System for disposing alternative fuel based on cement kiln

Abstract

The invention provides a system for disposing alternative fuel based on a cement kiln, comprising: a preheating mechanism suitable for preheating a raw material to obtain a hot raw material; the conversion mechanism is suitable for containing alternative fuel and heating the alternative fuel to a preset temperature at which combustible gas and solid products are generated; and the decomposition mechanism is communicated with the preheating mechanism and the conversion mechanism and is suitable for accommodating combustible gas for combustion so as to calcine the hot raw material and the solid product to form a decomposition product.

Description

Technical Field

[0001] This disclosure relates to the cement production sector, and more particularly to a system for disposing of alternative fuels in cement kilns. Background Technology

[0002] As one of the industries with the highest carbon emissions, the cement industry faces enormous pressure to reduce carbon emissions. Traditional cement kiln fuels, such as fossil fuels like coal, not only have high carbon emissions but also cause serious environmental pollution problems. Therefore, developing and applying alternative fuel technologies has become an important measure for energy conservation and carbon reduction in the cement industry.

[0003] With continuous technological advancements, cement kiln alternative fuel combustion systems have achieved efficient combustion of various alternative fuels. Waste textiles, biomass, waste plastics, and waste screenings from municipal solid waste can be fed into cement kilns for combustion, replacing traditional fossil fuels. This system not only solves the problem of solid waste disposal but also reduces fossil fuel consumption in cement kiln production lines. However, currently, cement kilns primarily use alternative fuels by pre-treating them before adding them to the precalciner or directly adding them to an external furnace. These methods suffer from low thermal efficiency or increased NOx emissions. Summary of the Invention

[0004] In view of this, the present disclosure provides a system for disposing of alternative fuels based on cement kilns.

[0005] The system for disposing of alternative fuels based on cement kilns provided in this disclosure includes: a preheating mechanism suitable for preheating raw materials to obtain hot raw materials; a conversion mechanism suitable for containing alternative fuels and heating the alternative fuels to a preset temperature for generating combustible gases and solid products; and a decomposition mechanism, which is connected to the preheating mechanism and the conversion mechanism respectively, and is suitable for containing combustible gases for combustion to calcine the hot raw materials and solid products to form decomposition products.

[0006] According to embodiments of this disclosure, the preheating mechanism is also connected to the conversion mechanism and is suitable for heating alternative fuels to a preset temperature using the heat of the hot raw materials.

[0007] According to embodiments of this disclosure, a dispensing valve is also included, suitable for distributing at least a portion of the hot raw material to the conversion mechanism to regulate the temperature within the conversion mechanism.

[0008] According to embodiments of this disclosure, the conversion mechanism includes a rotary kiln to simultaneously feed the alternative fuel and hot raw materials into the decomposition mechanism while the alternative fuel generates combustible gas.

[0009] According to embodiments of this disclosure, an air intake mechanism is also included, which is connected to the conversion mechanism and is adapted to adjustably blow air into the conversion mechanism to cause the alternative fuel to undergo pyrolysis and / or gasification reactions to produce combustible gas.

[0010] According to an embodiment of this disclosure, a first pipeline and a second pipeline are provided between the conversion mechanism and the decomposition mechanism. The first pipeline is suitable for conveying combustible gas to the decomposition mechanism, and the second pipeline is suitable for conveying hot raw materials and solid products to the decomposition mechanism.

[0011] According to embodiments of this disclosure, the preheating mechanism includes two preheating units, at least one of which is connected to the conversion mechanism.

[0012] According to embodiments of this disclosure, it also includes a calcination mechanism adapted to calcine the decomposition products into clinker.

[0013] According to an embodiment of the present disclosure, each preheating unit includes a preheating section, which is located upstream of the decomposition mechanism according to the conveying direction of the raw material, and is suitable for performing step-by-step preheating of the raw material; and a separation section, which is located between the decomposition mechanism and the calcination mechanism, and is suitable for conveying the decomposition products generated in the decomposition mechanism (3) to the calcination structure, and is also suitable for returning the flue gas generated by the decomposition mechanism and / or the calcination mechanism to the preheating section.

[0014] According to embodiments of this disclosure, it further includes: a burner disposed within the calcination mechanism and connected to the conversion mechanism for burning combustible gas.

