Horizontal rich-thin direct-current burner and operation method

Abstract

The invention discloses a horizontal rich-thin direct-current burner and an operation method, the horizontal rich-thin direct-current burner comprises a tangential pulverized coal combustion boiler, direct-current primary air pulverized coal burners are arranged at all round corners of the tangential pulverized coal combustion boiler, and direct-current secondary air burners are arranged at the bottoms of all the direct-current primary air pulverized coal burners; the thick primary air powder pipelines and the thin primary air powder pipelines are arranged at the input ends of the direct-current primary air pulverized coal burners and the input ends of the direct-current secondary air burners respectively. The external concentrator, the direct-flow primary air pulverized coal burner, the direct-flow secondary air burner, the guide vane, the first flow regulating valve, the second flow regulating valve, the thick primary air pulverized coal pipeline, the thin primary air pulverized coal pipeline, the thick primary air pulverized coal outlet and the thin primary air pulverized coal outlet are arranged. The low-load stable combustion can be realized without external assistance, and the effects of high-load combustion efficiency and environmental protection performance are considered, so that the practical use is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power plant boiler combustion, and particularly relates to a horizontal thick-thin straight-flow combustor and an operation method. BACKGROUND

[0002] With large-scale development of new energy such as wind power and photovoltaic power, the demand for thermal power as a peak-shaving power source is increasingly urgent. The four-corner tangential coal powder combustion boiler widely used in power plants in China faces the problems of poor low-load stable combustion, low high-load burnout rate and high NOx emission during deep peak shaving. X In the prior art, the stable combustion load without oil injection can only reach 30%-40% of the rated load. If the load is to be further reduced, auxiliary stable combustion technologies such as micro-oil, plasma or medium-frequency electric heating need to be relied on, which has the disadvantages of high operation cost, poor coal adaptability and complex system. In addition, the traditional straight-flow combustor cannot realize precise thick-thin distribution of coal powder, resulting in low combustion efficiency and excessive pollutant emission, which cannot meet the technical requirements of deep peak shaving. Therefore, it is a technical problem to be solved to develop a combustor structure that can realize low-load stable combustion without external assistance and balance high-load combustion efficiency and environmental performance. SUMMARY

[0003] The purpose of the present application is to solve the above problems, and provide a horizontal thick-thin straight-flow combustor and an operation method, which can realize low-load stable combustion without external assistance and balance high-load combustion efficiency and environmental performance.

[0004] To solve the above technical problems, the present application adopts the following technical scheme: a horizontal thick-thin straight-flow combustor, comprising: A tangential coal powder combustion boiler, wherein each fillet of the tangential coal powder combustion boiler is provided with a straight-flow primary air coal powder combustor, and the bottom of each straight-flow primary air coal powder combustor is provided with a straight-flow secondary air combustor; A plurality of thick primary air powder pipes and thin primary air powder pipes, which are respectively arranged at the input ends of the straight-flow primary air coal powder combustors and the straight-flow secondary air combustors; A plurality of external concentrators, each having two output ends, wherein each output end of the external concentrator is provided with a thick primary air powder outlet and a thin primary air powder outlet, and the corresponding thick primary air powder pipe is in communication with the corresponding thick primary air powder outlet, and the corresponding thin primary air powder pipe is in communication with the thin primary air powder outlet; The internal part of the external concentrator is provided with a plurality of second guide vanes arranged in a stepped and inclined manner, and each second guide vane has a corresponding gap between the second guide vanes, and each second guide vane is located between the input end and the output end of the external concentrator; The direct flow primary air pulverized coal burner comprises a first shell, a plurality of first guide vanes arranged in a stepped and inclined manner are arranged in the first shell, a baffle is arranged at the first guide vanes close to the output end of the first shell, a blunt body is arranged at the output end of the first shell, and the first shell has two output ends, which are a dense coal powder injection port and a light coal powder injection port respectively, so as to form a horizontal direction dense and light coal powder distribution structure.

