A pulverized biomass burner suitable for a cfb boiler

Abstract

The utility model discloses a kind of powdered biomass burners suitable for CFB boiler, including variable passage delivery cooling structure, the variable passage delivery cooling structure one end is connected with biomass burner body import intercommunication, the cooling fluid buffer tank is equipped with in the biomass burner body spout outside cover, annular perimeter wind spout is formed between the cooling fluid buffer tank opening inner wall and biomass burner body spout outer wall, fluid flow guide pipe is communicatively arranged between the cooling fluid buffer tank one side outer wall and variable passage delivery cooling structure, through the design of powdered biomass direct combustion, pelletizing process is saved, burner adopts the collaborative design of perimeter wind spout and passage switching valve plate, carrier wind and perimeter wind double cooling when operating, reduce the burning loss of burner under the positive pressure high-temperature environment of CFB boiler. Overall realizes that powdered biomass is efficiently, safely combusted in CFB boiler, improves biomass energy utilization efficiency, prolongs the service life of burner.

Description

Technical Field

[0001] This utility model relates to the field of CFB boilers, and more specifically, to a powdered biomass burner suitable for CFB boilers. Background Technology

[0002] In the field of biomass co-firing in CFB boilers (circulating fluidized bed boilers), existing technologies typically require biomass to be pelletized before it can be fed into the boiler for combustion, which is cumbersome and increases costs. At the same time, the furnace of a CFB boiler is a positive pressure and high temperature environment. When existing biomass burners are shut down, their nozzles are easily burned and deformed by the high-temperature flue gas scouring and radiation. There is a lack of adapted structures for the direct combustion of powdered biomass, and there are no effective means to solve the problem of burner burn-out during shutdown under positive pressure conditions. This results in low biomass energy utilization efficiency and high burner maintenance costs, which restricts the economical and efficient utilization of biomass energy in CFB boilers.

[0003] How to invent a powdered biomass burner suitable for CFB boilers to improve these problems has become an urgent problem to be solved by those skilled in the art. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides a powdered biomass burner suitable for CFB boilers, aiming to improve the problems in the prior art where biomass must be pelletized before it can be burned in CFB boilers, resulting in a complicated process and high cost. Furthermore, the biomass burner nozzles are prone to burn-out and deformation when shut down under positive pressure and high temperature in CFB boilers, and there is a lack of adaptable structures for direct combustion of powdered biomass and protective measures for positive pressure shutdown.

[0005] This utility model is implemented as follows: A powdered biomass burner suitable for CFB boilers includes a variable path conveying and cooling structure. The variable path conveying and cooling structure includes a gas-solid two-phase medium conveying channel, a cooling fluid conveying channel, and a burner connecting pipe. One end of the gas-solid two-phase medium conveying channel, the cooling fluid conveying channel, and the burner connecting pipe are all connected to a channel confluence and connection part. A channel switching valve plate is rotatably installed between the inner walls of both sides of the channel confluence and connection part. The channel switching valve plate is connected to a valve plate drive component. One end of the burner connecting pipe is connected to the inlet of the biomass burner body. A cooling fluid buffer tank is provided outside the nozzle of the biomass burner body. The cooling fluid buffer tank is coaxially arranged with the biomass burner body and has an opening at one end corresponding to the nozzle of the biomass burner body. An annular perimeter air nozzle is formed between the inner wall of the opening and the outer wall of the nozzle of the biomass burner body. One end of a fluid guide pipe is connected to one side of the outer wall of the cooling fluid buffer tank. One end of the fluid guide pipe is connected to one side of the outer wall of the cooling fluid conveying channel.

[0006] In a preferred embodiment of this utility model, a flow regulating valve is connected to the fluid guide pipe.

[0007] In a preferred embodiment of this utility model, the cooling fluid buffer tank includes a conical gathering part and a cylindrical guide part. The cylindrical guide part is coaxially distributed with the nozzle of the biomass burner body, and the gap between the cylindrical guide part and the nozzle of the biomass burner body is a perimeter air nozzle. The cylindrical guide part and the conical gathering part are integrally formed. A sealing mounting hole corresponding to the biomass burner body is opened on the end face of the conical gathering part away from the cylindrical guide part. The biomass burner body is fixedly installed in the sealing mounting hole.

[0008] In a preferred embodiment of this utility model, a variable grating mechanism is installed at the end of the cylindrical guide portion away from the conical gathering portion, corresponding to the perimeter air nozzle area.

