Denitration and dust removal integrated biomass grate boiler
By integrating denitrification and dust removal equipment into the biomass boiler, the problems of excessively long flue and susceptibility of the equipment to fly ash have been solved, achieving efficient flue gas treatment and stable boiler operation, while reducing costs and floor space.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JINAN BOILER GRP
- Filing Date
- 2025-05-12
- Publication Date
- 2026-05-08
AI Technical Summary
The existing denitrification and dust removal equipment of biomass boilers are arranged independently, which results in excessively long flue lengths, high resistance, waste of resources, large footprints, and the denitrification equipment is susceptible to poisoning and failure due to fly ash, leading to unstable boiler operation.
The denitrification and dust removal equipment are integrated within the boiler body. The flue gas first passes through the dust removal and then enters the denitrification process. High-temperature denitrification equipment is used, combined with a cylindrical protective plate with a horizontal cross-section in the shape of the Chinese character "日" to prevent flue gas from entering and reduce the length and resistance of the flue.
It improves the continuous operating time of the boiler and the service life of the catalyst, reduces operating costs and flue gas resistance, enhances dust removal and denitrification effects, and reduces land occupation and construction costs.
Smart Images
Figure CN224215307U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of boiler technology, and in particular to a grate-type biomass boiler that burns biomass. Background Technology
[0002] Biomass boilers, as important equipment for biomass energy utilization, are boilers that directly burn biomass as fuel and are widely used in heating, industrial production, and power generation. Biomass boilers use a variety of fuels with complex compositions. Compared to traditional coal-fired boilers, biomass fuels have a higher nitrogen content, therefore producing more nitrogen oxides (NOx) pollutants during combustion. NOx is a critical air pollutant that directly or indirectly harms the environment, buildings, plants, animals, and humans. Therefore, before emissions, flue gas needs to undergo denitrification treatment to reduce NOx levels and ensure the safety of emitted gases. Currently in the thermal power plant industry, boiler equipment and environmental protection equipment are generally considered two separate sectors. Boiler equipment requires design and production by qualified manufacturers, while environmental protection equipment such as denitrification, dust removal, and desulfurization systems need to be integrated with the boiler design. These systems are typically located outside the boiler body, in the flue gas duct after the boiler's outlet flue. This means that in biomass power plant design, the boiler specialist only considers the boiler itself, and the environmental protection specialist only considers environmental protection. They are generally arranged independently and connected by a flue gas duct. Flue gas is drawn from the boiler body through the flue gas duct and enters the environmental protection equipment. The treated flue gas needs to be introduced into some heat-receiving surfaces at the end of the flue gas flow through another flue. During the introduction and extraction process, the flue is relatively long, generally at least 30 meters long, and the flue needs to avoid the boiler steel frame, diagonal bracing, etc., which adds multiple bends and turns, further increasing the flue resistance. This not only wastes steel but also increases the power consumption of the induced draft fan. Therefore, this layout is complex, with long flues, many bends, high resistance, and a large footprint. In addition, the boiler equipment and environmental protection equipment are arranged independently, requiring their own steel frames for support, which leads to the waste of resources and energy. Summary of the Invention
[0003] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a biomass grate boiler with integrated denitrification and dust removal to solve the problems existing in the background technology.
[0004] The technical solution adopted by this utility model to achieve the above objectives is as follows:
[0005] A biomass grate boiler with integrated denitrification and dust removal includes a furnace, and a second, third, and fourth flue sequentially connected to the furnace outlet. The second, third, and fourth flues are all vertically arranged. The inlet of the second flue is connected to the furnace outlet. The lower ends of the second and third flues are connected, and the upper ends of the third and fourth flues are connected via a top-turning flue. The boiler is characterized by: a first-panel superheater installed in the upper part of the furnace; a second-panel superheater installed in the second flue; a serpentine tube superheater installed in the third flue; and a denitrification device, an economizer, and a tail-end heating surface sequentially arranged according to the flue gas flow direction in the fourth flue. A dust removal device is installed in the top-turning flue, dividing the flue into a pre-dust removal flue and a pre-denitrification flue.