[0005] Further, the first flow regulating valve is arranged on the light primary air powder pipeline, and the second flow regulating valve is arranged on the dense primary air powder pipeline.

[0006] The dense primary air speed adjusting range is 18-30 m / s, and the light primary air speed adjusting range is 16-28 m / s.

[0007] Further, the external concentrator is used for separating the primary air powder into two air flows of dense and light, the separation ratio of the dense and light coal powder quantity is 8:2-6:4, the separation ratio of the air quantity is 7:3-6:4, the concentration of the dense side coal powder after separation is 1.20-1.32 kg of coal powder / kg of air, and the concentration of the light side coal powder is 0.62-0.74 kg of coal powder / kg of air.

[0008] Further, the first guide vanes in the first shell are arranged in sequence along the flow direction of the primary air powder, can cooperate with the baffles to perform secondary concentration on the dense primary air powder, and the blunt body is used for strengthening the ignition stability of the dense coal powder air flow.

[0009] A running method of a horizontal dense and light direct flow burner, according to the load adjustment of the tangential coal powder combustion boiler, the opening degree of the corresponding flow regulating valve is adjusted, which is used for controlling the air speed and concentration of the dense and light primary air powder, and the method comprises the following steps: S1, when a high load condition (higher than 50% rated load) is running, the opening degree of the first flow regulating valve and the second flow regulating valve is adjusted to 80%-100%, wherein the dense primary air speed is 24-28 m / s, the dense coal powder concentration is 1.28-1.32 kg of coal powder / kg of air, the light primary air speed is 26-30 m / s, and the light coal powder concentration is 0.70-0.74 kg of coal powder / kg of air; S2, when 40%-50% rated load is running, the opening degree of the first flow regulating valve and the second flow regulating valve is adjusted to 60%-80%, wherein the dense primary air speed is 20-24 m / s, the dense coal powder concentration is 1.24-1.28 kg of coal powder / kg of air, the light primary air speed is 22-26 m / s, and the light coal powder concentration is 0.66-0.70 kg of coal powder / kg of air; S3, when the rated load is 0%-40%, the opening of the first flow regulating valve and the second flow regulating valve is adjusted to 50%-60%, wherein the concentration primary air speed is 18-20 m / s, the concentration coal powder concentration is 1.22-1.24 kg coal powder / kg air, the dilute primary air speed is 20-22 m / s, and the dilute coal powder concentration is 0.64-0.66 kg coal powder / kg air; S4, when the rated load is 20% and below, the opening of the first flow regulating valve and the second flow regulating valve is adjusted to 40%-50%, wherein the concentration primary air speed is 16-18 m / s, the concentration coal powder concentration is 1.20-1.22 kg coal powder / kg air, the dilute primary air speed is 18-20 m / s, and the dilute coal powder concentration is 0.62-0.64 kg coal powder / kg air.

[0010] The beneficial effects of the present application are embodied in: In the present application, by means of the setting of the external concentrator, the direct-flow primary air coal powder burner, the direct-flow secondary air burner, the guide vane, the first flow regulating valve, the second flow regulating valve, the concentration primary air powder pipeline, the dilute primary air powder pipeline, the concentration primary air powder outlet and the dilute primary air powder outlet, low-load stable combustion can be realized without external assistance, and the effects of high-load combustion efficiency and environmental protection performance are also taken into account, thereby facilitating actual use. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present application; Figure 2 It is a structural schematic diagram of the direct-flow primary air coal powder burner in the present application; Figure 3 It is a side view schematic diagram of the direct-flow primary air coal powder burner in the present application; Figure 4 It is a structural schematic diagram of the direct-flow secondary air burner in the present application; Figure 5 It is a side view schematic diagram of the direct-flow secondary air burner in the present application; Figure 6 It is an installation schematic diagram of the direct-flow primary air coal powder burner in the present application; Figure 7 It is an ignition schematic diagram of the tangential coal powder combustion boiler in the present application.

