Porous nozzle combustor and targeted adding combustion device of cement kiln

Abstract

The invention discloses a porous nozzle combustor and a targeted adding combustion device of a cement kiln, and solves the problem that stable production of the cement kiln is affected due to non-uniform heat distribution caused by complex and changeable properties of alternative fuels in the prior art. The multi-hole nozzle combustor comprises a feeding cavity and a mixed spraying cavity which are connected, a multi-hole nozzle is arranged at the outlet end of the feeding cavity and comprises a center gas nozzle and a plurality of side nozzles, the side nozzles are distributed on a circle with the center gas nozzle as the center, a ventilation pipeline is arranged in the feeding cavity, and the mixed spraying cavity is communicated with the center gas nozzle. The ventilation pipeline is communicated with the central gas nozzle, and the side nozzles are communicated with the feeding chamber; and flow guide fins are arranged in the mixed spraying chamber and are spirally arranged by taking the central gas nozzle as a circle center. According to the porous nozzle burner, optimized nozzle layout and mixed spraying cavity design are adopted, and pyrolysis gas and solid products are promoted to be fully mixed; the flow guide fins spirally arranged in the mixed spraying cavity enable pyrolysis gas to form rotating gas flow, the rotating gas flow violently collides and wraps solid particles, a stable and efficient combustion gas-solid flow state is formed, and the combustion stability is improved.

Description

Technical Field

[0001] This invention relates to the field of cement production equipment technology, and in particular to a burner and combustion device. Background Technology

[0002] With increasingly stringent environmental requirements and adjustments to the energy structure, the cement industry urgently needs to find alternative fuels to pulverized coal. The application of numerous alternative materials, such as biomass and industrial waste residues, in cement production is gradually emerging. However, the gaseous and solid products generated after the pyrolysis of these alternative materials have complex and variable properties. On the one hand, the composition of pyrolysis gas differs significantly from the flue gas produced by pulverized coal combustion, with different calorific values, ignition points, and combustion rates. On the other hand, the particle size, shape, and flowability of pyrolysis solid products also vary considerably. Traditional nozzle burners used for pulverized coal combustion cannot accurately deliver pyrolysis gas and solid products to specific reaction zones within the cement kiln, leading to incomplete combustion, uneven heat distribution, and consequently affecting the quality of cement clinker, increasing production costs, and limiting the large-scale, efficient utilization of alternative materials.

[0003] In addition, existing combustion devices, such as a cement kiln alternative fuel gasification staged combustion device with authorization announcement number CN 206494852 U, reduce the generation of nitrogen oxides by using staged combustion; however, the alternative fuel particles are too large and the dispersion in the furnace is uneven, which will affect the stable production of cement kilns. Summary of the Invention

[0004] To address the shortcomings in the aforementioned background technology, this invention proposes a multi-hole nozzle burner and a targeted combustion device for cement kilns, which solves the problem in the prior art where uneven heat distribution due to the complex and variable properties of alternative fuels affects the stable production of cement kilns.

[0005] The technical solution of this invention is implemented as follows: A multi-hole nozzle burner includes a feed chamber and a mixing chamber connected to each other. The feed chamber has a multi-hole nozzle at its outlet end, extending into the mixing chamber. The multi-hole nozzle includes a central gas nozzle and several side nozzles distributed on a circle centered on the central gas nozzle. A venting pipe is provided within the feed chamber, connected to the central gas nozzle, and the side nozzles are also connected to the feed chamber. Guide ribs are provided within the mixing chamber, arranged spirally around the central gas nozzle. The feed chamber is used for the separate flow of pyrolysis gas and pyrolysis solid products after pyrolysis. These products are then mixed and ejected through the multi-hole nozzle in the mixing chamber, ensuring thorough mixing of the gas and solid phases to form a uniform and stable mixed flow, laying the foundation for subsequent efficient combustion.

