Hearth of high-magnification circulating fluidized bed boiler
By designing a fully water-cooled air panel and extended wall structure in a circulating fluidized bed boiler, the problems of difficulty and low efficiency of high-moisture fuels are solved, and efficient combustion and low NOx emissions are achieved, which are suitable for high-moisture and low-calorie fuels.
Patent Information
- Application Number
- CN202323273308.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-01
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2033-12-01
AI Technical Summary
Existing circulating fluidized bed boilers are prone to problems such as difficulty in ignition of fuel, low boiler efficiency, and inability to meet rated parameters when burning fuel with particularly large water content.
A furnace of a high-rate circulating fluidized bed boiler is designed, and it adopts a fully water-cooled air panel, an extension wall and multiple air outlets to ensure full combustion of fuel and even distribution of heat, including the upper area of the furnace, an extension wall area, a transition area and In the ignition area of the lower part of the furnace, the extension wall is arranged close to the water-cooled wall pipe, and a secondary air outlet is set in the transition area and the suspension area.
It improves boiler efficiency, ensures low NOx emissions, is suitable for the stable combustion of high-water and low-calorie fuels, extends the boiler maintenance cycle, and simplifies the maintenance and operation of the boiler.
Smart Images
Figure CN222186928U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of thermal energy engineering, in particular to a furnace of a high-rate circulating fluidized bed boiler. Background Art
[0002] Circulating fluidized bed boiler is a clean combustion equipment with a good commercialization degree and wide application, especially in the field of high moisture and low calorific value fuel combustion. After a long period of development, the technology and equipment are very mature, and most fuels can burn well, but for fuels with particularly high moisture content (Mar more than 40%), such as furfural slag, sludge, livestock manure and other high moisture and low calorific value fuels, general boilers will have problems such as fuel ignition difficulties, or boilers cannot reach rated parameters, or boiler efficiency is low. Utility Model Content
[0003] The utility model aims to solve the technical problems existing in the prior art and provide a furnace of a high-rate circulating fluidized bed boiler.
[0004] To achieve the above-mentioned purpose, the technical solution provided by the utility model is: a furnace of a high-rate circulating fluidized bed boiler, the furnace including an upper furnace area, an extended wall area, a transition area, and a lower furnace ignition area, and the bottom of the furnace adopts a fully water-cooled air distribution plate; the transition area is the connection area between the furnace and the fully water-cooled air distribution plate, the lower furnace ignition area includes a dense phase area above the air distribution plate and an ignition area below the air distribution plate, and the ignition area below the air distribution plate adopts under-bed ignition; the transition area includes a transition area and a suspension area, above the suspension area is the extended wall area, and the upper furnace area is located above the extended wall area.
[0005] Preferably, the furnace is composed of the upper dense phase area of the air distribution plate, the transition area, and the suspension area from bottom to top; the upper dense phase area of the air distribution plate is arranged with a wind hood and is completely covered with wear-resistant refractory castables; the transition area is partially or completely covered with wear-resistant refractory castables.
[0006] Preferably, the extended wall area is arranged with an extended wall, and the extended wall is composed of 3 to 5 water-cooled wall tubes arranged close to the water-cooled wall tubes in the furnace direction, and the pitch is smaller than that of the water-cooled wall.
[0007] Preferably, there are three ways to arrange the extension wall. The first is that the extension wall forms a system of its own and is connected with an external header. The second is that the extension wall and the water-cooled wall tubes are connected with a header. The third is that the extension wall and the water-cooled wall tubes are directly connected, and a throttling orifice plate is installed in the middle of the water-cooled wall tubes to which the extension wall is directly connected.
[0008] Preferably, the superheater screen, furnace flue gas outlet and rope hole are arranged in the upper area of the furnace; the lower secondary air is arranged in the suspension area; the middle secondary air and upper secondary air are also arranged in the extended wall area; the lower secondary air, feeding port, return port and limestone feeding port are arranged in the transition area; the ignition area below the air distribution plate is arranged with a full water-cooled air chamber, a primary air inlet and an ignition device.
[0009] Preferably, the air volume of the fully water-cooled air distribution plate accounts for 40-45%, the upper secondary air, middle secondary air, and lower secondary air account for 45-50%, the feeding air volume of the feeding port accounts for 3-5%, and the return air volume of the return port accounts for 3-5%.
[0010] Beneficial effects of the utility model:
[0011] The utility model is more suitable for fuels with particularly high water content (Mar more than 40%), such as furfural slag, sludge, livestock manure and other high-moisture and low-calorific value fuels, and solves the problems of fuel ignition difficulty, boiler failure to reach rated parameters, and low boiler efficiency, and has higher boiler efficiency; it is suitable for fuels with low calorific value or high water content and meets the requirements of low NO x Emission requirements. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.