[0015] According to the system for treating alternative fuels based on cement kilns provided in this disclosure, the raw materials are preheated by a preheating mechanism, and the alternative fuels are heated to a preset temperature by a conversion mechanism. This can evaporate excess moisture and generate high-temperature and reducible combustible gases and solid products. While improving the heat utilization rate, the reducible combustible gases can also remove NOx from the decomposition mechanism, thereby reducing NOx generation. Attached Figure Description

[0016] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 A block diagram illustrating a system for handling alternative fuels in a cement kiln according to an embodiment of the present disclosure is shown schematically; and

[0018] Figure 2 A schematic diagram of a cement kiln-based alternative fuel disposal system according to another embodiment of the present disclosure is shown.

[0019] Figure Labels

[0020] 1. Preheating mechanism;

[0021] 11. Preheating section;

[0022] 12. Separation section;

[0023] 2. Transformation institutions;

[0024] 3. Disassembly mechanism;

[0025] 4. Air intake mechanism;

[0026] 5. Feeding mechanism;

[0027] 6. Calcination mechanism. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0030] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0031] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0032] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0033] In related technologies, cement kilns can process alternative fuels in the following ways. First, after pretreatment such as crushing and screening, the alternative fuel is directly fed into the decomposition furnace for combustion. However, this method suffers from high energy consumption and operating costs due to some alternative fuels being in large pieces before entering the plant. Furthermore, the high moisture content and long burnout time of most alternative fuels can lead to incomplete combustion, affecting the normal calcination of cement clinker. Second, the alternative fuel is directly fed into external furnaces such as hot pan furnaces or stepped furnaces. Combustion occurs within these external furnaces, and the resulting high-temperature flue gas enters the decomposition furnace, where the alternative fuel undergoes a combustion reaction, releasing a large amount of heat, which is absorbed by the raw materials. However, this method suffers from uneven temperature distribution within the external furnaces and high NOx emissions. Third, after simple pretreatment, the alternative fuel is fed into furnace types such as bubbling bed furnaces or circulating fluidized bed furnaces. Gasification occurs in these furnaces, and the resulting CO, H2, and other combustible gases, along with the ash from the alternative fuel, are fed into the decomposition furnace. This method usually involves directly blowing cold air into the gasifier. However, once the blown-in cold air enters the kiln system, it will increase the system's heat consumption and reduce the heat utilization efficiency of the alternative fuel.

[0034] Figure 1 An overall block diagram of a system for disposing of alternative fuels in a cement kiln, according to an embodiment of the present disclosure, is shown schematically.

[0035] According to the system for disposing of alternative fuels based on cement kilns provided in this disclosure, such as Figure 1 As shown, it includes a preheating mechanism 1, a conversion mechanism 2, and a decomposition mechanism 3. The preheating mechanism 1 is used to preheat raw materials to obtain hot raw materials. The conversion mechanism 2 is used to contain alternative fuels and heat them to a preset temperature for producing combustible gases and solid products. The decomposition mechanism 3 is connected to the preheating mechanism 1 and the conversion mechanism 2, and is used to contain combustible gases for combustion to calcine the hot raw materials and solid products to form decomposition products.

[0036] In some embodiments, the preheating unit 1 can utilize the waste heat from a cement kiln or other heat source to preheat the raw meal to a preset temperature, thereby converting it into hot raw meal. Raw meal is the original material in the cement manufacturing process, including limestone, clay, and other minerals.

[0037] In some embodiments, alternative fuels include, but are not limited to, biomass, waste plastics, waste tires, waste textiles, sludge, medical waste, waste textiles, coal-based solid waste, biomass, municipal solid waste, etc.

[0038] In some embodiments, the alternative fuel is heated to a preset temperature in the conversion unit 2. The preset temperature may be sufficient to cause the fuel to undergo pyrolysis or gasification, thereby producing combustible gases and solid products. Combustible gases include carbon monoxide, hydrogen, methane, etc. Solid products include combustible carbonaceous solids (such as carbon black) and non-combustible solids (such as ash). The decomposition unit 3 can accommodate the combustion of combustible gases and combustible carbonaceous solids.

[0039] In some embodiments, the decomposition mechanism 3 can be a decomposition furnace, in which combustible gas is burned to generate high temperatures, and the raw materials undergo a decomposition reaction under high temperatures to obtain decomposition products. The decomposition products include the decomposition of calcium carbonate into carbon dioxide, calcium oxide, and other compounds.

[0040] In this implementation, the raw material is preheated by the preheating mechanism 1, and the alternative fuel is heated to a preset temperature by the conversion mechanism 2. This can evaporate the excess water in the alternative fuel and generate high-temperature and reducible combustible gas and solid products. While improving the heat utilization rate, the reducible combustible gas can also remove NOx from the decomposition mechanism and reduce NOx generation.