[0006] Further preferably, the feeding chamber includes a fixedly connected inner shell and an outer shell, forming an annular sealed cavity between the inner shell and the outer shell; a venting pipe is disposed inside the inner shell, a multi-hole nozzle is connected to the inner shell, and the inner shell has a first feed inlet and a second feed inlet on the feed side, the second feed inlet being connected to the venting pipe; the first feed inlet is connected to the inner shell. The inner shell and the outer shell of the feeding chamber are made of double-layer high-temperature resistant alloy steel, and the annular sealed cavity formed between the inner shell and the outer shell uses an air insulation layer, which can effectively prevent the internal high temperature from escaping to the external environment, and also utilize the buffering effect of the air insulation layer to reduce the stress generated by the thermal expansion and contraction of the burner.

[0007] Further optimized, the inner shell is equipped with helical blades, which are rotatably mounted on the ventilation pipe and correspond to the first feed inlet; the outer shell is equipped with a waste heat outlet; and the side nozzle is equipped with a wear-resistant ceramic liner. During the feeding process at the first feed inlet, the helical blades are driven to rotate, causing disturbance of the pyrolysis solid products in the inner shell and giving the solid particles a pre-swirling initial velocity. After entering the side nozzle, it forms a double-layer coating of "swirling to direct current" at the flame root, resulting in better flame stabilization.

[0008] Further optimization involves a mixing spray chamber comprising a mixing spray shell, which is coaxially aligned with the multi-hole nozzle. Guide ribs are located between the mixing spray shell and the multi-hole nozzle. A guide vane is installed at the nozzle outlet to precisely adjust the pyrolysis gas injection direction according to the kiln's airflow requirements, guiding the pyrolysis gas deeper into the high-temperature zone at the center of the cement kiln to ensure complete combustion.

[0009] A targeted combustion device for a cement kiln includes a pyrolysis furnace, a rotary kiln, and a multi-hole nozzle burner. The feed inlet of the pyrolysis furnace is connected to a storage silo via a feed pipe. The discharge outlet of the pyrolysis furnace is connected to a solid-gas separation device. The gas outlet of the solid-gas separation device is connected to the first feed inlet of the multi-hole nozzle burner, and the discharge outlet of the solid-gas separation device is connected to the second feed inlet of the multi-hole nozzle burner. The nozzle of the multi-hole nozzle burner is connected to the rotary kiln, and the raw material inlet of the rotary kiln is connected to a pre-combustion tower via a raw material pipe.

[0010] Further optimization involves connecting the waste heat outlet on the outer shell of the multi-hole nozzle burner to the pre-combustion tower and / or pyrolysis furnace via a waste heat recovery pipe; this facilitates waste heat recovery and improves energy utilization.

[0011] Further optimization reveals that the solid-gas separation device includes an outer tank and an inner screening tank located inside the outer tank. The upper part of the outer tank has a first gas outlet pipe, and one side of the outer tank has a first feed pipe connected to the inner screening tank. The bottom of the inner screening tank has a first discharge port, and the lower part of the outer tank has a second discharge port. The material exiting the pyrolysis furnace is separated into gas and fixed particles of suitable size by the solid-gas separation device. This gas then enters a multi-hole nozzle burner for further injection mixing, forming a stable and efficient gas-solid flow state. This improves the combustion instability caused by the complex properties of the pyrolysis products of the substitute material, ensuring a stable combustion process in the cement kiln and guaranteeing the quality of cement clinker.

[0012] Further preferred, the inner screening tank includes an upper smooth cylinder and a lower screening cylinder connected sequentially from top to bottom, with screening holes evenly distributed on the lower screening cylinder; used to screen out solid products of suitable particle size, improve combustion efficiency, and at the same time avoid clogging the nozzle.

[0013] Further optimization involves a conical lower screening cylinder; a first vent pipe is connected to the top of the upper smooth cylinder, and a vent hole is provided on the outer wall between the outer tank and the upper smooth cylinder for easy outflow of pyrolysis gas from both the inner and outer tanks.

[0014] Further optimization involves providing a guide plate at the bottom of the outer tank corresponding to the second discharge port, which is connected to the second inlet of the multi-hole nozzle burner; the first exhaust pipe is connected to the first inlet of the multi-hole nozzle burner; the first discharge port is connected to the pyrolysis furnace via a return pipe; and the remaining material with larger particle size that has not been completely pyrolyzed is re-entered into the pyrolysis furnace for re-pyrolysis, thereby improving the utilization rate of the substitute.

