A staged combustion rotary kiln burner and method of controlling the same

Abstract

The application provides a staged combustion rotary kiln burner and a control method thereof, and relates to the technical field of rotary kilns.The burner comprises a rotary kiln, which comprises a kiln body; the burner is arranged in the inner cavity of the kiln body, and the burner comprises a main combustion nozzle arranged at the outlet of a burner lance and a plurality of multistage supplementary combustion nozzles arranged in the circumferential direction on the side wall of the burner lance; the burner lance is sequentially divided into an A section corresponding to the middle section area of the kiln body, a B section corresponding to the front section area of the kiln body and a C section corresponding to the top section area of the kiln body in the injection direction; the multistage supplementary combustion nozzles comprise a plurality of first-stage supplementary combustion nozzles arranged in the circumferential direction on the A section, a plurality of second-stage supplementary combustion nozzles arranged on the B section and a plurality of third-stage supplementary combustion nozzles arranged on the C section.The application optimizes the combustion efficiency, reduces the emission of nitrogen oxides, realizes the controllable distribution of the flame in the horizontal direction and the circumferential direction, improves the concentration and rigidity of the flame and reduces the emission of pollutants.

Description

Technical Field

[0001] This invention relates to the field of rotary kiln technology, and more specifically to a staged combustion rotary kiln burner and its control method. Background Technology

[0002] In modern industrial production, especially in the production of proppant for oil fracturing, rotary kilns play a crucial role. Traditional lime rotary kilns, when processing non-limestone materials such as oil fracturing proppants, face new demands, including complex temperature control, the thermal stability of raw materials, and the production requirements for high-quality products. These non-limestone materials often require precise and uniform heat treatment at specific temperatures to ensure their physical and chemical properties meet more stringent industrial application standards.

[0003] Traditional rotary kiln burners face numerous challenges, such as insufficient flame length, uneven combustion distribution, and low fuel utilization efficiency. These problems not only affect production efficiency and product quality but also lead to energy waste and increased environmental pollution. Currently, staged combustion in rotary kilns optimizes thermal efficiency, improves temperature uniformity, reduces energy consumption, and decreases NOx emissions by introducing fuel at different stages or locations. Additionally, designs that integrate preheaters and rotary kilns preheat raw materials, reducing the energy required within the kiln and thus improving energy efficiency and reducing pollutant emissions during combustion. Furthermore, some methods utilize oxygen-enriched technology to improve combustion efficiency and calcination quality while simultaneously attempting to reduce NOx formation.

[0004] However, current rotary kiln burner designs primarily focus on adjusting the overall internal structure of the kiln for staged combustion. This leads to limited applicability and increases the overall system complexity, making overall furnace control more difficult. Furthermore, due to the movement within the rotary kiln, the material is at an angle, resulting in insufficient utilization of flame combustion energy. Summary of the Invention

[0005] In view of this, embodiments of this application provide a staged combustion rotary kiln burner and its control method to solve the problems of insufficient flame length, uneven combustion distribution, and low fuel efficiency in existing rotary kiln burners during combustion.

[0006] This application provides the following technical solution: a rotary kiln burner with staged combustion, comprising:

[0007] A rotary kiln, including a kiln body, wherein the kiln body is a hollow cylindrical structure;

[0008] The burner is disposed in the inner cavity of the kiln body, and the burner includes a main combustion nozzle disposed at the outlet of the burner lance and a multi-stage supplementary combustion nozzle disposed circumferentially on the side wall of the burner lance.

[0009] The burner nozzle is divided into sections A, B, and C in the spray direction. Section A corresponds to the middle section of the kiln body, section B corresponds to the front section of the kiln body, and section C corresponds to the top section of the kiln body. The multi-stage supplementary firing nozzle includes multiple primary supplementary firing nozzles arranged circumferentially in section A, multiple secondary supplementary firing nozzles arranged circumferentially in section B, and multiple tertiary supplementary firing nozzles arranged circumferentially in section C.

