Beta-shaped element combustor ignition and stable combustion device
By designing a shell-shaped burner, the interaction between the cold pulverized coal airflow and the high-temperature flame is utilized to solve the problem of burner ignition stability under low load in existing pulverized coal boilers, achieving high-efficiency, low-NOx combustion and stable combustion under ultra-low load.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG XIANGHUAN ENVIRONMENTAL TECH CO LTD
- Filing Date
- 2023-09-20
- Publication Date
- 2026-05-15
AI Technical Summary
When existing pulverized coal boilers are running at low loads, it is difficult to control the temperature and mixing amount of the recirculating and reheating flame, resulting in poor ignition stability. In particular, under low load conditions, the burner has difficulty maintaining stable combustion.
The U-shaped burner is adopted. By setting the inlet structure, throat expansion channel, expansion channel and ignition device in the burner, the combustion is decoupled from the combustion in the pulverized coal boiler. The interaction between the cold pulverized coal airflow and the high temperature flame is used for pre-ignition to form a stable high temperature flame and ensure stable ignition in the burner.
It achieves high-temperature stable combustion in boilers under low-load conditions, maintains stable combustion under ultra-low loads, adapts to various combustion organization forms in boiler furnaces, and improves combustion efficiency and burnout effect.
Smart Images
Figure CN117287696B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of combustion technology, specifically relating to a shell-shaped element burner ignition and stabilization device. Background Technology
[0002] In the field of existing pulverized coal boilers and their burners, pulverized coal burners are mainly classified into two types: direct-flow pulverized coal burners and swirl pulverized coal burners. The combustion organization and ignition / stabilization of existing pulverized coal boilers are inseparable, both igniting at the burner outlet within the furnace and then burning within the furnace (except for industrial pulverized coal combustion devices). Existing swirl burners rely on recirculation heat as the ignition heat source, and recirculation heat is one of the core issues in swirl burner stabilization technology. Existing direct-flow burners with a tangential combustion method rely on the upstream rotating flame merging with primary air as the ignition source. The temperature and mixing rate of the recirculation heat flame are the core issues for stable combustion. The difficulty in controlling the recirculation heat and the upstream flame supply has become a constraint on the ignition and stable combustion of existing pulverized coal boilers and their burners, especially when the boiler is operating at low load, the furnace flame temperature or recirculation flow rate decreases, making stable ignition even more difficult.
[0003] Modern pulverized coal burners are essentially injectors that mix air and pulverized coal. They rely on the flame inside the furnace to supply ignition heat, working together to achieve ignition and combustion. Under low loads, the furnace temperature is low, recirculation and heat recovery are weakened, ignition conditions deteriorate, and may even fail to meet the requirements. Stable ignition and combustion are crucial for boiler operation at low loads and for ensuring complete combustion. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a shell-shaped burner ignition and stabilization device. This device truly achieves combustion within the burner, decoupling it from combustion within the pulverized coal boiler and thus remaining unaffected by the boiler's combustion conditions and load. The shell-shaped burner ignition and stabilization device ignites the pulverized coal before feeding it into the boiler. This device advances the physical space and reaction timing of combustion, enabling the boiler to maintain stable high-temperature combustion under low load conditions, achieving stable operation of coal-fired boilers at ultra-low loads (below 20% of rated load).
[0005] To achieve the above objectives, the technical solution of the present invention is as follows:
[0006] The ignition and stabilization device for the shell-shaped burner proposed in this invention includes an inlet structure, a burner shell, a throat expansion channel, an expansion channel, an outlet structure, and an ignition device.
[0007] The cold pulverized coal gas outlet of the aforementioned inlet structure is located at the center of the bottom of the burner shell;
[0008] The outlet structure is connected to the bottom of the burner housing;
[0009] A throat expansion channel and an expansion channel are provided inside the burner housing; the throat expansion channel is fixed at the center of the bottom of the burner housing, and its top is connected to the expansion channel through a cylindrical channel; and the connection between the throat expansion channel and the inlet structure is semi-closed with a pre-reserved notch.
[0010] An ignition device is installed on the top of the burner housing, opposite to the expansion channel.