[0012] In the drawings: 1, external concentrator; 2, straight-flow primary air pulverized coal burner; 201, first shell; 202, first guide vane; 203, dense coal powder injection port; 204, light coal powder injection port; 205, baffle; 206, blunt body; 3, straight-flow secondary air burner; 301, second shell; 302, straight-flow secondary air channel; 4, guide vane; 5, first flow regulating valve; 6, second flow regulating valve; 7, dense primary air pulverized coal pipeline; 8, light primary air pulverized coal pipeline; 9, dense primary air pulverized coal outlet; 10, light primary air pulverized coal outlet; 11, tangentially cut pulverized coal combustion boiler. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0014] Please refer to Figures 1-7 The present application discloses a horizontal dense and light straight-flow burner, which comprises a tangentially cut pulverized coal combustion boiler 11, the tangentially cut pulverized coal combustion boiler 11 can be a four-corner tangentially cut boiler or an eight-corner tangentially cut boiler, each corner of the tangentially cut pulverized coal combustion boiler 11 is provided with a straight-flow primary air pulverized coal burner 2, the bottom of each straight-flow primary air pulverized coal burner 2 is provided with a straight-flow secondary air burner 3, and the input ends of each straight-flow primary air pulverized coal burner 2 and the straight-flow secondary air burner 3 are configured with a dense primary air pulverized coal pipeline 7 and a light primary air pulverized coal pipeline 8 which are in communication with each other.

[0015] In an embodiment, the device further comprises a plurality of external concentrators 1, each external concentrator 1 has two output ends, each output end of the external concentrator 1 is respectively configured with a dense primary air pulverized coal outlet 9 and a light primary air pulverized coal outlet 10 which are in communication with each other, and the corresponding dense primary air pulverized coal pipeline 7 is in communication with the corresponding dense primary air pulverized coal outlet 9, the corresponding light primary air pulverized coal pipeline 8 is in communication with the light primary air pulverized coal outlet 10, a plurality of second guide vanes 4 which are ladder-shaped and obliquely distributed are installed in the internal part of the external concentrator 1, and each second guide vane 4 has a corresponding gap between each second guide vane 4, and each second guide vane 4 is located between the input end and the output end of the external concentrator 1.

[0016] The direct flow primary air pulverized coal burner 2 comprises a first shell 201, a plurality of first guide vanes 202 are arranged in the first shell 201 in a stepped and inclined manner, a baffle 205 is arranged at the first guide vanes 202 close to the output end of the first shell 201, a blunt body 206 is arranged at the output end of the first shell 201, and the first shell 201 has two output ends, which are a dense coal powder outlet 203 and a light coal powder outlet 204 respectively, so as to form a horizontal direction dense and light coal powder distribution structure, and the direct flow secondary air burner 3 comprises a second shell 301 and a direct flow secondary air channel 302 arranged at the input end of the second shell 301, and the direct flow secondary air channel 302 is connected with the light primary air powder outlet 10 through the light primary air powder pipeline 8.

