak shaving, comprising: Combustion apparatus, including combustion space; A preheating device, wherein fuel particles are adapted to be fluidized within the preheating device to form solid fuel and gaseous fuel, the preheating device being connected to the combustion space via a first channel, at least the gaseous fuel entering the combustion space via the first channel; A storage device is adapted to receive and store at least a portion of solid fuel from a preheating device via a second channel, one end of which is connected to the solid fuel outlet of the preheating device, and the other end of which is connected to the solid fuel inlet of the storage device. in: The storage device is adapted to deliver solid fuel to the combustion space via a third channel, one end of which is connected to the first solid fuel outlet of the storage device; The storage device is adapted to deliver solid fuel to the preheating device via a fourth channel, one end of which is connected to the second solid fuel outlet of the storage device, and the other end of which is connected to the solid fuel return port of the preheating device. The first shift is the normal operating state of the combustion device under electrical load. The combustion device operates at more than 25% of its rated load. The preheating device maintains oxygen-deficient oxidation conditions. At this time, there is no thermal fuel stored in the storage device or it is in a small storage state. The preheating device continuously supplies gaseous fuel to the combustion device. The second shift is when the combustion device is not under electrical load but is in standby mode with ultra-low heat load. When switching from the first shift to the second shift, the high-temperature solid fuel in the preheating device is sent to the storage device, and the coal feed rate of the preheating device is reduced, so that the interior of the preheating device is converted to an oxidizing atmosphere.

2. The combustion device for peak shaving according to claim 1, wherein: The solid fuel inlet of the storage device is located on the upper or top side of the storage device.

3. The combustion device for peak shaving according to claim 2, wherein: The solid fuel inlet of the storage device is lower than the solid fuel outlet of the preheating device.

4. The combustion device for peak shaving according to claim 1, wherein: The solid fuel outlet of the preheating unit is equipped with a first control valve to control the amount and rate at which solid fuel enters the storage unit.

5. The combustion device for peak shaving according to claim 1, wherein: The storage device includes a storage section and a conveying section. The storage section is provided with a solid fuel inlet. A second control valve is provided between the storage section and the conveying section. The second control valve controls the unidirectional flow of solid fuel from the storage section to the conveying section.

6. The combustion device for peak shaving according to claim 5, wherein: The second control valve includes a pneumatic valve, a mechanical valve, or a gravity valve.

7. The combustion device for peak shaving according to claim 5, wherein: The storage section is positioned higher than the delivery section so as to utilize at least gravitational potential energy to deliver solid fuel to the delivery section.

8. The combustion device for peak shaving according to claim 7, wherein: The storage section is located above the conveying section and is connected to the conveying section through a connecting channel with a cross-sectional area smaller than that of the storage section. The second control valve is provided on the connecting channel.

9. The combustion device for peak shaving according to claim 8, wherein: The second control valve is a plate valve, a mushroom valve, or an impeller feed valve.

10. The combustion device for peak shaving according to claim 5, wherein: The conveying unit includes a pneumatic conveying inlet, through which conveying gas enters. The conveying gas, carrying the solid fuel, is adapted to enter the combustion space from the first solid fuel outlet via the third channel, or the conveying gas, carrying the solid fuel, is adapted to enter the solid fuel return port from the second solid fuel outlet via the fourth channel.

11. The combustion device for peak shaving according to claim 10, wherein: The transported gas includes nitrogen, carbon dioxide, or pressurized steam from a combustion device.

12. The combustion device for peak shaving according to claim 1, wherein: The storage device is provided with an inert gas inlet, through which inert gas is suitable for entering the storage device.

13. The combustion device for peak shaving according to claim 12, wherein: The inert gas includes nitrogen, carbon dioxide, or flue gas from the combustion device with an oxygen content of less than 5%.

14. The combustion device for peak shaving according to claim 1, wherein: The walls of the storage device are made of thermal insulation material.

15. The combustion device for peak shaving according to claim 1, wherein: The storage capacity of the solid fuel in the storage device is set to 0.5-3.0 times the amount of circulating material in the preheating device.

16. The combustion device for peak shaving according to claim 15, wherein: The storage capacity of the solid fuel in the storage device is set to 0.5-1.0 times the amount of circulating material in the preheating device.

17. The combustion device for peak shaving according to claim 1, wherein: The solid fuel outlet of the preheating unit is located in the fuel particle enrichment area of ​​the preheating unit.

18. The combustion device for peak shaving according to claim 17, wherein: The preheating device includes a circulating fluidized bed consisting of a riser, a separator, and a return feeder. The solid fuel outlet of the preheating device is located on the lower or bottom side of the riser or at the return feeder. or The preheating device includes a bubbling bed, and the solid fuel outlet of the preheating device is located above the air distribution device of the bubbling bed and below the interface between the dilute phase region and the dense phase region.

19. The combustion device for peak shaving according to any one of claims 1-17, wherein: The combustion device is a boiler, and the combustion space is a furnace; and / or, The preheating device is a bubbling bed or a circulating fluidized bed.

20. The combustion device for peak shaving according to claim 19, wherein: The combustion space is provided with at least one first combustion space inlet communicating with the first channel, and at least one second combustion space inlet communicating with the third channel.

21. The combustion device for peak shaving according to claim 19, wherein: The boiler includes multiple first combustion space inlets, which are arranged on the same floor and / or multiple layers; and The preheating device includes a preheating device that is simultaneously connected to the plurality of first combustion space inlets, or the preheating device includes a plurality of preheating devices, one or more of which are connected to one or more of the plurality of first combustion space inlets.

22. The combustion device for peak shaving according to claim 21, wherein: The boiler is a tangentially circular pulverized coal boiler, and the plurality of first combustion space inlets include four first combustion space inlets located at the same elevation in the furnace; or The boiler is a swirl-flow counter-current pulverized coal boiler, and the plurality of first combustion space inlets include 4, 5, or 6 first combustion space inlets located at the same elevation in the furnace; or The boiler is a counter-coil pulverized coal boiler, and the plurality of first combustion space inlets include two first combustion space inlets diagonally arranged at the same level in the furnace.

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