[0011] As a further technical solution, the cold coal powder airflow outlet of the inlet structure is designed with a narrowing, which allows the cold coal powder airflow to form a high-speed jet. By drawing in high-temperature airflow, the mixing and heat exchange of the high-temperature and low-temperature airflows are enhanced.
[0012] As a further technical solution, the inlet structure includes an inlet channel for cold pulverized coal airflow, a 90° turning channel, and an outlet channel for cold pulverized coal airflow; the inlet channel for cold pulverized coal airflow is a horizontal channel, the outlet channel for cold pulverized coal airflow is a vertical channel, and the outlet channel is a constricted pipe.
[0013] As a further technical solution, the outlet channel extends into the throat scaling channel, and the bottom of the throat scaling channel is connected to the 90-degree turn channel through a connecting pipe, with a notch provided on the connecting pipe.
[0014] As a further technical solution, the throat expansion channel is a tapered tube with a bottom diameter larger than the top diameter. The throat expansion channel is located at the lower center of the circular shell, at the outlet channel of the cold pulverized coal gas flow. The purpose of setting the throat expansion channel is to allow the primary air jet to enter at high speed from the bottom, draw in some of the high-temperature gas flow, heat or ignite it, and continue heating in the central expansion tube through heat conduction and radiation heat exchange until the top encounters a high-temperature flame and is fully ignited.
[0015] As a further technical solution, the expansion channel is a conical tube with a bottom diameter smaller than the top diameter. The expansion channel is a cold pulverized coal gas outlet channel that receives high-speed primary airflow and mixed high-temperature flue gas flow. It gradually expands along the circular shell. During the expansion flow process, it continuously receives radiation and mixed heating from the flame center until stable ignition.
[0016] As a further technical solution, the outlet structure is a variable diameter channel, the diameter of which is equal to the diameter of the bottom of the burner housing at the connection end with the burner housing.
[0017] As a further technical solution, the ignition device is an oil gun (natural gas) ignition device.
[0018] As a further technical solution, the inlet channel of the cold pulverized coal gas flow and the outlet channel of the high-temperature flame of the inlet structure are located on opposite sides of the burner shell. Preferably, the axis of the inlet channel of the cold pulverized coal gas flow and the axis of the outlet channel of the high-temperature flame are on the same straight line.
[0019] As a further technical solution, when the ignition device is a plasma ignition device, it is located below the outlet of the throat expansion channel and above the primary air nozzle; that is, there are two types of ignition devices in this invention: one is oil (natural gas) gun ignition, installed at the outlet of the primary air flow deformation channel; the other is plasma ignition, installed at the outlet of the primary air throat nozzle. The oil gun ignition device of the U-shaped burner is located at the outlet of the primary air flow expansion channel, using the primary air flow as the combustion-supporting flow, and is not suitable for other airflows, such as secondary air; the plasma ignition device of the U-shaped burner is located above the primary air nozzle, where the coal / coke powder concentration is high, resulting in high plasma ignition efficiency.
[0020] The shell-shaped element burner stabilization device in this invention is ignited outside the furnace and inside the burner, and then sent into the furnace for further combustion after ignition; the shell-shaped element burner stabilization device has, but is not limited to, a high-speed jet suction effect to obtain ignition heat and achieve ignition.
[0021] The ignition mechanism of the shell-shaped burner ignition and stabilization device is as follows: the cold pulverized coal gas flow and the high-temperature flame gas flow after ignition are interactive. The high-temperature flame heats the cold pulverized coal gas flow to the ignition point through radiation heat transfer and mixing. After ignition, the flame spreads radially from the center outward until the entire gas flow is burned.
[0022] The high-temperature flame stream after combustion is partially mixed with the cold pulverized coal stream, and part of it is sent to the boiler through the outlet to continue combustion.
[0023] The center of the ignition and stabilization device of the shell-shaped burner contains a stable high-temperature flame and a low-speed rotating airflow. This airflow continuously outputs or transports heat to the cold pulverized coal airflow, and is constantly replenished from the ignition airflow.
