Stable combustion device for ultralow load of pulverized coal boiler in power plant
By designing an ultra-low load combustion stabilization device for pulverized coal boilers in power plants, the problem of unstable coal combustion in traditional thermal power units during low load operation is solved, efficient and stable combustion is achieved, and the peak shaving capacity and operation efficiency of thermal power units are improved.
Patent Information
- Application Number
- CN202421821496.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-07-30
AI Technical Summary
When the traditional thermal power unit is running at low load due to deep peak shaving, the coal powder in the furnace is unstable, and fire extinguishing is prone to occur, which affects the operating efficiency and grid stability.
An ultra-low load combustion stabilization device for pulverized coal boilers in power plants is designed, including a coal powder conveying system and a coal powder combustion stabilization system. The coal powder conveying system consists of a coal powder thick and thin separator, a rotor metering scale, an electric gas locker and a drainage injection pump. The coal powder combustion stabilization system includes a gasification burner and a DCS control system. The partial combustion and gasification of the coal powder is achieved through the gasification burner, and the mixture of steam and air is combined for stable combustion.
It significantly improves the combustion efficiency of coal powder, can burn stably under low load, reduces operating costs, improves the peak shaving capacity and operating efficiency of the boiler, and ensures the stable operation of the power grid.
Smart Images
Figure CN222836857U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of low-load stable combustion of pulverized coal boilers, and specifically relates to an ultra-low-load stable combustion device for pulverized coal boilers in power plants. Background Art
[0002] In recent years, with the continuous optimization of China's power structure, the proportion of renewable energy such as hydropower and photovoltaics in the power generation field has increased significantly. However, renewable energy is affected by weather, seasons, and day and night changes, and has significant intermittent, volatile and random characteristics, which to a certain extent limits its absorption capacity and peak-shaving capacity, which is slightly insufficient compared to the stability and reliability of thermal power generation. In order to ensure the stability and reliability of power supply, thermal power units need to have deep peak-shaving capabilities to effectively cope with the volatility and uncertainty of new energy power generation.
[0003] However, when traditional thermal power units are operated at low loads for deep peak regulation, the amount of coal entering the furnace will be significantly reduced, resulting in a significant reduction in the calorific value of the coal and a decrease in the furnace temperature. This low-load operation delays the ignition point of the coal powder in the furnace, significantly reduces the combustion stability, and makes the boiler prone to fire extinguishing. This not only affects the operating efficiency and economic benefits of the thermal power units, but may also pose a threat to the stable operation of the power grid.
[0004] At present, the low-load stable combustion technology of coal-fired boilers has become a hot topic in the power industry. The existing technologies mainly include auxiliary fuel stable combustion technology, plasma stable combustion technology, oxygen-enriched stable combustion technology and air preheating stable combustion technology. Although these technologies have improved the combustion stability of boilers at low loads to a certain extent, there are still many problems. For example, although the auxiliary fuel stable combustion technology can improve the combustion stability, it increases the operating cost; although the plasma stable combustion technology can ignite the pulverized coal airflow, it has poor adaptability to coal types and requires large equipment investment; although the oxygen-enriched stable combustion technology and air preheating stable combustion technology can improve the combustion effect of pulverized coal, they also have problems such as high operating cost and poor safety.
[0005] In response to the above problems, some new low-load stable combustion technologies have been proposed. For example, the low-load stable combustion technology of coal gasification coupled pulverized coal boilers uses high-temperature combustion gas to ignite the primary air pulverized coal flow through partial combustion and gasification of pulverized coal in the gasification burner, thus achieving ultra-low load stable combustion of the boiler. However, this technology still has some problems in practical application, such as low pulverized coal concentration and unstable transportation under low load, which limits its widespread application in existing power plants.
[0006] Therefore, how to develop a low-load stable combustion technology for coal-fired boilers that can meet the requirements of low-load stable combustion and has wide adaptability to coal types, low operating costs and high safety is of great significance to improving the peak-shaving capacity and operating efficiency of thermal power units. Utility Model Content
[0007] Aiming at the technical problems of unstable pulverized coal combustion and unstable transportation when the pulverized coal boiler of a power plant is running at low load, the utility model provides a combustion stabilizing device for the ultra-low load of the pulverized coal boiler of a power plant.
