A substitute fuel incineration boiling furnace suitable for a cement kiln

Abstract

The utility model belongs to cement kiln disposal technical field, disclose a kind of alternative fuel incineration boiling furnace suitable for cement kiln, including boiling furnace body, the top of boiling furnace body is equipped with alternative fuel import, alternative fuel import place is equipped with material lifting device, the material lifting device includes driving motor, transmission mechanism, material lifting plate and heat shield, the driving motor and material lifting plate in the transmission mechanism connection are in furnace outside, the heat shield is arranged in the outside of transmission mechanism as its support and protection, driving motor drives transmission mechanism to drive material lifting plate to swing up and down.This boiling furnace is blown and the reasonable flow rate design by the material lifting effect and air cannon of material lifting device, fuel is in suspension in hearth, air cannon is blown to the violent disturbance of material combustion, destroys the original flame layer generated in combustion process, improves the combustion condition of material surface, promotes the full burnout of material, shortens the combustion time of material.

Description

Technical Field

[0001] This utility model belongs to the field of cement kiln co-processing technology, specifically relating to a fluidized bed furnace for alternative fuel combustion in cement kilns. Background Technology

[0002] To achieve energy conservation and emission reduction goals, the cement industry is actively promoting the use of alternative fuels to replace traditional fossil fuels. However, due to the unstable source of alternative fuels, their type, calorific value, and moisture content fluctuate significantly, making it difficult to achieve good coupling with the existing fossil fuel incineration system in the precalciner. This leads to problems such as large fluctuations in the operating conditions of the combustion system and incomplete combustion of alternative fuels. Currently, direct combustion in the precalciner places high demands on the particle size and moisture content of the alternative fuels. If the processing volume is too high, the particle size of the alternative fuel will be too large, resulting in uneven dispersion in the furnace, which will affect the stable production of the cement kiln.

[0003] Traditional alternative fuels cannot achieve complete combustion in the decomposition furnace, resulting in fluctuating flue gas temperatures, oxygen levels, and even oxygen-deficient combustion. This produces harmful gases that affect kiln operation, leading to a decrease in clinker yield and quality, and hindering the significant improvement in alternative fuel utilization. Therefore, there is an urgent need to develop a novel alternative fuel pre-combustion device to ensure complete combustion of the alternative fuel before it enters the decomposition furnace, thereby improving combustion efficiency, reducing the amount of incompletely burned materials entering the furnace, and ultimately minimizing the impact on cement clinker production quality. Utility Model Content

[0004] To address the problems and shortcomings of existing technologies, this utility model provides a fluidized bed furnace for alternative fuel combustion suitable for cement kilns. This fluidized bed furnace causes the fuel to continuously tumble and move forward within the furnace chamber, maintaining a near-suspended state, resulting in higher combustion efficiency, reducing the amount of incompletely burned alternative fuel entering the decomposition furnace, and minimizing the impact on the quality of cement clinker production.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0006] A fluidized bed furnace for alternative fuel combustion in cement kilns includes a fluidized bed furnace body. The top of the fluidized bed furnace body is provided with an alternative fuel inlet. A lifting device is provided at the alternative fuel inlet. The lifting device includes a drive motor, a transmission mechanism, a lifting plate, and a heat insulation cover. The transmission mechanism connects the drive motor located outside the furnace and the lifting plate inside the furnace. The heat insulation cover is located outside the transmission mechanism to support and protect it. The drive motor drives the transmission mechanism to make the lifting plate swing up and down.

[0007] Furthermore, the transmission mechanism includes a drive shaft, a rotary transmission block, a connecting rod, a fixed shaft, and a transmission shaft. One end of the drive shaft is connected to the output shaft of the drive motor. The rotary transmission block rotatably connects the drive shaft and the connecting rod. Both ends of the connecting rod are fixed to the transmission shaft via the fixed shaft. The transmission shaft is fixedly connected to the lifting plate. The connecting rod rotates with the rotary transmission block, thereby causing the lifting plate to swing up and down.

[0008] Furthermore, the rotary transmission block includes a first bushing, a second bushing, and a connecting block connecting the first bushing and the second bushing. The first bushing and the second bushing are arranged perpendicular to each other. The first bushing is fixed to the end of the drive shaft. The second bushing is provided with an insert rod, and the connecting rod is provided with a sliding groove. The second bushing is sleeved on the connecting rod, and the insert rod is inserted into the sliding groove of the connecting rod.

[0009] Furthermore, it also includes a fixed incineration bed, which is located at the bottom of the fluidized bed furnace body. It includes an inclined fixed bed plate and multiple stepped sections, each of which is equipped with a compressed air nozzle. The compressed air nozzle is connected to an air cannon and a gas storage tank.