[0006] By adopting the above technical solution, the flue gas entering from the third flue first undergoes dust removal by a dust removal device, and then the dust-removed flue gas enters the denitrification equipment for reaction. This avoids the denitrification equipment being affected by alkali metals in fly ash, which could lead to catalyst poisoning and failure. It also prevents ash accumulation in the denitrification equipment, thus avoiding boiler shutdown and increasing the boiler's continuous operating time and catalyst lifespan. Dust removal of the flue gas inside the boiler reduces ash accumulation and low-temperature corrosion on the boiler's tail-end heating surfaces, reduces flue gas resistance during operation, increases the lifespan of the tail-end heating surfaces, and lowers operating costs. Installing high-temperature denitrification equipment inside the boiler reduces the ammonia escape concentration at the boiler outlet, preventing low-temperature corrosion on the tail-end heating surfaces due to excessive ammonia escape concentration, and further extending the lifespan of the tail-end heating surfaces.
[0007] In the aforementioned integrated denitrification and dust removal biomass grate boiler, the dust removal equipment and denitrification equipment are supported on the boiler body steel frame.
[0008] By adopting the above technical solution, the dust removal equipment and denitrification equipment are also arranged within the boiler body. Compared with the existing technology, the length of the connecting flue between the boiler and the environmental protection equipment is greatly shortened, the flue gas turns are reduced, the flue gas resistance is reduced, the heat loss is reduced, the boiler efficiency is improved, and the dust removal and denitrification effects are enhanced. Moreover, it occupies a small area and has a low construction cost.
[0009] In the above-mentioned integrated denitrification and dust removal biomass grate boiler, a grate and slag outlet are provided at the lower part of the furnace, and an air chamber is provided at the lower part of the grate; ash discharge outlets are provided at the lower parts of the second and third flues, and slag removers are provided at the lower parts of the slag outlet and ash discharge outlet; an ash guide pipe is provided at the lower part of the dust removal equipment, and the lower end of the ash guide pipe extends into the liquid surface of the slag remover.
[0010] Furthermore, a cylindrical protective plate is installed between the slag outlet, the ash discharge outlet and the slag remover. The upper end of the cylindrical protective plate is connected to the slag outlet and the ash discharge outlet, and the lower end of the cylindrical protective plate extends into the liquid surface inside the slag remover.
[0011] Furthermore, the horizontal cross-section of the cylindrical guard plate is in the shape of a Chinese character 'ri' (日), and the two square shapes of the 'ri' shape respectively correspond to the slag discharge port and the ash fall port.
[0012] By adopting the above technical solution, a cylindrical guard plate with a horizontal cross-section in the shape of a Chinese character 'ri' is arranged at the lower parts of the slag discharge port and the ash fall port, and the two square shapes of the 'ri' shape respectively correspond to the slag discharge port and the ash fall port, which can prevent the flue gas in the furnace from flowing into the second flue and the third flue.
[0013] In the above denitration and dust removal integrated biomass grate boiler, the serpentine tube superheater includes an upper serpentine tube superheater and a lower serpentine tube superheater.
[0014] In the above denitration and dust removal integrated biomass grate boiler, the tail heating surface can be the heating surface of an air preheater.
[0015] In the above denitration and dust removal integrated biomass grate boiler, the tail heating surface can also be the heating surface of a flue gas cooler.