[0041] According to embodiments of this disclosure, such as Figure 1 As shown, the preheating mechanism 1 can also be connected to the conversion mechanism 2, which is suitable for heating alternative fuels to a preset temperature using the heat of the hot raw materials.

[0042] According to embodiments of this disclosure, the system further includes a distributing valve adapted to distribute at least a portion of the hot raw material to the conversion mechanism 2 to regulate the temperature within the conversion mechanism 2.

[0043] In this implementation, the preheated raw material has a higher temperature. By heating the raw material to replace fuel, the overall thermal efficiency of the system can be improved. Controlling the flow rate of the raw material via a distribution valve allows for flexible adjustment of the temperature within the conversion mechanism 2.

[0044] In some embodiments, a connecting pipe is provided between the preheating mechanism 1 and the conversion mechanism 2, and between the preheating mechanism 1 and the decomposition mechanism 3, and a distributing valve can be installed on the connecting pipe. A portion of the hot raw material is fed into the preheating mechanism 1 through the distributing valve and the connecting pipe to mix with the alternative fuel, thereby heating the alternative fuel with the hot raw material. A portion of the hot raw material is directly fed into the decomposition mechanism 3 through the distributing valve and the connecting pipe for calcination.

[0045] In some implementations, the amount of hot raw material input into the conversion mechanism does not exceed 50% of the total amount of hot raw material, in order to ensure normal temperature distribution within the decomposition structure 3 and prevent local high temperatures that could affect the decomposition efficiency of the hot raw material in the decomposition mechanism 3.

[0046] In some embodiments, the amount of hot raw material fed to the conversion unit 2 can be controlled according to the amount of alternative fuel disposed of, and then the amount of hot raw material input can be adjusted through the distribution valve according to the temperature of the conversion unit 2. When the temperature inside the conversion unit 2 needs to be increased, the opening of the distribution valve to the conversion unit 2 can be increased, allowing more hot raw material to flow into the conversion unit 2, thereby increasing its temperature. Conversely, when the temperature needs to be decreased, the opening of the distribution valve to the conversion unit 2 can be decreased.

[0047] For example, waste textiles can be used as alternative fuel, with a disposal rate of 5-20 t / h. The reaction temperature is controlled by adjusting the ratio of hot raw materials based on the disposal rate of the alternative fuel. For instance, if the reaction temperature of waste textiles is controlled at 500℃, and the consumption rate is 5 t / h, the hot raw material consumption rate is approximately 15 t / h. The hot raw material consumption rate can be adjusted according to the monitored reaction temperature. When the temperature is below 500℃, the opening of the dispensing valve to the conversion mechanism 2 can be increased to increase the hot raw material consumption rate; conversely, when the temperature is above 500℃, the opening of the dispensing valve to the conversion mechanism 2 can be decreased to reduce the hot raw material consumption rate. When the waste textile consumption rate is 10 t / h, the hot raw material consumption rate can be increased to approximately 30 t / h by adjusting the opening of the dispensing valve.

[0048] According to an embodiment of this disclosure, a first pipeline and a second pipeline are provided between the conversion mechanism 2 and the decomposition mechanism 3. The first pipeline is suitable for conveying combustible gas to the decomposition mechanism 3, and the second pipeline is suitable for conveying hot raw materials and solid products to the decomposition mechanism 3.

[0049] In some embodiments, only one pipeline may be provided between the conversion mechanism 2 and the decomposition mechanism 3 to input the combustible gas and solid products into the decomposition mechanism 3 together.

[0050] According to an embodiment of this disclosure, the conversion mechanism 2 includes a rotary kiln to simultaneously feed the alternative fuel and hot raw materials into the decomposition mechanism 3 while the alternative fuel generates combustible gas.

[0051] In this implementation, a rotary kiln is used as the conversion mechanism 2. Based on the different processing volumes of alternative fuels, the residence time of the alternative fuel in the conversion mechanism 2 can be adjusted by the rotation speed of the rotary kiln, thereby facilitating the temperature control in the conversion mechanism 2.

[0052] For example, using waste textiles as alternative fuel, the actual processing capacity is 5-20 t / h, depending on the supply of alternative fuel. The rotary kiln can be 15 m long, 3.8 m inner diameter, 3.0° angle, and its rotation speed is adjustable from 0.5-5 rpm. With the same alternative fuel, the larger the feed rate, the faster the rotary kiln rotates to maintain a constant filling rate. For instance, when the waste textile processing capacity is 10 t / h, the rotary kiln rotation speed is 1 rpm, and the filling rate is approximately 14%; when the processing capacity reaches 20 t / h, the rotary kiln rotation speed is 2 rpm, and the filling rate is also approximately 14%.

