CN113958950B

CN113958950B - Device for coal-fired power plant coal-hydrogen-oxygen synergistic strengthening stable combustion

Info

Publication number: CN113958950B
Application number: CN202111345442.6A
Authority: CN
Inventors: 刘鑫; 刘岗; 任建兴; 李芳芹; 蔡健明
Original assignee: Shanghai Electric Power University
Current assignee: Shanghai Electric Power University
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2023-10-13
Anticipated expiration: 2041-11-15
Also published as: CN113958950A

Abstract

The application discloses a device for coal-fired power plant coal-hydrogen synergistic strengthening stable combustion, which comprises a hydrogen production unit, a water electrolysis hydrogen production device and a hydrogen nozzle, wherein the hydrogen production unit comprises a water electrolysis hydrogen production device and a water electrolysis hydrogen nozzle; the pulverized coal and hydrogen air mixing unit comprises a concentrating plate, a primary air pulverized coal pipeline and a pulverized coal and hydrogen air mixing chamber, one end of the primary air pulverized coal pipeline is connected with the pulverized coal and hydrogen air mixing chamber, the concentrating plate is sleeved outside the primary air pulverized coal pipeline and the pulverized coal and hydrogen air mixing chamber, and a hydrogen nozzle is connected with the pulverized coal and hydrogen air mixing chamber; the high-temperature reflux unit comprises an oxygen channel, a reflux flue gas pipeline and a hearth. The device for the coal-hydrogen synergistic strengthening stable combustion of the coal-fired power plant can utilize the load difference of peaks and valleys to produce hydrogen by electrolyzing water, and hydrogen is directly used for mixing primary air, so that the ignition energy of coal powder air flow is reduced from the source. The combustion stability can be enhanced, the method can adapt to the change of various coals, and can save fuel oil, thereby achieving the effect of low-load stable combustion.

Description

Device for coal-fired power plant coal-hydrogen-oxygen synergistic strengthening stable combustion

Technical Field

The application relates to the technical field of oxygen-enriched combustion of power station boilers, in particular to a device for coal-hydrogen synergistic enhanced stable combustion of a coal-fired power plant.

Background

With the development of renewable energy sources, the energy structure is adjusted, and the problem of new energy source digestion is increasingly outstanding. Because wind power and photovoltaic have the characteristics of intermittence, volatility, randomness, low reactive power supply performance, weak short-time short-circuit current supply capability and the like, the safety of a power system can be influenced to a certain extent. The safe operation of the power system is crucial in the important stage of the rapid development in China. In order to solve the dilemma of new energy consumption, multiple sides of a power source side, a power grid side and a load side are combined together, so that the flexibility of the whole power system is improved. The flexibility of the power supply side is improved to the maximum extent, and the peak shaving capacity is the strongest. In a period of time in the future, the main power in the power system of China is still coal power, the thermal power generation is relatively stable, and the peak shaving potential is large, so that the thermal power flexibility transformation is the mode with optimal economy and most obvious effect in the deep peak shaving.

The hydrogen energy has excellent performance, high combustion heat value, environmental protection and cleanness. In terms of energy utilization rate, hydrogen energy is generally higher than other forms of energy, such as biological fuel, fossil fuel and chemical fuel, and has high ignition point and high speed, which is three times of the heat value of common gasoline. From the aspect of environmental protection, the hydrogen energy is clean and nontoxic, and can not generate harmful substances such as carbon dioxide, carbon monoxide, sulfur dioxide, dust particles and the like, and can not damage the natural environment. The electrolytic water hydrogen production is a clean, high-efficiency and sustainable hydrogen production technology, the hydrogen production process is simple, the hydrogen purity can reach 99.999%, and the product purity is high. The hydrogen production by water electrolysis is not limited by the existence of reliable and qualified outsourcing hydrogen conditions around the power plant, and the hydrogen production cost is low in the service life of the equipment. Currently, some of the technologies applied hydrogen energy is from the deep peak shaving field, but there are often certain problems, such as instability and increased unsafe caused by directly utilizing hydrogen for ignition.