[0013] Figure 1 It is the front view of the utility model;
[0014] Figure 2 It is a cross-sectional view of the suspension area of the utility model;
[0015] Figure 3 This is a top view of the water-cooled air distribution plate of the utility model;
[0016] Figure 4 This is a schematic diagram of the first arrangement form of the extension wall of the utility model;
[0017] Figure 5 This is a schematic diagram of the first arrangement form of the extension wall of the utility model;
[0018] Figure 6 It is a schematic diagram of the first arrangement form of the extension wall of the utility model.
[0019] Figure annotation:
[0020] 1- Upper furnace area 2- Extension wall area 3- Transition area 4- Ignition area at the bottom of the furnace DETAILED DESCRIPTION
[0021] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.
[0022] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0023] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0024] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0025] Reference Figure 1-Figure 3 The preferred embodiment of the utility model is a furnace of a high-rate circulating fluidized bed boiler, which includes an upper furnace area 1, an extended wall area 2, a transition area 3, and a lower furnace ignition area 4, and the bottom of the furnace adopts a full water-cooled air distribution plate; the transition area 3 is the connection area between the furnace and the full water-cooled air distribution plate, the lower furnace ignition area 4 includes a dense phase area above the air distribution plate and an ignition area below the air distribution plate, and the ignition area below the air distribution plate adopts under-bed ignition; the transition area 3 includes a transition area and a suspension area, above the suspension area is the extended wall area 2, and the upper furnace area 1 is located above the extended wall area 2.
[0026] In this embodiment, the extended wall area 2 is arranged with an extended wall, and the extended wall is arranged with 3 to 5 water-cooled wall tubes close to the water-cooled wall tubes in the furnace direction, and the pitch is smaller than that of the water-cooled wall.
[0027] There are three ways to arrange the extension wall. The first is that the extension wall is a self-contained system, connected by a header. Figure 4 As shown; the second is that the extension wall and the water-cooled wall tubes are connected by a header, such as Figure 5As shown; the third is that the extension wall is directly connected to the water-cooled wall tube, and a throttling orifice plate is installed in the middle of the water-cooled wall tube directly connected to the extension wall, such as Figure 6 shown.
[0028] The furnace is composed of the upper dense phase area of the air distribution plate, the transition area and the suspension area from bottom to top; the upper dense phase area of the air distribution plate is arranged with a hood and is completely covered with wear-resistant refractory castables; the transition area is partially or completely covered with wear-resistant refractory castables.
[0029] The upper area 1 of the furnace is arranged with the superheater screen (not set below high pressure), the furnace flue gas outlet and the rope hole; the suspension area is arranged with the lower secondary air; the extended wall area 2 is also arranged with the middle secondary air and the upper secondary air; the transition area 3 is arranged with the lower secondary air, the feeding port, the return port and the limestone feeding port; the ignition area below the fully water-cooled air distribution plate is arranged with the fully water-cooled air chamber, the primary air inlet and the ignition device.
[0030] The air volume of the full water-cooled air distribution plate accounts for 40-45%, the upper secondary air, middle secondary air and lower secondary air account for 45-50%, the feeding air volume of the feeding port accounts for 3-5%, and the return air volume of the return port accounts for 3-5%.
[0031] Working principle: The fuel enters the furnace through the feed port and falls into the hot bed material in the dense phase area. The temperature of the hot bed material is 700℃~850℃. The air share in this area is only 40~45%. The reducing atmosphere flue gas produced by oxygen-deficient combustion contains dry distillation volatiles, a large amount of water vapor, broken fuel particles, RO2 produced by combustion, N2 brought in by air, and other sundries and their compounds brought in by fuel. The flue gas rises from the bottom of the furnace, passes through the transition zone, suspension zone and the upper area 1 of the furnace in turn, and finally leaves the furnace through the furnace outlet. During this period, the secondary air is injected into the flue gas in three layers in turn, while increasing the flue gas disturbance, accelerating the contact and combustion of combustibles and air in the horizontal and vertical three-dimensional furnace, ensuring that the fuel is fully burned and burned in the furnace, and evenly distributing heat to the heating surfaces such as water-cooled walls, extension walls and screens. Thereby achieving the purpose of both stable combustion and ensuring the rated parameters of the boiler.