[0009] In a preferred embodiment of this utility model, one end of the fluid guide tube is connected to the conical gathering part, and the connection point is located on one side of the axis of the conical gathering part.

[0010] In a preferred embodiment of this utility model, the channel confluence and connection part is an integral hollow cylindrical structure. The gas-solid two-phase medium conveying channel and the burner connecting pipe extend horizontally and are coaxially arranged and symmetrically distributed on both sides of the channel confluence and connection part. The cooling fluid conveying channel extends vertically and forms a T-shaped structure with the gas-solid two-phase medium conveying channel and the burner connecting pipe at an angle of 90°. The surface of the channel switching valve plate facing the inner wall of the channel confluence and connection part is arc-shaped and fits against the inner wall of the channel confluence and connection part. The other end of the channel switching valve plate is rotatably connected between the axes of the inner walls on both sides of the channel confluence and connection part and is connected to the valve plate drive component.

[0011] In a preferred embodiment of this utility model, the outer wall of the channel intersection and connection section is provided with an equipment installation structure.

[0012] The beneficial effects of this utility model are as follows: This utility model provides a powdered biomass burner suitable for CFB boilers through the above design. During use, the direct combustion of powdered biomass eliminates the pelletizing process, simplifying the process and reducing costs. The burner employs a coordinated design of perimeter air nozzles and channel switching valve plates, providing dual cooling from both carrier air and perimeter air during operation. During shutdown, high-pressure fluidizing air in the cold section is directly introduced into the burner, reducing burner burnout under the positive pressure and high temperature environment of the CFB boiler. Overall, it achieves efficient and safe combustion of powdered biomass in CFB boilers, improving biomass energy utilization efficiency, extending burner lifespan, and reducing equipment maintenance costs, combining the advantages of energy conservation, environmental protection, and efficient industrial equipment operation. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a schematic perspective view of the overall structure provided by the embodiment of this utility model; Figure 2 A perspective view illustrating the overall structure of this utility model; Figure 3 A perspective view illustrating the overall structure of this utility model; Figure 4 A three-dimensional schematic view of the overall structure provided for the embodiment of this utility model.

[0015] In the diagram: 1-Gas-solid two-phase medium conveying channel; 2-Cooling fluid conveying channel; 3-Burner connecting pipe; 4-Channel confluence and connection part; 5-Biomass burner body; 6-Fluid guide pipe; 7-Cooling fluid buffer tank; 8-Equipment installation structure; 401-Channel switching valve plate; 402-Valve plate drive component; 601-Flow regulating valve; 701-Perimeter air nozzle; 702-Variable grating mechanism; 703-Conical gathering part; 704-Cylindrical guide part; 705-Sealing mounting hole. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0017] Please see Figures 1 to 4This utility model provides a technical solution: a powdered biomass burner suitable for CFB boilers, comprising a variable path conveying and cooling structure. The variable path conveying and cooling structure includes a gas-solid two-phase medium conveying channel 1, a cooling fluid conveying channel 2, and a burner connecting pipe 3. One end of each of the gas-solid two-phase medium conveying channel 1, cooling fluid conveying channel 2, and burner connecting pipe 3 is connected to a channel confluence and communication portion 4. A channel switching valve plate 401 is rotatably installed between the inner walls of both sides of the channel confluence and communication portion 4. The channel switching valve plate 401 is connected to a valve plate drive component 402. One end of the burner connecting pipe 3 is connected to the inlet of the biomass burner body 5. The outer cover of the nozzle of the biomass burner body 5 is provided with a cooling fluid buffer tank 7. The cooling fluid buffer tank 7 is coaxially arranged with the biomass burner body 5 and has an opening at one end corresponding to the nozzle of the biomass burner body 5. The inner wall of the opening and the outer wall of the nozzle of the biomass burner body 5 form an annular peripheral air nozzle 701. One end of the fluid guide pipe 6 is connected to the outer wall of one side of the cooling fluid buffer tank 7. One end of the fluid guide pipe 6 is connected to the outer wall of one side of the cooling fluid delivery channel 2.