Meanwhile, from the viewpoint of constructing conditions favorable for stable combustion of pulverized coal, the pulverized coal airflow is expected to timely catch fire in a certain distance away from the burner nozzle, so that the pulverized coal airflow flow is reasonably organized, and a local high pulverized coal concentration, high temperature and proper oxygen concentration region for promoting the pulverized coal airflow to timely heat up and catch fire is formed. When the boiler runs under low load, the coal feeding amount and the coal powder concentration are greatly reduced, so that the ignition heat required by the ignition of the coal powder airflow is increased, the ignition position is delayed, and the flame stability is poor. At present, the combustion condition of unstable combustion, insufficient kinetic energy transmission and incapability of adjusting the combustion of pulverized coal exists in the boiler combustion. How to design a burner device that is fuel efficient, environmentally friendly and capable of stable combustion in low load mode becomes a key issue.

Disclosure of Invention

This section is intended to summarize some aspects of embodiments of the application and to briefly introduce some preferred embodiments, which may be simplified or omitted in this section, as well as the description abstract and the title of the application, to avoid obscuring the objects of this section, description abstract and the title of the application, which is not intended to limit the scope of this application.

The present application has been made in view of the above and/or problems occurring in the prior art.

Therefore, the application aims to solve the technical problems that the existing burner cannot utilize the load difference of peaks and valleys and cannot indirectly utilize electrolyzed water to produce hydrogen to carry out coal-hydrogen-oxygen synergistic combustion, and the transportation kinetic energy is insufficient, the combustion condition cannot be regulated and the combustion stability is insufficient.

In order to solve the technical problems, the application provides the following technical scheme: a device that is used for coal-fired power plant coal oxyhydrogen to strengthen stable burning in coordination which characterized in that: the hydrogen production device comprises a hydrogen production unit, a water electrolysis hydrogen production device and a hydrogen nozzle, wherein the hydrogen nozzle is connected with the water electrolysis hydrogen production device;

the pulverized coal and hydrogen air mixing unit comprises a concentrating plate, a primary air pulverized coal pipeline and a pulverized coal and hydrogen air mixing chamber, one end of the primary air pulverized coal pipeline is connected with the pulverized coal and hydrogen air mixing chamber, the concentrating plate is sleeved outside the primary air pulverized coal pipeline and the pulverized coal and hydrogen air mixing chamber, and the hydrogen nozzle is connected with the pulverized coal and hydrogen air mixing chamber;

the high-temperature reflux unit comprises an oxygen channel, a reflux flue gas pipeline and a hearth, wherein the oxygen channel is connected with the pulverized coal hydrogen air mixing chamber and the hearth, and the reflux flue gas pipeline is connected with the oxygen channel and the hearth.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: the high-temperature backflow unit further comprises a secondary air channel, and the secondary air channel is connected with the hearth.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: an axial swirl blade and a pull rod are arranged in the secondary air channel, and one end of the pull rod is connected with the axial swirl blade.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: the middle part of the oxygen channel is a scaling structure of the venturi tube.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: an annular partition plate is arranged in the hearth and connected to the middle of the hearth.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: and a blunt body is further arranged in the hearth and connected to the middle part of the annular partition plate.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: the return flue gas pipeline is provided with a valve, and the valve is positioned at the joint of the return flue gas pipeline and the hearth.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: the hydrogen nozzle is provided with a hydrogen regulating valve, and the hydrogen regulating valve is positioned at the end head of the hydrogen nozzle.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: and the reflux flue gas pipeline, the secondary air channel and a part of the oxygen channel are arranged on a refractory wall body, and the refractory wall body is connected with the hearth.

As a preferable scheme of the device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in the coal-fired power plant, the application comprises the following steps: the fireproof wall is provided with a sliding groove, the sliding groove is formed in two sides of the fireproof wall, and one end of the pull rod is arranged in the sliding groove.

