Primary air powder system for deep peak regulation

Abstract

The present invention discloses a primary air powder system for deep peak regulation, which includes a burner, a main air powder duct and a regulating air powder duct. The burner has a main air powder nozzle and a regulating air powder nozzle. The regulating air powder nozzle is concentrically arranged with the main air powder nozzle. The main air powder nozzle and the regulating air powder nozzle are connected to a coal mill. One end of the main air powder duct is connected to the outlet of the coal mill, and the other end of the main air powder duct is connected to the main air powder nozzle of the burner. The regulating air powder duct is connected to the outlet of the coal mill, and the other end of the regulating air powder duct is connected to the regulating air powder nozzle of the burner. The primary air powder system for deep peak regulation provided by the present invention has the advantages of high operational reliability and good low-load combustion stability.

Description

Technical Field

[0001] The present invention relates to the field of deep peak regulation technology, and in particular to a primary air-powder system for deep peak regulation. Background Art

[0002] At present, the relevant technologies for reducing the air-coal ratio or increasing the coal powder concentration under deep peak-shaving conditions mainly include external coal powder separators, optimization of coal powder concentration devices inside burners, optimization of combustion operation control, reduction of the number of operating pulverizers and operation of powder cutting pipes, all of which have certain defects.

[0003] The external pulverized coal separator performs pre-separation of thick and thin coal outside the main burner, separating a part of the exhaust gas. The thick pulverized coal is sent into the furnace through the main burner, and the exhaust gas is sent into the furnace from the side of the main burner. This technology only reduces the primary air rate and air-coal ratio of the main burner, and the degree of increasing the pulverized coal concentration is limited. Generally, the pulverized coal concentration can only be increased to about 0.5kg / kg. At the same time, the pulverized coal concentration of fine pulverized coal in the exhaust gas is very low, and the overall adjustment margin is small; the optimization of the pulverized coal concentration device inside the burner can only locally concentrate the pulverized coal in the burner nozzle to form a high-concentration pulverized coal, and the overall pulverized coal concentration at the burner outlet cannot be changed; the optimization of combustion operation control mainly reduces the primary air rate and air-coal ratio during operation. The air rate can reduce the ignition heat, but the reduction is limited due to the requirement that the medium flow rate in the air-powder duct is not less than 18m / s, and its adaptability to deep peak-shaving conditions is low; reducing the number of operating pulverizers can reduce the pulverized coal concentration at the burner outlet, but reduces the reliability of the boiler during deep peak-shaving operation. If a single pulverizer operates abnormally, it is easy to cause a boiler fire extinguishing and shutdown accident; the pulverized coal pipe operation mainly cuts off the burners on both sides of the furnace and does not add pulverized coal during deep peak-shaving, and only operates the burner in the middle of the furnace to increase the pulverized coal concentration of a single burner. This method is not conducive to the control and adjustment of operating parameters, and is prone to parameter deviations in boiler steam temperature and flue gas temperature. Summary of the Invention

[0004] The present invention is made based on the inventor's discovery and recognition of the following facts and problems: the adjustment range of the wind-to-powder ratio in the related art is narrow.

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0006] To this end, an embodiment of the present invention proposes a primary air powder system for deep peak regulation, which has the advantages of high operational reliability and good low-load combustion stability.

[0007] According to an embodiment of the present invention, a primary air powder system for deep peak regulation includes a burner, a main air powder duct and a regulating air powder duct, the burner has a main air powder nozzle and a regulating air powder nozzle, the regulating air powder nozzle is concentrically arranged with the main air powder nozzle, the main air powder nozzle and the regulating air powder nozzle are connected to a coal mill, one end of the main air powder duct is connected to the outlet of the coal mill, the other end of the main air powder duct is connected to the main air powder nozzle of the burner, the regulating air powder duct is connected to the outlet of the coal mill, and the other end of the regulating air powder duct is connected to the regulating air powder nozzle of the burner.

[0008] The primary air powder system for deep peak regulation according to the embodiment of the present invention has the advantages of high operational reliability and good low-load combustion stability.

[0009] In some embodiments, the regulating air-powder duct corresponds one-to-one to the main air-powder duct.

[0010] In some embodiments, at least a portion of the regulating air-powder duct is concentrically nested within the main air-powder duct.

[0011] In some embodiments, the flow cross-sectional area of ​​the regulating air-powder duct is 25% to 40% of the flow cross-sectional area of ​​the main air-powder duct.