[0010] Furthermore, the fixed bed board is inclined at a 30° angle to the horizontal plane.

[0011] Furthermore, the compressed air nozzle includes an upper housing and a lower housing, with multiple flow-guiding baffles disposed between the upper housing and the lower housing.

[0012] Furthermore, the compressed air nozzle is trumpet-shaped, with the upper housing and lower housing forming an angle of 20 to 35°, and the fan angle being 35 to 50°.

[0013] Furthermore, the fluidized bed furnace body includes a furnace wall and a furnace shell disposed on the outer side of the furnace wall. The furnace wall includes, from the inside to the outside, a casting layer, an insulation layer, and a calcium silicate board layer.

[0014] Furthermore, the top of the fluidized bed furnace body is also provided with a C4 raw material inlet, and a material spillage buffer is provided at the C4 raw material inlet.

[0015] Furthermore, the front end of the fluidized bed furnace body is provided with a tertiary air inlet, and the rear end is provided with a flue gas outlet.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This utility model discloses a fluidized bed furnace for alternative fuel combustion in cement kilns. Through the lifting action of a lifting device, the injection of air cannons, and a reasonable flow rate design, the fuel is suspended in the furnace. The air cannons violently disturb the combustion of the material, disrupting the original flame layer and improving the combustion conditions on the material surface, promoting complete combustion and shortening the combustion time. A reasonable combustion chamber structure and heat insulation design ensure a high flue gas temperature and effectively control dioxin formation. This further improves the combustion efficiency of the alternative fuel, reduces incomplete combustion of alternative fuel entering the decomposition furnace, and minimizes the impact on the quality of cement clinker production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0019] Figure 2 for Figure 1 AA sectional view.

[0020] Figure 3 This is a schematic diagram of the material lifting device of this utility model.

[0021] Figure 4 This is a schematic diagram of the lifting plate of this utility model in one state.

[0022] Figure 5 This is a schematic diagram of the lifting plate of this utility model in state two.

[0023] Figure 6 This is a schematic diagram of the lifting plate of this utility model in state three.

[0024] Figure 7 This is a schematic diagram of the lifting plate of this utility model in state four.

[0025] Figure 8 This is a front sectional view of the compressed air nozzle of this utility model.

[0026] Figure 9 This is a side sectional view of the compressed air nozzle of this utility model.

[0027] The components are: 1. Furnace wall; 1-1. Casting layer; 1-2. Insulation layer; 1-3. Calcium silicate board layer;

[0028] 2. Furnace shell;

[0029] 3. Material spillage buffer;

[0030] 4. Incineration fixed bed; 4-1. Fixed bed board;

[0031] 5. Drive motor;

[0032] 6. Transmission mechanism; 6-1. Drive shaft; 6-2. Rotary transmission block; 6-3. Connecting rod; 6-4. Fixed shaft; 6-5. Transmission shaft;

[0033] 7. Lifting plates;

[0034] 8. Heat shield;

[0035] 9. Temperature and pressure measurement points;

[0036] 10. Cold air inlet;

[0037] 11. Manhole;

[0038] 12. Inspect the door;

[0039] 13. Compressed air nozzle; 13-1 Drainage baffle;

[0040] 14. Gas storage tank. Detailed Implementation

[0041] The specific embodiments of this utility model will be further explained below with reference to the accompanying drawings.

[0042] like Figure 1-9 As shown, a fluidized bed combustion furnace suitable for cement kilns is installed in front of the decomposition furnace and includes a fluidized bed furnace body, a feeding device, a combustion fixed bed, and an air cannon system.

[0043] The fluidized bed furnace body includes a furnace wall 1 and a furnace shell 2 located outside the furnace wall 1. The furnace wall 1 adopts a three-layer structure design, consisting of, from the inside out: a casting layer 1-1, an insulation layer 1-2, and a calcium silicate board layer 1-3. The casting layer 1-1 can be cast using mullite or corundum castable. The insulation layer 1-2 can be made of lightweight insulation materials such as nano-insulation boards or lightweight castables. The calcium silicate board layer 1-3 can be made of high-temperature calcium silicate boards, such as HCS-20 or HCS-27. This design increases the insulation thickness while reducing the weight of the furnace wall 1. The furnace shell 2 is made of modular steel plates, which reduces the amount of welding work on site. The furnace wall 1 and the furnace shell 2 work together to provide good heat insulation for the fluidized bed furnace, which is beneficial for controlling the flue gas temperature inside the furnace.