The application has the beneficial effects that: the device for the coal-hydrogen synergistic strengthening stable combustion of the coal-fired power plant utilizes the load difference of peaks and valleys to produce hydrogen by electrolyzing water, hydrogen is directly used for mixing primary air, the ignition energy of coal powder airflow is reduced from the source, the mixing of hydrogen also increases the pneumatic conveying of primary air coal powder particles, and the problem of insufficient pneumatic conveying kinetic energy of the primary air caused by load reduction is avoided. The byproduct oxygen of hydrogen production can also be used as a combustion improver to further strengthen the ignition of coal dust. In the coal-oxyhydrogen collaborative combustion device, an axial swirl vane and a backflow flue gas pipeline are further arranged to adjust the combustion condition of coal powder entering a hearth after combustion, so that the combustion stability is enhanced, the device can adapt to the change of multiple coal types, can save fuel oil and achieves the effect of low-load stable combustion.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is a schematic cross-sectional view of an overall structure of a device for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to an embodiment of the present application;

FIG. 2 is a schematic cross-sectional view of a furnace in an apparatus for enhanced combustion of coal and hydrogen in a coal-fired power plant according to an embodiment of the present application;

FIG. 3 is a schematic cross-sectional view of a refractory wall in an apparatus for enhanced combustion of coal and hydrogen in a coal-fired power plant according to an embodiment of the present application;

FIG. 4 is a schematic top view of a refractory wall in an apparatus for enhanced, coordinated, and stabilized combustion of coal and hydrogen in a coal-fired power plant according to an embodiment of the present application;

FIG. 5 is a graph illustrating a conventional combustor gas flow velocity profile according to one embodiment of the present application.

FIG. 6 is a graph showing the airflow velocity profile of an apparatus for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to an embodiment of the present application.

Detailed Description

In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present application is not limited to the specific embodiments disclosed below.

In the following detailed description of the embodiments of the present application, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration only, and in which is shown by way of illustration only, and in which the scope of the application is not limited for ease of illustration. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.

Further still, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

Referring to fig. 1 and 3, the present embodiment provides a device for stabilizing combustion by synergistic reinforcement of coal and hydrogen in a coal-fired power plant, which comprises a hydrogen production unit 100 including an electrolytic water hydrogen production device 101 and a hydrogen nozzle 102, wherein the hydrogen nozzle 102 is connected to the electrolytic water hydrogen production device 101;

the pulverized coal and hydrogen air mixing unit 200 comprises a concentrating plate 201, a primary air pulverized coal pipeline 202 and a pulverized coal and hydrogen air mixing chamber 203, one end of the primary air pulverized coal pipeline 202 is connected with the pulverized coal and hydrogen air mixing chamber 203, the concentrating plate 201 is sleeved outside the primary air pulverized coal pipeline 202 and the pulverized coal and hydrogen air mixing chamber 203, and the hydrogen nozzle 102 is connected with the pulverized coal and hydrogen air mixing chamber 203;

the high-temperature backflow unit 300 comprises an oxygen channel 301, a backflow flue gas pipeline 302 and a hearth 304, wherein the oxygen channel 301 is connected with the pulverized coal hydrogen air mixing chamber 203 and the hearth 304, and the backflow flue gas pipeline 302 is connected with the oxygen channel 301 and the hearth 304.

Specifically, the outlet of the primary air pulverized coal pipeline 202 is connected with the inlet of the pulverized coal hydrogen air mixing chamber 203, and the hydrogen nozzle 102 is obliquely inserted above the side wall of the pulverized coal hydrogen air mixing chamber 203, so that the entering direction of hydrogen can follow the pulverized coal direction in an oblique insertion mode.

Specifically, the concentration plate 201 is arranged outside the pipe wall of the primary air pulverized coal pipe 302, and the concentration plate 201 is in a symmetrical middle bulge shape, so that pulverized coal flows can be concentrated in a middle position, and the pulverized coal concentration in the middle part is increased, so that the pulverized coal is easier to ignite, and fuel is saved.