[0016] In the above denitration and dust removal integrated biomass grate boiler, the dust removal equipment adopts one of cyclone dust removal, bag dust removal, and multi-tube dust removal. Beneficial effects
[0017] In the technical solution of the present application, the flue gas entering from the third flue first passes through the dust removal equipment for dust removal, and then the dust-removed flue gas enters the denitration equipment for reaction, avoiding the denitration equipment being affected by alkali metals in the fly ash, resulting in catalyst poisoning and failure, and at the same time avoiding the accumulation of ash in the denitration equipment, resulting in boiler shutdown, improving the continuous operation time of the boiler and the service life of the catalyst. After the flue gas is dust-removed inside the boiler, the ash accumulation and low-temperature corrosion of the tail heating surface of the boiler are reduced, the flue gas resistance during operation is reduced, the service life of the tail heating surface is improved, and the operation cost is reduced. By arranging a high-temperature denitration equipment inside the boiler, the ammonia slip concentration at the boiler outlet is reduced, preventing the tail heating surface from generating low-temperature corrosion due to excessive ammonia slip concentration, and improving the service life of the tail heating surface. Arranging the dust removal equipment and the denitration equipment within the scope of the boiler body, compared with the prior art, the lengths of the inlet and outlet flue ducts are greatly shortened, the heat dissipation loss is reduced, the boiler efficiency is improved, and the dust removal and denitration effects can be improved; moreover, the floor area is small and the construction cost is low. A cylindrical guard plate with a horizontal cross-section in the shape of a Chinese character 'ri' is arranged at the lower part of the slag discharge port, and the two square shapes of the 'ri' shape respectively correspond to the slag discharge port and the ash fall port, which can prevent the flue gas in the furnace from flowing into the second flue and the third flue. Brief description of the drawings
[0018] Figure 1 It is a schematic diagram of the present utility model.
[0019] In the diagram: 1 Steam drum, 2 First screen superheater, 3 Furnace, 4 Second screen superheater, 5 Grate, 6 Wind chamber, 7 Second flue, 8 Slag outlet, 9 Cylindrical guard plate, 10 Ash outlet, 11 Third flue, 12 Slag remover, 13 Lower serpentine tube superheater, 14 Upper serpentine tube superheater, 15 Ash pipe, 16 Flue before dust removal equipment, 17 Dust removal equipment, 18 Flue before denitrification equipment, 19 Denitrification equipment, 20 Economizer, 21 Fourth flue, 22 Tail heating surface, 23 Outlet flue. Detailed Implementation
[0020] To clearly illustrate the technical features of this utility model, the following non-limiting embodiments, in conjunction with the accompanying drawings, will provide further explanation of this utility model. Example 1:
[0021] Please see Figure 1 A biomass grate boiler with integrated denitrification and dust removal includes a boiler body steel frame, a furnace 3, and a second flue 7, a third flue 11, and a fourth flue 21 sequentially connected to the outlet of the furnace 3. The furnace 3 is enclosed by a membrane wall and serves as the channel for fuel ignition and flue gas flow. The furnace can be divided into different flue gas channels as needed; in this embodiment, there are three. The second flue 7, third flue 11, and fourth flue 21 are all vertically arranged. The inlet of the second flue 7 is connected to the outlet of the furnace 3. The lower ends of the second and third flues are connected, and the upper ends of the third and fourth flues are connected via a top-turning flue. A first screen-type superheater 2 is installed in the upper part of the furnace 3, a second screen-type superheater 4 is installed in the second flue, and a serpentine tube superheater is installed in the third flue 11. In this embodiment, the serpentine tube superheater has two stages, including an upper serpentine tube superheater 14 and a lower serpentine tube superheater 13. Within the fourth flue duct 21, a denitrification device 19, an economizer 20, and a tail heating surface 22 are sequentially arranged according to the flue gas flow direction. In this embodiment, the tail heating surface 22 is the heating surface of the air preheater. The denitrification device is used to remove nitrogen oxides (NOx) from the flue gas; in this embodiment, catalytic reduction denitrification (SCR) is used. A dust removal device 17 is installed in the furnace top turning flue to remove fly ash from the flue gas. The dust removal device 17 can be a multi-tube dust collector, a cyclone dust collector, a bag filter, or other dust removal methods. In this embodiment, the dust removal device 17 is a cyclone dust collector. The dust removal device 17 divides the furnace top turning flue into a flue duct 16 before the dust removal device and a flue duct 18 before the denitrification device.