[0018] It should be noted that the variable-path cooling structure includes a gas-solid two-phase medium conveying channel 1, a cooling fluid conveying channel 2, and a burner connecting pipe 3. These three components respectively handle the conveying of the powdered biomass and carrier air mixture, the conveying of high-pressure cooling air, and the transition connection. The gas-solid two-phase medium conveying channel 1 is made of wear-resistant and high-temperature resistant steel pipe, which can withstand material wear and high-temperature corrosion for a long time. The cooling fluid conveying channel 2 uses thickened steel pipe to adapt to the requirements of high-pressure operating conditions. The burner connecting pipe 3 is made of the same material as the gas-solid two-phase medium conveying channel 1 to ensure structural compatibility. The channel junction connection part 4 is a hollow cylindrical structure with precision machining inside, providing space for smooth rotation of the channel switching valve plate 401. The channel switching valve plate 401 is fan-shaped and made of high-temperature resistant alloy material with a wear-resistant coating. Its arc-shaped surface fits tightly with the inner wall of the channel junction connection part 4, effectively preventing leakage during medium switching. The valve plate drive component 402 is preferably a stepper motor with high-precision angle control capability, which can accurately drive the channel switching valve plate 401 to rotate 90°, realizing stable alternating conduction of the gas-solid medium channel and the cooling fluid channel. The cooling fluid buffer tank 7 is made of high-temperature resistant stainless steel and is arranged coaxially with the biomass burner body 5. A gap is reserved between the inner wall of its opening and the outer wall of the nozzle of the biomass burner body 5 to form an annular peripheral air nozzle 701. This gap is precision machined to ensure uniformity and ensure that the cooling air is sprayed out evenly. The fluid guide pipe 6 is made of stainless steel and introduces the cooling air in the cooling fluid delivery channel 2 into the cooling fluid buffer tank 7 to provide peripheral cooling protection for the nozzle of the biomass burner body 5.

[0019] Please see Figures 2 to 4 A flow regulating valve 601 is connected to the fluid guide pipe 6.

[0020] The flow regulating valve 601 can be either an electrically operated ball valve or a pneumatic regulating valve. By changing the valve opening, the flow rate of cooling air entering the cooling fluid buffer tank 7 can be controlled, thereby precisely regulating the wind speed of the perimeter air nozzle 701 and keeping the wind speed stable within the design range. In actual operation, the operator can adjust the opening of the flow regulating valve 601 based on the real-time operating load and furnace temperature data of the CFB boiler, either through the automatic control system or manual operation. This ensures that the burner nozzles receive continuous and effective cooling while preventing excessive cooling air from affecting the combustion efficiency in the furnace, thus achieving a balance between cooling effect and combustion efficiency.

[0021] Furthermore, the cooling fluid buffer tank 7 includes a conical gathering part 703 and a cylindrical guide part 704. The cylindrical guide part 704 is coaxially distributed with the nozzle of the biomass burner body 5 and the gap between the cylindrical guide part 704 and the nozzle of the biomass burner body 5 is a perimeter air nozzle 701. The cylindrical guide part 704 and the conical gathering part 703 are integrally formed. A sealing mounting hole 705 corresponding to the biomass burner body 5 is opened on the end face of the conical gathering part 703 away from the cylindrical guide part 704. The biomass burner body 5 is fixedly installed in the sealing mounting hole 705.

[0022] The conical gathering part 703 and the cylindrical guide part 704 of the cooling fluid buffer tank 7 are manufactured using an integrated molding process. The material is high-temperature resistant stainless steel, possessing both high-temperature resistance and corrosion resistance, making it suitable for the high-temperature environment surrounding the boiler furnace. An annular sealing groove is formed on the inner wall of the sealing mounting hole 705, with a metal spiral wound sealing gasket embedded within. When the biomass burner body 5 is installed into the sealing mounting hole 705, the metal spiral wound sealing gasket achieves a sealed connection between the two, effectively preventing cooling air leakage from the installation gap. The gap between the cylindrical guide part 704 and the nozzle of the biomass burner body 5 forms the perimeter air nozzle 701, ensuring that the cooling air is evenly distributed around the nozzle circumference, providing all-round, dead-angle-free cooling protection and preventing nozzle burn-out due to insufficient localized cooling.

[0023] Furthermore, a variable grating mechanism 702 is installed at the end of the cylindrical guide portion 704 away from the conical gathering portion 703, corresponding to the area of ​​the perimeter air nozzle 701.

[0024] The variable grating mechanism 702 consists of multiple uniformly distributed arc-shaped blades in a ring. These blades are forged from a high-temperature resistant alloy, possessing sufficient structural strength and high-temperature resistance. The arc-shaped blades are connected to electric drive devices such as servo motors via connecting rods. Once activated, the drive devices rotate all the arc-shaped blades synchronously. By changing the opening angle between the blades, the effective diameter of the perimeter air nozzle 701 can be precisely adjusted, thereby controlling the wind speed and flow rate of the perimeter wind. The blades employ an overlapping design, with optimized overlap lengths between adjacent blades to ensure no air leakage during adjustment. The blade surfaces are polished to reduce wind resistance during cooling airflow, improve cooling air flow efficiency, and enhance heat exchange between the cooling air and the nozzle outer wall.

