A combustion control method for waste spinning substitute fuel of a cement kiln decomposing furnace

Abstract

The application discloses a kind of waste spinning alternative fuel combustion control method for cement kiln decomposing furnace, comprising the following steps: waste textile raw material is treated to obtain shaped alternative fuel;Shaped alternative fuel is transported to multiple independent fuel branch, and the terminal pulverizing device of independently adjustable speed is set on each fuel branch, and outlet end is connected to material injection pipe, and the outlet end of material injection pipe corresponds to a combustion area in decomposing furnace;At least one set of sensors is installed in each combustion area for real-time acquisition of combustion state parameters;According to the deviation between the combustion state parameters collected in real time in each combustion area and the set target range, at least one of the following control adjustments is performed: feed amount of material injection pipe;Particle size of fuel fed into material injection pipe;Fuel injection angle and / or speed of material injection pipe;Angle of guide vane at the inlet of three-stage air of decomposing furnace.The application can improve the stability of waste spinning as alternative fuel in the combustion in decomposing furnace and reduce pollutant emissions.

Description

Technical Field

[0001] This invention relates to the field of waste textile treatment technology, and more specifically to a combustion control method for waste textile alternative fuels used in cement kiln decomposition furnaces. Background Technology

[0002] With increasing global emphasis on sustainable development and environmental protection, the recycling of waste textiles has become a research hotspot. Converting waste textiles into alternative fuels (such as RDF) for use in cement kiln decomposition furnaces can solve the problem of waste textile disposal and reduce fossil fuel consumption.

[0003] However, in existing technologies, waste textiles as alternative fuels have the following prominent problems: First, the morphology, calorific value, and moisture content of waste textiles fluctuate greatly, leading to unstable combustion after entering the decomposition furnace, causing temperature fluctuations, incomplete combustion, and the generation of reducing gases (such as carbon monoxide); Second, waste textiles cannot achieve the fineness of coal powder, making them prone to incomplete combustion in localized areas. The high concentration of carbon monoxide produced interferes with the ammonia denitrification reaction, increases ammonia consumption, and triggers calcium sulfate reduction, leading to crusting, blockage, and increased sulfur oxide emissions; In addition, the loose and low bulk density of waste textiles poses a risk of spontaneous combustion during storage, and the fuzzy dust generated during processing poses a risk of explosion. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a combustion control method for waste textile alternative fuel used in cement kiln decomposition furnaces, which can improve the combustion stability of waste textiles as alternative fuel in the decomposition furnace and reduce pollutant emissions.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for combustion control of waste textile alternative fuel for cement kiln decomposition furnaces includes the following steps:

[0007] Waste textile raw materials are subjected to impurity removal, primary coarse crushing, secondary fine crushing, moisture and calorific value homogenization, and molding treatment in sequence to obtain molded alternative fuel and store it.

[0008] The shaped alternative fuel is delivered by a distributor to multiple independent fuel branches. Each fuel branch is equipped with a final crushing device with independently adjustable rotation speed, and the outlet end of each fuel branch is connected to a spray pipe. Multiple combustion zones are divided within the decomposition furnace, with the outlet end of each spray pipe corresponding to one combustion zone within the decomposition furnace. The outlet ends of different spray pipes are distributed at different heights and circumferential positions within the decomposition furnace. At least one set of sensors is installed in each combustion zone within the decomposition furnace to collect combustion state parameters of that combustion zone in real time. The combustion state parameters include carbon monoxide concentration, temperature, and oxygen concentration.

[0009] For each combustion zone, a target range for the combustion state parameters of that combustion zone is set. Based on the deviation between the real-time collected combustion state parameters of each combustion zone and the target range set for that combustion zone, at least one of the following controls and adjustments are performed independently on each combustion zone: adjusting the feed rate of the corresponding injector pipe; adjusting the rotation speed of the final crushing device on the corresponding fuel branch to change the fuel particle size fed into the injector pipe; adjusting the fuel injection angle and / or speed of the corresponding injector pipe; adjusting the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to that combustion zone to change the air inlet direction and swirl intensity of that combustion zone.

[0010] The working principle of this invention is as follows: First, in the pretreatment stage, waste textiles are sequentially subjected to impurity removal, two-stage crushing, moisture and calorific value homogenization, and molding treatment. This process transforms waste textile raw materials with complex origins and fluctuating properties into molded alternative fuels with uniform size, stable moisture content, and stable calorific value. This pretreatment process ensures that the quality of the molded alternative fuel entering the decomposition furnace is controllable, reducing the fluctuation range of molded alternative combustion from the source.

[0011] Secondly, in the combustion control stage of the decomposition furnace, the shaped alternative fuel is divided into multiple independent combustion branches by a distributor. Each combustion branch is equipped with a final pulverizing device with independently adjustable rotation speed. This allows for online adjustment of the fed fuel particle size according to the actual needs of different combustion zones, achieving spatially differentiated distribution of combustion particle size. Simultaneously, each injection pipe corresponds to a combustion zone, and the outlets are distributed at different heights and circumferential positions within the decomposition furnace. Combined with independent sensors (carbon monoxide, temperature, oxygen) installed in each combustion zone, the combustion conditions of that zone can be acquired in real time.

[0012] Finally, based on the deviation between the combustion state parameters collected from each combustion zone and the set target range, several adjustment methods are available: adjusting the feed rate, adjusting the rotation speed of the final pulverizer to change the feed particle size, adjusting the fuel injection angle and / or velocity through the injector, and adjusting the angle of the guide vanes at the corresponding tertiary air inlet. The first three adjustments directly affect fuel supply characteristics, while adjusting the angle of the guide vanes at the corresponding tertiary air inlet affects the local flow field. Feed rate adjustment has a fast response, but over-adjustment may cause product quality issues; feed particle size adjustment has a slightly slower response but significantly impacts combustion dynamics; injection angle / velocity can change the fuel trajectory and residence time in the furnace; and the guide vane angle optimizes oxygen mixing by changing the local swirl intensity and airflow direction. The combined use of these four adjustment methods gives the control strategy multiple redundancies and synergistic optimization capabilities, enabling it to adapt to various operating conditions ranging from slight fluctuations to severe deviations.

[0013] In summary, this invention integrates pretreatment of waste textiles as alternative fuel, multi-path zoned feeding, online adjustment of feed particle size, adjustment of injection parameters, and adjustment of the tertiary air inlet guide vanes, achieving active control of the entire chain from raw materials to combustion. Compared with existing technologies, this solution significantly reduces carbon monoxide emissions and temperature fluctuations caused by fuel properties and uneven feeding, increases the replacement ratio of waste textiles with pulverized coal, and improves the combustion stability of waste textiles as alternative fuel in the decomposition furnace, while reducing pollutant emissions.