[0053] In some embodiments, the conversion mechanism 2 may also be a fluidized bed, a fixed bed, or other similar device. The fluidized bed or fixed bed is used to heat the alternative fuel to a preset temperature, generating combustible gas and solid products.

[0054] According to embodiments of this disclosure, such as Figure 1 As shown, the system also includes an air intake mechanism 4, which is connected to the conversion mechanism 2 and is adapted to adjustably blow air into the conversion mechanism 2 so that the alternative fuel undergoes pyrolysis and / or gasification reactions to produce combustible gas.

[0055] Specifically, when air is blown into the conversion mechanism 2 through the air intake mechanism 4, the alternative fuel undergoes a gasification or partial gasification reaction, producing combustible gases (CO, H2, CH4, etc.) and solid products. When air is not blown into the conversion mechanism 2, the alternative fuel undergoes a pyrolysis reaction, producing combustible gases (CO, H2, etc.) and solid products.

[0056] In this implementation, by controlling the air intake mechanism 4 to blow air into the conversion mechanism 2, the alternative fuel undergoes a gasification reaction to generate reducing combustible gas, thus achieving denitrification. Simultaneously, the amount of air blown in can be reduced or even eliminated, allowing the alternative fuel to undergo a pyrolysis reaction, also generating reducing combustible gas. While achieving denitrification, the reduced use of cold air improves the system's thermal efficiency.

[0057] In some embodiments, whether or not air is blown into the conversion unit 2 can be determined based on the type of alternative fuel. For example, when the alternative fuel is organic solid waste such as biomass, waste plastics, waste tires, waste textiles, sludge, or medical waste, air may not be blown into the conversion unit 2, allowing the alternative fuel to primarily undergo a pyrolysis reaction. When the alternative fuel is coal-based solid waste, biomass, or municipal solid waste, air may be blown into the conversion unit 2, allowing the alternative fuel to primarily undergo a gasification reaction, and the amount of air blown in can be determined based on the amount of alternative fuel disposed of, its calorific value, and its content.

[0058] In some embodiments, such as Figure 1As shown, the system also includes a feeding mechanism 5, which is suitable for feeding alternative fuel into the conversion mechanism 2. The feeding mechanism 5 and the conversion mechanism 2 can be connected by a three-gate valve, a screw feeder, a belt conveyor, etc., to feed alternative fuel into the conversion mechanism 2.

[0059] In some embodiments, such as Figure 1 As shown, the preheating mechanism can be equipped with a preheating unit, which includes a preheating section 11 and a separation section 12. The preheating section is located upstream of the decomposition mechanism 3, according to the raw material conveying direction, and is suitable for staged preheating of the raw material. The separation section 12 is located between the decomposition mechanism 3 and the calcination mechanism 6, and is suitable for conveying the decomposition products generated in the decomposition mechanism 3 to the calcination mechanism 6; it is also suitable for recirculating the flue gas generated by the decomposition mechanism 3 and / or the calcination mechanism 6 back to the preheating section 11.

[0060] Specifically, the preheating section 11 includes multiple preheaters connected in sequence (such as...). Figure 1 Preheaters A, B, C, and D are shown. The last stage preheater of preheating section 11 (i.e., Figure 2 The preheater (D) is connected to both the conversion mechanism 2 and the decomposition mechanism 3. The raw material entering the kiln at room temperature is first fed into preheater A, where it exchanges heat with and separates from the high-temperature flue gas before entering the second-stage preheater B. This process continues until the raw material separated in the fourth-stage preheater D reaches a temperature of 740-800℃. Part of the hot raw material exiting the fourth-stage preheater D enters the conversion mechanism 2 through a distribution valve, while the other part enters the decomposition mechanism 3.

[0061] The separation section 12 is located downstream of the decomposition mechanism 3. The separation section 12 may only have one preheater (e.g., Figure 1 The preheater E is shown. Preheater E is connected to the decomposition mechanism 3 and receives the decomposition products and combustion flue gas from the decomposition mechanism 3. Preheater E can return the flue gas to preheater D, using the flue gas preheating to preheat the raw materials in reverse. Preheater E also conveys the decomposition products to the calcination mechanism 6. Simultaneously, the calcination mechanism 6 can return the combustion flue gas to the decomposition mechanism 3 and preheater E to fully utilize the waste heat of the flue gas to preheat the raw materials.