[0008] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a combustion stabilizing device for ultra-low load of pulverized coal boiler in power plant, comprising a pulverized coal conveying system and a pulverized coal combustion stabilizing system. The pulverized coal conveying system is composed of a pulverized coal concentration separator, a rotor metering scale, an electric air lock and a drainage jet pump. The pulverized coal inlet of the pulverized coal concentration separator is connected to the pulverized coal conveying pipeline, and its pulverized coal outlet is connected to the furnace of the pulverized coal boiler. The outer branch port of the pulverized coal concentration separator is connected to the material inlet of the drainage jet pump through the rotor metering scale and the electric air lock in turn; the pulverized coal combustion stabilizing system comprises a gasification burner and a matching DCS control system, and the DCS control system is used to control the gasification burner. Operating conditions: the material outlet of the drainage jet pump is connected to the central pulverized coal channel of the gasification burner; the drainage jet pump is used to stably transport the material to the gasification burner; the secondary air transport unit is connected to the outer ring secondary air channel of the gasification burner; the steam transport unit is connected to the protective gas channel at the bottom of the gasification burner; the steam transport unit transports steam and air mixture into the gasification burner according to actual operating conditions to achieve stable operation of pulverized coal combustion and gasification in the furnace; the gasification burner is installed in the center of the boiler burner; the pulverized coal enters the gasification burner under the action of the drainage jet pump for partial combustion and gasification; the gas-solid two-phase flow products after gasification are sprayed into the furnace of the pulverized coal boiler through the boiler burner for combustion.
[0009] As a further explanation and limitation of the above technical solution, the coal powder thick-lean separator is composed of four continuously bent 45° elbows and straight pipe sections on both sides. The coal powder inlet is the left straight pipe section, and the coal powder outlet is the right straight pipe section. The guide component is located at the first 45° elbow. When the coal powder is transported to the guide component, the fluid flow direction changes, and the flow direction is along the tangent direction of the pipeline. The separation component is located at the second 45° elbow. The coal powder is guided by the first 45° elbow, and a diversion will occur at the second 45° elbow, so that a coal powder dense phase flow is formed on the outside of the pipeline and a coal powder dilute phase flow is formed on the inside of the pipeline. The outer branch port is located at the third 45° elbow, and its axial direction is consistent with the tangent direction of the first 45° elbow. The separated coal powder dense phase flow is discharged along the outer branch port, and the dilute phase flow is discharged from the coal powder outlet of the straight pipe section after being guided by the fourth 45° elbow along the inside of the pipeline.
[0010] As a further supplement to the above technical solution, the entire pipeline of the coal powder thick-thin separator is provided with a ceramic anti-wear layer inside, and the connecting part of its outer branch port extending into the pipeline is provided with a ceramic anti-wear layer inside and outside.
[0011] As a further supplement to the above technical solution, the ratio of the diameter of the outer branch port of the pulverized coal thick-lean separator to its inlet and outlet diameters is 1 / 5 to 1 / 3.
[0012] As a further supplement to the above technical solution, a regulating valve is provided on the outer branch port of the pulverized coal thick-thin separator, and the regulating valve controls the amount and concentration of pulverized coal by adjusting the cross-sectional size of the outer branch port.
[0013] As a further explanation and limitation of the above technical solution, the gasification burner is composed of a three-channel nozzle and a furnace body, wherein the three-channel nozzle of the gasification burner is composed of a diesel drying furnace system, a central coal powder channel and an outer ring secondary air channel, and the diesel drying furnace system is composed of a diesel pressurized atomization gun and a high-energy igniter; the furnace body of the gasification burner is divided into three sections: a preheating section, a gasification section and an outlet section. The preheating section is an eccentric cone mouth, and its center line position deviates upward with a tapering angle of 90 to 180°. The gasification section is a cylindrical structure with a protective gas channel for a steam and air mixture at the bottom. The outlet section is an eccentric cone mouth, and its center line position deviates downward with a tapering angle of 30 to 90°.
[0014] As a further supplement to the above technical solution, the diameter of the outlet section barrel is 1 / 5 to 1 / 2 times the diameter of the gasification section barrel.