[0025] Furthermore, one end of the fluid guide tube 6 is connected to the conical gathering part 703, and the connection point is located on one side of the axis of the conical gathering part 703.

[0026] One end of the fluid guide pipe 6 is positioned off-center from the axis of the conical gathering section 703, creating an eccentric connection that allows the cooling air to form a spiral flow trajectory inside the cavity after entering the conical gathering section 703. This spiral flow not only prolongs the residence time of the cooling air in the cooling fluid buffer tank 7, allowing it to fully contact the inner wall of the cooling fluid buffer tank 7 and the outer wall of the biomass burner body 5 nozzle, thus improving heat exchange efficiency, but also makes the cooling air gradually more evenly distributed as it flows towards the peripheral air nozzle 701, further optimizing the cooling effect of the nozzle and avoiding cooling blind spots caused by excessively low local wind speeds.

[0027] Furthermore, the channel junction connection part 4 is a hollow cylindrical structure. The gas-solid two-phase medium conveying channel 1 and the burner connecting pipe 3 extend horizontally and are coaxially arranged and symmetrically distributed on both sides of the channel junction connection part 4. The cooling fluid conveying channel 2 extends vertically and forms a T-shaped structure with the gas-solid two-phase medium conveying channel 1 and the burner connecting pipe 3 at an angle of 90°. The surface of the channel switching valve plate 401 facing the inner wall of the channel junction connection part 4 is arc-shaped and fits against the inner wall of the channel junction connection part 4. The other end of the channel switching valve plate 401 is rotatably connected between the axes of the inner walls on both sides of the channel junction connection part 4 and connected to the valve plate drive component 402.

[0028] The channel junction connection part 4 is made of high-strength, high-temperature resistant alloy material, and its inner wall is precision ground to ensure that the gas-solid two-phase medium conveying channel 1 and the burner connecting pipe 3 are horizontally coaxial and symmetrically distributed on both sides of the channel junction connection part 4. Together with the vertically extending cooling fluid conveying channel 2, they form a T-shaped structure with a 90° angle, allowing the channel switching valve plate 401 to complete the alternating switching of the two channels with only a 90° rotation, simplifying the operation logic. The arc-shaped surface of the channel switching valve plate 401 and the contact surface with the inner wall of the channel junction connection part 4 are precision ground to ensure good sealing performance under the positive pressure environment of the CFB boiler. The valve plate drive component 402 uses a stepper motor, which is fixedly connected to the rotating shaft of the channel switching valve plate 401 via a coupling. The stepper motor has high torque output and high-precision angle control characteristics, enabling stable operation under the complex high-temperature and vibration conditions of the boiler, accurately controlling the rotation angle of the channel switching valve plate 401, and ensuring the reliability of channel switching.

[0029] Furthermore, an equipment installation structure 8 is provided on the outer wall of the channel intersection and connection section 4.

[0030] The equipment installation structure 8 is a standard flange structure, integrally formed on the outer wall of the channel junction and connection part 4. The flange is forged from high-strength steel, and its dimensions and bolt hole distribution are perfectly compatible with the matching flange at the reserved hole of the water-cooled wall bend in the CFB boiler. During installation, the burner is aligned with the flange at the reserved hole of the water-cooled wall through this flange structure, and then fastened with high-strength bolts. The pre-tightening force of the bolts ensures the firmness of the connection. This structure resists the thrust generated by the positive pressure of the CFB boiler furnace, ensuring the stability of the burner's position during long-term operation, preventing displacement or shaking. At the same time, it ensures precise communication between the nozzle of the biomass burner body 5 and the furnace, providing structural protection for the stable injection and combustion of biomass powder.