[0014] Preferably, the following target ranges are set for the combustion state parameters of each combustion zone: the concentration of carbon monoxide in each combustion zone is set not higher than a first concentration threshold, the concentration of oxygen in each combustion zone is set not lower than a first oxygen threshold, and the temperature in each combustion zone is set not lower than a first temperature threshold; wherein, the carbon monoxide parameter in the combustion state parameters has the first priority, the oxygen parameter has the second priority, and the temperature parameter has the third priority.

[0015] When the carbon monoxide concentration in a combustion zone exceeds the first concentration threshold, the first priority adjustment method is applied to that combustion zone.

[0016] When the concentration of carbon monoxide in a combustion zone is not higher than the first concentration threshold and the concentration of oxygen is lower than the first oxygen threshold, the second priority adjustment method is applied to the combustion zone.

[0017] When the carbon monoxide concentration in a combustion zone is not higher than the first concentration threshold, the oxygen concentration is not lower than the first oxygen threshold, and the temperature is lower than the first temperature threshold, the third priority adjustment method is applied to the combustion zone.

[0018] When multiple combustion state parameters in a certain combustion zone deviate from their respective target ranges at the same time, only the combustion state parameter with the highest priority is adjusted according to the method corresponding to its deviation from the target range.

[0019] In this way, by clearly defining the target ranges for each combustion state parameter and establishing a priority rule (carbon monoxide > oxygen > temperature), when multiple combustion state parameters deviate simultaneously, only the adjustment of the highest priority combustion state parameter is executed, avoiding mutual interference between different adjustment actions. This is because excessive carbon monoxide is a direct manifestation of incomplete combustion in the decomposition furnace, posing the greatest threat to cement kiln operation (affecting denitrification and triggering sulfur reduction), and therefore must be addressed first; insufficient oxygen is secondary, while the impact of temperature deviation is relatively small. This priority strategy enables the system to make correct decisions under complex operating conditions, improving the robustness and efficiency of regulation.

[0020] Preferably, each combustion zone in the decomposition furnace is set with its own independent first concentration threshold, first oxygen threshold, and first temperature threshold. The first concentration threshold of each combustion zone decreases sequentially from the bottom to the top of the decomposition furnace. The first oxygen threshold and first temperature threshold of each combustion zone are set in segments sequentially from the bottom to the top of the decomposition furnace. The variation range of the first concentration threshold of all combustion zones is 100-300 ppm, the variation range of the first oxygen threshold of all combustion zones is 2-5%, and the variation range of the first temperature threshold of all combustion zones is 850-1150°C.

[0021] At least three layers of sensors are installed in each combustion zone along the height of the decomposition furnace, and at least four sensors are evenly installed in each layer along the circumference of the decomposition furnace.

[0022] Thus, the first concentration threshold for carbon monoxide decreases from the bottom to the top of the decomposition furnace, while the first oxygen threshold and the first temperature threshold are set in segments. This is because the temperature field and component distribution within the decomposition furnace exhibit a gradient: the lower part has a strong reducing atmosphere and tends to have higher carbon monoxide levels, therefore the first carbon monoxide concentration threshold can be set higher; the upper part has a strong oxidizing atmosphere, higher oxygen levels, and higher temperatures, so the first oxygen threshold and the first temperature threshold should be adjusted according to the actual process. Simultaneously, the sensors are arranged in a grid, which ensures the representativeness of the monitoring and the resolution of the control, avoiding frequent malfunctions or response lags caused by a single threshold.

[0023] Preferably, the first priority adjustment method is as follows: firstly, by increasing the rotation speed of the final crushing device on the fuel branch corresponding to the combustion zone, the fuel particle size fed into the corresponding injection pipe is reduced; if the carbon monoxide concentration does not drop below the first concentration threshold within the set first time period, the feed rate of the injection pipe is further reduced; if the carbon monoxide concentration still does not drop below the first concentration threshold within the set second time period, the injection angle at the outlet end of the injection pipe is adjusted to deflect towards the center of the decomposition furnace, and the injection speed is increased at the same time.

[0024] Once the carbon monoxide concentration drops below the first concentration threshold and remains stable for more than a set time, the following steps are taken in reverse order: first, restore the injection angle and injection speed at the outlet of the spray nozzle; then restore the feed rate of the spray nozzle; and finally restore the rotation speed of the final crushing device.

[0025] Thus, the primary adjustment method employs a three-step strategy: reducing feed particle size, decreasing feed rate, and adjusting injection angle / velocity. This is because reducing feed particle size increases the fuel's specific surface area, accelerating the combustion reaction and being the most direct means of controlling carbon monoxide. If this is ineffective, the feed rate is reduced to decrease the load. Finally, the residence time of the fuel in the high-temperature zone is extended by changing the injection direction (deflecting towards the center) and increasing the velocity. Recovery is performed in the reverse order to avoid abrupt changes. This method utilizes combustion dynamics principles, adaptively adjusting in stages to achieve both rapid response and avoid over-adjustment.

[0026] Preferably, the second priority adjustment method is as follows: first, increase the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone; if the oxygen concentration does not rise to a level not lower than the first oxygen threshold within the set third time period, then simultaneously perform the operations of reducing the feed rate of the injection pipe and reducing the fuel particle size, wherein the reduction of the fuel particle size is achieved by increasing the rotation speed of the final crushing device on the corresponding fuel branch.

[0027] When the oxygen concentration rises to a level not lower than the first oxygen threshold and remains stable for more than a set time, it is restored in reverse order: first, the feed rate of the injection pipe and the rotation speed of the final crushing device on the corresponding fuel branch are restored, and then the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone is restored.

[0028] During the execution of the second priority adjustment method, the carbon monoxide concentration in the combustion zone is collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the second priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged.

[0029] Thus, the second priority adjustment method is as follows: first, increase the angle of the guide vanes in the corresponding combustion zone to increase the tertiary airflow and swirl intensity; if this is ineffective, simultaneously reduce the feed rate and particle size. This is because insufficient oxygen is often due to insufficient local air supply or excessive fuel; increasing the guide vane angle directly increases the oxygen supply to that combustion zone. If oxygen is still insufficient, it indicates excessive fuel or excessive feed particle size, therefore, both feed and particle size are reduced simultaneously. Carbon monoxide is continuously monitored during the adjustment process; if carbon monoxide levels exceed the limit, the system immediately switches to the first priority adjustment method, ensuring strict adherence to the priority rules. The recovery sequence is the reverse of the adjustment sequence to ensure system stability.

[0030] Preferably, the third priority adjustment method is as follows: first, increase the feed rate of the spray pipe; if the temperature does not rise to a level not lower than the first temperature threshold within the set fourth time period, then reduce the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone.

[0031] When the temperature rises to a level not lower than the first temperature threshold and remains stable for more than the set time, it is restored in reverse order: first, the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone is restored, and then the feeding amount of the injection pipe is restored.