[0015] The beneficial effects of this invention are as follows: the central gas nozzle of the multi-hole nozzle burner can finely adjust the pyrolysis gas injection direction according to the airflow field inside the kiln, and the annularly distributed side nozzles can accurately control the flow rate of solid products according to the particle size, so that the fuel can fully reach the key areas inside the cement kiln that require heating, allowing the pyrolysis products to burn fully in the appropriate position, avoiding heat waste, effectively improving energy utilization and reducing production costs.

[0016] The multi-hole nozzle burner of this invention adopts an optimized nozzle layout and mixing chamber design to promote the full mixing of pyrolysis gas and solid products. The spirally arranged guide ribs in the mixing chamber cause the pyrolysis gas to form a rotating airflow, which violently collides and entrains the solid particles, forming a stable and efficient gas-solid flow state, improving combustion stability, and improving the combustion instability caused by the complex properties of the pyrolysis products of the substitute materials. This ensures a stable combustion process in the cement kiln and guarantees the quality of cement clinker.

[0017] The feed chamber of the multi-hole nozzle burner of this invention adopts a double-layer high-temperature resistant alloy steel outer shell and an air insulation layer, which has good heat insulation and stress buffering performance and can adapt to high-temperature working conditions. It can also utilize the buffering effect of the air insulation layer to reduce the stress generated by thermal expansion and contraction of the burner. The annular sealing cavity simultaneously undertakes the dual functions of "heat recovery + heat preservation", eliminating the need for an additional heat exchanger and reducing volume and weight simultaneously. It is suitable for harsh production environments and reduces maintenance costs.

[0018] This invention relates to a targeted combustion device for cement kilns. It utilizes a multi-nozzle burner to precisely control the delivery of pyrolysis gas and solid products, achieving targeted delivery. This ensures complete combustion and uniform heat distribution, thereby improving the calcination quality of cement clinker. Furthermore, the device employs a solid-gas separation unit to separate solids from pyrolysis gas, allowing appropriately sized particles of solid products and pyrolysis gas to be smoothly injected into the rotary kiln from the multi-nozzle burner, thus differentiating combustion stability. Additionally, a waste heat recovery pipeline can collect excess preheating and reintroduce it to the pyrolysis furnace, significantly saving energy consumption and reducing economic costs. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the multi-hole nozzle burner structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the multi-hole nozzle burner of the present invention; Figure 3 A schematic diagram of the targeted combustion device for a cement kiln. Figure 4 This is a schematic diagram of the internal structure of a solid-gas separation device. Detailed Implementation

[0021] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1, such as Figure 1As shown, a multi-hole nozzle burner is disclosed. In this embodiment, the multi-hole nozzle burner includes a feed chamber 601 and a mixing chamber 602 connected to each other. The feed chamber is used for the pyrolysis gas and pyrolysis solid products to flow separately into the feed chamber after pyrolysis. Then, they are mixed and sprayed out through the multi-hole nozzle in the mixing chamber, which fully mixes the gas and solid phases to form a uniform and stable mixed flow, laying the foundation for subsequent efficient combustion. The outlet end of the feed chamber 601 is provided with a multi-hole nozzle 603, which extends into the mixing chamber 602. The material medium in the feed chamber 601 enters the mixing chamber through the multi-hole nozzle and is then mixed in the mixing chamber. This ensures that the fuel fully reaches the key areas in the cement kiln that require heating, allowing the pyrolysis products to burn fully in the appropriate locations, avoiding heat waste, effectively improving energy utilization, and reducing production costs.