[0024] The beneficial effects of this invention are as follows:
[0025] 1. This invention utilizes a shell-shaped burner ignition and stabilization device. The primary air-coal powder gas flow enters the shell-shaped burner and mixes with the high-temperature flame gas flow, easily obtaining ignition heat. The cylindrical shell-shaped burner has a high-temperature stable flame at its center, which continuously radiates and mixes the primary air flow for heat exchange, facilitating complete ignition. The presence of a high-temperature flame at the center of the cylinder allows for continuous ignition and mixing of primary air-coal powder, as well as continuous outflow of high-temperature flame, creating a continuous swirling renewal. Ignition does not require other combustion-supporting gases; only the primary air flow is needed. The wall surface temperature is low, the flow rate is high, and slag accumulation on the wall surface is minimal.
[0026] 2. The ignition and stabilization device for the shell-shaped element burner proposed in this invention has a primary air jet inlet and a throat expansion channel located at the center of the cylinder. After the airflow is heated and ignited, it turns back downwards from the top. In the middle and lower part, the ignition airflow is divided into two parts: one part mixes with the primary air cooling airflow through a reserved opening, and the other part flows out from the high-temperature airflow outlet. To prevent slag accumulation, it is generally arranged vertically. The cold coal powder airflow of the shell-shaped element burner and the high-temperature airflow after ignition generally flow in opposite directions, but the two airflows form a certain angle. The primary air jet is injected at high speed from the bottom, drawing in part of the high-temperature airflow, heating or igniting it. It is continuously heated in the central expansion tube through heat conduction and radiation heat exchange until it encounters the high-temperature flame at the top and is fully ignited.
[0027] 3. The shell-shaped burner ignition and stabilization device of this invention, when used in conjunction with various boiler furnaces, forms a completely new combustion mode and a new combustion organization form, adapting to high-efficiency, low-NOx combustion and other requirements. During low-load boiler operation, it allows secondary combustion in the furnace, ensuring rapid and complete combustion, advancing the reaction time of combustion in the boiler, and concentrating the physical space of combustion. This enables stable operation of coal-fired boilers at ultra-low loads (below 20% of rated load).
[0028] 4. In the ignition and stabilization device of the shell-shaped burner of the present invention, the entire airflow presents a swirling state. At the center of the swirling flow, the oxygen content is relatively abundant and the temperature is high, making it easy to ignite and resulting in good semi-gasification effect. Corresponding to different air / pulverized coal fuel ratios, the shell-shaped burner can be used for semi-gasification, gasification, and complete combustion. Attached Figure Description
[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0030] Figure 1 This is a schematic diagram of the axial structure of the shell-shaped burner ignition and stabilization device in Example 1.
[0031] Figure 2 This is a schematic diagram of the ignition and stabilization device for the shell-shaped burner in Example 1.
[0032] Figure 3 This is a schematic diagram of the main structure of the shell-shaped burner ignition and stabilization device in Example 1.
[0033] Figure 4 This is a schematic diagram of the main structure of the shell-shaped burner ignition and stabilization device disclosed in Example 2.
[0034] The components include: 1. Inlet structure; 2. Burner shell; 3. Throat expansion channel; 4. Expansion channel; 5. Outlet structure; 6. Ignition device; and 7. Notch. Detailed Implementation
[0035] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0037] Example 1
[0038] This embodiment discloses a shell-shaped burner ignition and stabilization device, including: an inlet structure 1, a burner shell 2, a throat expansion channel 3, an expansion channel 4, an outlet structure 5, and an ignition device 6;
[0039] An inlet structure 1 and an outlet structure 5 are provided at the bottom of the burner housing 2. A throat expansion channel 3 and an expansion channel 4 are provided inside the burner housing 2. An ignition device 6 is provided at the top of the burner housing 2. The throat expansion channel 3 is fixed at the center of the bottom of the burner housing 2, and its top is connected to the expansion channel 4 via a cylindrical channel. The connection between the throat expansion channel 3 and the inlet structure 1 is semi-closed, i.e., a notch 7 is provided. Figure 3 As shown;
[0040] The inlet structure 1 is connected to the center of the bottom of the burner shell 2. The inlet structure 1 has a 90° corner. The inlet channel of the inlet structure 1 is a horizontal channel and the outlet channel is a vertical channel. The outlet position of the vertical channel forms a constriction to serve as the outlet of cold pulverized coal gas flow, forming a high-speed jet. By drawing in high-temperature gas flow, the mixing and heat exchange of the high-temperature and low-temperature gas flow are enhanced.