[0032] When executing the third priority adjustment method, the carbon monoxide concentration and oxygen concentration in the combustion zone are collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the third priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged. When the collected carbon monoxide concentration in the combustion zone does not rise to the first concentration threshold and the oxygen concentration drops and falls below the first oxygen threshold, the third priority adjustment method is immediately stopped and the second priority adjustment method is executed.

[0033] Thus, the third priority adjustment method is: first increase the feed rate; if this is ineffective, decrease the guide vane angle (to reduce cold air mixing). This is because low temperature is usually caused by insufficient fuel input or excessive cold air. Increasing the feed rate directly increases the heat release per unit time, making it the preferred method for raising the temperature, and it responds quickly. If raising the temperature is ineffective within the set time period, it indicates that the tertiary air volume may be too large (strong cooling effect). In this case, decreasing the guide vane angle in the corresponding area can reduce the local excess air coefficient, reduce the dilution of the flame by cold air, and thus increase the temperature. Once the temperature recovers, reversing the order (first restoring the vane angle, then restoring the feed rate) can avoid secondary disturbances.

[0034] Simultaneously, carbon monoxide and oxygen concentrations are monitored in real time during the third-priority adjustment process. If the carbon monoxide concentration exceeds the limit, the temperature increase is immediately stopped and the first-priority adjustment method is executed, while maintaining the guide vane angle to prevent further increase in carbon monoxide concentration. If the oxygen concentration is too low, the second-priority adjustment method is executed immediately. This nested priority strategy ensures that temperature adjustment does not sacrifice combustion efficiency and safety, achieving optimal control through multi-parameter coordination.

[0035] Preferably, the guide vanes at the tertiary air inlet of the decomposition furnace include multiple parallel blades with a gap of 1-3 mm between adjacent blades. The multiple parallel blades are divided into multiple groups according to the position of the combustion zone. Each combustion zone corresponds to a group of blades. Each group of blades is driven by an independent servo motor and equipped with an angle sensor. The blade angles in each group are adjusted synchronously, and the servo motor can drive the blade angles in the same group to be adjusted within the range of 0-90°.

[0036] When the carbon monoxide concentration in a certain combustion zone in the decomposition furnace is higher than that in the adjacent combustion zone, the average angle of the blade group corresponding to that combustion zone is adjusted so that the average angle of the blade group corresponding to that combustion zone is 5-15° greater than the average angle of the blade group corresponding to the adjacent combustion zone.

[0037] In this way, the blades are grouped, with each group corresponding to a combustion zone. Blades within a group are adjusted synchronously, while those between groups are adjusted independently. The gap between adjacent blades is 1-3 mm, ensuring airtightness and wear resistance. When the carbon monoxide concentration in a certain combustion zone is higher than that in adjacent combustion zones, the blade angle of that group is increased by 5-15°, thereby increasing the tertiary airflow and swirl intensity in that combustion zone, promoting local oxygen mixing, and improving combustion.

[0038] Preferably, an auxiliary burner is also provided in the cone region at the bottom of the decomposition furnace; the output power of the auxiliary burner is uniformly adjusted according to the overall situation of the combustion state parameters of all combustion zones. The adjustment method of the output power of the auxiliary burner is as follows: real-time acquisition of carbon monoxide concentration, temperature and oxygen concentration of all combustion zones, calculation of the average value of each combustion state parameter, comparison of the average value of each combustion state parameter with its corresponding global target value, and activation of the auxiliary burner when the average value of any combustion state parameter exceeds the corresponding global target value; and deactivation of the auxiliary burner when the average value of all combustion state parameters drops below the corresponding global target value and remains stable for more than a set time.

[0039] In this way, by introducing an auxiliary burner, its output power is uniformly adjusted based on the deviation between the average values ​​of carbon monoxide, oxygen, and temperature in all combustion zones and the global target value. This solves the problem of insufficient local adjustment capability when different combustion state parameters deviate simultaneously in multiple combustion zones. The auxiliary burner improves the overall combustion atmosphere from the root by providing additional heat and combustion assistance, avoiding over-adjustment of individual combustion zones. The auxiliary burner complements local priority adjustment, preserving the fine control of zones while enhancing the macroscopic stability of the entire furnace. At the same time, the auxiliary burner's adjustment is based on average values ​​rather than extreme values, avoiding over-activation of the auxiliary burner due to a single extreme point.

[0040] Preferably, the impurity removal method is as follows: magnetic separation is used to remove ferromagnetic metal impurities from waste textile raw materials, and air separation or sieving is used to remove heavy inert impurities from waste textile raw materials.

[0041] The primary coarse crushing method is to crush waste textile raw materials into fragments with a size of less than 10 centimeters.

[0042] The secondary fine crushing method is to further crush the fragments after the primary coarse crushing to a size range of 2-5 cm.

[0043] The method for homogenizing moisture and calorific value is as follows: Waste textile fragments of different batches, calorific values, and moisture content are mixed in a homogenization chamber to form a mixture. The homogenization chamber is equipped with multiple moisture sensors and a near-infrared spectrometer. The moisture sensors are used to detect the average moisture content of the mixture in real time, and the near-infrared spectrometer is used to detect the calorific value characteristics of the mixture in real time. When the average moisture content of the mixture is higher than a preset upper limit, hot air is introduced into the homogenization chamber. When the average moisture content of the mixture is lower than a preset lower limit, atomized water is sprayed into the homogenization chamber. When the calorific value of the mixture deviates from a preset benchmark value, the mixing ratio of waste textile fragments with different calorific value grades is adjusted.

[0044] The molding process involves compressing the homogenized mixture into block or rod-shaped fuel with a set shape and density under heating and pressurization conditions.

[0045] In this way, magnetic separation and air separation in the pretreatment process remove ferrous and heavy impurities respectively, avoiding damage to subsequent equipment; two-stage crushing gradually reduces size and improves efficiency; multiple sensors in the homogenization chamber provide real-time feedback to adjust moisture and calorific value, ensuring consistent fuel properties, which is the foundation for stable combustion; heating and pressurizing molding increases fuel density and calorific value, facilitating storage and transportation. This pretreatment method systematically solves the problems of large fluctuations, looseness, and complex composition of waste textile raw materials, providing high-quality fuel for stable combustion in the decomposition furnace.