[0044] The top front end of the fluidized bed furnace body is provided with a substitute fuel inlet, which serves as the main fuel inlet. The middle of the top of the fluidized bed furnace body is provided with a C4 raw material inlet. A feeding buffer 3 is provided at the C4 raw material inlet to provide a certain buffering effect on the raw material entering the furnace, preventing the lower temperature raw material from entering the furnace under the action of gravity and impacting the fuel combustion.

[0045] The front end of the fluidized bed furnace body is provided with a tertiary air inlet, which is connected to the tertiary air pipe of the cement kiln to provide hot air for combustion of alternative fuels. The rear end of the fluidized bed furnace body is provided with a flue gas outlet.

[0046] A lifting device is installed at the alternative fuel inlet. The lifting device includes a drive motor 5, a transmission mechanism 6, a lifting plate 7, and a heat insulation cover 8. The drive motor 5 is located outside the furnace and supported by a steel structure. The transmission mechanism 6 is a mechanical linkage structure and is located inside the furnace, within the heat insulation cover 8. The heat insulation cover 8 is bolted to the fluidized bed furnace body to prevent the transmission mechanism 6 from being exposed to a high-temperature environment and reducing its service life. The lifting plate 7 is connected to the transmission mechanism 6, and the heat insulation cover 8 provides heat insulation protection and support for the transmission mechanism 6.

[0047] Specifically, the transmission mechanism 6 includes a drive shaft 6-1, a rotary transmission block 6-2, a connecting rod 6-3, a fixed shaft 6-4, and a transmission shaft 6-5. One end of the drive shaft 6-1 is connected to the output shaft of the drive motor 5 on the outside, and the other end is connected to the rotary transmission block 6-2. At the same time, the drive shaft 6-1 is connected to the outside of the fluidized bed furnace body through bearings to maintain the stability of the drive shaft 6-1. The rotary transmission block 6-2 includes a first bushing and a second bushing arranged perpendicularly to each other, and a connecting block connecting the first bushing and the second bushing. The first bushing is fixed to the end of the drive shaft 6-1. The connecting rod 6-3 is provided with a sliding groove. The second bushing is sleeved on the connecting rod 6-3. At the same time, the second bushing is provided with an insert rod that is inserted into the sliding groove of the connecting rod 6-3. The two ends of the connecting rod 6-3 are fixed to the transmission shaft 6-5 through the fixed shaft 6-4. The transmission shaft 6-5 is fixedly connected to the two ends of the lifting plate 7. At the same time, the two ends of the transmission shaft 6-5 are connected to the heat insulation cover 8 through bearings.

[0048] The first bushing rotates circumferentially with the drive shaft 6-1, causing the second bushing to rotate synchronously circumferentially with the drive shaft 6-1 as the center. At the same time, the insert rod on the second bushing slides back and forth along the slide groove on the connecting rod 6-3. Since the insert rod is limited in the slide groove, the connecting rod 6-3 rotates in the forward or reverse direction along its own circumference under the drive of the second bushing. This, in turn, drives the lifting plate 7 to swing up and down through the transmission shaft 6-5, so that the fuel entering from the alternative fuel inlet is lifted or dropped.

[0049] The operation process of the lifting device is as follows:

[0050] In the initial state, the second bushing of the rotary transmission block 6-2 is located at the 3 o'clock position of the drive shaft 6-1 and on the right half of the connecting rod 6-3. The lifting device is in a horizontal position. Figure 4 As shown;

[0051] When the drive motor 5 is started, its output shaft drives the drive shaft 6-1 to rotate 90° counterclockwise. Simultaneously, the first bushing of the rotating transmission block 6-2 rotates counterclockwise, causing the second bushing of the rotating transmission block 6-2 to rotate to the 12 o'clock position of the drive shaft 6-1. This, in turn, causes the second bushing to move to the left along the connecting rod 6-3 until it reaches the center position of the connecting rod 6-3. At the same time, the insert rod, being confined within the slide groove, causes the connecting rod 6-3 to rotate clockwise, which in turn drives the lifting plate 7 to move downwards by 45° via the transmission shaft 6-5. Figure 5 As shown;

[0052] The drive shaft 6-1 continues to rotate 90° counterclockwise. Simultaneously, the first bushing of the rotary transmission block 6-2 drives the second bushing to rotate to the 9 o'clock position of the drive shaft 6-1. The second bushing of the rotary transmission block 6-2 moves to the left half of the connecting rod 6-3. The insert rod drives the connecting rod 6-3 to rotate counterclockwise, causing the lifting plate 7 to move upwards by 45° and return to the horizontal position. Figure 6 As shown;