[0017] In the embodiment, the primary air powder enters the external concentrator 1 from the input end thereof, and is preliminarily separated into two streams of dense and light air flow under the sequential covering and guiding of the second guide vanes 4, wherein the dense primary air powder enters the direct flow primary air pulverized coal burner 2 through the dense primary air powder pipeline 7, and then is secondarily concentrated by the first guide vanes 202 and the baffle 205 in the first shell 201, and is sprayed out from the dense coal powder outlet 203 and the light coal powder outlet 204 to enter the furnace of the tangentially cut coal powder combustion boiler 11, and the light primary air powder enters the direct flow secondary air burner 3 through the light primary air powder pipeline 8, and the direct flow secondary air enters the second shell 301 in a direct flow manner through the direct flow secondary air channel 302, and enters the furnace of the tangentially cut coal powder combustion boiler 11 under the cooperation of the primary air and the secondary air. Through the above-mentioned manner, the primary air powder is efficiently separated into two streams of coal powder air flow with significant difference in concentration by using the inertial separation principle of gas-solid two-phase flow. Under the low load condition, the dense coal powder air flow enters the dense coal powder outlet 203, the ignition heat demand is significantly reduced due to the large increase in the concentration of the coal powder, the temperature rising rate of the coal powder particles is accelerated, the volatilization time is shortened, and a stable ignition flame can be formed in a very short time to establish a reliable initial fire source. At the same time, the light coal powder air flow is sprayed into the furnace from the light coal powder outlet 204 and rapidly participates in combustion under the high temperature of the ignited dense coal powder flame. This staged combustion method not only completely eliminates the safety hazards such as flame flickering and extinguishing under the low load condition, but also realizes the long-term safe and stable operation under the low load (such as 15% of the rated load) without any external combustion support, thereby providing a reliable technical guarantee for the coal power unit to participate in deep peak shaving, and solving the technical problem of deep peak shaving which has plagued the industry for a long time.

[0018] In addition, by the above method, by adjusting the distribution ratio and combustion characteristics of the thick and thin pulverized coal gas flow according to the load change of the tangent circle pulverized coal combustion boiler 11, the thick pulverized coal gas flow is guided to the central high-temperature area of the straight-flow primary air pulverized coal burner 2 for concentrated combustion, due to the high pulverized coal concentration, the volatilization is concentrated, and the pulverized coal is rapidly ignited and burned in the high-temperature environment, a large amount of heat is released, the local temperature is significantly improved, the residence time of the pulverized coal in the high-temperature area is prolonged, and favorable conditions are created for complete combustion of the coke. The thin pulverized coal gas flow is injected from the periphery, on the one hand, it provides the required supplemental oxygen amount for combustion, avoids local excessive oxygen deficiency leading to incomplete combustion, and on the other hand, the thin pulverized coal gas flow is rapidly heated and ignited after mixing with the high-temperature thick pulverized coal flame, realizing secondary combustion of the pulverized coal, and further improving the combustion efficiency. The above fine combustion organization mode ensures that the pulverized coal can be fully burned under different load conditions.

[0019] And the device realizes the accurate separation of the pulverized coal, forms two streams of pulverized coal gas flow with significant concentration difference, and establishes a staged combustion mode in the furnace. The thick pulverized coal gas flow burns in a high-temperature, oxygen-deficient reducing atmosphere, and the nitrogen element in the pulverized coal is mainly converted into intermediate products such as HCN and NH3, and under the action of a large amount of reducing gases such as CO and H2, the generated NO X is reduced to N2, thereby significantly inhibiting the generation of fuel-type NO X Therefore, it is convenient for actual use.

[0020] In one embodiment, the first flow regulating valve 5 is arranged on the thin primary air pulverized coal pipeline 8, and the second flow regulating valve 6 is arranged on the thick primary air pulverized coal pipeline 7. The thick primary air speed regulating range is 18-30 m / s, and the thin primary air speed regulating range is 16-28 m / s.

[0021] In specific implementation, the first flow regulating valve 5 and the second flow regulating valve 6 can adjust the wind speed and the wind volume ratio of the thick and thin primary air according to the load change in real time, further optimize the oxygen concentration distribution of the combustion zone, make the entire combustion process always away from the stoichiometric ratio, realize low-temperature and low-oxygen combustion, and thereby maximize the reduction of the generation of NO X .

[0022] In one embodiment, the external concentrator 1 is used to separate the primary air pulverized coal into thick and thin two streams, and the separation ratio of the thick and thin pulverized coal volume is 8:2-6:4, and the separation ratio of the air volume is 7:3-6:4. After separation, the concentration of the thick side pulverized coal is 1.20-1.32 kg of pulverized coal / kg of air, and the concentration of the thin side pulverized coal is 0.62-0.74 kg of pulverized coal / kg of air.