[0010] It also includes a burner delivery system, which includes delivery pipes connected to the main combustion nozzle and the multi-stage supplementary combustion nozzle, and sensors installed in the kiln body cavity. Regulating valves are installed on the delivery pipes. The burner delivery system also includes a control system, which is connected to the sensors and the regulating valves, and is used to dynamically control the opening degree of the regulating valves based on real-time data collected by the sensors.

[0011] According to one embodiment of this application, the region in which the lowest longitudinal point of the burner nozzle is offset by 20-30° against the rotation direction of the rotary kiln is defined as the deflection region. The arrangement density of the multi-stage supplementary combustion nozzles on the side wall of the burner nozzle gradually increases from the highest longitudinal point to the lowest longitudinal point, and the arrangement density reaches its maximum in the deflection region.

[0012] According to one embodiment of this application, the primary combustion nozzle is positioned 13D-15D away from the main combustion nozzle, the secondary combustion nozzle is positioned 7D-8D away from the main combustion nozzle, and the tertiary combustion nozzle is positioned 3D-4D away from the main combustion nozzle; wherein, D is the diameter of the main combustion nozzle.

[0013] According to one embodiment of this application, the sensor includes a temperature sensor and a pressure sensor, used to collect temperature and pressure data inside the kiln in real time.

[0014] According to one embodiment of this application, the burner delivery system further includes a filter and a flow meter, the filter and the flow meter being respectively disposed on the delivery pipeline.

[0015] According to one embodiment of this application, the nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle decrease sequentially, and the nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle do not exceed 0.15D, where D is the diameter of the main combustion nozzle, and the injection angle and injection speed of the nozzles are adjustable.

[0016] According to one embodiment of this application, the burner further includes a flame monitoring system and a combustion efficiency monitoring system. The flame monitoring system is disposed above the combustion hood of the kiln body and is used to detect the stability of the flame inside the kiln. The combustion efficiency monitoring system includes the flame monitoring system and a temperature monitoring system disposed inside the kiln, and is used to determine the combustion efficiency inside the kiln through the flame monitoring system and the temperature monitoring system.

[0017] This application also provides a control method for a staged combustion rotary kiln burner, applied to the staged combustion rotary kiln burner as described above, comprising:

[0018] Several sensors are respectively installed in the middle section, front section and top section of the kiln body;

[0019] The temperature values ​​of each area inside the kiln are collected in real time by sensors. If the collected temperature value is lower than the first temperature threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle is increased; if the collected temperature value is higher than the second temperature threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle is decreased.

[0020] The pressure values ​​of each area inside the kiln are collected in real time by sensors. If the collected pressure value is lower than the first pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is increased; if the collected pressure value is higher than the second pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is decreased.

[0021] According to one embodiment of this application, the control method further includes: detecting the flame stability in the kiln through a flame monitoring system; if the flame stability does not meet the set stability standard, adjusting the air-to-fuel ratio of the main combustion nozzle or the multi-stage supplementary combustion nozzle; wherein the flame stability includes flame color and flame stability.

[0022] According to one embodiment of this application, the control method further includes: detecting the combustion efficiency in the kiln through a combustion efficiency monitoring system; when the detected combustion efficiency is lower than a set efficiency standard, first adjusting the nozzle angle and nozzle flow rate of the main combustion nozzle; if the combustion efficiency still does not meet the set efficiency standard, then sequentially adjusting the nozzle angle and nozzle flow rate of the third-stage supplementary combustion nozzle and the second-stage supplementary combustion nozzle; finally adjusting the nozzle angle and nozzle flow rate of the first-stage supplementary combustion nozzle until the combustion efficiency meets the set efficiency standard.

