Tertiary air system and coal pulverizing system
By introducing a bypass pipe and adjustable damper into the boiler's tertiary air system, the amount of pulverized coal entering the upper part of the combustion chamber is increased, which solves the problem of insufficient boiler power, increases the temperature of superheated steam and reheated steam, and optimizes combustion efficiency.
Patent Information
- Application Number
- CN202423172981.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-12-23
AI Technical Summary
Existing boilers suffer from insufficient heating power when burning anthracite and low volatile coal, making it difficult to raise the temperature of superheated steam and reheated steam. Furthermore, increasing the pulverized coal content in the primary air leads to insufficient oxygen in the lower part of the combustion chamber, resulting in incomplete combustion of pulverized coal.
By installing a bypass pipe between the pulverized coal transmission pipeline downstream of the pulverized coal separator and the air inlet of the pulverizer, and connecting an adjustable damper in series in the bypass pipe, the pulverized coal content in the tertiary air is increased, allowing more pulverized coal to enter the upper and middle layers of the combustion chamber, thereby adjusting the combustion zone to improve boiler power and steam temperature.
Without altering the combustion chamber structure, the overall thermal output of the boiler was improved, the temperature of superheated steam and reheated steam was increased, and the controllability of the combustion process was achieved, while reducing construction difficulty and modification costs.
Smart Images
Figure CN223726403U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of boiler, more specifically, to a tertiary air system, in addition, the utility model relates to a coal making system comprising the tertiary air system. BACKGROUND
[0002] Generally, when burning anthracite and low-volatile inferior coal on a power station boiler, the coal making system adopts a middle bin storage type hot air powder feeding mode, at this time, in the pulverized coal boiler system, the air required for boiler combustion is divided into three kinds: primary air, secondary air and tertiary air. The primary air is the air that carries the pulverized coal into the furnace through the pipeline, the proportion of the primary air is usually determined according to the size of the volatile matter, the pulverizing method and the conveying concentration of the gas-powder mixture, and at the same time, the oxygen quantity for the early stage of coal combustion is met. The secondary air is the hot air that is fed into the furnace through the separate nozzle of the burner, and the secondary air is gradually mixed with the primary air after entering the furnace. The secondary air provides oxygen for the combustion of the pulverized coal, and can strengthen the agitation of the gas flow, and provide oxygen for the complete combustion of the pulverized coal. The tertiary air is the gas after the separation of the pulverized coal in the coal making system when burning anthracite, low-volatile coal and other fuels that are not easy to ignite, and is also called exhaust gas. The tertiary air contains 10-15% of the pulverized coal, and is directly injected into the furnace through a separate tertiary air pipeline and nozzle.
[0003] In actual use, the primary air and the secondary air are mostly fed into the middle and lower layers of the combustion chamber, i.e. the main combustion area is the middle and lower layers of the combustion chamber, and the tertiary air is fed into the middle and upper layers of the combustion chamber. When the output end of the boiler is under high load, there is a problem of insufficient heating power, which can cause the temperature of the superheated steam and the reheated steam of the system to be substandard. However, if the content of the pulverized coal in the primary air is increased, it will cause insufficient oxygen in the middle and lower layers of the combustion chamber, and the combustion of the pulverized coal will not be sufficient, which has little effect on the overall heat output of the boiler, and even has a negative effect, which is not conducive to the improvement of the temperature of the superheated steam and the reheated steam.
[0004] In summary, how to solve the problem of insufficient power of the existing boiler, which causes the temperature of the superheated steam and the reheated steam to be difficult to improve, is a problem that needs to be solved by the technical personnel in the field at present. Utility model content
[0005] Therefore, the utility model aims at providing a tertiary air system, by increasing a bypass pipe, conducting the pulverized coal conveying pipe and the air inlet of the powder discharger, increasing the content of the pulverized coal in the tertiary air, and then making more pulverized coal enter the middle and upper layers of the combustion chamber, so that the middle and upper layers and the middle and lower layers of the combustion chamber are used as the combustion area at the same time, and then the power of the boiler is improved without changing the combustion chamber of the boiler, which is conducive to the improvement of the temperature of the superheated steam and the reheated steam.
[0006] The utility model discloses a further purpose is to provide a kind of pulverizing system comprising above-mentioned three times wind system, with identical technical features, can solve identical technical problems.