Specifically, the pulverized coal hydrogen-air mixing chamber 203 adopts a self-cooling design, and by arranging a longer fuel nozzle, on one hand, the mixing of fuel and oxygen can be delayed, and on the other hand, the cooling of the oxygen to the nozzle is facilitated, and the nozzle is prevented from being burnt. The tail part of the pulverized coal hydrogen air mixing chamber 203 is designed as a reducing pipe to accelerate the pulverized coal hydrogen air mixture, and a reflux zone is formed at the outlet, which is beneficial to the reflux of the reflux flue gas.

When the coal-fired power plant needs deep peak shaving, the generator set is difficult to reach a low-load operation state, and high load is often maintained, and the excessive load is used for hydrogen production by water electrolysis. The redundant load of the coal-fired power plant is converted and is prepared into hydrogen through the electrolytic water hydrogen production device 101, the hydrogen enters the pulverized coal hydrogen-air mixing chamber 203 through the hydrogen nozzle 102, at the moment, the hydrogen is fused with the pulverized coal passing through the primary air pulverized coal pipeline 302, meanwhile, the oxygen channel 301 is sprayed with a proper amount of pure oxygen at a certain speed, and the secondary air channel 303 is sprayed with air for combustion. The hydrogen is mixed in the primary air, so that the ignition energy of the primary air pulverized coal is reduced, and the ignition performance is improved; in order to realize pneumatic conveying of pulverized coal particles in a primary air pipeline, the air flow speed is ensured to be greater than the critical conveying speed, so that the fact that the conventional technology cannot directly reduce primary air quantity to improve the pulverized coal air flow concentration under low load is determined, the pneumatic conveying of the pulverized coal particles of the primary air is further increased by hydrogen, the problem that the pneumatic conveying kinetic energy of the primary air is insufficient due to load reduction is avoided, meanwhile, oxygen obtained by hydrogen production can be used as oxygen-enriched combustion of a combustor, combustion is enhanced, combustion performance is improved, the instant use of hydrogen is realized, and the safety problem in the hydrogen storage and transportation process is avoided.

Further, the hydrogen nozzle 102 is provided with a hydrogen regulating valve 102a, and the hydrogen regulating valve 102a is located at the end of the hydrogen nozzle 102.

It should be noted that, the hydrogen adjusting valve 102a is disposed at the upper end of the hydrogen nozzle 102, which can play a role in protecting hydrogen from high pressure, and prevent hydrogen from excessively entering the pulverized coal hydrogen-air mixing chamber for combustion, thereby causing unbalance of air-fuel ratio; meanwhile, the low-pressure protection function of the hydrogen is achieved, the condition that the too little hydrogen enters a pulverized coal hydrogen-air mixing chamber to burn to cause excessive oxygen, tempering or fire occurs is prevented, and therefore the whole furnace combustion field is stabilized.

Example 2

Referring to fig. 1-3, the present embodiment provides, based on the previous embodiment, a device for coal-hydrogen synergistic enhanced stable combustion of a coal-fired power plant, including a hydrogen production unit 100, including an electrolyzed water hydrogen production device 101 and a hydrogen spout 102, where the hydrogen spout 102 is connected to the electrolyzed water hydrogen production device 101;

Further, the middle portion of the oxygen channel 301 is a venturi constriction.

It should be noted that, the device adopts the staged feeding of the combustion improver, specifically, the oxygen channel 301 designs the scaling structure of the venturi pipeline in the middle position, the throat is connected with the backflow flue gas pipeline 302, the throat forms low pressure to realize entrainment of a large amount of furnace gas, preheat oxygen, be favorable to forming the stable high temperature region which promotes rapid temperature rise of the pulverized coal gas flow, strengthen the low-load stable combustion capability of the burner, play the purpose of increasing the uniformity of furnace temperature, strengthen the combustion stability of the hearth, also can adjust the negative pressure in the hearth, the reflux amount of hot flue gas and the preheating degree of the pulverized coal gas flow, adjust the local wind-coal ratio and pre-combustion intensity, change the ignition characteristic of the pulverized coal gas flow, meet the flexibility requirement of the depth peak regulating unit, and simultaneously, be favorable to the cooling of the oxygen to the nozzle by setting longer fuel nozzles.