[0023] Compared with existing technologies, the beneficial effects achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: By designing a rotary kiln burner with multi-stage combustion function, and through more advanced staged combustion technology and improvements to the burner nozzle, the embodiments of this invention further optimize combustion efficiency and reduce nitrogen oxide emissions, achieving controllable flame distribution in the horizontal and circumferential directions, improving flame concentration and rigidity, resulting in more uniform combustion distribution, optimized energy utilization, and reduced pollutant emissions. Based on this, compared with traditional staged combustion technology, the burner design of the embodiments of this invention emphasizes operational flexibility and ease of maintenance. Its design takes into account the need for easy adjustment and rapid response to changes in the production process, while also being structurally simpler, reducing maintenance difficulty and cost. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the rotary kiln burner structure according to the first embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the rotary kiln burner structure according to the second embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the control method for the rotary kiln burner according to an embodiment of the present invention;

[0028] Among them, 1-kiln body, 2-multi-stage supplementary combustion nozzle, 2-1-first stage supplementary combustion nozzle, 2-2-second stage supplementary combustion nozzle, 2-3-third stage supplementary combustion nozzle, 3-main combustion nozzle. Detailed Implementation

[0029] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0030] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] like Figures 1-2 As shown, this embodiment of the invention provides a rotary kiln burner with staged combustion, comprising: a rotary kiln, including a kiln body 1, the kiln body 1 being a hollow cylindrical structure; a burner, the burner being disposed in the inner cavity of the kiln body 1, the burner including a main combustion nozzle 3 disposed at the outlet of the burner lance and multi-stage supplementary combustion nozzles 2 circumferentially disposed on the side wall of the burner lance; the burner lance is sequentially divided into sections A, B, and C in the injection direction, the position of section A corresponding to the middle section of the kiln body 1, the position of section B corresponding to the front section of the kiln body 1, and the position of section C corresponding to the top section of the kiln body 1; the multi-stage supplementary combustion nozzles 2 include circumferentially disposed on the side wall of the burner lance. The system includes multiple primary combustion nozzles 2-1 arranged in section A, multiple secondary combustion nozzles 2-2 arranged circumferentially in section B, and multiple tertiary combustion nozzles 2-3 arranged circumferentially in section C; it also includes a burner delivery system, which includes delivery pipes connected to the main combustion nozzle 3 and the multi-stage combustion nozzles 2 respectively, and sensors installed in the inner cavity of the kiln body 1. Regulating valves are installed on the delivery pipes. The burner delivery system also includes a control system, which is connected to the sensors and the regulating valves respectively, and is used to dynamically control the opening degree of the regulating valves based on real-time data collected by the sensors.

[0032] This invention employs staged combustion technology, introducing fuel and air at different stages within the kiln and controlling the combustion process by real-time monitoring and adjustment of combustion parameters in each stage, thereby achieving optimized thermal efficiency and reducing pollutant emissions. Its core principles are: Temperature control: By controlling the supply of fuel and air in stages, the kiln temperature can be more accurately controlled, thus ensuring a more precise fuel supply within the rotary kiln zone. Nitrogen oxide (NOx) emission reduction: Staged combustion reduces NOx formation at the source, making the fuel range more concentrated. Combustion efficiency: By optimizing the combustion process, staged combustion technology can improve thermal efficiency and reduce energy consumption.

[0033] The staged combustion in this embodiment of the invention is designed with a focus on the regional distribution of energy, with the main combustion nozzle 3 and the multi-stage supplementary combustion nozzle 2 working in concert. Through dynamic adjustment, the heat distribution in the kiln is precisely controlled.