[0015] As a further explanation and limitation of the above technical solution, the furnace body of the gasification burner is composed of a metal shell, a heat insulating material and a refractory castable.
[0016] As a further supplement to the above technical solution, the gasification burner includes two installation modes: horizontal and vertical. The bottom of the gasification burner is fixedly connected by a steel structure bracket, and the top is hoisted and connected by a spring hanger.
[0017] As a further supplementary explanation of the above technical solution, the bottom of the gasification burner is fixedly connected by a steel structure bracket, and the top of the gasification burner is hoisted and connected by a spring hanger.
[0018] Compared with the existing low-load stable combustion technology, the utility model provides an optimization scheme for the ultra-low-load stable combustion device of the pulverized coal boiler in a power plant, and its main beneficial effects are reflected in the following aspects:
[0019] 1. The utility model realizes partial combustion and gasification of pulverized coal in the furnace through the design of gasification burner. The gas-solid two-phase flow products after gasification are further burned in the furnace of the boiler, which significantly improves the combustion efficiency of pulverized coal. At the same time, it can easily cope with coal-fired boilers of any type and scale of coal, especially solves the combustion and ignition problems of high-grade low-activity coal such as lean coal and anthracite, and greatly improves the combustion efficiency of the boiler.
[0020] 2. The utility model utilizes a steam delivery unit to deliver a mixture of steam and air to the gasification burner according to actual working conditions. No special supporting engineering or safety measures are required. The operation is simple and the system can be flexibly adjusted when the load fluctuates, thus ensuring the stability and reliability of operation.
[0021] 3. The utility model can be flexibly configured and installed according to boilers with different combustion modes through the gasification burner. It is applicable to pulverized coal boilers of both counter-combustion mode and four-corner tangential circle combustion mode, and has strong universality.
[0022] 4. The utility model transforms the existing pulverized coal boiler, and its operating condition can be reduced to less than 20% of the unit load, meeting the requirements of ultra-low load peak regulation and providing greater operating flexibility for the power plant.
[0023] 5. The utility model adopts high-temperature fuel gas for combustion-assisted combustion by coal pulverization and quality improvement, which not only has high combustion efficiency, but also has simple process and low operating cost. Even when the load is reduced to 20%, there will be no additional operating cost, and the unit can achieve rapid peak regulation from full load to low load conditions. It can not only greatly reduce the amount of nitrogen oxides generated during coal pulverization, but also avoid the generation of pollutants such as tar, dust, VOCs, etc., making a positive contribution to environmental protection.
[0024] 6. The utility model is compact, easy to install, and highly adaptable, and can be widely used in various types of coal-fired boilers. At the same time, it can also stably burn pulverized coal during the peak load regulation of the boiler, as well as burn coal, biomass, organic carbon-containing waste, etc., and has broad application prospects.
[0025] 7. The utility model can replace the boiler micro-oil ignition system through the gasification burner, realize oil-free ignition cold start, and ensure the stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a structural schematic diagram of the ultra-low load stabilizing combustion device used for a pulverized coal boiler in a power plant in the utility model;
[0027] Figure 2 It is a structural schematic diagram of the thick and thin coal powder separator in the utility model;
[0028] Figure 3This is the layout diagram of the gasification burner for a four-corner tangential subcritical 350MW coal-fired boiler;
[0029] Figure 4 This is the layout diagram of the gasification burner for an opposed supercritical 350MW coal-fired boiler.
[0030] In the figure: the pulverized coal boiler is 1, the pulverized coal thick and thin separator is 2, the rotor metering scale is 3, the electric air lock is 4, the drainage jet pump is 5, the gasification burner is 6, the secondary air delivery unit is 7, the steam delivery unit is 8, and the regulating valve is 9.
[0031] Among them, the specific structure of the coal powder thick-thin separator is: the coal powder inlet is 201, the coal powder outlet is 202, the first 45° elbow is 203, the second 45° elbow is 204, the third 45° elbow is 205, the fourth 45° elbow is 206, the guide assembly is 207, the separation assembly is 208, and the outer branch port is 209. DETAILED DESCRIPTION
[0032] In order to further illustrate the technical solution of the utility model, the following Figures 1 to 4 ,According to the design scheme and on-site transformation implementation, we further illustrate the utility model through three embodiments. Embodiment 1
[0033] As attached Figure 1 and 2 As shown, a combustion stabilizing device for ultra-low load of pulverized coal boiler in power plant includes two parts: pulverized coal conveying system and pulverized coal combustion stabilizing system.