[0031] Working principle: The valve plate drive component 402 drives the channel switching valve plate 401 to rotate and block the cooling fluid delivery channel 2 connection port, opening the gas-solid two-phase medium delivery channel 1 and the burner connection pipe 3. The mixture of powdered biomass and carrier air enters the biomass burner body 5 through the channel confluence connection part 4 and is injected into the CFB boiler furnace for combustion. At the same time, the cooling air enters the cooling fluid buffer tank 7 through the cooling fluid delivery channel 2 and the fluid guide pipe 6. After forming a spiral flow in the conical gathering part 703, it is ejected from the annular peripheral air nozzle 701, which, together with the carrier air, cools the nozzle of the biomass burner body 5 and the area of ​​the channel switching valve plate 401. The variable grating mechanism 702 can adjust the diameter of the peripheral air nozzle 701 to control the wind speed. When shut down, the valve plate drive component 402 drives the switching valve plate 401 to rotate in the opposite direction, cutting off the gas-solid channel and connecting the cooling fluid delivery channel 2 to the burner connection pipe 3. The high-pressure fluidizing air in the cold section is directly introduced into the biomass burner body 5. Combined with the continuous cold air from the perimeter air nozzle 701, the residual heat of the burner is carried away in two ways, preventing it from being burned by the high temperature of the furnace. The entire burner is fixed to the water-cooled wall of the CFB boiler through the equipment installation structure 8, ensuring structural stability under positive pressure conditions and realizing safe and efficient direct combustion of powdered biomass in the CFB boiler and equipment protection.

[0032] It should be noted that the specific models and specifications of the biomass burner body 5, flow regulating valve 601, and variable grating mechanism 702 need to be selected and determined according to the actual specifications of the device. The specific selection calculation method adopts the existing technology in this field, so it will not be described in detail.

[0033] The power supply and operating principle of the biomass burner body 5, the flow regulating valve 601, and the variable grating mechanism 702 are clear to those skilled in the art and will not be described in detail here.

[0034] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A pulverized biomass burner suitable for CFB boilers, characterized in that, The system includes a variable-path cooling structure, comprising a gas-solid two-phase medium transport channel, a cooling fluid transport channel, and a burner connecting pipe. One end of each of the gas-solid two-phase medium transport channel, the cooling fluid transport channel, and the burner connecting pipe is connected to a channel junction. A channel switching valve plate is rotatably mounted between the inner walls of both sides of the channel junction. The channel switching valve plate is connected to a valve plate drive component. One end of the burner connecting pipe is connected to the inlet of the biomass burner body. A cooling fluid buffer tank is provided outside the biomass burner body nozzle. The cooling fluid buffer tank is coaxially arranged with the biomass burner body and has an opening at one end corresponding to the biomass burner body nozzle. The inner wall of the opening and the outer wall of the biomass burner body nozzle form an annular perimeter air nozzle. One end of a fluid guide pipe is connected to one side of the outer wall of the cooling fluid buffer tank, and one end of the fluid guide pipe is connected to one side of the outer wall of the cooling fluid transport channel.

2. The pulverized biomass burner suitable for CFB boilers as described in claim 1, characterized in that: A flow regulating valve is connected to the fluid guide pipe.

3. The pulverized biomass burner suitable for CFB boilers as described in claim 1, characterized in that: The cooling fluid buffer tank includes a conical gathering part and a cylindrical guide part. The cylindrical guide part is coaxially distributed with the nozzle of the biomass burner body, and the gap between the cylindrical guide part and the nozzle of the biomass burner body is a perimeter air nozzle. The cylindrical guide part and the conical gathering part are integrally formed. A sealing mounting hole corresponding to the biomass burner body is opened on the end face of the conical gathering part away from the cylindrical guide part. The biomass burner body is fixedly installed in the sealing mounting hole.

4. The pulverized biomass burner suitable for CFB boilers as described in claim 3, characterized in that: A variable grating mechanism is installed at the end of the cylindrical guide section away from the conical gathering section, corresponding to the perimeter air nozzle area.

5. The pulverized biomass burner suitable for CFB boilers as described in claim 3, characterized in that: One end of the fluid guide tube is connected to the conical gathering part, and the connection point is located on one side of the axis of the conical gathering part.

6. The pulverized biomass burner suitable for CFB boilers as described in claim 1, characterized in that: The channel confluence and connection section is a hollow cylindrical structure. The gas-solid two-phase medium conveying channel and the burner connecting pipe extend horizontally and are coaxially arranged and symmetrically distributed on both sides of the channel confluence and connection section. The cooling fluid conveying channel extends vertically and forms a T-shaped structure with the gas-solid two-phase medium conveying channel and the burner connecting pipe at a 90° angle. The surface of the channel switching valve plate facing the inner wall of the channel confluence and connection section is arc-shaped and fits against the inner wall of the channel confluence and connection section. The other end of the channel switching valve plate is rotatably connected between the axes of the inner walls on both sides of the channel confluence and connection section and is connected to the valve plate drive component.

7. The pulverized biomass burner suitable for CFB boilers as described in claim 1, characterized in that: The outer wall of the connecting section of the channel is provided with an equipment installation structure.

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