[0062] In some embodiments, the preheater may be a suspension preheater, a cyclone preheater, a vertical cylinder preheater, or a combined preheater.

[0063] Figure 2 A schematic diagram of a cement kiln-based alternative fuel disposal system according to another embodiment of the present disclosure is shown.

[0064] According to embodiments of this disclosure, such as Figure 2As shown, the preheating mechanism 1 includes two preheating units, at least one of which is connected to the conversion mechanism 2.

[0065] Specifically, such as Figure 2 As shown, the two preheating units are connected in parallel to the decomposition mechanism. The preheating section 11 of one of the preheating units is also connected to the conversion mechanism 2, and a portion of the hot raw material is input into the conversion mechanism 2 and a portion of the hot raw material is input into the decomposition mechanism 3. The other preheating unit is not connected to the conversion mechanism and inputs all the hot raw material into the decomposition mechanism.

[0066] In some implementations, the preheating sections 11 of both preheating units can be connected to the conversion mechanism 2. When a large amount of material needs to be processed or the preheating efficiency needs to be improved, both preheaters can be used at the same time. When production demand is low, one of the preheaters can be used alone, thereby achieving optimal resource allocation.

[0067] According to embodiments of this disclosure, such as Figure 1 and 2 As shown, the system also includes a calcination mechanism 6, which is suitable for calcining decomposition products into clinker.

[0068] In some embodiments, the calcining mechanism 6 can be a rotary kiln, which can be connected to the decomposition mechanism 3. It can receive the decomposition products generated from the reaction in the decomposition mechanism 3, and can simultaneously introduce pulverized coal fuel and high-temperature secondary air into the calcining mechanism 6 for combustion, thereby calcining the decomposition products in one step to finally obtain clinker.

[0069] According to embodiments of this disclosure, the combustion system further includes a burner disposed within a calcination mechanism and connected to a conversion mechanism for burning combustible gas.

[0070] In some embodiments, in order to ensure the stable operation of the system and the quality of cement clinker, the calcining unit 6 can be connected to the conversion unit 2 or other high-temperature fuel supply units in addition to the conventional fuel supply unit, so as to simultaneously supply high-temperature combustible gas fuel and conventional pulverized coal fuel, and utilize the high-temperature combustible gas fuel and the normal-temperature pulverized coal fuel to calcine the decomposition products.

[0071] Understandably, because the combustible gas in conversion unit 2 has a high temperature, while the pulverized coal fuel is at room temperature, the temperature difference between the two is significant. Therefore, after the combustible gas and pulverized coal fuel are injected into calcination unit 6, they have different combustion rates. Due to the large difference in combustion rates between different fuels at different temperatures, the high-temperature fuel will form a short flame and burn rapidly, while the low-temperature fuel will have an excessively long flame, resulting in flame segmentation and affecting the calcination effect of cement clinker.

[0072] Based on the above problems, the burner of this embodiment is configured as a multi-channel burner, comprising a burner body. The burner body is provided with a first fuel channel and a second fuel channel. The first fuel channel can be connected to a conventional fuel supply mechanism, suitable for injecting room-temperature pulverized coal into the calcining mechanism 6. The second fuel channel can be connected to a conversion mechanism 2 or other high-temperature fuel supply mechanism, suitable for injecting combustible gas from the conversion mechanism 2 or other high-temperature fuel supply mechanism into the calcining mechanism 6, wherein the injection velocity of the combustible gas can be configured to be greater than the injection velocity of the pulverized coal.

[0073] In this embodiment, the first fuel channel and the second fuel channel can simultaneously deliver combustible gas and pulverized coal fuel to the calcining mechanism 6 for ignition. The injection speed of the combustible gas is set to be higher than that of the pulverized coal fuel, so that the combustible gas fuel is rapidly injected forward, thereby lengthening the flame and making the combustion process more stable and uniform, thus avoiding the phenomena of local overheating and short flame burning.

[0074] The burner body is also equipped with a swirl duct, an axial flow duct, and a cooling duct. The swirl duct is located inside the first combustion channel of the burner body and is connected to an external air source to form a swirling airflow around the burner body. The axial flow duct is located between the first fuel channel and the second fuel channel of the burner body and is connected to an external air source to form an axial flow airflow around the burner body.