[0023] In this preferred embodiment, the multi-hole nozzle 603 includes a central gas nozzle 606 and several side nozzles 604. The side nozzles 604 are distributed on a circle centered on the central gas nozzle 606. The central nozzle is located at the center of the burner front end and has a large-diameter tapering structure, responsible for the high-speed injection of the main pyrolysis gas flow. The internal flow channel of the central gas nozzle 606 undergoes a special polishing treatment, which greatly reduces the friction between the airflow and the inner wall of the flow channel, minimizing energy loss of the pyrolysis gas during flow and further ensuring the high-speed injection of the pyrolysis gas. The side nozzles are uniformly distributed small-diameter nozzles used to inject pyrolysis solid products. The side nozzles 604 are evenly distributed in one or more rings around the central gas nozzle. These small-diameter nozzles bear the important task of injecting the pyrolysis solid products into the cement kiln. The nozzle orifice design of each ring follows a strict rule. Based on a detailed analysis of the particle size distribution of the pyrolysis solid products, the nozzle orifice diameter gradually decreases from the inside to the outside. This is because the pyrolysis solid products near the central gas nozzle are significantly affected by the high-speed airflow of the central pyrolysis gas. Smaller particles can better follow the airflow, so the inner ring nozzles use smaller orifices to ensure that small solid particles can be ejected at a higher speed and fully mixed with the pyrolysis gas. The outer ring nozzles, on the other hand, are for larger solid particles. Larger orifices prevent large particles from clogging the nozzles and allow them to be evenly dispersed around the pyrolysis gas at a suitable outlet velocity, achieving a uniform gas-solid distribution across the entire cross-section. The orifice diameter of each ring of nozzles decreases from the inside to the outside according to the solid particle size distribution, ensuring that particles of different sizes are evenly dispersed at different outlet velocities. In this embodiment, the feed chamber 601 is equipped with a ventilation pipe 608, which is connected to the central gas nozzle 606. The ventilation pipe directly introduces the incoming pyrolysis gas into the central gas nozzle, reducing energy loss. Side nozzles 604 are connected to the feed chamber 601 and are used for ejecting pyrolysis solid particles from the feed chamber. It should be noted that solenoid valves for flow control can be installed on the feed pipes corresponding to the central gas nozzle and the side nozzles to precisely control the gas and solid flow rates of each nozzle, achieving dynamic optimization of targeted dosing. In this embodiment, a guide rib 605 is provided in the mixing chamber 602, and the guide rib 605 is arranged in a spiral shape with the central gas nozzle 606 as the center. The spirally arranged guide rib in the mixing chamber causes the pyrolysis gas to form a rotating airflow, which violently collides and entrains the solid particles, forming a stable and efficient gas-solid flow state. This improves the combustion instability caused by the complex properties of the pyrolysis products of the substitute material, ensures a stable combustion process in the cement kiln, and guarantees the quality of cement clinker.

[0024] Example 2, as Figure 2As shown, a multi-hole nozzle burner is further optimized based on Embodiment 1. In this embodiment, the feed chamber 601 includes a fixedly connected inner shell 61-1 and outer shell 61-2; the inner shell 61-1 and outer shell 61-2 are made of double-layer high-temperature resistant alloy steel shells. An annular sealed cavity is formed between the inner shell 61-1 and the outer shell 61-2; that is, an air gap is formed between the inner shell and the outer shell, which has good heat insulation and stress buffering performance, adapting to high-temperature conditions; and can also utilize the buffering effect of the air insulation layer to reduce the stress generated by the burner due to thermal expansion and contraction; therefore, the annular cavity simultaneously undertakes the dual functions of "heat recovery + heat preservation", eliminating the need for an additional heat exchanger, and reducing volume and weight simultaneously. In this embodiment, the ventilation pipe 608 is installed inside the inner shell 61-1, and the multi-hole nozzle 603 is connected to the inner shell 61-1. The inner shell 61-1 has a first feed inlet 609 and a second feed inlet 610 on the feed side. The second feed inlet 610 is connected to the ventilation pipe 608, and the first feed inlet 609 is connected to the inner shell 61-1. The first feed inlet 609 is used for feeding pyrolysis solids, which are then ejected through the side nozzle 604. The second feed inlet 610 is used for the entry of pyrolysis gas, which is directly introduced into the ventilation pipe 608 and then ejected through the central gas nozzle 606. The guide ribs in the mixing chamber 602 can be ribs with adjustable angles. According to the airflow field requirements inside the kiln, the direction of pyrolysis gas injection can be precisely adjusted to guide the pyrolysis gas into the high-temperature zone in the center of the cement kiln, ensuring complete combustion. The mixing chamber is located at the front end of the multi-hole nozzle assembly and is the space for the initial mixing of pyrolysis gas and solid products of a specific particle size. The inner wall of the chamber is designed with spiral guide ribs. After the pyrolysis gas is ejected at high speed from the central nozzle, it forms a rotating airflow under the guidance of the guide ribs. This airflow collides and entrains the solid particles ejected from the annular nozzle, promoting full mixing of the gas and solid phases and forming a uniform and stable mixed flow, which lays the foundation for subsequent efficient combustion.