[0022] In this embodiment, the dust removal device 17 and the denitration device 19 are supported on the steel frame of the boiler body. A grate 5 and a slag discharge port 8 are arranged at the lower part of the furnace chamber 3, and an air chamber 6 is arranged under the grate 5; ash discharge ports 10 are arranged at the lower parts of the second flue 7 and the third flue 11, a slag scraper 12 is arranged under the slag discharge port 8 and the ash discharge ports 10, a dust flow pipe 15 is arranged under the dust removal device 17, and the lower end of the dust flow pipe 15 extends into the liquid level in the slag scraper 12. A cylindrical guard plate 9 is arranged between the slag discharge port 8, the ash discharge ports 10 and the slag scraper 12. The upper end of the cylindrical guard plate 9 is connected to the slag discharge port 8 and the ash discharge ports 10, and the lower end of the cylindrical guard plate 9 extends into the liquid level in the slag scraper 12. The horizontal cross-section of the cylindrical guard plate 9 is in the shape of a Chinese character 'ri' (日), and the two square shapes of the 'ri' shape respectively correspond to the slag discharge port 8 and the ash discharge ports 10.
[0023] Working principle:
[0024] The biomass fuel is forcedly fed into the furnace chamber by a front furnace feeder and falls onto the grate 5 by gravity. The required primary air is sent into the furnace chamber 3 from the air chamber 6 under the grate 5, so that the fuel burns on the grate 5; a large amount of flue gas generated by combustion flows in the furnace chamber 3 and successively passes through the first platen superheater 2, the second platen superheater 4, the lower serpentine tube superheater 13 and the upper serpentine tube superheater 14; after passing through the above heating surfaces, the flue gas is cooled down and then enters the dust removal device 17 through the pre-dust removal device flue 16. Because the flue gas is cooled down when flowing through the previous heating surfaces, it can ensure that the dust removal device 17 does not coke; the dust-free flue gas after being dust-removed by the dust removal device 17 is introduced into the denitration device 19 through the pre-denitration device flue 18. Because the fly ash and the like in the flue gas have been removed after passing through the dust removal device 17, it can ensure that the denitration device 19 is not blocked; the flue gas after passing through the denitration device 19 is clean flue gas after dust removal and denitration. These clean flue gases then successively pass through the economizer 20 and the remaining tail heating surfaces 22 to continue absorbing the waste heat in the flue gas and improve the boiler efficiency. The flue gas after passing through the tail heating surfaces 22 enters the boiler outlet flue 23 and is connected to the environmental protection equipment through the subsequent flue to perform further environmental protection treatment on the flue gas to ensure up-to-standard discharge. The residue after burning on the grate 5 is discharged out of the furnace through the slag discharge port 8 and falls into the slag scraper 12; at the same time, the fly ash separated by the dust removal device 17 also falls into the slag scraper 12 through the dust flow pipe 15. The slag scraper 12 can granulate the residue after fuel combustion and the fly ash separated by the dust removal device 17 in water and convey them to the slag collection box or subsequent treatment equipment through a chain plate or a scraper.
[0025] Boiler flue gas flow:
[0026] The flue gas passes sequentially through the furnace 3, the second flue 7, and the third flue 11, and then sequentially washes over the first screen superheater 2, the second screen superheater 4, the lower serpentine tube superheater 13, and the upper serpentine tube superheater 14. After passing through the furnace top turning flue, it enters the tail heating surface 22. In the turning flue, the flue gas is dusted by the dust removal equipment 17. In the fourth flue 21, it passes sequentially through the denitrification equipment 19, the economizer 20, and the tail heating surface before entering the outlet flue 23. It is then connected to the environmental protection equipment through subsequent flues and finally discharged through the chimney. Example 2:
[0027] Please see Figure 1 A biomass grate boiler with integrated denitrification and dust removal includes a boiler body steel frame, a furnace 3, and a second flue 7, a third flue 11, and a fourth flue 21 sequentially connected to the outlet of the furnace 3. The furnace 3 is enclosed by a membrane wall and serves as the channel for fuel ignition and flue gas flow. The furnace can be divided into different flue gas channels as needed; in this embodiment, there are three. The second flue 7, third flue 11, and fourth flue 21 are all vertically arranged. The inlet of the second flue 7 is connected to the outlet of the furnace 3. The lower ends of the second and third flues are connected, and the upper ends of the third and fourth flues are connected via a top-turning flue. A first screen-type superheater 2 is installed in the upper part of the furnace 3, a second screen-type superheater 4 is installed in the second flue, and a serpentine tube superheater is installed in the third flue 11. In this embodiment, the serpentine tube superheater has two stages, including an upper serpentine tube superheater 14 and a lower serpentine tube superheater 13. Within the fourth flue duct 21, a denitrification device 19, an economizer 20, and a tail heating surface 22 are sequentially arranged according to the flue gas flow direction. In this embodiment, the tail heating surface 22 is the heating surface of a flue gas cooler. The denitrification device is used to remove nitrogen oxides (NOx) from the flue gas; in this embodiment, catalytic reduction denitrification (SCR) is used. A dust removal device 17 is installed within the furnace top turning flue to remove fly ash from the flue gas. The dust removal device 17 can be a multi-tube dust collector, a cyclone dust collector, a bag filter, or other dust removal methods. In this embodiment, the dust removal device 17 is a bag filter. The dust removal device 17 divides the furnace top turning flue into a flue duct 16 before the dust removal device and a flue duct 18 before the denitrification device.
