Circulating fluidized bed
By installing structures such as air caps, air distribution plates, guide plates, and cyclone separators in the circulating fluidized bed boiler, the airflow and ash separation are optimized, solving the problems of low efficiency and coking when biomass fuel is blended, and achieving efficient combustion and stable operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-21
- Publication Date
- 2026-03-17
AI Technical Summary
Conventional circulating fluidized bed boilers have poor working efficiency, poor combustion characteristics, and are prone to coking when co-firing biomass fuels, which affects heat transfer efficiency and operational stability.
The circulating fluidized bed is equipped with a wind cap, air distribution plate, guide plate, spiral wound heat exchange tube bundle and cyclone separator. The height and angle of the guide plate are adjusted by electric push rod to optimize airflow disturbance, enhance fuel mixing and separation effect, and achieve coarse and fine ash separation by adjusting baffle, prevent coking and improve combustion efficiency.
It improves the combustion efficiency of biomass fuel, extends fuel residence time, reduces the carbon content of fly ash, and enhances the operational stability and heat exchange efficiency of the boiler.
Smart Images
Figure CN224003700U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of industrial boiler technology, and in particular to a circulating fluidized bed. Background Technology
[0002] The main structure of a circulating fluidized bed (CFB) boiler consists of two parts: the combustion chamber and the circulating furnace. Its biggest difference from bubbling fluidized bed combustion technology is its high operating velocity, which enhances heterogeneous reaction processes such as combustion and desulfurization. This allows for the expansion of boiler capacity to a level acceptable to the power industry. CFB boilers have effectively solved fundamental problems in thermodynamics, mechanics, and materials science, as well as engineering issues such as expansion, wear, and overheating, making them an advanced technology for the energy utilization of difficult-to-burn solid fuels (such as coal gangue, oil shale, municipal solid waste, sludge, and other waste materials).
[0003] Based on practical application, conventional circulating fluidized bed boilers exhibit poor operating efficiency when co-firing biomass fuels. For example, on the one hand, the combustion characteristics of biomass fuels differ significantly from those of coal, while conventional circulating fluidized bed boilers are typically designed for coal combustion processes. Therefore, they perform poorly in terms of biomass fuel adaptability, making it difficult to simultaneously achieve the goals of high-efficiency combustion and low emissions. On the other hand, due to the low melting point of biomass fuel ash, it easily forms coke in the boiler furnace, which not only reduces heat transfer efficiency but also affects the boiler's operational stability. Utility Model Content
[0004] The purpose of this invention is to provide a circulating fluidized bed to solve the technical problem of poor working efficiency of conventional circulating fluidized beds when co-firing biomass fuels.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] The circulating fluidized bed body is equipped with an air cap and air distribution plate, and the air cap and air distribution plate is equipped with a guide plate. The air cap and air distribution plate has four mounting holes in its radial direction. Each mounting hole is equipped with an electric push rod, and the electric push rod is equipped with a guide plate. The circulating fluidized bed body is equipped with a spiral wound heat exchange tube bundle in the transition section between the dense phase region and the dilute phase region. The circulating fluidized bed body is equipped with a cyclone separator, and the inlet of the cyclone separator is equipped with guide vanes.
[0007] Optionally, the guide plate is an arc-shaped steel plate with serrated edges, and the lifting height of the electric push rod is 50mm to 300mm.
[0008] Optionally, the bottom pitch of the spiral wound heat exchanger tube bundle is 20cm, and the top pitch of the spiral wound heat exchanger tube bundle is 40cm.
[0009] Optionally, a first rotating shaft is provided at the bottom end of the guide vane, and an adjusting rod is provided on one side of the first rotating shaft. The adjusting rod extends outward and is connected to an adjusting knob. The adjusting angle of the guide vane is 30°-45°.
[0010] Optionally, the cyclone separator is provided with a rotatable adjustable baffle. The cyclone separator is divided into an upper chamber and a lower chamber by the adjustable baffle. The diameter of the upper chamber is larger than the diameter of the lower chamber, and the cone angle of the lower chamber is smaller than the cone angle of the upper chamber.
[0011] Optionally, a motor is provided on one side of the cyclone separator, and the output end of the motor extends into the cyclone separator and is connected to a second rotating shaft, which is connected to the adjustable baffle.
[0012] Optionally, the adjustable baffle can rotate from 0° to 90°.