[0034] (i) The pulverized coal conveying system is composed of a pulverized coal thick-thin separator 2, a rotor metering scale 3, an electric air lock 4 and a drainage jet pump 5. The pulverized coal inlet 201 of the pulverized coal thick-thin separator 2 is connected to the pulverized coal conveying pipeline, and its pulverized coal outlet 202 is connected to the furnace of the pulverized coal boiler 1. The outer branch port 209 of the pulverized coal thick-thin separator 2 is connected to the material inlet of the drainage jet pump 5 through the rotor metering scale 3 and the electric air lock 4 in sequence.
[0035] Furthermore, the pulverized coal thick-thin separator 2 is composed of four continuously bent 45° elbows and straight pipe sections on both sides. The pulverized coal inlet 201 is a left straight pipe section, and the pulverized coal outlet 202 is a right straight pipe section. The guide component 207 is located at the first 45° elbow 203. When the pulverized coal is transported to the guide component 207, the fluid flow direction changes, and the flow direction is along the tangent direction of the pipeline. The separation component 208 is located at the second 45° elbow 204. The pulverized coal is guided by the first 45° elbow 203 and flows in the second 45° elbow 204. A split flow will be generated, so that a coal powder dense phase flow is formed on the outside of the pipeline, and a coal powder dilute phase flow is formed on the inside of the pipeline. The outer branch port 209 is located at the third 45° elbow 205, and its axial direction is consistent with the tangent direction of the first 45° elbow 203. The separated coal powder dense phase flow is discharged along the outer branch port 209, and the dilute phase flow is discharged from the straight pipe section coal powder outlet 202 after being guided by the fourth 45° elbow 206 along the inside of the pipeline. The ratio of the outer branch port diameter of the coal powder thick-thin separator 2 to its inlet and outlet diameter is 1 / 5 to 1 / 3. It should be noted that the inner side of the entire section of the pipeline of the coal powder thick-thin separator 2 is provided with a ceramic anti-wear layer, and the inner and outer sides of the connecting part of the outer branch port extending into the pipeline are provided with a ceramic anti-wear layer.
[0036] (ii) The pulverized coal stable combustion system includes a gasification burner 6 and a matching DCS control system. The DCS control system is used to control the operating conditions of the gasification burner 6. The material outlet of the drainage jet pump 5 is connected to the central pulverized coal channel of the gasification burner 6. The drainage jet pump 5 is used to stably transport the material to the gasification burner 6. The secondary air transport unit 7 is connected to the outer ring secondary air channel of the gasification burner 6. The steam transport unit 8 is connected to the protective gas channel at the bottom of the gasification burner 6. The steam transport unit 8 transports steam and air mixture into the gasification burner 6 according to actual working conditions to achieve stable operation of pulverized coal combustion and gasification in the furnace. The gasification burner 6 is installed in the center of the boiler burner. The pulverized coal enters the gasification burner 6 under the action of the drainage jet pump 5 to undergo partial combustion and gasification. The gas-solid two-phase flow products after gasification are sprayed into the furnace of the pulverized coal boiler 1 through the boiler burner for combustion.
[0037] Furthermore, the gasification burner 6 is composed of a three-channel nozzle and a furnace body, wherein the furnace body is composed of a metal shell, a heat-insulating material and a refractory castable, wherein the refractory material used in the gasification burner 6 has an allowable use temperature of >1200°C and a compressive strength of ≥60MPa; the thermal conductivity of the heat-insulating material is ≤0.5 W / m·k. The three-channel nozzle of the gasification burner 6 is composed of a diesel oven system, a central pulverized coal channel and an outer ring secondary air channel, and the diesel oven system is composed of a diesel pressurized atomizing gun and a high-energy igniter; the furnace body of the gasification burner 6 is divided into three sections: a preheating section, a gasification section and an outlet section, the diameter of the outlet section barrel is 1 / 5 to 1 / 2 times the diameter of the gasification section barrel, the preheating section is an eccentric cone mouth, and its centerline position deviates upward, with a tapering angle of 90 to 180°, the gasification section is a cylindrical structure, and a protective gas channel for a steam and air mixture is provided at the bottom, the outlet section is an eccentric cone mouth, and its centerline position deviates downward, with a tapering angle of 30 to 90°.