[0012] In some embodiments, each coal mill corresponds to two groups of the main air-powder ducts, the first group of the main air-powder ducts is connected to the burner in the center of the furnace, and the second group of the main air-powder ducts is connected to the burners on both sides of the furnace.

[0013] In some embodiments, each group of the main air-powder ducts has at least two.

[0014] In some embodiments, the primary air-powder system for deep peak regulation further includes a detection device, which includes a first detection device and a second detection device. The first detection device is arranged on the main air-powder duct, and the second detection device is arranged on the regulating air-powder duct.

[0015] In some embodiments, the first detection device and the second detection device both include a flow detector and a flow velocity detector.

[0016] In some embodiments, the regulating air-powder duct and the main air-powder duct are respectively provided with shut-off doors.

[0017] In some embodiments, the primary air-powder system for deep peak regulation further includes a control device, which includes a control cabinet and a signal cable. The control cabinet is connected to the shut-off doors of the main air-powder duct and the regulating air-powder duct respectively through the signal cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of a primary air-powder system for deep peak regulation according to an embodiment of the present invention.

[0019] Figure 2 It is a partial schematic diagram of the nozzle of a primary air powder system for deep peak regulation according to an embodiment of the present invention.

[0020] Figure numerals: 1. Main air-powder duct; 2. Adjusting air-powder duct; 3. Furnace; 4. Main air-powder nozzle; 5. Adjusting air-powder nozzle; 6. Coal mill; 7. Detection device; 8. Control cabinet; 9. Signal cable; 10. Shut-off door. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0022] According to the embodiment of the present invention, the primary air powder system for deep peak regulation, such as Figure 1 and Figure 2 As shown, the primary air powder system for deep peak shaving includes a burner, a main air powder duct 1, and a regulating air powder duct 2. The burner has a main air powder nozzle 4 and a regulating air powder nozzle 5. The regulating air powder nozzle 5 is arranged concentrically with the main air powder nozzle 4. The main air powder nozzle 4 and the regulating air powder nozzle 5 are connected to the pulverizer 6. One end of the main air powder duct 1 is connected to the outlet of the pulverizer 6, and the other end of the main air powder duct 1 is connected to the main air powder nozzle 4 of the burner. The regulating air powder duct 2 is connected to the outlet of the pulverizer 6, and the other end of the regulating air powder duct 2 is connected to the regulating air powder nozzle 5 of the burner. The concentric arrangement of the main air powder nozzle 4 and the regulating air powder nozzle 5 enables the main air powder duct 1 and the regulating air powder duct 2 to be arranged concentrically. Under non-deep peak shaving conditions, the main air powder duct 1 supplies the primary air and coal powder mixture required for burner combustion. Under deep peak shaving conditions, the main air powder duct 1 is switched to the regulating air powder duct 2. Under deep peak-shaving conditions, the pulverized coal concentration in air-powder duct 2 is controlled within a range of 0.50 to 0.65 kg / kg. The flow rate of the primary air and pulverized coal mixture in air-powder duct 2 is adjusted to no less than 18 m / s to prevent dust accumulation within the duct, and the flow rate of the primary air and pulverized coal mixture is controlled to no more than 35 m / s to ensure that duct wear is within a controllable range. By significantly adjusting the pulverized coal concentration in individual air-powder ducts and burners to change the air-powder ratio, low-load combustion stability is improved, solving the problem of stable boiler combustion under deep peak-shaving conditions.

[0023] The primary air powder system for deep peak regulation according to the embodiment of the present invention has the advantages of high operational reliability and good low-load combustion stability.

[0024] In some embodiments, as Figure 1 and Figure 2 As shown, the regulating air-powder duct 2 corresponds to the main air-powder duct 1 one to one.

[0025] Specifically, the one-to-one correspondence between the regulating air-powder duct 2 and the main air-powder duct 1 is convenient for switching the regulating air-powder duct 2 to replace the main air-powder duct 1 to transport the primary air and coal powder mixture under deep peak load conditions.

[0026] In some embodiments, as Figure 1 and Figure 2 As shown, at least part of the regulating air-powder duct 2 is concentrically nested in the main air-powder duct 1 .

[0027] Specifically, one end of the regulating air-powder duct 2 adjacent to the burner is nested in the main air-powder duct 1 so that the regulating air-powder duct 2 is connected to the regulating air-powder nozzle 5. A portion of the regulating air-powder duct 2 is embedded in the main air-powder duct 1 to reduce the wear of the regulating air-powder duct 2 by coal powder.

[0028] In some embodiments, the flow cross-sectional area of ​​the air-powder duct 2 is adjusted to 25% to 40% of the flow cross-sectional area of ​​the main air-powder duct 1 .