[0013] Compared with the prior art, the beneficial effects of this utility model include at least the following:
[0014] The height of the guide plate is adjusted by an electric push rod to enhance airflow turbulence, ensuring thorough mixing of biomass fuels of different densities (such as straw and sawdust) with the bed material. This prevents uneven fluidization or short-circuit combustion of fuel. At the same time, the guide plate is equipped with serrated edges, which further enhances the turbulence effect, prolongs the residence time of fuel in the furnace, improves the volatile matter burnout rate, and reduces the carbon content of fly ash, thereby achieving the goal of significantly improving the working efficiency of the entire circulating fluidized bed. Attached Figure Description
[0015] Figure 1 A schematic diagram of the overall structure of the circulating fluidized bed provided by this utility model;
[0016] Figure 2 A schematic diagram of the air cap and air plate structure of the circulating fluidized bed provided by this utility model;
[0017] Figure 3 A schematic diagram of the guide vane structure for the circulating fluidized bed provided by this utility model;
[0018] Figure 4 A schematic diagram of the cyclone separator structure for a circulating fluidized bed provided by this utility model;
[0019] Figure 5 A schematic diagram of the spiral wound heat exchanger tube bundle structure of the circulating fluidized bed provided by this utility model.
[0020] Legend:
[0021] 1. Circulating fluidized bed body; 101. Air cap and air distribution plate; 102. Guide plate; 103. Spiral wound heat exchange tube bundle; 104. Cyclone separator; 105. Guide vane; 106. Mounting hole; 107. Electric push rod; 108. First rotating shaft; 109. Adjusting rod; 110. Adjusting knob; 111. Adjustable baffle; 112. Second rotating shaft; 113. Motor. Detailed Implementation
[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.
[0023] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be provided below with reference to relevant embodiments, and several embodiments of this utility model will be given. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of this utility model more thorough and complete.
[0024] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0026] Please refer to the following: Figures 1 to 5This utility model provides a technical solution for a circulating fluidized bed, comprising: a circulating fluidized bed body 1, a wind cap cloth plate 101 disposed inside the circulating fluidized bed body 1, a guide plate 102 disposed on the wind cap cloth plate 101, four mounting holes 106 radially opened on the wind cap cloth plate 101, an electric push rod 107 installed in each mounting hole 106, a guide plate 102 mounted on the electric push rod 107, the guide plate 102 being an arc-shaped steel plate with serrated edges, and the lifting height of the electric push rod 107 being 50mm-300mm; a spiral wound heat exchange tube bundle 103 embedded in the part of the circulating fluidized bed body 1 at the transition section between the dense phase zone and the dilute phase zone, a cyclone separator 104 disposed inside the circulating fluidized bed body 1, and a guide vane 105 disposed at the inlet of the cyclone separator 104.
[0027] The circulating fluidized bed provided in this application solves key problems in biomass co-firing through synergistic optimization of air distribution adjustment, coking suppression, and separation enhancement, while maintaining the compactness of the circulating fluidized bed structure for biomass co-firing in boilers. Simultaneously, by adjusting the height of the guide plate 102 to change the local fluidization velocity, large particle deposition or short-circuit combustion of light fuels is prevented, thereby significantly improving the overall working efficiency of the fluidized bed.
[0028] In further embodiments of this application, such as Figure 5 As shown, the bottom pitch of the spiral wound heat exchange tube bundle 103 is 20cm, and the top pitch of the spiral wound heat exchange tube bundle 103 is 40cm. The spiral structure designed in this way increases the probability of ash particle collision, making it easier for the adhered ash layer to fall off, reducing coking, and the variable pitch optimizes the heat exchange gradient to avoid local overheating.