[0032] As a preferred embodiment of the utility model, it may also have the following additional technical features:
[0033] For high-rate circulating fluidized bed boilers, due to the high flue gas velocity in the furnace (4m / s and above), the furnace cross-section is small, resulting in less evaporation heating surface. Therefore, it is necessary to expand the heating surface in the furnace. An extension wall is specially set up here. The extension wall is arranged with 3 to 5 water-cooled wall tubes close to the water-cooled wall tubes in the direction of the furnace. The pitch is smaller than that of the water-cooled wall. At the same time, 1 to 2 layers of secondary air are arranged in this area. The advantages of this furnace setting are: 1. Segmented combustion, so that the volatile matter is concentrated in this area for full combustion, and NO is reduced xgeneration rate; 2. Strengthen flue gas disturbance, reduce Q3 and Q4 losses, and facilitate full fuel combustion; 3. The setting of the extension wall increases the evaporation heating surface, especially for boilers below medium and high pressure, which provides a guarantee for the boiler evaporation heat absorption. 4. Reduce the heat absorption at the bottom of the furnace, increase the regional heat share, maintain the flue gas temperature at a reasonable level, and ensure rapid ignition and stable combustion of the fuel. 5. The flue gas volume along the furnace elevation is more uniform, the furnace cross-section is inverted trapezoidal, the layout is more reasonable and compact, and the metal consumption is reduced. 6. There is no factor of mutual interference between multiple beds, and there is no need to consider the ignition and operation of multiple beds, which makes the maintenance and operation of the boiler simpler; 7. The full water-cooled air distribution plate, the full water-cooled air chamber and the ignition structure under the bed, the full water-cooled air chamber and the burner are simply connected, and the operation is safe and convenient. 8. The dense phase area is arranged with a hood and is fully covered with wear-resistant refractory castables, which minimizes the wear of the furnace, greatly extends the boiler maintenance cycle, and ensures the long-term stable operation of the boiler. 9. For fuels with low calorific value or high water content, the lower part of the suspension zone and the transition zone can be covered with wear-resistant refractory castables to cover part of the heating surface to ensure the furnace temperature and stable combustion. 10. For high-pressure and above boilers, a screen superheater can be arranged in the suspension zone to ensure the superheated steam parameters. 11. The furnace outlet is arranged on the upper part of the rear wall, and double rows of rope holes are arranged on the top of the furnace (usually three in each row) for easy maintenance. 12. The furnace is suspended on the large plate beam, and when running, it expands downward as a whole.
[0034] The utility model is more suitable for fuels with particularly high water content (Mar more than 40%), such as furfural slag, sludge, livestock manure and other high-moisture and low-calorific value fuels, and solves the problems of fuel ignition difficulty, boiler failure to reach rated parameters, and low boiler efficiency, and has higher boiler efficiency; it is suitable for fuels with low calorific value or high water content and meets the requirements of low NO x Emission requirements.
[0035] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.
[0036] The above description is only a preferred implementation mode of the present utility model. Any technical solution that achieves the purpose of the present utility model by basically the same means belongs to the protection scope of the present utility model.
Claims
1. A furnace of a high-rate circulating fluidized bed boiler, characterized in that: The furnace comprises an upper furnace area (1), an extended wall area (2), a transition area (3), and a lower furnace ignition area (4), wherein a fully water-cooled air distribution plate is used at the bottom of the furnace; the transition area (3) is a connection area between the furnace and the fully water-cooled air distribution plate, and the lower furnace ignition area (4) comprises an upper dense phase area of the air distribution plate and a lower ignition area of the air distribution plate, wherein the lower ignition area of the air distribution plate adopts under-bed ignition; the transition area (3) comprises a transition area and a suspension area, wherein the upper part of the suspension area is the extended wall area (2), and the upper furnace area (1) is located above the extended wall area (2).
2. The furnace of a high-rate circulating fluidized bed boiler according to claim 1, characterized in that: The furnace is composed of the upper dense phase area of the air distribution plate, the transition area and the suspension area from bottom to top; the upper dense phase area of the air distribution plate is arranged with a hood and is completely covered with wear-resistant refractory castables; the transition area is partially or completely covered with wear-resistant refractory castables.
3. The furnace of a high-rate circulating fluidized bed boiler according to claim 1, characterized in that: The extension wall area (2) is arranged with an extension wall, and the extension wall is arranged with 3 to 5 water-cooled wall tubes close to the water-cooled wall tubes in the furnace direction, and the pitch is smaller than that of the water-cooled wall.
4. The furnace of a high-rate circulating fluidized bed boiler according to claim 3, characterized in that: There are three ways to arrange the extension wall. The first is that the extension wall is a self-contained system connected with an external header. The second is that the extension wall and the water-cooled wall tubes are connected with a header. The third is that the extension wall and the water-cooled wall tubes are directly connected, and a throttling orifice plate is installed in the middle of the water-cooled wall tubes to which the extension wall is directly connected.
5. The furnace of a high-rate circulating fluidized bed boiler according to claim 1, characterized in that: The upper area (1) of the furnace is provided with a superheater screen, a furnace smoke outlet and a rope hole; the suspension area is provided with lower secondary air; the extended wall area (2) is also provided with middle secondary air and upper secondary air; the transition area (3) is provided with lower secondary air, a feeding port, a return port and a limestone feeding port; the ignition area below the air distribution plate is provided with a full water-cooled air chamber, a primary air inlet and an ignition device.
6. The furnace of a high-rate circulating fluidized bed boiler according to claim 5, characterized in that: The air volume of the full water-cooled air distribution plate accounts for 40-45%, the upper secondary air, middle secondary air and lower secondary air account for 45-50%, the feeding air volume of the feeding port accounts for 3-5%, and the return air volume of the return port accounts for 3-5%.