[0023] In an embodiment, the first guide vanes 202 inside the first shell 201 are arranged in sequence along the direction of the flow of the pulverized coal, and can cooperate with the baffle 205 to perform secondary concentration on the concentrated primary pulverized coal, and the bluff body 206 is used to strengthen the ignition stability of the concentrated pulverized coal flow.

[0024] As another embodiment of the present application, a method for operating the horizontal concentration direct-flow combustor is also included, and the opening degree of the corresponding flow regulating valve is adjusted according to the load adjustment of the tangential coal combustion boiler 11, so as to control the wind speed and concentration of the concentrated and diluted primary pulverized coal: S1, when the high load condition (higher than 50% rated load) is operated, the opening degree of the first flow regulating valve 5 and the second flow regulating valve 6 is adjusted to 80%-100%, wherein the concentrated primary wind speed is 24-28 m / s, the concentrated pulverized coal concentration is 1.28-1.32 kg of pulverized coal / kg of air, the diluted primary wind speed is 26-30 m / s, and the diluted pulverized coal concentration is 0.70-0.74 kg of pulverized coal / kg of air; S2, when the 40%-50% rated load is operated, the opening degree of the first flow regulating valve 5 and the second flow regulating valve 6 is adjusted to 60%-80%, wherein the concentrated primary wind speed is 20-24 m / s, the concentrated pulverized coal concentration is 1.24-1.28 kg of pulverized coal / kg of air, the diluted primary wind speed is 22-26 m / s, and the diluted pulverized coal concentration is 0.66-0.70 kg of pulverized coal / kg of air; S3, when the 0%-40% rated load is operated, the opening degree of the first flow regulating valve 5 and the second flow regulating valve 6 is adjusted to 50%-60%, wherein the concentrated primary wind speed is 18-20 m / s, the concentrated pulverized coal concentration is 1.22-1.24 kg of pulverized coal / kg of air, the diluted primary wind speed is 20-22 m / s, and the diluted pulverized coal concentration is 0.64-0.66 kg of pulverized coal / kg of air; S4, when the 20% and below rated load is operated, the opening degree of the first flow regulating valve 5 and the second flow regulating valve 6 is adjusted to 40%-50%, wherein the concentrated primary wind speed is 16-18 m / s, the concentrated pulverized coal concentration is 1.20-1.22 kg of pulverized coal / kg of air, the diluted primary wind speed is 18-20 m / s, and the diluted pulverized coal concentration is 0.62-0.64 kg of pulverized coal / kg of air.

[0025] It should be noted that if the present application involves directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications will also change accordingly.

[0026] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0027] In addition, "a plurality of" means two or more.

[0028] The above only describes the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A horizontal concentrated-lean direct-flow burner, characterized in that, include: A tangential pulverized coal combustion boiler (11) is provided with a DC primary air pulverized coal burner (2) at each rounded corner, and a DC secondary air burner (3) is provided at the bottom of each DC primary air pulverized coal burner (2). Multiple concentrated primary air pulverized coal pipes (7) and dilute primary air pulverized coal pipes (8) are respectively installed at the input ends of each of the DC primary air pulverized coal burners (2) and DC secondary air burners (3); Multiple external concentrators (1) are provided, each with two output ends. Each output end of the external concentrator (1) is provided with a concentrated primary air powder outlet (9) and a dilute primary air powder outlet (10). The corresponding concentrated primary air powder pipe (7) is connected to the corresponding concentrated primary air powder outlet (9), and the corresponding dilute primary air powder pipe (8) is connected to the dilute primary air powder outlet (10). The external concentrator (1) is provided with a plurality of second guide vanes (4) arranged in a stepped and inclined manner, and each second guide vane (4) has a corresponding gap between them, and each second guide vane (4) is located between the input end and the output end of the external concentrator (1). The DC primary air pulverized coal burner (2) includes a first housing (201). The interior of the first housing (201) is provided with a plurality of first guide vanes (202) arranged in a stepped and inclined manner. A baffle (205) is provided at the first guide vane (202) near the output end of the first housing (201). A blunt body (206) is provided at the output end of the first housing (201). The first housing (201) has two output ends, which are a concentrated pulverized coal nozzle (203) and a dilute pulverized coal nozzle (204), respectively, to form a horizontal concentrated and dilute pulverized coal distribution structure.