[0041] Furthermore, in this embodiment, the inlet structure 1 is a circular channel, and the outlet channel of the inlet structure 1 extends into the throat scaling channel 3.
[0042] Furthermore, in this embodiment, the burner shell 2 is a cylindrical or near-cylindrical shell. The cold pulverized coal gas flow at the inlet has sufficient mixing conditions with the gas flow after high-temperature combustion (gasification) to obtain ignition heat and reach the ignition temperature. The high-temperature combustion flame vortex formed by the circular shell is pushed to the primary air outlet. The high-temperature flame part is mixed with the primary air, and the ignition heat is obtained through mixing to ignite the primary air pulverized coal. The high-temperature flame part flows out of the shell-shaped burner through the outlet and enters the next device, such as a boiler.
[0043] Furthermore, in this embodiment, the throat-expanding channel 3 is located at the center of the burner housing 2, i.e., at the outlet of the primary air nozzle. The purpose of setting the throat-expanding channel 3 is to allow the primary air jet to enter at high speed from the bottom, and to draw in a portion of the high-temperature airflow through the pre-reserved opening in the throat-expanding channel 3 for heating or ignition. The airflow is continuously heated in the throat-expanding channel 3 through heat conduction and radiation heat exchange until it encounters a high-temperature flame at the top, achieving full ignition. Furthermore, in this embodiment, the throat-expanding channel 3 is a conical cylindrical structure with a large bottom diameter and a small top diameter. Its bottom is connected to the outer wall of the inlet structure 1 through a connecting channel, and a pre-reserved opening 7 is provided on the connecting pipe. This allows the heated and ignited airflow to bend back downwards from the top and then mixed into the primary air cooling airflow through the opening 7 in the lower middle part. The throat-expanding channel 3 in this invention mainly serves to draw in a portion of the high-temperature airflow, acting as an ejector to increase the amount of high-temperature airflow returned and to ensure thorough mixing with the primary air and coal.
[0044] Furthermore, in this embodiment, the expansion channel 4 is a cold pulverized coal gas outlet channel, receiving high-speed primary airflow and mixed high-temperature flue gas flow. It gradually expands along the circular shell, continuously receiving radiation and mixing heating from the flame center until stable ignition. The expansion channel 4 can be arranged in an irregular shape (such as a stacked or toothed shape) to enhance the mixing of the cold and hot airflows and coordinate their flow. The expansion channel 4 can be a semi-open partition or a louver-like partition. In this embodiment, the expansion channel 4 is a cylindrical structure with a small bottom diameter and a large top diameter. The expansion channel 4 allows the mixed airflow to expand slowly to meet the spatial requirements for combustion or gasification, ensuring complete combustion or gasification of the pulverized coal.
[0045] Furthermore, such as Figure 1 As shown, the outlet structure 5 is connected to the right side of the burner shell, and the shell-shaped element burner flows out from the side opposite to the inlet structure 1. The outlet structure 5 is a 90-degree turning device, with one end connected to the bottom of the burner shell 2. After the 90-degree turn, the other end flows out horizontally from the shell-shaped element burner. That is, the outlet of the outlet structure 5 and the inlet structure 1 are located on opposite sides of the burner shell 2. This design is more reasonable because, after simulation calculations and experimental verification of the pulverized coal combustion airflow, the data obtained is more reasonable, and it can meet the space requirements for equipment control layout.
[0046] Furthermore, the outlet flame gas composition of the aforementioned shell-shaped burner stabilizing device is generally, but not limited to, incomplete combustion, such as the semi-gasification combustion state of primary air pulverized coal, or the complete combustion state.
[0047] The aforementioned shell-shaped element burner stabilization device ignites outside the furnace and inside the burner, and then sends the ignited component into the furnace for further combustion. The aforementioned shell-shaped element burner stabilization device has, but is not limited to, a high-speed jet suction effect to obtain ignition heat and achieve ignition.
[0048] Furthermore, in this embodiment, the ignition device is an oil gun (natural gas) ignition device, which is set above the primary air expansion channel to ignite the primary air pulverized coal until a stable high-temperature flame is formed at the center of the shell-shaped element burner. This ignition device uses the primary air flow as the combustion-supporting flow and does not use other air flows, such as secondary air. The ignition mechanism of the shell-shaped element burner ignition and stabilization device is as follows: the cold pulverized coal flow and the high-temperature flame flow after ignition are interactive. The high-temperature flame heats the cold pulverized coal flow through radiation heat transfer and mixing to reach the ignition point. After ignition, the flame spreads radially from the center outward until the entire flow is burned.