[0029] Therefore, the peak-shaving air-powder pipeline can achieve a larger range of air-powder ratio adjustment under deep peak-shaving conditions.

[0030] In some embodiments, as Figure 1 and Figure 2 As shown, each coal mill 6 corresponds to two groups of main air-powder ducts 1 , the first group of main air-powder ducts 1 is connected to the burner in the center of the furnace 3 , and the second group of main air-powder ducts 1 is connected to the burners on both sides of the furnace 3 .

[0031] Specifically, when adjusting from a non-deep peak-shaving condition to a deep peak-shaving condition, the primary air and pulverized coal mixture is switched from the main air-pulverized coal duct 1 to the regulating air-pulverized coal duct 2. The switching is performed one pulverizer 6 at a time. When a single pulverizer 6 is switched, the first group of main air-pulverized coal ducts 1 corresponding to the burner in the middle of the furnace 3 is switched first, and then the second group of main air-pulverized coal ducts 1 corresponding to the burners on both sides of the furnace 3 are switched. That is, the primary air and pulverized coal mixture in the first group of main air-pulverized coal ducts 1 is first switched to the two regulating air-pulverized coal ducts 2 corresponding to the first group of main air-pulverized coal ducts 1, and then the primary air and pulverized coal mixture in the second group of main air-pulverized coal ducts 1 is switched to the two regulating air-pulverized coal ducts 2 corresponding to the second group of main air-pulverized coal ducts 1. By grouping the first and second groups, the impact of the air-pulverized coal duct switching operation on the continuous and stable operation of the boiler can be minimized.

[0032] In some embodiments, as Figure 1 and Figure 2 As shown, each group of main air-powder ducts 1 has at least two.

[0033] Specifically, when each group of main air-powder ducts 1 has two, each coal mill 6 corresponds to four main air-powder ducts 1 and four regulating air-powder ducts 2 , and the plurality of main air-powder ducts 1 can disperse the powder supply amount of the coal mill 6 .

[0034] In some embodiments, as Figure 1 and Figure 2 As shown, the primary air-powder system for deep peak regulation also includes a detection device 7, which includes a first detection device 7 and a second detection device 7. The first detection device 7 is arranged on the main air-powder duct 1, and the second detection device 7 is arranged on the regulating air-powder duct 2.

[0035] Specifically, the first detection device 7 and the second detection device 7 respectively measure and calculate the medium flow rate, flow velocity and coal powder concentration of the main air-powder duct 1 and the regulating air-powder duct 2. When the coal powder concentration is lower than 0.50 kg / kg or the medium flow rate is lower than 18 m / s, the first detection device 7 or the second detection device 7 sends data to the control device to switch the regulating air-powder duct 2.

[0036] In some embodiments, the first detection device 7 and the second detection device 7 both include a flow detector and a flow velocity detector.

[0037] Specifically, the flow detector is used to measure the flow rate of the medium in the pipeline, and the flow velocity detector is used to measure the flow velocity of the medium in the pipeline.

[0038] In some embodiments, as Figure 1 As shown, the regulating air-powder duct 2 and the main air-powder duct 1 are respectively provided with shut-off doors 10 .

[0039] Specifically, the shutoff door 10 is used to cut off the main air-powder duct 1 or the regulating air-powder duct 2, and can realize the opening and closing of the duct. The shutoff door 10 has a good sealing effect and is convenient for maintenance.

[0040] In some embodiments, as Figure 1 As shown, the primary air powder system for deep peak regulation also includes a control device, which includes a control cabinet 8 and a signal cable 9. The control cabinet 8 is connected to the shut-off doors 10 of the main air powder duct 1 and the regulating air powder duct 2 through the signal cable 9.

[0041] Specifically, when the coal powder concentration is lower than 0.50 kg / kg or the medium flow rate is lower than 18 m / s, the control cabinet 8 gives action instructions to the shut-off door 10 of the main air-powder duct 1 and the shut-off door 10 of the regulating air-powder duct 2, closing the shut-off door 10 of the main air-powder duct 1 and opening the shut-off door 10 of the regulating air-powder duct 2.