[0034] In specific implementation, the kiln burner nozzles in this embodiment of the invention include a main combustion nozzle 3 located on the side of the burner, and a multi-stage supplementary combustion nozzle 2 including multiple tertiary supplementary combustion nozzles 2-3 circumferentially arranged in the top section C of the kiln body, multiple secondary supplementary combustion nozzles 2-2 circumferentially arranged in the front section B of the kiln body, and multiple primary supplementary combustion nozzles 2-1 circumferentially arranged in the middle section A of the kiln body. The tertiary supplementary combustion nozzles 2-3 located in the top section C of the kiln body are responsible for providing auxiliary flames to the kiln, increasing the circumferential coverage of the flames; they help to uniformly heat the materials in the kiln, especially the materials near the kiln wall. The length and shape of the flame can be controlled by adjusting the nozzle angle and spray speed. The multiple secondary supplementary combustion nozzles 2-2 located in the front section B of the kiln body provide positive flame thrust to the kiln, helping the flames extend deeper into the kiln and preheating the materials at the front end of the kiln to optimize the subsequent heat treatment effect; the distribution and heat density of the flame can be adjusted through different nozzle configurations. The primary combustion nozzle 2-1, located in section A of the middle section of the kiln body, provides auxiliary combustion in the middle section of the kiln body 1, maintains uniform temperature inside the kiln, helps reduce the localization of high-temperature areas inside the kiln, thereby reducing NOx generation, and regulates the atmosphere inside the kiln, promoting the stability of the combustion process and the complete combustion of fuel.

[0035] During overall operation, the burner forms a three-dimensional flame control system through the coordinated action of two groups of lateral multi-stage supplementary combustion nozzles, enabling precise control of flame behavior and heat distribution.

[0036] The staged combustion technology of this invention allows for independent adjustment of the fuel-air mixing ratio in different zones (sections A, B, and C), optimizing combustion parameters and achieving environmental emission control and energy efficiency improvement. The main combustion nozzle 3 provides the primary heat source within the kiln, while the lateral multi-stage supplementary combustion nozzles 2 assist in regulating the combustion state, ensuring the continuity and uniformity of the heat treatment process. It is designed to generate a high-temperature, high-speed, concentrated flame to meet the requirements of high-temperature heat treatment inside the rotary kiln. The main combustion nozzle 3 is typically large, providing a stable flame and heat flow to maintain combustion continuity. The main combustion nozzle 3 ignites first during startup, providing initial heat to the kiln body and forming the basic combustion flame.

[0037] This invention, through the introduction of multi-stage afterburning nozzles 2 corresponding to multi-stage afterburning zones, in conjunction with the main combustion nozzles 3 in the main combustion zone, achieves high efficiency and controllability in the combustion process. This staged combustion technology not only improves the horizontal stiffness of the flame but also allows for control of flame expansion and intensity as needed, optimizing combustion efficiency and reducing energy consumption.

[0038] In one embodiment, the area where the lowest longitudinal point of the burner lance is offset by 20-30° against the rotation direction of the rotary kiln is defined as the deflection zone. The arrangement density of the multi-stage combustion nozzles 2 on the side wall of the burner lance gradually increases from the highest longitudinal point to the lowest longitudinal point, reaching its maximum in the deflection zone. This embodiment achieves higher efficiency through precise control of the flame by multiple side nozzles and controlling the overall lateral deflection of the flame. By utilizing non-uniformly arranged small nozzles in the multi-stage combustion zone, the combustion process is made more consistent with the material distribution within the kiln, optimizing the temperature distribution inside the rotary kiln and improving the quality and uniformity of the calcined material.

[0039] In one embodiment, the primary supplementary combustion nozzle 2-1 is positioned 13D-15D away from the main combustion nozzle 3, the secondary supplementary combustion nozzle 2-2 is positioned 7D-8D away from the main combustion nozzle 3, and the tertiary supplementary combustion nozzle 2-3 is positioned 3D-4D away from the main combustion nozzle 3; where D is the diameter of the main combustion nozzle 3. The primary, secondary, and tertiary supplementary combustion nozzles 2-1, 2-2, and 3-3 correspond to different areas within the kiln. By real-time monitoring of parameters such as temperature and pressure in these different areas, the gas flow rate, air-to-fuel ratio, and nozzle angle of each supplementary combustion nozzle can be adjusted in real-time, achieving precise control of combustion within the kiln, improving combustion efficiency, and reducing energy consumption.