[0029] Please refer to further details. Figure 3 and Figure 4In a further embodiment of this application, a first rotating shaft 108 is provided at the bottom end of the guide vane 105, and an adjusting rod 109 is provided on one side of the first rotating shaft 108. The adjusting rod 109 extends outward and is connected to an adjusting knob 110. The adjusting angle of the guide vane 105 is 30° to 45°. With this design, the airflow containing biomass fly ash is pre-accelerated by the guide vane 105, thereby improving the centrifugal capture efficiency of light particles. Furthermore, an adjustable baffle 111 is provided inside the cyclone separator 104. The cyclone separator 104 is divided into an upper chamber and a lower chamber distributed vertically by the adjustable baffle 111. The diameter of the upper chamber is 10% larger than that of the lower chamber, and the end cone angle of the lower chamber is reduced to 60°. The purpose of this design is to enhance the secondary separation of fine ash and promote the rapid separation of coarse ash. Rapid return combustion is achieved. Furthermore, an adjustable baffle 111 is rotatably mounted, and a motor 113 is mounted on one side of the cyclone separator 104. The output end of the motor 113 extends towards the cyclone separator 104 and is connected to a second rotating shaft 112. The second rotating shaft 112 is connected to the adjustable baffle 111, allowing for coordinated rotation of the adjustable baffle 111. The rotation angle of the adjustable baffle 111 is 0° to 90°. An ash content detection element is installed inside the cyclone separator 104, and the ash content detection element is electrically connected to the motor 113. Thus, the dual-chamber structure achieves graded separation of coarse ash (lower section) and fine ash (upper section). The coarse ash is directly returned to the furnace, while the fine ash enters the secondary combustion zone, reducing the carbon content of the fly ash.
[0030] Based on the specific content of the above embodiments, the working process of this utility model is described as follows: When using a circulating fluidized bed, biomass fuel and bed material are first fed into the bottom of the furnace of the circulating fluidized bed body 1 through the feeding system; primary air is evenly distributed through the air cap air distribution plate 101, so that the bed material and fuel form a fluidized state in the dense phase zone. At the same time, the electric push rod 107 adjusts the height of the guide plate 102 according to the fuel characteristics, and the arc-shaped guide plate 102 with serrated edges generates turbulence, optimizing the mixing of fuel and bed material.
[0031] Biomass fuel begins combustion in the dense phase zone, with volatiles rapidly released and burned. The combustion gas carries particles to the dilute phase zone, passes through the spiral-wound heat exchange tube bundle 103, and the dust-laden flue gas enters the cyclone separator 104. The guide vanes 105 pre-accelerate the airflow, improving the collection efficiency of light particles. Coarse particles quickly return to the furnace through the lower chamber for continued combustion. Fine particles enter the upper chamber for secondary separation. The adjustable baffle 111 is driven by the motor 113, and the ash content detection device (e.g., a sensor) detects the ash content in real time to automatically adjust the baffle angle to optimize the separation efficiency, ensuring that coarse ash is directly returned to the furnace and fine ash enters the secondary combustion zone.
[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A circulating fluid bed comprising a circulating fluid bed body, characterised in that: The circulating fluidized bed body is provided with a wind cap cloth wind board, the wind cap cloth wind board is provided with a guide plate, four installation holes are opened in the radial direction of the wind cap cloth wind board, an electric push rod is installed in each installation hole, a guide plate is installed on the electric push rod, a spiral winding heat exchange tube bundle is embedded in the transition section of the dense phase zone and the dilute phase zone in the circulating fluidized bed body, a cyclone separator is arranged in the circulating fluidized bed body, and guide vanes are arranged at the inlet of the cyclone separator.
2. The circulating fluidized bed according to claim 1, characterized in that: The guide plate is an arc-shaped steel plate, serrations are opened at the edge of the guide plate, and the lifting height of the electric push rod is 50-300 mm.
3. The circulating fluidized bed of claim 1, wherein: The inner bottom pitch of the spiral winding heat exchange tube bundle is 20 cm, and the inner top pitch of the spiral winding heat exchange tube bundle is 40 cm.
4. The circulating fluidized bed of claim 1, wherein: A first rotating shaft is arranged at the bottom end of the guide vane, an adjusting rod is arranged on one side of the first rotating shaft, an adjusting knob is connected to the adjusting rod extending outward, and the adjusting angle of the guide vane is 30-45°.
5. The circulating fluidized bed of claim 1, wherein: An adjustable baffle that can rotate is arranged in the cyclone separator, the cyclone separator is divided into an upper chamber and a lower chamber distributed in the upper and lower directions by the adjustable baffle, the diameter of the upper chamber is greater than that of the lower chamber, and the taper angle of the lower chamber is smaller than that of the upper chamber.
6. The circulating fluidized bed of claim 5, wherein: A motor is arranged on one side of the outside of the cyclone separator, a second rotating shaft is connected to the output end of the motor extending to the cyclone separator, and the second rotating shaft is connected to the adjustable baffle.
7. The circulating fluidized bed of claim 6, wherein: The rotation angle of the adjustable baffle is 0-90°.