[0025] In this embodiment, the inner shell 61-1 is equipped with a helical blade 611, which can be a three- or four-bladed structure. It is rotatably mounted on the ventilation pipe 608 via bearings, and the helical blade 611 corresponds to the first feed inlet 609. As the pyrolysis solids enter the inner shell through the first feed inlet, they simultaneously drive the helical blades to rotate, giving the internal pyrolysis solids a pre-swirl velocity, allowing them to pass smoothly and evenly through the side nozzles and mix better with the pyrolysis gas. The outer shell 61-2 is equipped with a waste heat outlet 612. The sealed cavity between the outer and inner shells traps all the reverse radiant heat from the combustion chamber and the heat conducted through the nozzle end face. The waste heat outlet can guide the trapped hot air back to the secondary fan or directly preheat the fuel, improving the system's thermal efficiency by 3-5 percentage points. The side nozzle 604 is equipped with a wear-resistant ceramic liner; that is, the side nozzle is inlaid with a wear-resistant ceramic liner to enhance wear resistance and extend service life. Simultaneously, each side nozzle branch is equipped with an independent flow regulating valve, connected to an external control system, to achieve precise control of the solid particle flow rate.

[0026] In this embodiment, the mixing chamber 602 includes a mixing shell, which is similar to the outer shell and is also made of high-temperature alloy steel cylindrical shell. The mixing shell and the multi-hole nozzle 603 are arranged on the same central axis, and the guide ribs 605 are located between the mixing shell and the multi-hole nozzle 603. The guide ribs 605 are spirally distributed along the inner wall of the mixing chamber, like a winding mountain road, extending from the inlet end to the outlet end of the mixing chamber. This spiral structure can guide the pyrolysis gas to form a strong rotating airflow, significantly increasing the contact area and contact time between the pyrolysis gas and the solid products, and promoting more thorough mixing. Specifically, the spiral angle of the ribs has been precisely calculated and optimized to ensure that the pyrolysis gas can form a stable rotating airflow while avoiding excessive loss of airflow velocity due to an excessively large angle, or poor mixing effect due to an excessively small angle. In addition, the height and width of the ribs have also been carefully designed to effectively disturb the airflow without obstructing the airflow, thereby enhancing the mixing effect of the gas and solid phases.

[0027] Example 3, as Figure 3As shown, a targeted combustion device for cement kilns includes a pyrolysis furnace 3, a rotary kiln 8, and a porous nozzle burner 6 as described in Example 2. The feed inlet of the pyrolysis furnace 3 is connected to the storage silo 1 through the feed pipe 2. When alternative fuel is used to replace pulverized coal for cement production, the alternative fuel is first transported from the storage silo 1 to the pyrolysis furnace 3 through the feed channel 2. During the pyrolysis of municipal solid waste, the pyrolysis furnace 3 outputs a mixture of particulate solid products and pyrolysis gas. The outlet of the pyrolysis furnace 3 is connected to a solid-gas separation device 11. The particulate solid product and pyrolysis gas mixture output from the pyrolysis furnace are separated into pyrolysis solids and pyrolysis gas of suitable particle size by the solid-gas separation device 11. The outlet of the solid-gas separation device 11 is connected to the first inlet 609 of the multi-hole nozzle burner 6 through the pyrolysis gas outlet pipe 4. The separated pyrolysis gas enters the central gas nozzle of the multi-hole nozzle burner through the first inlet. The outlet of the solid-gas separation device 11 is connected to the second inlet 610 of the multi-hole nozzle burner 6 through the solid product outlet pipe 5, enters the inner shell through the second inlet, and is ejected through the side nozzles. The injection port of the multi-hole nozzle burner 6 is connected to the rotary kiln 8 for heating the rotary kiln. The raw material inlet of the rotary kiln 8 is connected to the pre-combustion tower 10 via the raw material pipeline 9. After being preheated by the preheater 10, the cement raw material enters the rotary kiln 8 through the raw material pipeline 9 to transfer heat with the solid products and pyrolysis gas, successfully obtaining clinker cement. In this embodiment, the waste heat outlet 612 on the outer shell 61-2 of the multi-nozzle burner 6 is connected to the pre-combustion tower 10 and / or the pyrolysis furnace 3 via the waste heat recovery pipeline 7. After the particulate solid products and pyrolysis gas are ejected from the multi-nozzle burner 6, the waste heat recovery pipeline 7 can collect the excess preheating and retransmit it to the pyrolysis furnace 3 or the intermediate pre-combustion tower 10. In this embodiment, the waste heat recovery pipeline 7 is preferred because it can collect the excess preheating and retransmit it to the pyrolysis furnace 3, which can greatly save energy consumption and reduce economic costs.