[0053] The drive shaft 6-1 continues to rotate counterclockwise by 90°. Simultaneously, the first bushing of the rotary transmission block 6-2 drives the second bushing to rotate to the 6 o'clock position of the drive shaft 6-1. The second bushing of the rotary transmission block 6-2 moves to the center position of the connecting rod 6-3. The insert rod drives the connecting rod 6-3 to continue rotating counterclockwise, causing the lifting plate 7 to move upward by 45°. Figure 7 As shown;

[0054] The drive shaft 6-1 continues to rotate 90° counterclockwise. Simultaneously, the first bushing of the rotary transmission block 6-2 drives the second bushing to rotate back to the 3 o'clock position of the drive shaft 6-1. The second bushing of the rotary transmission block 6-2 moves back to the right half of the connecting rod 6-3. The insert rod drives the connecting rod 6-3 to rotate clockwise, causing the lifting plate 7 to return to its initial horizontal position. Figure 4 As shown, the lifting device has now completed the entire lifting process.

[0055] The purpose of this design is to allow the lifting plate 7 to swing up and down, breaking up the fuel falling from above and throwing it outwards. This ensures that the fuel remains evenly dispersed when it enters the furnace, allowing it to burn more completely and efficiently, especially light fuels (such as waste textiles) under the influence of the tertiary air and compressed air from the air cannon, which in turn helps maintain a near-suspended state. During operation, the fuel status should be observed, and the swing frequency of the lifting plate 7 should be adjusted by controlling the motor speed.

[0056] The incineration fixed bed is located at the lower part of the fluidized bed furnace body and is an inclined fixed bed plate 4-1, which is inclined at a 30° angle to the horizontal plane. The fixed bed plate 4-1 has multiple stepped sections, which are cast from high-temperature and wear-resistant materials. Each section is equipped with a compressed air nozzle 13, including an upper shell and a lower shell. The upper shell and the lower shell form an angle of 20-35°, which is funnel-shaped to prevent fuel from entering the nozzle and causing blockage. The fan angle width of the compressed air nozzle 13 can be selected according to the width of the furnace body, generally 400-600mm. To ensure uniform airflow dispersion, the fan angle is best at 35-50°. Multiple flow guide baffles 13-1 are set between the upper shell and the lower shell, which divide the nozzle into multiple flow channels according to the nozzle width to enhance the compressed air injection effect.

[0057] The air cannon system includes multiple air cannons and an air storage tank 14. The air storage tank 14 is connected to the air cannons, and the air cannons are connected to the air inlets of the compressed air nozzles 13. By blowing compressed air through the air cannons, the fuel can be pushed forward from the front of the fluidized bed furnace to complete the drying, ignition, combustion, and burnout of the fuel. Finally, the ash and slag enter the decomposition furnace.

[0058] The gas source pressure of the gas storage tank 14 is 0.2-0.8 MPa. A valve is installed at the gas outlet of the gas storage tank 14, and the valve actuation pressure is 0.2-0.4 MPa. The capacity of the gas storage tank 14 varies slightly depending on its location. For example, the capacity of the gas storage tank 14 located at the alternative fuel inlet is 90L, the capacity of the gas storage tank 14 located in the middle of the furnace body is 70L, and the capacity of the gas storage tank 14 located at the furnace outlet is 90L.

[0059] The air cannons at the front of the furnace (the first 5 sections) are activated sequentially at 10-second intervals, the air cannons in the middle (6 sections) are activated sequentially at 15-20-second intervals, and the air cannons at the rear (2 sections) are activated sequentially at 10-second intervals. At the front of the furnace where fuel tends to accumulate and at the furnace outlet, the valve operating pressure can be appropriately increased (0.3-0.4 MPa). The alternative fuel at the front of the furnace and unburned material at the furnace outlet are prone to accumulation. Increasing the frequency and air pressure of the air cannons at these locations ensures the fuel is fully dispersed and suspended, guaranteeing combustion efficiency. Simultaneously, it also promptly blows unburned material into the decomposition furnace, preventing accumulation and coking at the furnace outlet.

[0060] The fluidized bed furnace body is equipped with multiple temperature and pressure measuring points 9 and a cold air inlet 10. The temperature and pressure measuring points 9 can detect the temperature and pressure inside the furnace during operation, and the cold air inlet 10 can blow in cold air to control the combustion temperature when the furnace temperature is too high.

[0061] The front of the fluidized bed furnace body is also provided with a manhole 11 for easy maintenance.

[0062] The fluidized bed furnace body is located on the upper side of each section of the combustion fixed bed and is equipped with inspection doors 12, which can be used to observe and intervene in the fuel combustion status and material accumulation. At the same time, the opening frequency and pressure setting of the air cannon can also be adjusted in a timely manner by observing the fuel status through the inspection doors.