[0028] In this embodiment, the dust removal device 17 and the denitration device 19 are supported on the steel frame of the boiler body. A grate 5 and a slag discharge port 8 are arranged at the lower part of the furnace chamber 3, and an air chamber 6 is arranged below the grate 5; ash discharge ports 10 are arranged at the lower parts of the second flue 7 and the third flue 11, and a slag scraper 12 is arranged below the slag discharge port 8 and the ash discharge ports 10. A downcomer 15 is arranged at the lower part of the dust removal device 17, and the lower end of the downcomer 15 extends into the liquid level in the slag scraper 12. A cylindrical guard plate 9 is arranged between the slag discharge port 8, the ash discharge ports 10 and the slag scraper 12. The upper end of the cylindrical guard plate 9 is connected to the slag discharge port 8 and the ash discharge ports 10, and the lower end of the cylindrical guard plate 9 extends into the liquid level in the slag scraper 12. The horizontal cross-section of the cylindrical guard plate 9 is in the shape of a Chinese character 'ri', and the two square shapes of the 'ri' shape respectively correspond to the slag discharge port 8 and the ash discharge ports 10.
[0029] The working principle and flue gas flow of this embodiment are the same as those of Embodiment 1. Embodiment 3:
[0030] Please refer to Figure 1 , a biomass grate boiler with integrated denitration and dust removal, including a steel frame of the boiler body, a furnace chamber 3, a second flue 7, a third flue 11, and a fourth flue 21 that are sequentially connected in series to the outlet of the furnace chamber 3. The furnace chamber 3 is enclosed by a membrane wall and is a channel for fuel ignition and flue gas flow. The furnace chamber can be divided into different flue gas channels as needed. In this embodiment, it is divided into three; the second flue 7, the third flue 11, and the fourth flue 21 are all arranged vertically. The inlet of the second flue 7 is connected to the outlet of the furnace chamber 3, the lower ends of the second flue and the third flue are connected, and the upper ends of the third flue 11 and the fourth flue 21 are connected through a furnace top turning flue. A first platen superheater 2 is arranged at the upper part of the furnace chamber 3, a second platen superheater 4 is arranged in the second flue, and a serpentine tube superheater is arranged in the third flue 11. In this embodiment, the serpentine tube superheater is arranged in two stages, including an upper serpentine tube superheater 14 and a lower serpentine tube superheater 13. A denitration device 19, a economizer 20, and a tail heating surface 22 are sequentially arranged in the fourth flue 21 according to the flue gas flow direction. In this embodiment, the tail heating surface 22 is the heating surface of an air preheater; the denitration device is used to remove nitrogen oxides (NOx) in the flue gas. In this embodiment, selective catalytic reduction (SCR) is adopted; a dust removal device 17 is arranged in the furnace top turning flue for removing fly ash in the flue gas. The dust removal device 17 can be multi-tube dust removal, cyclone dust removal, bag dust removal or other dust removal forms. In this embodiment, the dust removal device 17 adopts a multi-tube dust removal type dust collector. The dust removal device 17 divides the furnace top turning flue into a pre-dust removal device flue 16 and a pre-denitration device flue 18.