Further, an annular partition plate 304a is disposed in the furnace 304, and the annular partition plate 304a is connected to the middle of the furnace 304.

Further, a blunt body 304b is further disposed in the furnace 304, and the blunt body 304b is connected to the middle of the annular partition plate 304 a.

It should be noted that, the inner recirculation zone behind the bluff body and the outer recirculation zone on both sides of the stable combustion chamber are constructed by providing the bluff body 304b in the furnace 304. In this structure, a proper depth and width of the stable combustion chamber are required to generate a reasonable external reflux amount, and a large arrangement space is often required, so that in order to strengthen the external reflux on the basis of reducing the structural size of the stable combustion chamber a, an annular partition plate 304a is arranged in the hearth 304, so that an internal and external two-layer airflow channel is formed. The middle high-speed jet flow action can make the outer channel generate negative pressure, and the high-temperature smoke is sucked and flows back to the root of the pulverized coal airflow through the channel between the annular separation plate 304a and the end face of the stable combustion chamber A. Specifically, the annular partition plate 304a may be a steel plate, and adopts a hoisting mode;

specifically, the blunt body 304b is made of silicon carbide and silicon nitride, and is formed by casting a heat-resistant high-temperature material in one step. The material is a novel high-grade refractory material, almost maintains the strength and hardness at the same time as normal temperature at the high temperature of 1200-1400 ℃, and the highest safe use temperature can reach more than 1750 ℃. The blunt body made of the material has strong wear resistance, the service life can reach more than 60000 hours, and the blunt body can also be installed in a hoisting mode. The shape of the triangular body can reduce resistance in the direction of wind powder airflow as much as possible, wall-attached flow accelerates and disturbs, the primary air velocity at the tail of the blunt body is lower than the main air velocity due to the blocking interference effect of the small blunt body, a certain speed deviation is generated, and a speed reflux field is formed in the back area of the blunt body. Because the density of the air-powder mixture is much higher than that of air, the pulverized coal can have higher speed and inertia, and can continue to move axially after being blocked by the blunt body to flow around, pulverized coal particles can gather and stay at the boundary of the backflow area, and a pulverized coal concentration area with high concentration is formed. The high concentration coal powder area and the high temperature smoke reflux area are overlapped, which can ensure the ignition and stable combustion of coal powder particles, and the back of the blunt body has high enough smoke temperature, strong heat and mass exchange movement and low speed, and these factors create favorable conditions of fuel ignition and combustion flame stabilization.

Example 3

Referring to fig. 1-4, the present embodiment provides, based on the previous embodiment, a device for coal-hydrogen synergistic enhanced stable combustion of a coal-fired power plant, including a hydrogen production unit 100, including an electrolyzed water hydrogen production device 101 and a hydrogen spout 102, where the hydrogen spout 102 is connected to the electrolyzed water hydrogen production device 101;

Further, the high temperature reflow unit 300 further includes a secondary air passage 303, and the secondary air passage 303 is connected to the furnace 304.

Further, an axial swirl vane 303a and a pull rod 303a-1 are provided in the secondary air passage 303, and one end of the pull rod 303a-1 is connected to the axial swirl vane 303a.

Specifically, an annular secondary air channel 303 is arranged outside the oxygen channel 301, the secondary air channel 303 is an annular pipeline, the annular side surface is a trapezoid channel with narrow front and wide rear, axial swirl blades 303a are arranged in the secondary air channel 303, and the positions of the swirl blades 303a can be adjusted in the trapezoid secondary air channel through a pull rod 303 a-1.