[0049] After combustion, the high-temperature flame airflow is partially mixed with the incoming cold pulverized coal airflow through the opening 7, flows upward, and is combusted. The remaining airflow is directly sent into the boiler through the outlet structure to continue combustion.
[0050] The center of the ignition and stabilization device of the shell-shaped burner contains a stable high-temperature flame and a low-speed rotating airflow. This airflow continuously outputs or transports heat to the cold pulverized coal airflow, and is constantly replenished from the ignition airflow.
[0051] The shell-shaped burner oil gun ignition device is located at the outlet of the primary air flow expansion channel. It uses the primary air flow as the combustion-supporting flow and is not suitable for other air flows, such as secondary air.
[0052] Example 2
[0053] This embodiment provides another type of ignition and combustion stabilization device for a shell-shaped burner. The difference between this device and Embodiment 1 lies in the use of a different ignition device, such as... Figure 4 As shown, the ignition device in this embodiment is a plasma ignition device. The plasma ignition device is located below the throat expansion channel outlet and above the primary air nozzle. The plasma heats the pulverized coal particles until they burn, forming a stable high-temperature flame at the center of the U-shaped element burner. Ignition does not use other combustion-supporting gases; only the primary air flow is needed. The plasma ignition device of the U-shaped element burner is located above the primary air nozzle, where the pulverized coal / coke concentration is high, resulting in high plasma ignition efficiency.
[0054] The remaining devices are the same as in Embodiment 1, and will not be described in detail here.
[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A shell-shaped element burner ignition and stabilization device, characterized in that, This includes the inlet structure, burner housing, throat expansion channel, expansion channel, outlet structure, and ignition device; The cold pulverized coal gas outlet of the aforementioned inlet structure is located at the center of the bottom of the burner shell; The outlet structure is connected to the bottom of the burner housing; A throat expansion channel and an expansion channel are provided inside the burner shell. The throat expansion channel is fixed at the center of the bottom of the burner shell, and its top is connected to the expansion channel through a cylindrical channel. The connection between the throat expansion channel and the inlet structure is semi-closed with a pre-reserved notch. The inlet structure and the throat expansion channel are located at the center of the cylinder. After the airflow is heated and ignited, it turns back downward from the top and all around. In the middle and lower part, the ignition airflow is divided into two parts. One part is mixed with the refrigerant powder airflow through the pre-reserved notch, and the other part flows out from the outlet structure. An ignition device is installed on the top of the burner housing, opposite to the expansion channel.
2. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 1, characterized in that, The cold coal powder airflow outlet of the imported structure has a constricted design.
3. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 1, characterized in that, The inlet structure includes an inlet channel for cold pulverized coal airflow, a 90° turning channel, and an outlet channel for cold pulverized coal airflow; the inlet channel for cold pulverized coal airflow is a horizontal channel, the outlet channel for cold pulverized coal airflow is a vertical channel, and the outlet channel is a constricted pipe.
4. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 3, characterized in that, The outlet channel extends into the throat narrowing channel, and the bottom of the throat narrowing channel is connected to the 90° corner channel through a connecting pipe. A notch is provided on the connecting pipe.
5. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 3, characterized in that, The throat-scaling channel is a tapered tube with a bottom diameter larger than a top diameter.
6. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 3, characterized in that, The expansion channel is a tapered tube, with the bottom diameter being smaller than the top diameter.
7. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 3, characterized in that, The outlet structure is a variable diameter channel, the diameter of which is equal to the diameter of the bottom of the burner housing at the end where it connects to the burner housing.
8. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 1, characterized in that, The ignition device is an oil gun or a natural gas ignition device.
9. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 1, characterized in that, The inlet channel for the cold pulverized coal airflow and the outlet channel for the high-temperature flame of the inlet structure are located on opposite sides of the burner shell.
10. The ignition and combustion stabilization device for the shell-shaped burner as described in claim 9, characterized in that, When the ignition device is a plasma ignition device, it is located below the throat expansion channel outlet and above the primary air nozzle.