[0028] like Figure 4 As shown, in this embodiment, the solid-gas separation device 11 includes an outer tank 1101 and an inner screening tank 1102 disposed inside the outer tank 1101. The upper part of the outer tank 1101 is provided with a first gas outlet pipe 1103 for the smooth discharge of pyrolysis gas. A first feed pipe 1104 is provided on one side of the outer tank 1101, which is connected to the inner screening tank 1102. The particulate solid product and pyrolysis gas mixture output from the pyrolysis furnace enter the inner screening tank through the first feed pipe for cyclone separation. Small-diameter particulate solids are separated into the outer tank 1101; large-diameter particulate solids that are not separated are left in the inner screening tank. The bottom of the inner screening tank 1102 is provided with a first discharge port 1105; large-diameter particulate solids are discharged through the first discharge port. A second discharge port 1106 is provided at the lower part of the outer tank 1101; small-diameter particulate solids are discharged through the second discharge port to the multi-hole nozzle burner.

[0029] In this preferred embodiment, the inner screening tank 1102 includes an upper smooth cylinder 1102a and a lower screening cylinder 1102b connected sequentially from top to bottom. The lower screening cylinder 1102b has screening holes evenly distributed on it for screening out small-diameter solid particles that meet the requirements. The upper smooth cylinder facilitates the smooth discharge of pyrolysis gas; the lower screening cylinder 1102b is a conical cylinder, facilitating material discharge and cyclone screening; the first vent pipe 1103 is connected to the top of the upper smooth cylinder 1102a, facilitating the smooth discharge of pyrolysis gas from the inner screening tank to the first vent pipe. The first vent pipe 1103 has a vent hole on its outer wall between the outer tank 1101 and the upper smooth cylinder 1102a; the vent hole facilitates the smooth entry of pyrolysis gas from the outer tank into the first vent pipe.

[0030] In this preferred embodiment, the bottom of the outer tank 1101 is provided with a guide plate 1107 corresponding to the second discharge port 1106. The guide plate facilitates the smooth discharge of solids from the outer tank to the multi-hole nozzle burner. The second discharge port 1106 is connected to the second inlet 610 of the multi-hole nozzle burner 6. Solids from the outer tank enter the inner shell of the multi-hole nozzle burner through the second inlet. During the entry process, the spiral blades are pushed, giving the solid particles a pre-swirl initial velocity. After entering the side nozzle, a "swirling-direct flow" double-layer coating is formed at the root of the flame, resulting in better flame stabilization. The first exhaust pipe 1103 is connected to the first inlet 609 of the multi-hole nozzle burner 6. Pyrolysis gas enters the ventilation pipe through the first inlet. The first discharge port 1105 is connected to the pyrolysis furnace 3 through the return pipe 12. Large-diameter solids that are not separated in the inner screening tank re-enter the pyrolysis furnace 3 through the return pipe 12 for re-pyrolysis, improving the utilization rate of alternative fuels.