[0046] Preferably, the spontaneous combustion risk of the shaped alternative fuel in storage is monitored. The spontaneous combustion risk monitoring method includes: storing the shaped alternative fuel in multiple storage compartments separated by reinforced concrete walls; the floor of each storage compartment is laid with an impermeable layer, an aluminum silicate fiberboard insulation layer, and an aluminum alloy heat-conducting layer from bottom to top; an infrared thermal imager and a smoke detector are installed on the top of each storage compartment; multiple insertion thermocouples are installed on the four walls of the storage compartment, and the multiple insertion thermocouples are inserted into the shaped alternative fuel at different depths; an automatic sprinkler fire suppression system is also provided above each storage compartment, the automatic sprinkler fire suppression system including a water spray ring pipe and a carbon dioxide spray ring pipe;

[0047] When the infrared thermal imager detects that the temperature of any area on the surface of the shaped alternative fuel exceeds 60°C or the temperature of any inserted thermocouple exceeds 80°C, the water spray ring pipe is activated to spray the entire storage compartment containing the shaped alternative fuel with atomized water. If the reading of the infrared thermal imager or the inserted thermocouple that triggered the spray continues to rise within 5 minutes after the water spray ring pipe is activated, the carbon dioxide injection ring pipe is activated to inject carbon dioxide gas and all ventilation openings of the storage compartment are closed.

[0048] This low density of waste textile fuel makes it prone to spontaneous combustion due to internal heat buildup. Infrared thermal imaging and insertion thermocouples are used for multi-point monitoring, covering both the surface and interior of the pile. When the surface temperature exceeds 60°C or the internal temperature exceeds 80°C, water spray cooling is initiated first. If the temperature continues to rise within 5 minutes, carbon dioxide injection is activated and the compartment is sealed to extinguish the fire through asphyxiation. Simultaneously, the multi-layered ground structure (impermeable, insulating, and heat-conducting) prevents geothermal heat transfer and fuel moisture absorption. This spontaneous combustion risk monitoring method combines active cooling with extreme suppression, significantly reducing the risk of spontaneous combustion accidents and providing effective protection for the safe storage of waste textile fuel.

[0049] Compared with existing technologies, this invention obtains stable molded alternative fuel through waste textile pretreatment (impurity removal, multi-stage crushing, moisture and calorific value homogenization, and molding). The feed particle size is then adjusted as needed via multiple independent branches and a final crushing device, and the fuel is fed into the decomposition furnace in zones. Each combustion zone is equipped with sensors to monitor carbon monoxide, oxygen, and temperature in real time, and each zone has its own target range and parameter priority (CO > O2 > temperature). Corresponding first, second, or third priority adjustment methods are implemented for different parameter deviations, including adjusting the feed rate, particle size, injection angle / velocity, and guide vane angle, while also using an auxiliary burner. Thus, this invention achieves independent closed-loop control of multiple combustion zones within the decomposition furnace, solving a series of problems in traditional methods such as uneven combustion, excessive CO, denitrification interference, sulfur reduction, and spontaneous combustion risks. This significantly improves the combustion efficiency of waste textile alternative fuel, cement production stability, and environmental performance. Attached Figure Description

[0050] Appendix Figure 1 This is a flowchart of the combustion control method for waste textile alternative fuel used in the decomposition furnace of a cement kiln, according to the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0052] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0053] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation on the embodiments. Moreover, the method and / or process should not be limited to the steps performed in the written order; those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0054] This specific embodiment provides a combustion control method for waste textile alternative fuel in a cement kiln decomposition furnace, as shown in the attached figure. Figure 1 As shown, it includes the following steps:

[0055] Step S1) The waste textile raw materials are subjected to impurity removal, primary coarse crushing, secondary fine crushing, moisture and calorific value homogenization, and molding treatment in sequence to obtain molded alternative fuel and store it.

[0056] Specifically, the impurity removal methods are as follows: magnetic separation is used to remove ferromagnetic metal impurities from waste textile raw materials, and air separation or sieving is used to remove heavy inert impurities from waste textile raw materials; magnetic separation and air separation remove ferrous and heavy impurities respectively to avoid damage to subsequent equipment.

[0057] The primary coarse crushing method involves crushing waste textile materials into fragments smaller than 10 centimeters. The secondary fine crushing method further crushes the fragments after the primary coarse crushing into fragments between 2 and 5 centimeters in size. The two-stage crushing gradually reduces the size and improves efficiency.

[0058] The method for homogenizing moisture and calorific value is as follows: Waste textile fragments of different batches, calorific values, and moisture content are mixed in a homogenization chamber to form a mixture. The homogenization chamber is equipped with multiple moisture sensors and a near-infrared spectrometer. The moisture sensors are used to detect the average moisture content of the mixture in real time, and the near-infrared spectrometer is used to detect the calorific value characteristics of the mixture in real time. When the average moisture content of the mixture is higher than a preset upper limit, hot air is introduced into the homogenization chamber; when the average moisture content is lower than a preset lower limit, atomized water is sprayed into the homogenization chamber; when the calorific value of the mixture deviates from a preset benchmark value, the mixing ratio of waste textile fragments with different calorific value grades is adjusted. Multiple sensors in the homogenization chamber provide real-time feedback to adjust moisture and calorific value, ensuring consistent properties of the shaped fuel, which is the basis for stable combustion.

[0059] The molding process involves compressing the homogenized mixture into blocks or rods of fuel with a predetermined shape and density under heating and pressure. Heating and pressurizing improves fuel density and calorific value, facilitating storage and transportation. This pretreatment method systematically solves the problems of large fluctuations, looseness, and complex composition of waste textile raw materials, providing high-quality fuel for stable combustion in the decomposition furnace.

[0060] For example, the spontaneous combustion risk monitoring of stored molded alternative fuel includes the following methods: storing the molded alternative fuel in multiple storage compartments separated by reinforced concrete walls; the floor of each storage compartment is laid with an impermeable layer, an aluminum silicate fiberboard insulation layer, and an aluminum alloy heat-conducting layer from bottom to top; an infrared thermal imager and a smoke detector are installed on the top of each storage compartment; multiple insertion thermocouples are installed on the four walls of the storage compartment, and the multiple insertion thermocouples are inserted into the molded alternative fuel at different depths (e.g., 0.5, 1.0, 1.5 m); an automatic sprinkler fire suppression system is also installed above each storage compartment, the automatic sprinkler fire suppression system including a water spray ring pipe and a carbon dioxide spray ring pipe;

[0061] When the infrared thermal imager detects that the temperature of any area on the surface of the shaped alternative fuel exceeds 60°C or the temperature of any inserted thermocouple exceeds 80°C, the water spray loop is activated to spray the entire storage compartment containing the shaped alternative fuel. If, within 5 minutes of activating the water spray loop, the reading of the infrared thermal imager or the inserted thermocouple triggering the spray continues to rise, the carbon dioxide injection loop is activated to inject carbon dioxide gas, and all ventilation openings in the storage compartment are closed. For example, if the infrared thermal imager scans and finds that the surface temperature at the southeast corner reaches 62°C, and the reading of the 1.0m thermocouple at that location is 85°C, the top water spray loop of the storage compartment is immediately activated at a spray flow rate of 8L / min. After 5 minutes, if the infrared thermal imager shows that the temperature at that point has risen to 68°C and the thermocouple has risen to 88°C, the ventilation louvers and door of the compartment are closed, and the carbon dioxide injection loop (pressure 5MPa) is activated, spraying continuously for 30 seconds until the carbon dioxide concentration in the storage compartment reaches 40%. After the temperature drops below 50°C and stabilizes for 10 minutes, turn on the ventilation to remove carbon dioxide.