[0063] The working process of a fluidized bed boiler:

[0064] (1) Alternative fuels (waste textiles, garbage, etc.) enter the furnace after being lifted by the lifting device through the alternative fuel inlet and come into contact with hot air to start burning. The fuel falling on the inclined fixed bed plate 4-1 is continuously rolled by compressed air and floats and burns in the furnace. It passes through each stage in sequence. After burning out, the ash and flue gas enter the decomposition furnace with the tertiary air.

[0065] (2) Each section is equipped with a compressed air nozzle 13, and the air cannon sprays compressed air into the furnace at a set frequency;

[0066] (3) Hot air at 850~950℃ enters the furnace through the tertiary air interface to provide sufficient oxygen and combustion temperature for fuel combustion, and ensures the residence time of fuel combustion in the furnace at the designed flow rate;

[0067] (4) When the furnace temperature is too high (>1050℃) due to the use of high-calorific-value alternative fuel (waste textiles), cold air is blown in through the cold air inlet to reduce the furnace temperature and prevent overheating and coking. If the introduction of cold air still cannot guarantee a suitable furnace temperature, raw materials are added through the C4 raw material inlet to further reduce and control the furnace temperature.

[0068] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A fluidized bed furnace for alternative fuel combustion in cement kilns, characterized in that, The fluidized bed furnace body is provided with a substitute fuel inlet at the top of the fluidized bed furnace body. A lifting device is provided at the substitute fuel inlet. The lifting device includes a drive motor (5), a transmission mechanism (6), a lifting plate (7) and a heat insulation cover (8). The transmission mechanism (6) connects the drive motor (5) located outside the furnace and the lifting plate (7) inside the furnace. The heat insulation cover (8) is located on the outside of the transmission mechanism (6) as its support and protection. The drive motor (5) drives the transmission mechanism (6) to make the lifting plate (7) swing up and down.

2. The fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 1, characterized in that, The transmission mechanism (6) includes a drive shaft (6-1), a rotary transmission block (6-2), a connecting rod (6-3), a fixed shaft (6-4), and a transmission shaft (6-5). One end of the drive shaft (6-1) is connected to the output shaft of the drive motor (5). The rotary transmission block (6-2) rotatably connects the drive shaft (6-1) and the connecting rod (6-3). Both ends of the connecting rod (6-3) are fixed to the transmission shaft (6-5) through the fixed shaft (6-4). The transmission shaft (6-5) is fixedly connected to the lifting plate (7). The connecting rod (6-3) rotates with the rotary transmission block (6-2) to drive the lifting plate (7) to swing up and down.

3. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 2, characterized in that, The rotary transmission block (6-2) includes a first bushing, a second bushing, and a connecting block connecting the first bushing and the second bushing. The first bushing and the second bushing are arranged perpendicular to each other. The first bushing is fixed to the end of the drive shaft (6-1). The second bushing is provided with a plug rod. The connecting rod (6-3) is provided with a sliding groove. The second bushing is sleeved on the connecting rod (6-3) and the plug rod is inserted into the sliding groove of the connecting rod (6-3).

4. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 1, characterized in that, It also includes a fixed incineration bed, which is located at the bottom of the fluidized bed furnace body. It includes an inclined fixed bed plate (4-1) and multiple stepped sections. Each section is equipped with a compressed air nozzle (13), which is connected to an air cannon and a gas storage tank (14).

5. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 4, characterized in that, The fixed bed board (4-1) is inclined at a 30° angle to the horizontal plane.

6. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 4, characterized in that, The compressed air nozzle (13) includes an upper housing and a lower housing, and a plurality of flow guide baffles (13-1) are provided between the upper housing and the lower housing.

7. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 6, characterized in that, The compressed air nozzle (13) is trumpet-shaped, with the upper housing and lower housing forming an angle of 20 to 35°, and the fan angle being 35 to 50°.

8. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 1, characterized in that, The fluidized bed furnace body includes a furnace wall (1) and a furnace shell (2) located outside the furnace wall (1). The furnace wall (1) includes, from the inside to the outside, a casting layer (1-1), an insulation layer (1-2), and a calcium silicate board layer (1-3).

9. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 1, characterized in that, The top of the fluidized bed furnace body is also provided with a C4 raw material inlet, and a material spillage buffer (3) is provided at the C4 raw material inlet.

10. A fluidized bed furnace for alternative fuel combustion in cement kilns according to claim 1, characterized in that, The front end of the fluidized bed furnace body is provided with a tertiary air inlet, and the rear end is provided with a flue gas outlet.

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