[0038] In this embodiment, the gasification burner 6 includes two installation modes: horizontal and vertical. The bottom of the gasification burner 6 is fixedly connected by a steel structure bracket, and the top is hoisted and connected by a spring hanger. Embodiment 2
[0039] In the pulverized coal combustion system, in addition to the design optimization of the gasification burner, the precise control of the pulverized coal quantity and concentration is also crucial to ensure the stable operation of the boiler.
[0040] As attached Figure 1 As shown in the figure, we specially set a regulating valve 9 on the outer branch port of the coal powder thick-thin separator. By finely adjusting the regulating valve 9, we can effectively control the cross-sectional size of the outer branch port, thereby realizing precise control of the coal powder quantity and concentration. This design enables the system to flexibly adjust the supply of coal powder according to the real-time working condition changes, ensuring the stability and efficiency of coal powder combustion and gasification in the gasification burner.
[0041] This embodiment further improves the operating efficiency and stability of pulverized coal boilers by introducing a pulverized coal quantity and concentration control mechanism and optimizing the configuration of gasification burners, meeting the requirements of ultra-low load peak regulation. This achievement not only demonstrates our innovative strength in the field of pulverized coal combustion technology, but also provides strong technical support for energy conservation, emission reduction and efficient operation of coal-fired boilers.
[0042] In the above two embodiments, the gasification burner can be installed horizontally or vertically, the bottom of the gasification burner can be supported by a steel structure, and a spring hanger can be installed on the top. Embodiment 3
[0043] like Figure 3 and 4As shown, the gasification burner 6 can be flexibly configured and installed for boilers with different combustion modes. Specifically, for a pulverized coal boiler with hedge combustion mode, 4 to 8 sets of gasification burners are configured, evenly arranged at the center of the bottom / middle layer burners on the front wall and the back wall of the boiler; for a pulverized coal boiler with four-corner tangential combustion mode, 4 sets of gasification burners are configured, evenly arranged at the center of the main burners around the boiler furnace in a four-corner tangential manner. It can be seen that the above arrangement method can be flexibly configured. A single-layer arrangement requires 1 group of 4 gasification burners, and a double-layer arrangement requires 2 groups of 8 gasification burners.
[0044] By adopting the above-mentioned embodiments, we have modified the existing pulverized coal boiler operation system in the following different implementation methods. (1) Taking a 350MW four-corner tangential subcritical coal-fired boiler as an example, low-activity Daigo coal is used as raw material, and four gasification burners are arranged in a four-corner tangential form at the center of the burner of layer A at the bottom of the boiler. The method of the present invention can achieve stable combustion of the coal-fired boiler under a load of 105MW (30% working condition). (2) Taking a 350MW coal-fired boiler with four-corner tangential subcritical as an example, using low-activity Daigo coal as raw material, four gasification burners are arranged in a four-corner tangential form at the center of the burner layer A at the bottom of the boiler. The method of the present invention can achieve stable combustion of the coal-fired boiler under a load of 88MW (25% working condition). (3) Taking a 350MW coal-fired boiler with four-corner tangential subcritical as an example, using low-activity Daigo coal as raw material, four gasification burners are arranged in a four-corner tangential form at the center of the burner layer A at the bottom of the boiler. The method of the present invention can achieve stable combustion of the coal-fired boiler under a load of 70MW (20% working condition). (4) Taking a 350MW coal-fired boiler with four-corner tangential subcritical as an example, using low-activity Beixinyao coal as raw material, four gasification burners are arranged in a four-corner tangential form at the center of the burner layer A at the bottom of the boiler. The method of the present invention can achieve stable combustion of the coal-fired boiler under a load of 70MW (20% working condition). (5) Taking a 350MW coal-fired boiler with front and rear wall counter-impingement supercritical system as an example, with low-activity Beixinyao coal as raw material, 8 gasification burners are arranged symmetrically on the front and rear walls, with 4 burners arranged on the front wall and 4 burners arranged on the same level on the rear wall. The method of the present invention can achieve stable combustion of the coal-fired boiler under a load of 88MW (25% operating condition).