[0007] In order to realize the above-mentioned purpose, the utility model provides the following technical scheme:
[0008] A kind of three times wind system, comprising:
[0009] Bypass pipe, its upstream end is communicated with the coal powder transmission pipeline of the downstream arbitrary position of coal powder separator, downstream end is communicated with the air inlet of powder exhaust machine;
[0010] Adjustable damper, it is connected in series in the bypass pipe, for adjusting the flux in the bypass pipe.
[0011] Preferably, the upstream end of the bypass pipe is communicated with the coal powder transmission pipeline of the outlet of coarse powder separator, and the included angle between the center line of the upstream end of the bypass pipe and the center line of the coal powder transmission pipeline is an acute angle.
[0012] Preferably, the downstream end of the bypass pipe is communicated with the exhaust duct between the powder exhaust machine and the negative pressure environment of the pulverizing system;The included angle between the center line of the downstream end of the bypass pipe and the center line of the exhaust duct is an acute angle.
[0013] Preferably, the upstream end and the downstream end of the bypass pipe are connected in series with horizontal section, the adjustable damper is connected in series in the horizontal section of the bypass pipe, and the included angle between the horizontal section of the bypass pipe and the upstream end and / or downstream end is an obtuse angle.
[0014] Preferably, the elbow between the horizontal section of the bypass pipe and the upstream end and / or downstream end is a wear-resistant elbow.
[0015] Preferably, the control unit of the adjustable damper actuator is electrically connected with the central control module of the pulverizing system, for remotely controlling the flux adjustment of the adjustable damper.
[0016] Preferably, the burner nozzle communicated with the powder exhaust machine is at least three groups, the included angle between the connecting line of the burner nozzle and the horizontal section center of the combustion chamber and the injection axis of the burner nozzle is an acute angle, all the injection axes intersect each other and have a common tangent circle, and the center of the common tangent circle coincides with the horizontal section center of the combustion chamber.
[0017] A kind of pulverizing system, comprising the three times wind system of any one of the above.
[0018] The three times wind system provided by the utility model compared with prior art has at least the following beneficial effects:
[0019] 1. By setting the bypass pipe communicated with the coal powder transmission pipeline at the air inlet of the powder discharging machine, the qualified and capable coal powder for combustion in the coal powder system is mixed in the tertiary air through the bypass pipe and the action of the powder discharging machine, so that the content of the coal powder in the tertiary air is increased, the middle and upper layer area of the combustion chamber is used as the combustion area at the same time, and the heat energy is supplied together with the original combustion area, that is, the overall heat production efficiency of the boiler is improved without changing the combustion chamber, which helps to improve the temperature of the superheated steam and the reheated steam.
[0020] 2. By connecting the adjustable air door in the bypass pipe, the flux in the bypass pipe can be adjusted, that is, the addition amount of the coal powder in the tertiary air is changed, the conversion of the heat in the middle and upper layer area of the combustion chamber is effectively controlled, and the improvement effect of the temperature of the superheated steam and the reheated steam is controlled, that is, the heat conversion of the overall system is controllable.
[0021] 3. The upstream end of the bypass pipe is communicated with the coal powder transmission pipeline at the outlet of the separator instead of the coal powder transmission pipeline at the outlet of the coal powder bin, so that the decrease of the content of the coal powder in the primary air caused by the part of the coal powder entering the combustion chamber with the tertiary air is reduced, that is, the influence on the heat conversion of the middle and lower layer area of the combustion chamber is reduced.
[0022] The pulverizing system provided by the utility model has the same beneficial effects as the above-mentioned tertiary air system. ACCURACY
[0023] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only the embodiments of the utility model, and for the ordinary skilled in the art, other drawings can be obtained according to the provided drawings without the creative labor.
[0024] Figure 1 It is the structure schematic view of the pulverizing system and the tertiary air system provided by the utility model;
[0025] Figure 2 It is the assembly schematic view of the tertiary air system provided by the utility model in the pulverizing system;
[0026] Figure 3 It is the structure schematic view of the tertiary air system provided by the utility model;
[0027] Figure 4 It is the arrangement mode schematic view of the burner nozzle provided by the utility model.
[0028] Figures 1-4 In the middle:
[0029] 1, bypass pipe; 2, adjustable damper; 3, raw coal bin; 4, coal mill; 5, coarse powder separator; 6, fine powder separator; 7, powder bin; 8, powder exhaust machine; 9, burner nozzle. DETAILED DESCRIPTION
[0030] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.