[0040] In this embodiment of the invention, the burner delivery system is responsible for delivering fuel and air to the main combustion nozzle 3 and the multi-stage supplementary combustion nozzle 2. Specifically, the burner delivery system includes a fuel pump, delivery pipelines, regulating valves, and a control system to ensure the stability and adjustability of the fuel supply. The control system integrates sensors and actuators for real-time monitoring and adjustment of combustion parameters to achieve optimal combustion performance. The burner delivery system plays a central role in the entire combustion process, automatically adjusting the fuel and air supply based on changes in temperature and pressure within the kiln. The design of the delivery system ensures effective mixing of the fuel before it reaches the nozzles. During operation, the system adjusts the supply parameters in a timely manner through a feedback control loop to cope with changes in raw material properties or production process requirements.

[0041] In existing combustion systems, the burner delivery system is equipped with automated control functions, which can automatically adjust the fuel flow rate and supply rate based on real-time monitored combustion parameters. The control function of this system is a mature technology and will not be elaborated upon here.

[0042] In this embodiment, the sensors include a temperature sensor and a pressure sensor, used to collect temperature and pressure data inside the kiln in real time. In practice, sensors can be installed at different locations in different areas of the kiln to collect temperature and pressure values ​​from different areas, thereby achieving more precise control.

[0043] The burner delivery system also includes a filter and a flow meter, which are respectively installed on the delivery pipeline. The filter is used to filter fuel and air to ensure that the nozzles are not clogged after long-term use and to ensure the cleanliness of combustion inside the kiln. The flow meter is used to accurately display and control the flow rate of each nozzle, thereby making the combustion process more consistent with the distribution of materials inside the kiln, optimizing the internal temperature distribution, and improving the quality of the calcined materials.

[0044] According to one embodiment of this application, the nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle decrease sequentially, and the nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle do not exceed 0.15D, where D is the diameter of the main combustion nozzle, and the injection angle and injection speed of the nozzles are adjustable.

[0045] According to one embodiment of this application, the burner further includes a flame monitoring system and a combustion efficiency monitoring system. The flame monitoring system is disposed above the combustion hood of the kiln body and is used to detect the stability of the flame inside the kiln. The combustion efficiency monitoring system includes the flame monitoring system and a temperature monitoring system disposed inside the kiln, used to determine the combustion efficiency inside the kiln through the flame monitoring system and the temperature monitoring system. In a specific implementation, the flame monitoring system is a high-temperature infrared thermal imager disposed on the upper left side of the kiln combustion hood. The high-temperature infrared thermal imager can observe the entire flame situation from the direction of the main combustion nozzle, and can simultaneously observe the flame situation on the side walls, top, and bottom of the kiln.

[0046] This invention, through more advanced staged combustion technology and nozzle design, further optimizes combustion efficiency and improves flame morphology and heat distribution, ensuring a "fine yet powerful" flame while avoiding excessively high local temperatures, thereby reducing NOx formation. This is particularly important for the high energy efficiency and low environmental impact requirements in the preparation of oil fracturing proppant. Compared to traditional staged combustion technology, the burner design of this invention emphasizes operational flexibility and ease of maintenance. Its design considers the need for easy adjustment and rapid response to changes in the production process, while its simplified structure reduces maintenance difficulty and cost.

[0047] like Figure 3 As shown, this application also provides a control method for a staged combustion rotary kiln burner, applied to the staged combustion rotary kiln burner as described above, comprising:

[0048] Several sensors are respectively installed in the middle section, front section and top section of the kiln body;

[0049] The temperature values ​​of each area inside the kiln are collected in real time by sensors. If the collected temperature value is lower than the first temperature threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle is increased; if the collected temperature value is higher than the second temperature threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle is decreased.

[0050] The pressure values ​​of each area inside the kiln are collected in real time by sensors. If the collected pressure value is lower than the first pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is increased; if the collected pressure value is higher than the second pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is decreased.

[0051] In practice, the different ranges of the first and second temperature thresholds, as well as the first and second pressure thresholds, for each region are determined based on the characteristics of the raw materials, the required product quality, and the design parameters of the equipment. In the production of oil fracturing proppant, the preferred range for the first temperature threshold in each region is 750℃-950℃, and the preferred range for the second temperature threshold is 1200℃-1400℃.