[0045] In summary, after the transformation and commissioning, the operating conditions of the pulverized coal boiler were reduced to less than 20% of the unit load, the pulverized coal burnout rate was high, and the ultra-low load peak regulation requirements were met.
[0046] The above shows and describes the main features and advantages of the utility model. For those skilled in the art, it is obvious that the specific implementation of the utility model is not limited to the details of the above exemplary embodiments, and the creative ideas and design ideas of the utility model can be realized in other specific forms without departing from the spirit or basic features of the utility model, which should be equivalent to the protection scope disclosed in the technical solution of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, so it is intended to include all changes that fall within the meaning and scope of the equivalent elements of the claims in the utility model.
[0047] The utility model belongs to the technical field of low-load stable combustion of pulverized coal boilers, and specifically relates to a stable combustion device for ultra-low load pulverized coal boilers in power plants. The stable combustion device mainly includes two parts: a pulverized coal conveying system and a pulverized coal stable combustion system. The pulverized coal conveying system is composed of components such as a pulverized coal thick and thin separator, a rotor metering scale, an electric air lock, and a drainage jet pump, which ensures the precise supply of pulverized coal. The pulverized coal stable combustion system includes a gasification burner, a pulverized coal conveying unit, a hot secondary air conveying unit, a steam conveying unit, and a DCS control system. By optimizing the design and configuration of the gasification burner and combining the precise control of the pulverized coal amount and concentration, the stable combustion of the coal-fired boiler under ultra-low load is achieved.
[0048] The gasification burner adopts a unique design, including preheating section, gasification section and outlet section. The structural optimization of each section helps to improve the combustion efficiency. The regulating valve set on the pulverized coal concentration separator can accurately control the amount and concentration of pulverized coal to meet the needs of different working conditions. Through the DCS control system, the entire stable combustion process can be intelligently controlled to ensure the stable operation of the boiler.
[0049] The utility model has a simple process, small equipment space, and strong applicability. It can meet the current needs of coal-fired power plants to quickly increase and decrease loads, effectively solve the problem of unstable combustion of coal-fired boilers under ultra-low loads, and is of great significance for improving the operating efficiency of coal-fired boilers and energy conservation and emission reduction. Through actual application case verification, the device has achieved significant stable combustion effects on multiple different types of coal-fired boilers, meeting the requirements of ultra-low load peak regulation.
Claims
1. A combustion stabilization device for ultra-low load of a pulverized coal boiler in a power plant, comprising a pulverized coal boiler (1), characterized in that: The invention also comprises a pulverized coal conveying system and a pulverized coal combustion stabilization system. The pulverized coal conveying system comprises a pulverized coal concentration separator (2), a rotor metering scale (3), an electric air lock (4) and a drainage jet pump (5). The pulverized coal inlet (201) of the pulverized coal concentration separator (2) is connected to a pulverized coal conveying pipeline, and its pulverized coal outlet (202) is connected to the furnace of a pulverized coal boiler (1). The outer branch port (209) of the pulverized coal concentration separator (2) is connected to the material inlet of the drainage jet pump (5) through the rotor metering scale (3) and the electric air lock (4) in sequence. The pulverized coal combustion stabilization system comprises a gasification burner (6) and a matching DCS control system. The DCS control system is used to control the operating conditions of the gasification burner (6). The drainage jet pump (5) is connected to the feed pipe of the pulverized coal concentration separator (2). The material outlet is connected to the central pulverized coal channel of the gasification burner (6); the drainage jet pump (5) is used to stably transport the material to the gasification burner (6); the secondary air transport unit (7) is connected to the outer ring secondary air channel of the gasification burner (6); the steam transport unit (8) is connected to the protective gas channel at the bottom of the gasification burner (6); the steam transport unit (8) transports steam and air mixture into the gasification burner (6) according to actual working conditions to achieve stable operation of coal powder combustion and gasification in the furnace; the gasification burner (6) is installed at the center of the boiler burner; the pulverized coal enters the gasification burner (6) under the action of the drainage jet pump (5) to undergo partial combustion and gasification; the gas-solid two-phase flow product after gasification is sprayed into the furnace of the pulverized coal boiler (1) through the boiler burner for combustion.
2. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 1, characterized in that: The pulverized coal thick-thin separator (2) is composed of four continuously curved 45° elbows and straight pipe sections on both sides. The pulverized coal inlet (201) is a left straight pipe section, and the pulverized coal outlet (202) is a right straight pipe section. The flow guide component (207) is located at the first 45° elbow (203). When the pulverized coal is transported to the flow guide component (207), the flow direction of the fluid changes and the flow direction is along the tangent direction of the pipeline. The separation component (208) is located at the second 45° elbow (204). The pulverized coal passes through the first 45° elbow (203). Due to the guiding effect, a flow split will be generated at the second 45° elbow (204), so that a coal powder dense phase flow is formed on the outside of the pipeline and a coal powder dilute phase flow is formed on the inside of the pipeline. The outer branch port (209) is located at the third 45° elbow (205), and its axial direction is consistent with the tangent direction of the first 45° elbow (203). The separated coal powder dense phase flow is discharged along the outer branch port (209), and the dilute phase flow is discharged from the coal powder outlet (202) of the straight pipe section after the guiding effect of the fourth 45° elbow (206) along the inside of the pipeline.
3. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 2, characterized in that: The entire pipeline of the pulverized coal thick-thin separator (2) is provided with a ceramic anti-wear layer on the inside, and the connection part of the outer branch opening (209) extending into the pipeline is provided with a ceramic anti-wear layer on the inside and outside.
4. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 2, characterized in that: The ratio of the diameter of the outer branch port (209) of the pulverized coal thick-thin separator (2) to the diameter of its inlet and outlet is 1 / 5 to 1 / 3.
5. A combustion stabilizing device for ultra-low load of pulverized coal boiler in power plant according to any one of claims 1 to 4, characterized in that: A regulating valve (9) is provided on the outer branch port (209) of the pulverized coal thick-thin separator (2), and the regulating valve (9) controls the amount and concentration of pulverized coal by adjusting the cross-sectional size of the outer branch port.
6. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 5, characterized in that: The gasification burner (6) is composed of a three-channel nozzle and a furnace body, wherein the three-channel nozzle of the gasification burner (6) is composed of a diesel oven system, a central pulverized coal channel and an outer ring secondary air channel, and the diesel oven system is composed of a diesel pressurized atomization gun and a high-energy igniter; the furnace body of the gasification burner (6) is divided into three sections: a preheating section, a gasification section and an outlet section, the preheating section is an eccentric cone mouth, and its centerline position deviates upward, with a tapering angle of 90 to 180 degrees, the gasification section is a cylindrical structure, and a protective gas channel for a steam and air mixture is provided at the bottom, and the outlet section is an eccentric cone mouth, and its centerline position deviates downward, with a tapering angle of 30 to 90 degrees.
7. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 6, characterized in that: The diameter of the outlet section barrel is 1 / 5 to 1 / 2 times the diameter of the gasification section barrel.
8. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 6 or 7, characterized in that: The furnace body of the gasification burner (6) is composed of a metal shell, a heat insulating material and a refractory castable.
9. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 8, characterized in that: The gasification burner (6) includes two installation modes: horizontal / vertical. The bottom of the gasification burner (6) is fixedly connected via a steel structure bracket, and the top is hoisted and connected via a spring hanger.
10. The ultra-low load stabilizing combustion device for a pulverized coal boiler in a power plant according to claim 8, characterized in that: The gasification burner (6) has the following two configuration and installation modes according to the boilers with different combustion modes: for a pulverized coal boiler with counter combustion mode, 4 to 8 sets of gasification burners are configured and evenly arranged at the center of the bottom layer / middle layer burners on the front wall and the rear wall of the boiler; for a pulverized coal boiler with four-corner tangential combustion mode, 4 sets of gasification burners are configured and evenly arranged at the center of the main burners around the boiler furnace in a four-corner tangential combustion mode.