[0031] The core of the utility model is to provide a kind of tertiary air system, by increasing bypass pipe, the conduction coal powder transmission pipe and powder exhaust machine air inlet, make the coal content in tertiary air increase, and then make more coal powder enter into the middle upper layer of combustion chamber, make the middle upper layer and middle lower layer of combustion chamber simultaneously as combustion area, and then under the premise of not changing boiler combustion chamber, improve the power of boiler, it is favorable to improve the temperature of superheated steam and reheat steam.
[0032] Another core of the utility model is to provide a kind of pulverizing system comprising the above tertiary air system, with same technical features, can solve the same technical problems.
[0033] Please refer to Figures 1-4 A kind of tertiary air system, comprising:
[0034] Bypass pipe 1, its upstream end is communicated with the coal powder transmission pipeline of coal powder separator downstream arbitrary position, downstream end is communicated with the air inlet of powder exhaust machine 8;
[0035] Adjustable damper 2, it is connected in bypass pipe 1, for adjusting the flux in bypass pipe 1.
[0036] Traditional pulverizing system mainly includes raw coal bin 3, coal feeder, coal mill 4, coarse powder separator 5, fine powder separator 6 and powder bin 7 arranged in sequence, and the working process is that coal feeder transports raw coal in raw coal bin 3 into coal mill 4 to be crushed, the discharge is in powder form, enters coarse powder separator 5 to be separated for the first time, unqualified product returns to coal mill 4 to continue to be crushed and ground, qualified product enters fine powder separator 6 to be separated for the second time, and qualified coal powder is stored in powder bin 7, waits for coal powder to enter the combustion chamber of boiler with primary air and is combusted and used, in the process, the whole inside of pulverizing system is under negative pressure environment under the action of powder exhaust machine 8, and the exhaust airflow of powder exhaust machine 8 is introduced into the upper layer of boiler combustion chamber to be combusted, although there is part of coal powder in tertiary air, but its coal content is low, and the heat generated by its combustion is small, and the temperature rising effect on superheated steam and reheat steam is very small.
[0037] As shown in Figure 1 The coal powder in the coal powder conveying pipeline behind the coal powder separator is the qualified product meeting the combustion requirement, that is, the part of the coal powder is communicated with the pipeline of the tertiary air through the bypass pipe 1, and the part of the qualified coal powder in the coal powder conveying pipeline is extracted into the pipeline of the tertiary air by the negative pressure in the pipeline of the tertiary air, mixed with the tertiary air, enters into the combustion chamber through the burner nozzle 9 at the top of the combustion chamber, and is combusted to make the middle and upper parts of the combustion chamber also serve as the combustion area to convert heat, improve the overall heat output of the boiler, and help to improve the temperature of the superheated steam and the reheated steam.
[0038] Meanwhile, the adjustable air door 2 is arranged in the bypass pipe 1 to control the flux in the bypass pipe 1, that is, the content of the coal powder in the tertiary air is changed by changing the flux of the adjustable air door 2, and then the heat generated in the middle and upper layers of the combustion chamber is controlled, and then the output heat of the combustion chamber of the boiler is controllable, that is, the temperature rise of the superheated steam and the reheated steam is controllable.
[0039] In some embodiments, the upstream end of the bypass pipe 1 is communicated with the coal powder conveying pipeline at the outlet of the coarse powder separator 5, and the included angle between the center line of the upstream end of the bypass pipe 1 and the center line of the coal powder conveying pipeline is an acute angle.
[0040] As shown in Figure 2 In actual application of the coal pulverizing system, the coal powder conveying pipeline at the outlet of the coarse powder separator 5 is parallel to the exhaust pipeline at the air inlet of the powder discharger 8, the bypass pipe 1 is added at this position, the required pipeline length is small, the bypass pipe 1 does not interfere with other pipelines, and the construction is facilitated.
[0041] Meanwhile, the coal powder discharged from the outlet of the coarse powder separator 5 has met the combustion requirement of the combustion chamber, and the pipeline diameter of the coal powder conveying pipeline at the outlet of the coarse powder separator 5 is equal to that of the exhaust pipeline at the inlet of the powder discharger 8, so that the upstream end of the bypass pipe 1 is arranged near the outlet of the coarse powder separator 5 to effectively reduce the construction difficulty and save the modification cost of the original equipment.