[0062] Due to the low density of waste textile fuel, it is prone to spontaneous combustion due to internal heat accumulation. Infrared thermal imaging and insertion thermocouples are used for multi-point monitoring, covering both the surface and interior of the stockpile. When the surface temperature exceeds 60°C or the internal temperature exceeds 80°C, water spray cooling is initiated first; if the temperature continues to rise within 5 minutes, carbon dioxide injection is activated and the compartment is sealed to extinguish the fire through asphyxiation. Simultaneously, the multi-layered ground structure (seepage-proof, heat-insulating, and heat-conducting) prevents geothermal heat transfer and fuel moisture absorption. This spontaneous combustion risk monitoring method combines active cooling with extreme suppression, significantly reducing the risk of spontaneous combustion accidents and providing effective protection for the safe storage of waste textile fuel.

[0063] Step S2) The shaped alternative fuel is delivered by the distributor to multiple independent fuel branches. Each fuel branch is equipped with a final crushing device with independently adjustable speed. The outlet end of each fuel branch is connected to a spray pipe. Multiple combustion zones are divided in the decomposition furnace. The outlet end of each spray pipe corresponds to a combustion zone in the decomposition furnace. The outlet ends of different spray pipes are distributed at different heights and different circumferential positions in the decomposition furnace. At least one set of sensors is installed in each combustion zone in the decomposition furnace to collect the combustion state parameters of the combustion zone in real time. The combustion state parameters include carbon monoxide concentration, temperature and oxygen concentration.

[0064] For example, the guide vanes at the tertiary air inlet of the decomposition furnace include multiple parallel blades with a gap of 1-3 mm between adjacent blades. The multiple parallel blades are divided into multiple groups according to the position of the combustion zone. Each combustion zone corresponds to a group of blades. Each group of blades is driven by an independent servo motor and equipped with an angle sensor. The blade angles in each group are adjusted synchronously, and the servo motor can drive the blade angles in the same group to be adjusted in the range of 0-90°.

[0065] When the carbon monoxide concentration in a certain combustion zone in the decomposition furnace is higher than that in the adjacent combustion zone, the average angle of the blade group corresponding to that combustion zone is adjusted so that the average angle of the blade group corresponding to that combustion zone is 5-15° greater than the average angle of the blade group corresponding to the adjacent combustion zone.

[0066] The blades are grouped accordingly, with each group corresponding to a combustion zone. Blades within a group are adjusted synchronously, while those between groups are adjusted independently. The gap between adjacent blades is 1-3 mm, ensuring airtightness and wear resistance. When the carbon monoxide concentration in a certain combustion zone is higher than that in adjacent combustion zones, the blade angle of that group is increased by 5-15°, thereby increasing the tertiary airflow and swirl intensity in that combustion zone, promoting local oxygen mixing, and improving combustion.

[0067] Specifically, at least three layers of sensors are installed along the height of the decomposition furnace in each combustion zone, and at least four sensors are evenly arranged in each layer along the circumference of the decomposition furnace. The sensors are arranged in a grid pattern, which ensures the representativeness of monitoring and the resolution of control, and avoids frequent false alarms or response delays caused by a single threshold.

[0068] Step S3) Set the target range of combustion state parameters for each combustion zone. Based on the deviation between the real-time collected combustion state parameters of each combustion zone and the target range set for that combustion zone, independently perform at least one of the following control adjustments for each combustion zone: adjust the feed rate of the corresponding injection pipe; adjust the rotation speed of the final crushing device on the corresponding fuel branch to change the fuel particle size fed into the injection pipe; adjust the fuel injection angle and / or speed of the corresponding injection pipe; adjust the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone to change the air inlet direction and swirl intensity of the combustion zone.

[0069] Specifically, the following target ranges are set for the combustion state parameters of each combustion zone: the carbon monoxide concentration in each combustion zone is set not to exceed a first concentration threshold, the oxygen concentration in each combustion zone is set not to fall below a first oxygen threshold, and the temperature in each combustion zone is set not to fall below a first temperature threshold. Each combustion zone within the decomposition furnace has its own independent first concentration threshold, first oxygen threshold, and first temperature threshold. The first concentration threshold for each combustion zone decreases sequentially from the bottom to the top of the decomposition furnace. The first oxygen threshold and first temperature threshold for each combustion zone are set in segments sequentially from the bottom to the top of the decomposition furnace. The variation range of the first concentration threshold for all combustion zones is 100-300 ppm, the variation range of the first oxygen threshold for all combustion zones is 2-5%, and the variation range of the first temperature threshold for all combustion zones is 850-1150℃. Among the combustion state parameters, the carbon monoxide parameter has the first priority, the oxygen parameter has the second priority, and the temperature parameter has the third priority.

[0070] The first concentration threshold for carbon monoxide decreases from the bottom to the top of the decomposition furnace. The first oxygen threshold and the first temperature threshold are set in segments because the temperature field and component distribution in the decomposition furnace are gradients: the reducing atmosphere is strong in the bottom and carbon monoxide is high, so the first concentration threshold for carbon monoxide can be set higher; the oxidizing atmosphere is strong in the top and oxygen and temperature are also high, so the first oxygen threshold and the first temperature threshold should be adjusted according to the actual process.

[0071] Specifically, when the carbon monoxide concentration in a combustion zone exceeds the first concentration threshold, the first priority adjustment method is applied to that zone. When the carbon monoxide concentration in a combustion zone is not higher than the first concentration threshold, and the oxygen concentration is lower than the first oxygen threshold, the second priority adjustment method is applied. When the carbon monoxide concentration in a combustion zone is not higher than the first concentration threshold, the oxygen concentration is not lower than the first oxygen threshold, and the temperature is lower than the first temperature threshold, the third priority adjustment method is applied. When multiple combustion state parameters in a combustion zone deviate from their respective target ranges simultaneously, only the adjustment method corresponding to the deviation from the target range is applied to the highest priority combustion state parameter. By clearly defining the target ranges for each combustion state parameter and establishing a priority rule (carbon monoxide > oxygen > temperature), when multiple combustion state parameters deviate simultaneously, only the adjustment of the highest priority combustion state parameter is executed, avoiding mutual interference between different adjustment actions. This is because excessive carbon monoxide is a direct manifestation of incomplete combustion in the decomposition furnace, posing the greatest threat to cement kiln operation (affecting denitrification and triggering sulfur reduction), and therefore must be addressed first; insufficient oxygen is secondary, and the impact of temperature deviation is relatively small. This prioritization strategy enables the system to make correct decisions under complex operating conditions, improving the robustness and efficiency of regulation.