[0042] The method for using a primary air powder system for deep peak regulation includes the following steps:

[0043] Switch the main air-powder duct 1 to the regulating air-powder duct 2 for each coal mill 6, switch the main air-powder duct 1 in the middle of the furnace 3 to the regulating air-powder duct 2, and switch the main air-powder duct 1 on both sides of the furnace 3 to the regulating air-powder duct 2;

[0044] The flow measuring device on the main air-powder duct 1 detects the medium flow, flow velocity and coal powder concentration and sends the data to the control device. If the coal powder concentration or medium flow velocity is lower than the preset value, the shut-off door 10 of the main air-powder duct 1 is closed and the shut-off door 10 of the regulating air-powder duct 2 is opened.

[0045] When the non-deep peak-shaving operating condition is adjusted to the deep peak-shaving operating condition, the primary air and pulverized coal mixture is switched from the main air and pulverized coal duct 1 to the regulating air and pulverized coal duct 2. This switching is performed one pulverizer 6 at a time. When switching a single pulverizer 6, the air and pulverized coal duct corresponding to the two burners in the middle of the furnace 3 is switched first, followed by the air and pulverized coal ducts corresponding to the two burners on both sides of the furnace 3. That is, the primary air and pulverized coal mixture in the Z2 and Z3 main air and pulverized coal ducts 1 is first switched to the S2 and S3 regulating air and pulverized coal ducts 2, and then the primary air and pulverized coal mixture in the Z1 and Z4 main air and pulverized coal ducts 1 is switched to the S1 and S4 regulating air and pulverized coal ducts 2. The above operating method is intended to minimize the impact of the air and pulverized coal duct switching operation on the continuous and stable operation of the boiler.

[0046] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0048] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0049] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0050] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0051] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Any changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are within the scope of protection of the present invention.

Claims

1. A primary air-powder system for deep peak regulation, characterized in that: include: A burner, wherein the burner has a main air-powder nozzle and an adjusting air-powder nozzle, the adjusting air-powder nozzle is arranged concentrically with the main air-powder nozzle, and the main air-powder nozzle and the adjusting air-powder nozzle are connected to a coal mill; a main air-powder duct, one end of which is connected to the outlet of the coal mill, and the other end of which is connected to the main air-powder nozzle of the burner; and an air-powder regulating duct, the air-powder regulating duct being connected to the outlet of the coal mill, and the other end of the air-powder regulating duct being connected to the air-powder regulating nozzle of the burner; Under non-deep peak-shaving conditions, the main air-powder duct supplies the primary air and pulverized coal mixture required for burner combustion. Under deep peak-shaving conditions, the main air-powder duct is switched to the regulating air-powder duct. Under deep peak-shaving conditions, the pulverized coal concentration in the regulating air-powder duct is controlled within the range of 0.50 to 0.65 kg / kg, and the flow rate of the primary air and pulverized coal mixture in the regulating air-powder duct is not less than 18 m / s to ensure that no powder accumulates in the air-powder duct, and the flow rate of the primary air and pulverized coal mixture is not higher than 35 m / s to ensure that the pipeline wear is within a controllable range.

2. The primary air-powder system for deep peak regulation according to claim 1, characterized in that: The regulating air-powder duct corresponds to the main air-powder duct one by one.

3. The primary air-powder system for deep peak regulation according to claim 2, wherein at least a portion of the regulating air-powder duct is concentrically nested in the main air-powder duct.

4. The primary air-powder system for deep peak regulation according to claim 3, characterized in that: The flow cross-sectional area of ​​the regulating air-powder duct is 25% to 40% of the flow cross-sectional area of ​​the main air-powder duct.

5. The primary air-powder system for deep peak regulation according to claim 1, characterized in that: Each coal mill has two groups of main air-powder ducts. The first group of main air-powder ducts is connected to the burner in the center of the furnace, and the second group of main air-powder ducts is connected to the burners on both sides of the furnace.

6. The primary air-powder system for deep peak regulation according to claim 5, characterized in that: Each group of main air-powder ducts has at least two.

7. The primary air-powder system for deep peak regulation according to claim 1, characterized in that: It also includes a detection device, which includes a first detection device and a second detection device. The first detection device is arranged on the main air-powder duct, and the second detection device is arranged on the regulating air-powder duct.

8. The primary air-powder system for deep peak regulation according to claim 7, characterized in that: The first detection device and the second detection device both include a flow detector and a flow velocity detector.

9. The primary air-powder system for deep peak regulation according to claim 1, characterized in that: The regulating air-powder duct and the main air-powder duct are respectively provided with shut-off doors.

10. The primary air-powder system for deep peak regulation according to claim 9, characterized in that: It also includes a control device, which includes a control cabinet and signal cables. The control cabinet is connected to the shut-off doors of the main air-powder duct and the regulating air-powder duct respectively through the signal cables.

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