[0042] Meanwhile, the included angle α1 between the bypass pipe 1 and the coal powder conveying pipeline is an acute angle, preferably 30° or 45°, which can reduce the scouring of the coal powder on the inner wall of the bypass pipe 1 to improve the service life of the bypass pipe 1.
[0043] In some embodiments, the upstream end of the bypass pipe 1 is communicated with the coal powder conveying pipeline at the inlet or outlet position of the fine powder separator 6, or a powder outlet is added on the powder bin 7 to be communicated with the upstream end of the bypass pipe 1, which all belong to the protection scheme of the present application.
[0044] In some embodiments, the downstream end of the bypass pipe 1 is communicated with the exhaust pipeline between the powder discharger 8 and the negative pressure environment of the coal pulverizing system, and the included angle between the center line of the downstream end of the bypass pipe 1 and the center line of the exhaust pipeline is an acute angle.
[0045] AsFigure 1 and Figure 2 As shown in the figure, the exhaust duct is connected between the air outlet of the pulverizer 8 and the fine powder separator 6. The negative pressure generated in the pulverizer 8 can exhaust the air in the fine powder separator 6 and the entire pulverizing system, so that the entire pulverizing system is in a negative pressure state, and the coal powder is prevented from overflowing. That is, there is a continuous airflow in the exhaust duct. When the airflow flows through the interface position between the bypass pipe 1 and the exhaust duct, a negative pressure is generated in the bypass pipe 1 at the same time, which forces the coal powder in the coal powder conveying pipe to enter the exhaust duct through the bypass pipe 1, and then mixes with the tertiary air in the exhaust duct, and then enters the combustion chamber for combustion.
[0046] At the same time, the angle α4 between the downstream end of the bypass pipe 1 and the exhaust duct is an acute angle, preferably 30°, 45°, etc. Similarly, the scouring of the coal powder on the inner wall of the exhaust duct can be reduced, so as to improve the service life of the exhaust duct.
[0047] In some embodiments, a horizontal section is connected between the upstream end and the downstream end of the bypass pipe 1. The adjustable damper 2 is connected in the horizontal section of the bypass pipe 1, and the angle between the horizontal section and the upstream end and / or the downstream end is an obtuse angle.
[0048] In some embodiments, the adjustable damper 2 is arranged in the horizontal section of the bypass pipe 1, which is convenient for construction. The angles α2 and α3 between the horizontal section and the upstream end and the downstream end are obtuse angles, preferably 120°, 135°, etc. The bending degree between the horizontal section and the upstream end and the downstream end is reduced, so as to reduce the scouring of the coal powder on the inner wall of the bypass pipe 1, and improve the service life of the bypass pipe 1.
[0049] In some embodiments, the elbow between the horizontal section and the upstream end and / or the downstream end of the bypass pipe 1 is a wear-resistant elbow.
[0050] The elbow connected between the horizontal section and the upstream end and the downstream end is designed as a wear-resistant elbow, which increases the wear resistance of the inner wall, and further improves the overall service life of the bypass pipe 1.
[0051] In some embodiments, the control unit of the actuator of the adjustable damper 2 is electrically connected with the central control module of the pulverizing system, for remotely controlling the flux adjustment of the adjustable damper 2.
[0052] In the design of the bypass pipe 1 and the adjustable damper 2, the control unit of the actuator of the adjustable damper 2 is electrically connected with the central control module of the pulverizing system, that is, the adjustable damper 2 is controlled integrally with the pulverizing system. According to the temperature requirements of the superheated steam and the reheated steam, the flux of each component in the pulverizing system and the adjustable damper 2 can be synchronously adjusted remotely.
[0053] In some embodiments, the powder discharging machine 8 is communicated with at least three groups of burner nozzles 9, the included angle between the line connecting the horizontal section center of the combustion chamber and the jet axis of the burner nozzles 9 is an acute angle, all the jet axes of the burner nozzles 9 intersect with each other and have a common tangent circle, and the center of the common tangent circle coincides with the horizontal section center of the combustion chamber.