Further, a sliding groove 401 is provided on the refractory wall 400, the sliding groove 401 is provided on both sides of the refractory wall 400 and parallel to the secondary air channel 303, and one end of the pull rod 303a-1 is provided in the sliding groove 401.

It should be noted that, the fireproof wall 400 is cylindrical, the sliding groove 401 is formed on two sides of the fireproof wall 400, the pull rod 303a-1 is L-shaped, one end of the pull rod extends out of the sliding groove 401, so that an operator can conveniently hold the sliding groove 401 for adjustment, the opening of the sliding groove 401 is sealed by silicone rubber, and the tightness of the secondary air channel 303 is ensured.

Further, the return flue gas duct 302 is provided with a valve 302a, the valve 302a being located at the junction of the return flue gas duct 302 and the furnace 304.

Further, the return flue gas duct 302, the secondary air duct 303 and a part of the oxygen duct 301 are disposed on the refractory wall 400, and the refractory wall 400 is connected to the furnace 304.

It should be noted that, when the boiler needs low load operation, before combustion, the pull rod 303a-1 may be pulled to move the swirl vane to the tail of the secondary air channel, so that all the secondary air is ejected out of the burner in a swirl manner, increasing the strength of backflow and increasing the flue gas disturbance. When the boiler is in variable load operation, the cyclone blades can be reasonably moved forwards according to the load condition of the boiler, so that the proportion of the direct current wind is increased, the proportion of the cyclone wind is reduced, and the purpose of reasonably distributing the direct current wind and the cyclone wind is achieved. In addition, the rotational flow strength can be changed by adjusting the angle of the axial blades, so that the length and the area of the high-temperature backflow area can be adjusted, the formation of the high-temperature backflow area can also help to inhibit the generation of NOx, the combustion can be enhanced, and the stable combustion of the pulverized coal airflow under low load can be promoted.

It should be noted that, the number of the backflow flue gas pipelines 302 is 2, and the valves 302a are respectively arranged, when in combustion, the valves 302a in the backflow flue gas pipelines 302 can be selectively opened or closed according to the combustion condition, and if both the valves are opened, oxygen can be preheated when the boiler runs under low load, so that the combustion of the boiler is more stable and the flameout is avoided; when the boiler is in normal operation and the problems of flameout and unstable combustion do not exist, one or two of the boilers can be selected to be closed.

The whole working principle of the device is as follows:

the pulverized coal airflow is sent to a primary air pulverized coal pipeline 202 through a coal mill, and a central concentrated pulverized coal airflow and an edge dilute phase pulverized coal airflow are formed under the action of a concentrating plate 201. At the same time, the hydrogen nozzle 102 sprays hydrogen into the primary air pulverized coal pipeline 202, and the hydrogen mixed pulverized coal airflow is combusted in the pulverized coal hydrogen air mixing chamber 203. The oxygen passage 301 injects a proper amount of pure oxygen at a certain speed, and the secondary air passage 303 injects air. When the boiler is in load reduction or low load operation, the pull rod 303a-1 is pulled to move the cyclone blade 303a to the tail part, the proportion of cyclone wind is increased, the proportion of direct wind is reduced, and meanwhile, the angle of the axial blade of secondary wind is increased to increase the cyclone strength, so that the area of a backflow area at the burner nozzle is increased. The furnace 304 is provided with a blunt body 304b and an annular partition plate 304a, and the blunt body 304b constructs an inner reflux zone behind the blunt body 304b and outer reflux zones at two sides of the stable combustion chamber. The annular separation plate 304a can form an inner layer air flow channel and an outer layer air flow channel, the outer layer channel generates negative pressure under the action of middle high-speed jet flow, high-temperature smoke is sucked in and flows back to the root of pulverized coal air flow through the channel between the annular separation plate 304a and the end face of the stable combustion chamber A. Therefore, two high-temperature backflow areas are formed in the hearth 304, and the construction of the high-temperature backflow areas of the hearth 304 can keep the average temperature of the outlet area of the burner at a higher level, so that the low-load stable combustion performance of the unit is improved. Meanwhile, by adjusting the opening of the valve 302a and matching with the venturi pipeline structure designed by the oxygen channel 301, the reflux flue gas can enter the oxygen channel 301 through the reflux flue gas pipeline 302 by utilizing the action of pressure difference, the temperature is improved by heating oxygen through the reflux flue gas, the low-load stable combustion capability of the burner is further enhanced, the coal type of the combustion device has wide application range, and the flexibility of deep peak regulation of the thermal power unit can be improved.