[0072] Specifically, the first priority adjustment method is as follows: First, by increasing the rotation speed of the final crushing device on the fuel branch corresponding to the combustion zone, the fuel particle size fed into the corresponding injection pipe is reduced; if the carbon monoxide concentration does not drop below the first concentration threshold within the set first time period, the feed rate of the injection pipe is further reduced; if the carbon monoxide concentration still does not drop below the first concentration threshold within the set second time period, the injection angle at the outlet end of the injection pipe is adjusted to deflect towards the center of the decomposition furnace, and the injection speed is increased at the same time; when the carbon monoxide concentration drops below the first concentration threshold and remains stable for more than the set time, it is restored in reverse order: that is, first the injection angle and injection speed at the outlet end of the injection pipe are restored, then the feed rate of the injection pipe is restored, and finally the rotation speed of the final crushing device is restored.

[0073] The second priority adjustment method is as follows: First, increase the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone; if the oxygen concentration does not rise to a level not lower than the first oxygen threshold within the set third time period, then simultaneously reduce the feed rate of the injection pipe and reduce the fuel particle size, wherein the reduction of fuel particle size is achieved by increasing the rotation speed of the final crushing device on the corresponding fuel branch; when the oxygen concentration rises to a level not lower than the first oxygen threshold and remains stable for more than the set time, restore it in reverse order: that is, first restore the feed rate of the injection pipe and the rotation speed of the final crushing device on the corresponding fuel branch, and then restore the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone.

[0074] During the execution of the second priority adjustment method, the carbon monoxide concentration in the combustion zone is collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the second priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged.

[0075] The third priority adjustment method is as follows: First, increase the feed rate of the spray pipe; if the temperature does not rise to a level not lower than the first temperature threshold within the set fourth time period, then reduce the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone; when the temperature rises to a level not lower than the first temperature threshold and remains stable for more than the set time, restore it in reverse order: that is, first restore the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone, and then restore the feed rate of the spray pipe.

[0076] When executing the third priority adjustment method, the carbon monoxide concentration and oxygen concentration in the combustion zone are collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the third priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged. When the collected carbon monoxide concentration in the combustion zone does not rise to the first concentration threshold and the oxygen concentration drops and falls below the first oxygen threshold, the third priority adjustment method is immediately stopped and the second priority adjustment method is executed.

[0077] Therefore, the primary adjustment method is a three-step strategy: reducing feed particle size, decreasing feed rate, and adjusting injection angle / velocity. This is because reducing feed particle size increases the fuel's specific surface area, accelerating the combustion reaction and being the most direct way to control carbon monoxide. If this is ineffective, the feed rate is reduced to decrease the load. Finally, the residence time of the fuel in the high-temperature zone is extended by changing the injection direction (deflecting towards the center) and increasing the velocity. Recovery is performed in reverse order to avoid abrupt changes. This method utilizes combustion dynamics principles, adaptively adjusting in stages, enabling both rapid response and avoiding over-adjustment.

[0078] The second priority adjustment method is as follows: First, increase the angle of the guide vanes in the corresponding combustion zone to increase the tertiary airflow and swirl intensity; if this is ineffective, simultaneously reduce the feed rate and particle size. This is because insufficient oxygen is often due to insufficient local air supply or excessive fuel; increasing the guide vane angle directly increases the oxygen supply to that combustion zone. If oxygen is still insufficient, it indicates excessive fuel or excessive feed particle size, therefore, feed and particle size are reduced simultaneously. Carbon monoxide is continuously monitored during the adjustment process; if carbon monoxide levels exceed the limit, the system immediately switches to the first priority adjustment method, ensuring strict adherence to the priority rules. The recovery sequence is the reverse of the adjustment sequence to ensure system stability.

[0079] The third priority adjustment method is as follows: first increase the feed rate; if this is ineffective, reduce the guide vane angle (to reduce cold air mixing). This is because low temperature is usually caused by insufficient fuel input or excessive cold air. Increasing the feed rate directly increases the heat release per unit time, making it the preferred method for raising the temperature, and it responds quickly. If raising the temperature is ineffective within the set time period, it indicates that the tertiary air volume may be too large (strong cooling effect). In this case, reducing the guide vane angle in the corresponding area can reduce the local excess air coefficient, reduce the dilution of the flame by cold air, and thus raise the temperature. Once the temperature recovers, reversing the order (first restoring the vane angle, then restoring the feed rate) can avoid secondary disturbances.

[0080] Simultaneously, carbon monoxide and oxygen concentrations are monitored in real time during the third-priority adjustment process. If the carbon monoxide concentration exceeds the limit, the temperature increase is immediately stopped and the first-priority adjustment method is executed, while maintaining the guide vane angle to prevent further increase in carbon monoxide concentration. If the oxygen concentration is too low, the second-priority adjustment method is executed immediately. This nested priority strategy ensures that temperature adjustment does not sacrifice combustion efficiency and safety, achieving optimal control through multi-parameter coordination.

[0081] Specifically, an auxiliary burner is installed in the cone area at the bottom of the decomposition furnace. The output power of the auxiliary burner is uniformly adjusted according to the overall combustion state parameters of all combustion zones. The adjustment method of the auxiliary burner output power is as follows: real-time collection of carbon monoxide concentration, temperature and oxygen concentration in all combustion zones, calculation of the average value of each combustion state parameter, comparison of the average value of each combustion state parameter with its corresponding global target value, and activation of the auxiliary burner when the average value of any combustion state parameter exceeds the corresponding global target value; and deactivation of the auxiliary burner when the average value of all combustion state parameters drops below the corresponding global target value and remains stable for more than a set time.

[0082] By introducing an auxiliary burner, its output power is uniformly adjusted based on the deviation of the average values ​​of carbon monoxide, oxygen, and temperature across all combustion zones from the global target value. This solves the problem of insufficient local adjustment capability when different combustion state parameters deviate simultaneously in multiple combustion zones. The auxiliary burner improves the overall combustion atmosphere at its source by providing additional heat and combustion support, avoiding over-adjustment of individual combustion zones. The auxiliary burner complements local priority adjustment, preserving fine-grained control of zones while enhancing the overall macroscopic stability of the furnace. Furthermore, the auxiliary burner's adjustment is based on average values ​​rather than extreme values, preventing over-activation of the auxiliary burner due to a single extreme point.

[0083] The working principle of this invention is as follows: First, in the pretreatment stage, waste textiles are sequentially subjected to impurity removal, two-stage crushing, moisture and calorific value homogenization, and molding treatment. This process transforms waste textile raw materials with complex origins and fluctuating properties into molded alternative fuels with uniform size, stable moisture content, and stable calorific value. This pretreatment process ensures that the quality of the molded alternative fuel entering the decomposition furnace is controllable, reducing the fluctuation range of molded alternative combustion from the source.