[0054] As shown in the figure, by limiting the arrangement of the burner nozzles 9, the jet axes of the burner nozzles 9 intersect with each other and have a common tangent circle, that is, the tertiary air sprayed by different burner nozzles 9 interferes with each other, forming a gas flow rotating around the center of the combustion chamber, avoiding the flame produced by the tertiary air to be too long and contact the inner wall of the combustion chamber, and improving the service life of the combustion chamber. Figure 4
[0055] According to the calculation of the load and the amount of fuel into the furnace, when the maximum power demand of the unit is met, the tertiary air is increased by 10t of coal powder, that is, the single powder discharging machine 8 is increased by 5t, and according to the single pulverizing output of 40t, the diameter cross-sectional area of the bypass pipe 1 is 1 / 8 of the coal powder conveying pipeline, the diameter of the coal powder conveying pipeline is φ1420mm, that is, the minimum value of the pipeline diameter of the bypass pipe 1 should be DN500, and in actual operation, a margin of 1.2 times is reserved, and the diameter of DN600 pipeline is selected.
[0056] Calculation process:
[0057] Pulverizing pipeline cross-sectional area ;
[0058] Bypass pipeline cross-sectional area ;
[0059] Bypass pipe radius , that is, the diameter is 0.5m;
[0060] Through operation verification, when the unit is operated at full load, the main and reheat steam temperature can be increased by about 10-15℃ through the bypass pipe, the economic efficiency of the unit operation is improved, the coal consumption is reduced by 1.36g / kwh, according to the standard coal price of 881yuan / t, the fuel cost of a 330MW unit can be saved by about 190,000yuan per year according to 200 hours of calculation.
[0061] In addition to the tertiary air system disclosed in the above embodiments, the utility model also provides a pulverizing system comprising the above tertiary air system and a pulverizing system, and the structure of other parts of the pulverizing system can refer to the prior art, which will not be repeated here.
[0062] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same and similar parts of each embodiment can be referred to each other.
[0063] The above has carried out the detailed introduction to the three times wind system and the pulverizing system provided by the utility model. The principle and the implementation mode of the utility model are described by applying specific examples in this paper, and the above example is only used for helping to understand the method and the core idea of the utility model. It should be pointed out that for ordinary skilled person in the art, without departing from the principle of the utility model, the utility model can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the utility model claim.
Claims
1. A tertiary air system characterized in that, The bypass pipe (1) is connected with the coal powder conveying pipe at the downstream of the coal powder separator, and the upstream end of the bypass pipe (1) is connected with the air inlet of the powder discharger (8). The adjustable air door (2) is connected in series in the bypass pipe (1) for adjusting the flux in the bypass pipe (1). The upstream end of the bypass pipe (1) is connected with the coal powder conveying pipe at the outlet of the coarse powder separator (5), and the downstream end of the bypass pipe (1) is connected with the air discharging pipe between the powder discharger (8) and the negative pressure environment of the coal pulverizing system for increasing the content of the coal powder in the tertiary air. The included angle between the center line of the upstream end of the bypass pipe (1) and the center line of the coal powder conveying pipe is an acute angle.
2. The tertiary air system of claim 1, wherein The included angle between the center line of the downstream end of the bypass pipe (1) and the center line of the air discharging pipe is an acute angle.
3. The tertiary air system of claim 1, wherein, The adjustable air door (2) is connected in series in the horizontal section of the bypass pipe (1), and the included angle between the horizontal section of the bypass pipe (1) and the upstream end and / or the downstream end is an obtuse angle.
4. The tertiary air system of claim 1, wherein The elbow between the horizontal section of the bypass pipe (1) and the upstream end and / or the downstream end is a wear-resistant elbow.
5. The tertiary air system of claim 4, wherein, The control unit of the actuator of the adjustable air door (2) is electrically connected with the central control module of the coal pulverizing system for remotely controlling the flux adjustment of the adjustable air door (2).
6. The tertiary air system of claim 4, wherein, The burner nozzle (9) connected with the powder discharger (8) is at least three groups, the included angle between the line connecting the center of the horizontal section of the combustion chamber and the jet axis of the burner nozzle (9) is an acute angle, all the jet axes intersect with each other and have a common tangent circle, and the center of the common tangent circle coincides with the center of the horizontal section of the combustion chamber.
7. The tertiary air system according to any one of claims 1 to 6, characterized in that The tertiary air system comprises the tertiary air system according to any one of claims 1-7.
8. A flour milling system characterized by, The tertiary air system comprises the tertiary air system according to any one of claims 1-7.