[0031] Alternative fuels are mainly divided into three categories: biomass, industrial waste, and municipal solid waste-derived fuels. Industrial waste includes waste tires, petroleum coke, and coal tar residue. Waste tires have a high hydrocarbon content and a calorific value of around 30 MJ / kg, close to that of pulverized coal, providing sufficient heat. However, they contain sulfur and heavy metals, and combustion may cause pollution, requiring desulfurization and exhaust gas treatment equipment. Petroleum coke has a high carbon content and low volatile matter, offering good combustion stability, but its high combustion temperature places high demands on refractory materials.

[0032] Biomass alternative fuels include straw, sawdust, and rice husks. Their typical characteristics include relatively low carbon content, high oxygen content, and high volatile matter content, making them easy to ignite and burn quickly. However, their calorific value is generally lower than that of pulverized coal, typically between 15-20 MJ / kg. Due to their high oxygen content, the theoretical air requirement during combustion is small, reducing the need for combustion air supply. However, because of their low energy density, large-scale use requires substantial storage and transportation equipment.

[0033] Municipal solid waste derived fuel (RDF) is produced from sorted and processed municipal solid waste. It has a complex composition and fluctuating calorific value, ranging from approximately 12-25 MJ / kg. Its advantages include waste reduction and resource recovery, but the processing is complex, contains many impurities, and requires strict control during combustion to prevent clogging and equipment corrosion.

[0034] Replacing pulverized coal combustion with alternative fuels can reduce cement production's reliance on traditional fossil fuels and decrease carbon emissions. However, different alternative fuels have significantly different characteristics, requiring targeted adjustments to combustion equipment and process parameters, such as adjusting burner structure and optimizing air distribution, to ensure stable and efficient combustion, guarantee cement clinker quality, and achieve green and sustainable development in the cement industry.

[0035] A corresponding flow control and monitoring system can also be configured in the cement production process for intelligent monitoring. The flow control and monitoring system consists of two parts: an intelligent valve group and detection sensors. The intelligent valve group comprises multiple high-precision flow regulating valves, installed on the various delivery pipelines for pyrolysis gas and solid products, and connected to the burner nozzles. The intelligent valve group receives real-time signals from the kiln temperature, pressure, gas composition analyzer, and material flow sensor. The controller quickly calculates and automatically adjusts the valve opening, precisely controlling the gas and solid flow rates of each nozzle, achieving dynamic optimization for targeted dosing. Further design can be made for multi-hole nozzle burners: monitoring sensors are placed near the burner outlet and in the mixing chamber to monitor the mixing and injection status of pyrolysis products in real time. The feedback data is used to further correct the flow control parameters, ensuring the burner is always in optimal working condition. Specifically, real-time signals are continuously collected from the kiln temperature, pressure, gas composition analyzer, and material flow sensor. These signals are transmitted to the controller. The controller, based on preset logic and the collected data, quickly calculates the required pyrolysis gas and solid product flow rates for each nozzle under the current operating conditions. Simultaneously, monitoring sensors continuously monitor the mixing and injection status of pyrolysis products, transmitting the feedback data back to the controller. The controller further adjusts the flow control parameters based on this feedback data, forming a closed-loop control system to ensure the burner is always in optimal operating condition. For example, when the kiln temperature decreases, the controller calculates the required increase in the flow rate of pyrolysis gas and solid fuel based on the temperature sensor signal. It then controls the flow regulating valve to increase its opening, allowing more pyrolysis products to enter the burner, thereby raising the combustion temperature and meeting the needs of cement production.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-hole nozzle burner, characterized in that: The device includes a feed chamber (601) and a mixing spray chamber (602) connected to each other. The outlet end of the feed chamber (601) is provided with a multi-hole nozzle (603), and the multi-hole nozzle (603) extends into the mixing spray chamber (602). The multi-hole nozzle (603) includes a central air nozzle (606) and several side nozzles (604). The several side nozzles (604) are distributed on a circle centered on the central air nozzle (606). The feed chamber (601) is provided with a ventilation pipe (608), which is connected to the central air nozzle (606). The side nozzles (604) are connected to the feed chamber (601). The mixing spray chamber (602) is provided with a flow guide rib (605), which is spirally arranged with the central air nozzle (606) as the center.