2. The horizontal rich-lean direct-current burner according to claim 1, characterized in that: The light primary air-coal pipeline (8) is equipped with a first flow regulating valve (5), and the concentrated primary air-coal pipeline (7) is equipped with a second flow regulating valve (6). The primary air velocity adjustment range for concentrated air is 18-30 m / s, and the primary air velocity adjustment range for dilute air is 16-28 m / s.

3. The horizontal rich-lean direct-current burner according to claim 1, characterized in that: The external concentrator (1) is used to separate primary air and coal powder into two streams, one rich and one light. The ratio of the rich to light coal powder is 8:2-6:4, and the ratio of the air volume is 7:3-6:

4. After separation, the concentration of coal powder on the rich side is 1.20-1.32 kg coal powder / kg air, and the concentration of coal powder on the light side is 0.62-0.74 kg coal powder / kg air.

4. The horizontal rich-lean DC burner according to claim 1, characterized in that: The first guide vanes (202) inside the first housing (201) are arranged sequentially along the air-coal flow direction. They can cooperate with the baffle (205) to perform secondary concentration of the concentrated primary air-coal. The blunt body (206) is used to enhance the ignition stability of the concentrated coal-coal flow.

5. A method for operating a horizontal rich-lean direct-current burner, comprising the horizontal rich-lean direct-current burner according to any one of claims 1-4, characterized in that: Adjust the opening of the corresponding flow regulating valve according to the load of the tangential pulverized coal combustion boiler (11) to control the velocity and concentration of the primary air pulverized coal, including: S1. When operating under high load conditions (above 50% of rated load), the opening of the first flow regulating valve (5) and the second flow regulating valve (6) is adjusted to 80%-100%, wherein the primary air velocity of the concentrated primary air is 24-28m / s and the concentration of concentrated coal powder is 1.28-1.32kg coal powder / kg air, and the primary air velocity of the light primary air is 26-30m / s and the concentration of light coal powder is 0.70-0.74kg coal powder / kg air; S2. When operating at 40%-50% rated load, the opening of the first flow regulating valve (5) and the second flow regulating valve (6) is adjusted to 60%-80%, wherein the primary air velocity of the concentrated primary air is 20-24m / s and the concentration of concentrated pulverized coal is 1.24-1.28kg pulverized coal / kg air, and the primary air velocity of the light primary air is 22-26m / s and the concentration of light pulverized coal is 0.66-0.70kg pulverized coal / kg air. S3. When operating at 0%-40% rated load, the opening of the first flow regulating valve (5) and the second flow regulating valve (6) is adjusted to 50%-60%, wherein the primary air velocity of the concentrated primary air is 18-20m / s and the concentration of concentrated pulverized coal is 1.22-1.24kg pulverized coal / kg air, and the primary air velocity of the light primary air is 20-22m / s and the concentration of light pulverized coal is 0.64-0.66kg pulverized coal / kg air. When operating at 20% or below the rated load, the opening of the first flow regulating valve (5) and the second flow regulating valve (6) is adjusted to 40%-50%, wherein the primary air velocity of the concentrated primary air is 16-18m / s and the concentration of concentrated coal powder is 1.20-1.22kg coal powder / kg air, and the primary air velocity of the light primary air is 18-20m / s and the concentration of light coal powder is 0.62-0.64kg coal powder / kg air.

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