[0031] In this embodiment, the dust removal device 17 and the denitration device 19 are supported on the steel frame of the boiler body. A grate 5 and a slag discharge port 8 are provided at the lower part of the furnace chamber 3, and an air chamber 6 is provided below the grate 5; ash discharge ports 10 are provided at the lower parts of the second flue 7 and the third flue 11. A slag scraper 12 is provided below the slag discharge port 8 and the ash discharge ports 10. A downcomer 15 is provided below the dust removal device 17, and the lower end of the downcomer 15 extends into the liquid level in the slag scraper 12. A cylindrical guard plate 9 is provided between the slag discharge port 8, the ash discharge ports 10 and the slag scraper 12. The upper end of the cylindrical guard plate 9 is connected to the slag discharge port 8 and the ash discharge ports 10, and the lower end of the cylindrical guard plate 9 extends into the liquid level in the slag scraper 12. The horizontal cross-section of the cylindrical guard plate 9 is in the shape of a Chinese character 'Ri' (日), and the two square shapes of the 'Ri' shape respectively correspond to the slag discharge port 8 and the ash discharge ports 10.
[0032] The working principle and flue gas flow of this embodiment are the same as those of Embodiment 1.
[0033] Unless otherwise clearly specified and defined, the terms 'connected' and 'joined' shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.
[0034] Except for the technical features described in the specification, they are all known technologies to those skilled in the art.
[0035] The above-listed embodiments are only for understanding this utility model and are not limitations on the technical solutions described in this utility model. Those of ordinary skill in the relevant art can make various changes or deformations based on the technical solutions described in the claims. For example, the forms of the grate include but are not limited to water-cooled vibrating grates, chain grates, reciprocating grates, etc. Different types and quantities of superheaters can be selected according to different rated parameters of the boiler. All equivalent changes or deformations should be covered within the protection scope of the claims of this utility model.
Claims
1. A biomass grate boiler with integrated denitrification and dust removal, comprising a boiler body steel frame, a furnace, and a second flue, a third flue, and a fourth flue sequentially connected to the outlet of the furnace. The second, third, and fourth flues are all vertically arranged. The inlet of the second flue is connected to the outlet of the furnace. The lower ends of the second and third flues are connected, and the upper ends of the third and fourth flues are connected via a bend flue at the top of the furnace. The boiler is characterized by: A first platen superheater is arranged at the upper part of the furnace chamber, a second platen superheater is arranged in the second flue, a serpentine tube superheater is arranged in the third flue, and a denitration device, an economizer and a tail heating surface are arranged in sequence in the fourth flue according to the flue gas flow direction; a dust removal device is arranged in the furnace roof turning flue, and the dust removal device divides the furnace roof turning flue into a flue before the dust removal device and a flue before the denitration device.
2. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: The dust removal device and the denitration device are supported on the steel frame of the boiler body.
3. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: A grate and a slag discharge port are arranged at the lower part of the furnace chamber, and an air chamber is arranged under the grate; ash discharge ports are arranged at the lower parts of the second flue and the third flue, a slag scraper is arranged under the slag discharge port and the ash discharge ports, a downcomer is arranged under the dust removal device, and the lower end of the downcomer extends into the liquid level in the slag scraper.
4. The integrated denitrification and dust removal biomass grate boiler according to claim 3, characterized in that: A cylindrical guard plate is arranged between the slag discharge port, the ash discharge port and the slag scraper. The upper end of the cylindrical guard plate is connected to the slag discharge port and the ash discharge ports, and the lower end of the cylindrical guard plate extends into the liquid level in the slag scraper.
5. The integrated denitrification and dust removal biomass grate boiler according to claim 4, characterized in that: The horizontal section of the cylindrical guard plate is in the shape of a Chinese character 'Ri', and the two square shapes of the 'Ri' shape respectively correspond to the slag discharge port and the ash discharge port.
6. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: The serpentine tube superheater includes an upper serpentine tube superheater and a lower serpentine tube superheater.
7. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: The tail heating surface is the heating surface of an air preheater.
8. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: The tail heating surface is the heating surface of a flue gas cooler.
9. The integrated denitrification and dust removal biomass grate boiler according to claim 1, characterized in that: The dust removal device adopts one of cyclone dust removal, bag dust removal and multi-tube dust removal.