2. The multi-hole nozzle burner according to claim 1, characterized in that: The feeding chamber (601) includes an inner shell (61-1) and an outer shell (61-2) fixedly connected, forming an annular sealed cavity between the inner shell (61-1) and the outer shell (61-2); a ventilation pipe (608) is disposed inside the inner shell (61-1), a multi-hole nozzle (603) is connected to the inner shell (61-1), and the inner shell (61-1) has a first feed port (609) and a second feed port (610) on the feeding side, the second feed port (610) being connected to the ventilation pipe (608); the first feed port (609) being connected to the inner shell (61-1).

3. The multi-hole nozzle burner according to claim 2, characterized in that: The inner shell (61-1) is provided with a spiral blade (611), which is rotatably mounted on the ventilation pipe (608) and corresponds to the first feed port (609); the outer shell (61-2) is provided with a waste heat outlet (612); the side nozzle (604) is provided with a wear-resistant ceramic liner.

4. The multi-hole nozzle burner according to any one of claims 1 to 3, characterized in that: The mixing chamber (602) includes a mixing housing, which is arranged on the same central axis as the multi-hole nozzle (603), and the flow guide rib (605) is located between the mixing housing and the multi-hole nozzle (603).

5. A targeted combustion device for cement kilns, characterized in that: The pyrolysis furnace (3), rotary kiln (8), and the multi-hole nozzle burner (6) as described in claim 4 are included. The feed inlet of the pyrolysis furnace (3) is connected to the storage bin (1) through the feed pipe (2). The discharge port of the pyrolysis furnace (3) is connected to a solid-gas separation device (11). The gas outlet of the solid-gas separation device (11) is connected to the first feed inlet (609) of the multi-hole nozzle burner (6). The discharge port of the solid-gas separation device (11) is connected to the second feed inlet (610) of the multi-hole nozzle burner (6). The injection port of the multi-hole nozzle burner (6) is connected to the rotary kiln (8). The raw material inlet of the rotary kiln (8) is connected to the pre-combustion tower (10) through the raw material pipe (9).

6. The targeted combustion device for cement kilns according to claim 5, characterized in that: The waste heat outlet (612) on the outer shell (61-2) of the multi-hole nozzle burner (6) is connected to the pre-combustion tower (10) and / or the pyrolysis furnace (3) via the waste heat recovery pipe (7).

7. The targeted combustion device for cement kilns according to claim 5 or 6, characterized in that: The solid-gas separation device (11) includes an outer tank (1101) and an inner screening tank (1102) disposed inside the outer tank (1101). The upper part of the outer tank (1101) is provided with a first gas outlet pipe (1103), and the side of the outer tank (1101) is provided with a first feed pipe (1104). The first feed pipe (1104) is connected to the inner screening tank (1102). The bottom of the inner screening tank (1102) is provided with a first discharge port (1105), and the lower part of the outer tank (1101) is provided with a second discharge port (1106).

8. The targeted combustion device for cement kilns according to claim 7, characterized in that: The inner screening tank (1102) includes an upper smooth cylinder (1102a) and a lower screening cylinder (1102b) connected from top to bottom. Screening holes are evenly distributed on the lower screening cylinder (1102b).

9. The targeted combustion device for cement kilns according to claim 8, characterized in that: The lower screening cylinder (1102b) is a conical cylinder; the first vent pipe (1103) is connected to the top of the upper smooth cylinder (1102a), and the first vent pipe (1103) has a vent hole on the outer wall between the outer tank (1101) and the upper smooth cylinder (1102a).

10. The targeted combustion device for cement kilns according to claim 8 or 9, characterized in that: The bottom of the outer tank (1101) is provided with a guide plate (1107) corresponding to the second discharge port (1106). The second discharge port (1106) is connected to the second feed port (610) of the multi-hole nozzle burner (6). The first gas outlet pipe (1103) is connected to the first feed port (609) of the multi-hole nozzle burner (6). The first discharge port (1105) is connected to the pyrolysis furnace (3) through the return pipe (12).

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