[0052] In practical implementation, it is preferable to place temperature sensors at the feed end, the middle kiln, near the firing zone, and at the discharge end of the kiln. At the feed end, monitoring the initial temperature of the material entering the kiln helps control the heating rate and prevent thermal shock. Multiple temperature sensors are placed along the length of the middle kiln to monitor the temperature profile, ensuring uniform heating and identifying any cold spots. The area near the firing zone is the hottest part of the kiln, where the main chemical reactions occur. Multiple sensors may be needed to accurately capture temperature changes in this critical area. At the discharge end, the temperature of the material exiting the kiln is checked to ensure the product has reached the temperature required to complete the necessary reactions.

[0053] In practical implementation, it is preferable to place pressure sensors at the feed end, near the firing zone, and at the discharge end of the kiln. Monitoring the pressure at both ends of the kiln at the feed and discharge ends helps identify any blockages or abnormal airflow patterns; near the combustion zone, the pressure can indicate combustion efficiency and whether the airflow is balanced throughout the kiln.

[0054] In one embodiment, the method further includes: detecting the flame stability within the kiln using a flame monitoring system; if the flame stability does not meet a set stability standard, adjusting the air-to-fuel ratio of the primary supplementary combustion nozzle, secondary supplementary combustion nozzle, tertiary supplementary combustion nozzle, or main combustion nozzle. This process involves collecting data from the flame monitoring system to analyze flame stability and selecting appropriate nozzles for adjustment based on the spatial instability of the flame. Specifically, adjusting the air-to-fuel ratio can be achieved by increasing or decreasing the airflow rate, adjusted according to the flame color.

[0055] Specifically, the flame monitoring system uses a high-temperature infrared thermal imager to first assess the color and stability of the flame inside the kiln. If the flame appears bluish, it usually indicates relatively complete combustion. If stability is insufficient, the air supply needs to be reduced and fuel increased to enrich the mixture and enhance flame stability. Conversely, if the flame is yellowish or orange, it indicates incomplete combustion. In this case, the air supply should be increased and the fuel supply reduced to improve combustion efficiency and reduce harmful emissions.

[0056] After adjustments, flame stability is monitored again to ensure optimal combustion. This process requires multiple adjustments and consideration of other factors, such as kiln temperature, pressure, and material properties, to achieve the best results.

[0057] In one embodiment, the method further includes: detecting the combustion efficiency within the kiln using a combustion efficiency monitoring system; when the detected combustion efficiency is lower than a set efficiency standard, the system first adjusts the nozzle angle and flow rate of the main combustion nozzle; if the combustion efficiency still does not reach the set efficiency standard, the system then sequentially adjusts the nozzle angle and flow rate of the tertiary and secondary supplementary combustion nozzles, and finally adjusts the nozzle angle and flow rate of the primary supplementary combustion nozzle. After each adjustment, the system re-evaluates the combustion efficiency until the combustion efficiency meets the set efficiency standard.

[0058] The embodiments of the present invention, through the design of the burner control method, finely adjust the combustion nozzle to achieve precise control of the flame shape, optimize the flame concentration characteristics in the circumferential direction, and reduce the flame concentration characteristics in the axial direction. Thus, while maintaining strong combustion intensity, it avoids local overheating and reduces the formation of thermal NOx.

[0059] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A rotary kiln burner with staged combustion, characterized in that, include: A rotary kiln, including a kiln body, wherein the kiln body is a hollow cylindrical structure; The burner is disposed in the inner cavity of the kiln body, and the burner includes a main combustion nozzle disposed at the outlet of the burner lance and a multi-stage supplementary combustion nozzle disposed circumferentially on the side wall of the burner lance. The burner nozzle is divided into sections A, B, and C in the spray direction. Section A corresponds to the middle section of the kiln body, section B corresponds to the front section of the kiln body, and section C corresponds to the top section of the kiln body. The multi-stage supplementary firing nozzle includes multiple primary supplementary firing nozzles circumferentially arranged in section A, multiple secondary supplementary firing nozzles circumferentially arranged in section B, and multiple tertiary supplementary firing nozzles circumferentially arranged in section C. Sections A, B, and C are separated from each other, forming three independent regions. It also includes a burner delivery system, which includes delivery pipes connected to the main combustion nozzle and the multi-stage supplementary combustion nozzle, and sensors installed in the kiln body cavity. Regulating valves are installed on the delivery pipes. The burner delivery system also includes a control system, which is connected to the sensors and the regulating valves, and is used to dynamically control the opening degree of the regulating valves based on real-time data collected by the sensors.

2. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The area where the lowest point of the burner nozzle is offset by 20-30° against the rotation direction of the rotary kiln is defined as the deflection zone. The arrangement density of the multi-stage supplementary combustion nozzles on the side wall of the burner nozzle gradually increases from the highest point to the lowest point in the longitudinal direction, and the arrangement density reaches its maximum in the deflection zone.

3. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The primary combustion nozzle is positioned 13D-15D away from the main combustion nozzle, the secondary combustion nozzle is positioned 7D-8D away from the main combustion nozzle, and the tertiary combustion nozzle is positioned 3D-4D away from the main combustion nozzle; where D is the diameter of the main combustion nozzle.

4. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The sensors include temperature sensors and pressure sensors, used to collect temperature and pressure data inside the kiln in real time.

5. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The burner delivery system also includes a filter and a flow meter, which are respectively installed on the delivery pipeline.

6. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle decrease sequentially, and the nozzle sizes of the primary combustion nozzle, the secondary combustion nozzle, and the tertiary combustion nozzle do not exceed 0.15D, where D is the diameter of the main combustion nozzle, and the injection angle and injection speed of the nozzles are adjustable.

7. The rotary kiln burner with staged combustion according to claim 1, characterized in that, The burner also includes a flame monitoring system and a combustion efficiency monitoring system. The flame monitoring system is installed above the combustion hood of the kiln body and is used to detect the stability of the flame inside the kiln. The combustion efficiency monitoring system includes the flame monitoring system and a temperature monitoring system installed inside the kiln, which is used to determine the combustion efficiency inside the kiln through the flame monitoring system and the temperature monitoring system.

8. A control method for a rotary kiln burner with staged combustion as described in any one of claims 1 to 7, characterized in that, include: Several sensors are respectively installed in the middle section, front section and top section of the kiln body; The temperature values ​​of each area inside the kiln are collected in real time by sensors. If the collected temperature value is lower than the first temperature threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is increased. If the collected temperature value is higher than the second temperature threshold set for the corresponding area, the gas flow rate of the supplementary combustion nozzle for that area will be reduced. The pressure values ​​of each area inside the kiln are collected in real time by sensors. If the collected pressure value is lower than the first pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is increased; if the collected pressure value is higher than the second pressure threshold set for the corresponding area, the gas flow rate of the corresponding supplementary combustion nozzle in that area is decreased.

9. The control method according to claim 8, characterized in that, The control method further includes: The flame stability inside the kiln is detected by a flame monitoring system. If the flame stability does not meet the set stability standard, the air-to-fuel ratio of the main combustion nozzle or the multi-stage supplementary combustion nozzle is adjusted. The flame stability includes flame color and flame stability.

10. The control method according to claim 8, characterized in that, The control method further includes: The combustion efficiency in the kiln is monitored by a combustion efficiency monitoring system. When the monitored combustion efficiency is lower than the set efficiency standard, the nozzle angle and nozzle flow rate of the main combustion nozzle are adjusted first. If the combustion efficiency still does not meet the set efficiency standard, the nozzle angle and nozzle flow rate of the third-stage supplementary combustion nozzle and the second-stage supplementary combustion nozzle are adjusted in sequence. Finally, the nozzle angle and nozzle flow rate of the first-stage supplementary combustion nozzle are adjusted until the combustion efficiency meets the set efficiency standard.

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