Example 4

Referring to fig. 5 and 6, in this embodiment, the velocity profiles of the air streams in the combustor before and after optimization are selected for comparison test, and the velocity profiles are simulated by fluent software. The test results are compared by means of scientific demonstration, and the true effect of the method is verified.

FIG. 5 is a graph of a conventional combustor gas flow velocity profile. The velocity distribution after the burner nozzle can be seen that the velocity change gradient is smaller near the burner nozzle, which means that the flow is disturbed by the rotational flow of the secondary air and the heat exchange is weaker, and the larger negative pressure can not be generated, so that the reflux effect can not be generated, and the high-temperature flue gas in the furnace can not be sucked near the nozzle, thereby being unfavorable for igniting the coal dust.

FIG. 6 is a graph showing the velocity profile of the gas stream of a device for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to the present application. It can be seen that the highest velocity occurs at the burner ports and a high velocity occurs at the location of the bluff body 304b because of the blocking action of the bluff body 304b, the cross section of the wind powder flow becomes smaller and the velocity increases. Along the direction of the axis, the speed of the air flow gradually decreases, which means that a backflow area is started to appear at the outlet of the burner, the flowing characteristic of the pulverized coal particle jet is changed due to the influence of the blunt body on the flowing around, turbulent flow is generated in the area close to the blunt body, a vortex backflow area is generated, and negative pressure is generated, so that high-temperature flue gas burnt in the center of a hearth can be sucked. At the same time, it can be seen that a portion of the return flue gas enters the burner ports due to the negative pressure created by the venturi design of the oxygen conduit 301. The expansion of the reflow zone toward the center of the furnace illustrates that the reflow zone has greater capacity to absorb high temperature flue gas. In the figure, we can see that the length of the reflux zone can reach about one third of the whole space, and the reflux effect is obvious. From the velocity axial distribution of the blunt body 304b, we can also see that the velocity variation gradient is larger near the burner nozzle, which indicates that the flow is disturbed and the heat exchange is stronger, so that the pulverized coal airflow in the backflow zone can quickly perform heat and mass exchange with the rolled high-temperature flue gas, the pulverized coal in the backflow zone is quickly ignited, and the pulverized coal is quickly ignited. The velocity in the reflux zone is relatively low from the distribution diagram, and the residence time of the pulverized coal particles in the reflux zone is prolonged due to the reflux effect, so that the burning-out effect of the pulverized coal is facilitated.

In conclusion, the application aims at two factors which restrict the improvement of the low-load stable combustion performance of the burner when the coal-fired power plant carries out deep peak shaving, namely: (1) the coal dust concentration is greatly reduced, so that the ignition difficulty is increased; (2) the capability of the reflux area for sucking high-temperature smoke is weakened. The method creatively provides a mode of mixing hydrogen into primary air pulverized coal flow without influencing the long-term operation of the boiler, and solves the problem of fire difficulty caused by the reduction of pulverized coal concentration in low-load operation of the unit from the source. Aiming at the problem that the capability of the reflux area for absorbing high-temperature smoke is weak, the application deeply digs the potential of the high-temperature reflux area for promoting low-load stable combustion on the basis of a single high-temperature reflux area of the traditional burner, and provides a mode for constructing a double high-temperature reflux area: the boiler stable combustion is promoted by adjusting the opening degree of the axial swirl blades and constructing a large-area high-temperature backflow area by utilizing the differential pressure principle of a backflow flue gas pipeline. Is a low-load stable combustion technology which can be realized, is environment-friendly and has wide applicability.