[0075] By placing the axial flow duct between the first fuel channel and the second fuel channel, a negative pressure is created in the space near the axial flow duct to entrain combustible gas and pulverized coal fuel. At the same time, the swirling air ejected from the swirling channel generates a strong centrifugal force during its flow. The centrifugal force will entrain the surrounding fluid into the swirling air, so that the combustible gas and pulverized coal fuel are fully mixed with the air. Thus, the combustible gas is used to heat the pulverized coal fuel, thereby increasing the combustion rate of the pulverized coal fuel and achieving a match between the combustion rates of the combustible gas and the pulverized coal fuel.

[0076] In some embodiments, the burner can be configured as a sleeve structure, with the burner body including a first cylinder, a second cylinder, and a third cylinder. The second cylinder is sleeved outside the first cylinder, and the space between the first and second cylinders forms a first fuel passage. The third cylinder is sleeved outside the second cylinder, and the space between the second and third cylinders forms a second fuel passage. The first cylinder has a plurality of swirling holes arranged circumferentially, each swirling hole extending axially along the first cylinder to form a swirling air duct. The second cylinder has a plurality of axial flow holes arranged circumferentially, each axial flow hole extending axially along the second cylinder to form an axial flow air duct. A cooling air duct can be located in the middle of the first cylinder and can communicate with an external cold air source.

[0077] In this embodiment, the burner is configured as a five-channel structure including a first fuel channel, a second fuel channel, an axial flow duct, a swirl flow duct, and a cooling duct. The second fuel channel, which injects high-temperature combustible gas, is located on the outermost side. The injection velocity of the high-temperature combustible gas is greater than that of the normal-temperature pulverized coal fuel. This allows for balanced combustion of fuels at different temperatures, such as high-temperature fuel and normal-temperature fuel, ensuring the quality of clinker calcination.

[0078] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A system for disposing of alternative fuels in cement kilns, characterized in that, include: The preheating mechanism (1) is suitable for preheating raw materials to obtain hot raw materials; The conversion mechanism (2) is adapted to contain alternative fuel and heat the alternative fuel to a preset temperature to generate combustible gas and solid products; The decomposition mechanism (3) is connected to the preheating mechanism (1) and the conversion mechanism (2) respectively, and is suitable for containing combustible gas combustion to calcine the hot raw materials and the solid products to form decomposition products.

2. The system according to claim 1, characterized in that, The preheating mechanism (1) is also connected to the conversion mechanism (2) and is suitable for heating the alternative fuel to the preset temperature by the heat of the hot raw material.

3. The system according to claim 2, characterized in that, It also includes a distribution valve, which is suitable for distributing at least a portion of the hot raw material to the conversion mechanism (2) to regulate the temperature within the conversion mechanism (2).

4. The system according to claim 2, characterized in that, The conversion mechanism (2) includes a rotary kiln to simultaneously feed the alternative fuel and the hot raw material into the decomposition mechanism (3) when the alternative fuel generates combustible gas.

5. The system according to claim 1, characterized in that, It also includes an air intake mechanism (4) connected to the conversion mechanism (2) and adapted to adjustably blow air into the conversion mechanism (2) to cause the alternative fuel to undergo pyrolysis and / or gasification reactions to produce the combustible gas.

6. The system according to any one of claims 1 to 5, characterized in that, A first pipeline and a second pipeline are provided between the conversion mechanism (2) and the decomposition mechanism (3). The first pipeline is used to transport the combustible gas to the decomposition mechanism (3), and the second pipeline is used to transport the hot raw material and the solid product to the decomposition mechanism (3).

7. The system according to any one of claims 1 to 5, characterized in that, The preheating mechanism (1) includes two preheating units, at least one of which is connected to the conversion mechanism (2).

8. The system according to claim 7, characterized in that, It also includes a calcination mechanism (6) suitable for calcining the decomposition products into a mature product.

9. The system according to claim 8, characterized in that, Each of the preheating units includes, The preheating section (11) is located upstream of the decomposition mechanism (3) according to the conveying direction of the raw material, and is suitable for performing step-by-step preheating of the raw material; The separation section (12) is disposed between the decomposition mechanism (3) and the calcination mechanism (6), and is adapted to transport the decomposition products generated in the decomposition mechanism (3) to the calcination mechanism (6), and is also adapted to return the flue gas generated by the decomposition mechanism (3) and / or the calcination mechanism (6) to the preheating section (11).

10. The system according to claim 8, characterized in that, Also includes: A burner is disposed within the calcination mechanism (6) and connected to the conversion mechanism (2) to burn the combustible gas.

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