[0084] Secondly, in the combustion control stage of the decomposition furnace, the shaped alternative fuel is divided into multiple independent combustion branches by a distributor. Each combustion branch is equipped with a final pulverizing device with independently adjustable rotation speed. This allows for online adjustment of the fed fuel particle size according to the actual needs of different combustion zones, achieving spatially differentiated distribution of combustion particle size. Simultaneously, each injection pipe corresponds to a combustion zone, and the outlets are distributed at different heights and circumferential positions within the decomposition furnace. Combined with independent sensors (carbon monoxide, temperature, oxygen) installed in each combustion zone, the combustion conditions of that zone can be acquired in real time.

[0085] Finally, based on the deviation between the combustion state parameters collected from each combustion zone and the set target range, several adjustment methods are available: adjusting the feed rate, adjusting the rotation speed of the final pulverizer to change the feed particle size, adjusting the fuel injection angle and / or velocity through the injector, and adjusting the angle of the guide vanes at the corresponding tertiary air inlet. The first three adjustments directly affect fuel supply characteristics, while adjusting the angle of the guide vanes at the corresponding tertiary air inlet affects the local flow field. Feed rate adjustment has a fast response, but over-adjustment may cause product quality issues; feed particle size adjustment has a slightly slower response but significantly impacts combustion dynamics; injection angle / velocity can change the fuel trajectory and residence time in the furnace; and the guide vane angle optimizes oxygen mixing by changing the local swirl intensity and airflow direction. The combined use of these four adjustment methods gives the control strategy multiple redundancies and synergistic optimization capabilities, enabling it to adapt to various operating conditions ranging from slight fluctuations to severe deviations.

[0086] In summary, this invention integrates pretreatment of waste textiles as alternative fuel, multi-path zoned feeding, online adjustment of feed particle size, adjustment of injection parameters, and adjustment of the tertiary air inlet guide vanes, achieving active control of the entire chain from raw materials to combustion. Compared with existing technologies, this solution significantly reduces carbon monoxide emissions and temperature fluctuations caused by fuel properties and uneven feeding, increases the replacement ratio of waste textiles with pulverized coal, and improves the combustion stability of waste textiles as alternative fuel in the decomposition furnace, while reducing pollutant emissions.

[0087] Compared with existing technologies, this invention obtains stable molded alternative fuel through waste textile pretreatment (impurity removal, multi-stage crushing, moisture and calorific value homogenization, and molding). The feed particle size is then adjusted as needed via multiple independent branches and a final crushing device, and the fuel is fed into the decomposition furnace in zones. Each combustion zone is equipped with sensors to monitor carbon monoxide, oxygen, and temperature in real time, and each zone has its own target range and parameter priority (CO > O2 > temperature). Corresponding first, second, or third priority adjustment methods are implemented for different parameter deviations, including adjusting the feed rate, particle size, injection angle / velocity, and guide vane angle, while also using an auxiliary burner. Thus, this invention achieves independent closed-loop control of multiple combustion zones within the decomposition furnace, solving a series of problems in traditional methods such as uneven combustion, excessive CO, denitrification interference, sulfur reduction, and spontaneous combustion risks. This significantly improves the combustion efficiency of waste textile alternative fuel, cement production stability, and environmental performance.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for combustion control of waste textile substitute fuel in a cement kiln decomposition furnace, characterized in that, Includes the following steps: Waste textile raw materials are subjected to impurity removal, primary coarse crushing, secondary fine crushing, moisture and calorific value homogenization, and molding treatment in sequence to obtain molded alternative fuel and store it. The shaped alternative fuel is delivered by a distributor to multiple independent fuel branches. Each fuel branch is equipped with a final crushing device with independently adjustable rotation speed, and the outlet end of each fuel branch is connected to a spray pipe. Multiple combustion zones are divided within the decomposition furnace, with the outlet end of each spray pipe corresponding to one combustion zone within the decomposition furnace. The outlet ends of different spray pipes are distributed at different heights and circumferential positions within the decomposition furnace. At least one set of sensors is installed in each combustion zone within the decomposition furnace to collect combustion state parameters of that combustion zone in real time. The combustion state parameters include carbon monoxide concentration, temperature, and oxygen concentration. For each combustion zone, a target range for the combustion state parameters of that combustion zone is set. Based on the deviation between the real-time collected combustion state parameters of each combustion zone and the target range set for that combustion zone, at least one of the following controls and adjustments are performed independently on each combustion zone: adjusting the feed rate of the corresponding injection pipe; adjusting the rotation speed of the final crushing device on the corresponding fuel branch to change the fuel particle size fed into the injection pipe. Adjust the angle and / or speed of fuel injection into the corresponding injection pipe; adjust the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone to change the air intake direction and swirl intensity of the combustion zone.

2. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 1, characterized in that, The following target ranges are set for the combustion state parameters of each combustion zone: the concentration of carbon monoxide in each combustion zone is set not to exceed a first concentration threshold, the concentration of oxygen in each combustion zone is set not to be lower than a first oxygen threshold, and the temperature in each combustion zone is set not to be lower than a first temperature threshold; among these, the carbon monoxide parameter is the first priority, the oxygen parameter is the second priority, and the temperature parameter is the third priority. When the carbon monoxide concentration in a combustion zone exceeds the first concentration threshold, the first priority adjustment method is applied to that combustion zone. When the concentration of carbon monoxide in a combustion zone is not higher than the first concentration threshold and the concentration of oxygen is lower than the first oxygen threshold, the second priority adjustment method is applied to the combustion zone. When the carbon monoxide concentration in a combustion zone is not higher than the first concentration threshold, the oxygen concentration is not lower than the first oxygen threshold, and the temperature is lower than the first temperature threshold, the third priority adjustment method is applied to the combustion zone. When multiple combustion state parameters in a certain combustion zone deviate from their respective target ranges at the same time, only the combustion state parameter with the highest priority is adjusted according to the method corresponding to its deviation from the target range.

3. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 2, characterized in that, Each combustion zone in the decomposition furnace is set with its own independent first concentration threshold, first oxygen threshold, and first temperature threshold. The first concentration threshold of each combustion zone decreases sequentially from the bottom to the top of the decomposition furnace. The first oxygen threshold and first temperature threshold of each combustion zone are set in segments from the bottom to the top of the decomposition furnace. The variation range of the first concentration threshold of all combustion zones is 100-300ppm, the variation range of the first oxygen threshold of all combustion zones is 2-5%, and the variation range of the first temperature threshold of all combustion zones is 850-1150℃. At least three layers of sensors are installed in each combustion zone along the height of the decomposition furnace, and at least four sensors are evenly installed in each layer along the circumference of the decomposition furnace.

4. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 3, characterized in that, The first priority adjustment method is as follows: First, by increasing the rotation speed of the final crushing device on the fuel branch corresponding to the combustion zone, the fuel particle size fed into the corresponding injection pipe is reduced; if the carbon monoxide concentration does not drop below the first concentration threshold within the set first time period, the feed rate of the injection pipe is further reduced; if the carbon monoxide concentration still does not drop below the first concentration threshold within the set second time period, the injection angle at the outlet end of the injection pipe is adjusted to deflect towards the center of the decomposition furnace, and the injection speed is increased at the same time. Once the carbon monoxide concentration drops below the first concentration threshold and remains stable for more than a set time, the following steps are taken to restore the concentration in reverse order: first, restore the injection angle and injection speed at the outlet of the spray nozzle; then restore the feed rate of the spray nozzle; and finally restore the rotation speed of the final crushing device.

5. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 4, characterized in that, The second priority adjustment method is as follows: First, increase the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone; if the oxygen concentration does not rise to a level not lower than the first oxygen threshold within the set third time period, then simultaneously reduce the feed rate of the injection pipe and reduce the fuel particle size, wherein the reduction of the fuel particle size is achieved by increasing the rotation speed of the final crushing device on the corresponding fuel branch. When the oxygen concentration rises to no less than the first oxygen threshold and remains stable for more than the set time, it is restored in reverse order: first, the feed rate of the injection pipe and the rotation speed of the final crushing device on the corresponding fuel branch are restored, and then the angle of the guide vane at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone is restored. During the execution of the second priority adjustment method, the carbon monoxide concentration in the combustion zone is collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the second priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged.

6. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 5, characterized in that, The third priority adjustment method is as follows: first, increase the feed rate of the spray pipe; if the temperature does not rise to a level not lower than the first temperature threshold within the set fourth time period, then reduce the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone. When the temperature rises to a level not lower than the first temperature threshold and remains stable for more than the set time, it is restored in reverse order: first, the angle of the guide vanes at the tertiary air inlet of the decomposition furnace corresponding to the combustion zone is restored, and then the feeding amount of the injection pipe is restored. When executing the third priority adjustment method, the carbon monoxide concentration and oxygen concentration in the combustion zone are collected in real time. When the collected carbon monoxide concentration in the combustion zone rises and exceeds the first concentration threshold, the third priority adjustment method is immediately stopped and the first priority adjustment method is executed, while keeping the current guide vane angle unchanged. When the collected carbon monoxide concentration in the combustion zone does not rise to the first concentration threshold and the oxygen concentration drops and falls below the first oxygen threshold, the third priority adjustment method is immediately stopped and the second priority adjustment method is executed.

7. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 6, characterized in that, The guide vanes at the tertiary air inlet of the decomposition furnace include multiple parallel blades with a gap of 1-3mm between adjacent blades. The multiple parallel blades are divided into multiple groups according to the position of the combustion zone. Each combustion zone corresponds to a group of blades. Each group of blades is driven by an independent servo motor and equipped with an angle sensor. The blade angles in each group are adjusted synchronously, and the servo motor can drive the blade angles in the same group to be adjusted within the range of 0-90°. When the carbon monoxide concentration in a certain combustion zone in the decomposition furnace is higher than that in the adjacent combustion zone, the average angle of the blade group corresponding to that combustion zone is adjusted so that the average angle of the blade group corresponding to that combustion zone is 5-15° greater than the average angle of the blade group corresponding to the adjacent combustion zone.

8. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 7, characterized in that, An auxiliary burner is also installed in the conical region at the bottom of the decomposition furnace. The output power of the auxiliary burner is uniformly adjusted according to the overall combustion state parameters of all combustion zones. The adjustment method of the auxiliary burner output power is as follows: real-time collection of carbon monoxide concentration, temperature and oxygen concentration in all combustion zones, calculation of the average value of each combustion state parameter, comparison of the average value of each combustion state parameter with its corresponding global target value, and activation of the auxiliary burner when the average value of any combustion state parameter exceeds the corresponding global target value; and deactivation of the auxiliary burner when the average value of all combustion state parameters drops below the corresponding global target value and remains stable for a set time.

9. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 1, characterized in that, The impurity removal method is as follows: magnetic separation is used to remove ferromagnetic metal impurities from waste textile raw materials, and air separation or sieving is used to remove heavy inert impurities from waste textile raw materials. The primary coarse crushing method is to crush waste textile raw materials into fragments with a size of less than 10 centimeters. The secondary fine crushing method is to further crush the fragments after the primary coarse crushing to a size range of 2-5 cm. The method for homogenizing moisture and calorific value is as follows: Waste textile fragments of different batches, calorific values, and moisture content are mixed in a homogenization chamber to form a mixture. The homogenization chamber is equipped with multiple moisture sensors and a near-infrared spectrometer. The moisture sensors are used to detect the average moisture content of the mixture in real time, and the near-infrared spectrometer is used to detect the calorific value characteristics of the mixture in real time. When the average moisture content of the mixture is higher than a preset upper limit, hot air is introduced into the homogenization chamber. When the average moisture content of the mixture is lower than a preset lower limit, atomized water is sprayed into the homogenization chamber. When the calorific value of the mixture deviates from a preset benchmark value, the mixing ratio of waste textile fragments with different calorific value grades is adjusted. The molding process involves compressing the homogenized mixture into block or rod-shaped fuel with a set shape and density under heating and pressurization conditions.

10. The combustion control method for waste textile substitute fuel in a cement kiln decomposition furnace according to claim 1, characterized in that, The spontaneous combustion risk monitoring method for the molten alternative fuel in storage includes: storing the molten alternative fuel in multiple storage compartments separated by reinforced concrete walls; the floor of each storage compartment is laid with an impermeable layer, an aluminum silicate fiberboard insulation layer, and an aluminum alloy heat-conducting layer from bottom to top; an infrared thermal imager and a smoke detector are installed on the top of each storage compartment; multiple insertion thermocouples are installed on the four walls of the storage compartment, and the multiple insertion thermocouples are inserted into the molten alternative fuel at different depths; an automatic sprinkler fire suppression system is also installed above each storage compartment, the automatic sprinkler fire suppression system including a water spray ring pipe and a carbon dioxide injection ring pipe; When the infrared thermal imager detects that the temperature of any area on the surface of the shaped alternative fuel exceeds 60°C or the temperature of any inserted thermocouple exceeds 80°C, the water spray ring pipe is activated to spray the entire storage compartment containing the shaped alternative fuel with atomized water. If the reading of the infrared thermal imager or the inserted thermocouple that triggered the spray continues to rise within 5 minutes after the water spray ring pipe is activated, the carbon dioxide injection ring pipe is activated to inject carbon dioxide gas and all ventilation openings of the storage compartment are closed.

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