It is important to note that the construction and arrangement of the application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperature, pressure, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in this application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present applications. Therefore, the application is not limited to the specific embodiments, but extends to various modifications that nevertheless fall within the scope of the appended claims.

Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those not associated with the best mode presently contemplated for carrying out the application, or those not associated with practicing the application).

It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

It should be noted that the above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application, which is intended to be covered in the scope of the claims of the present application.

Claims

1. A device that is used for coal-fired power plant coal oxyhydrogen to strengthen stable burning in coordination which characterized in that: comprising the steps of (a) a step of,

the hydrogen production unit (100) comprises an electrolytic water hydrogen production device (101) and a hydrogen nozzle (102), wherein the hydrogen nozzle (102) is connected with the electrolytic water hydrogen production device (101);

the pulverized coal and hydrogen air mixing unit (200) comprises a concentrating plate (201), a primary air pulverized coal pipeline (202) and a pulverized coal and hydrogen air mixing chamber (203), one end of the primary air pulverized coal pipeline (202) is connected with the pulverized coal and hydrogen air mixing chamber (203), the concentrating plate (201) is sleeved outside the primary air pulverized coal pipeline (202) and the pulverized coal and hydrogen air mixing chamber (203), and the hydrogen nozzle (102) is connected with the pulverized coal and hydrogen air mixing chamber (203);

the high-temperature backflow unit (300) comprises an oxygen channel (301), a backflow flue gas pipeline (302) and a hearth (304), wherein the oxygen channel (301) is connected with the pulverized coal hydrogen air mixing chamber (203) and the hearth (304), and the backflow flue gas pipeline (302) is connected with the oxygen channel (301) and the hearth (304);

the high-temperature backflow unit (300) further comprises a secondary air channel (303), and the secondary air channel (303) is connected to the hearth (304);

an axial swirl blade (303 a) and a pull rod (303 a-1) are arranged in the secondary air channel (303), and one end of the pull rod (303 a-1) is connected with the axial swirl blade (303 a);

the middle part of the oxygen channel (301) is a venturi tube scaling structure.

2. The apparatus for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to claim 1, wherein: an annular separation plate (304 a) is arranged in the hearth (304), and the annular separation plate (304 a) is connected to the middle of the hearth (304).

3. The apparatus for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to claim 2, wherein: a blunt body (304 b) is further arranged in the hearth (304), and the blunt body (304 b) is connected to the middle of the annular partition plate (304 a).

4. The apparatus for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion according to claim 3, wherein: the return flue gas pipeline (302) is provided with a valve (302 a), and the valve (302 a) is positioned at the joint of the return flue gas pipeline (302) and the hearth (304).

5. The apparatus for coal-fired power plant coal-oxyhydrogen synergistic stabilization combustion according to claim 3 or 4, characterized in that: the hydrogen nozzle (102) is provided with a hydrogen regulating valve (102 a), and the hydrogen regulating valve (102 a) is positioned at the end of the hydrogen nozzle (102).

6. The device for coal-fired power plant coal-hydrogen-oxygen synergistic enhanced stable combustion according to claim 5, wherein: the backflow flue gas pipeline (302), the secondary air channel (303) and a part of the oxygen channel (301) are arranged on the fireproof wall body (400), and the fireproof wall body (400) is connected with the hearth (304).

7. The apparatus for coal-fired power plant coal-oxyhydrogen synergistic enhanced stable combustion of claim 6, wherein: the fireproof wall body (400) is provided with a sliding groove (401), the sliding groove (401) is formed in two sides of the fireproof wall body (400), and one end of the pull rod (303 a-1) is arranged in the sliding groove (401).