Flexible coal feeding system of coal-fired unit

Abstract

The utility model discloses a flexible coal feeding system of a coal-fired unit. The flexible coal feeding system comprises a plurality of coal bunkers used for loading fire coal with different heat values. Each coal bunker is internally provided with an externally-hung branch bunker, and a feeding port of each externally-hung branch bunker communicates with the side wall of the corresponding coal bunker. A discharge port of each coal bunker is connected with at least one coal feeder, and a two-way coal feeder is arranged below a discharge port of each external branch bunker. A plurality of bidirectional unloaders are arranged on a conveying belt of the bidirectional coal feeder; and the bidirectional unloader is configured to be arranged above a feeding hole of one coal feeder and is used for guiding the fire coal conveyed on the conveying belt to the corresponding coal feeder. According to the invention, fire coal adjustment is more flexible, the response speed is greatly improved, the stability and the transportation bearing capacity are better, and the cost is lower.

Description

Technical Field

[0001] The present invention belongs to the technical field of boilers, and particularly relates to a flexible coal feeding system for a coal-fired unit. Background Art

[0002] Existing coal-fired boilers either use a single coal bunker or multiple coal bunkers. When multiple coal bunkers are used, the fuel in each coal bunker is the same in principle, and its function is only for parallel or switched feeding. There is a technology of using an ignition coal bunker, that is, adding a separate ignition coal bunker, which is mainly used to store high-quality coal and is only used during ignition to ensure the ignition effect.

[0003] In actual operation, the load of a coal-fired boiler will change to a certain extent according to the working conditions. In order to adapt to this change, the existing technology mostly cooperates by adjusting the coal feeding amount. However, the response speed of adjusting the coal feeding amount is difficult to meet the needs of working condition adjustment, especially it is difficult to achieve rapid online adjustment. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the existing technology, the purpose of the present invention is to provide a flexible coal feeding system for a coal-fired unit, which solves the problem that the adjustment rate is difficult to match the working condition adjustment requirements when the load changes by adjusting the coal quality of the coal feeding instead of the coal feeding amount.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A flexible coal feeding system for a coal-fired unit includes a plurality of coal bunkers for respectively loading coals with different calorific values; an external bin is respectively arranged in each of the coal bunkers, and the feeding port of the external bin is communicated with the side wall of the corresponding coal bunker;

[0007] The discharge ports of each coal bunker are respectively connected to at least one coal feeder, and a two-way coal feeder is arranged below the discharge port of each external bin; a plurality of two-way dischargers are arranged on the conveyor belt of the two-way coal feeder;

[0008] The two-way discharger is configured to be arranged above the feeding port of a coal feeder to guide the coal transported on the conveyor belt to the corresponding coal feeder.

[0009] In one embodiment, a first valve is installed at the discharge port of each coal bunker.

[0010] In one embodiment, the external bin includes a square pyramid hopper at the upper part and a conical hopper at the lower part. The inlet of the square pyramid hopper is the feeding port of the external bin. A square-to-round blanking device is installed in the conical hopper. A pneumatic plugging removal device is installed on the side walls of the square pyramid hopper and the conical hopper. A rotary anti-blocking machine is installed in the conical hopper. The outlet of the conical hopper is the discharge port of the external bin, and a second valve is installed.

[0011] In one embodiment, the two-way coal feeder includes a chamber and a two-way belt conveyor installed in the chamber. A plurality of coal inlets are provided at the top of the chamber, and each coal inlet is connected to the discharge port of an external bin. A plurality of coal outlets are provided at the bottom of the chamber, and each coal outlet is connected to the inlet of a coal feeder.

[0012] In one embodiment, the coal outlets are located at both ends and positions between the two ends of the conveying direction of the two-way belt conveyor. Above the coal outlets arranged at the positions between the two ends, there is a two-way discharge device correspondingly.

[0013] In one embodiment, the two-way discharge device is installed on a vertical shaft and can move up and down along the vertical shaft to approach or move away from the coal being transported on the transport belt, and its width is the same as that of the transport belt.

[0014] In one embodiment, the two-way discharge device is in a rhomboid structure. The long axis projects onto the midline of the transport direction. Along the long axis and short axis of the rhomboid structure, the middle of its upper surface bulges, and both sides are in a slope structure, and each surface is a plane. Alternatively, the two-way discharge device is in an arc-shaped structure, and the side opposite to the transport direction is in a slope structure with a lower part at the bottom and a higher part at the top, and each surface is a plane or an arc surface. Alternatively, the two-way discharge device is in an S-shaped structure, and the side opposite to the transport direction is in a slope structure with a lower part at the bottom and a higher part at the top, and each surface is a plane or an arc surface. Alternatively, the two-way discharge device is a triangular prism, and one inclined surface of the triangular prism is opposite to the transport direction, and each surface is a plane or an arc surface.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The present invention uses a two-way coal feeder to receive different calorific value coals from each coal bin. Through this two-way coal feeder, the coals in different coal bins can be transferred to different coal feeders, so as to realize the mixing of coals in each coal bin. It is not necessary to pre-mix the coals, but to adjust according to the boiler load during operation, and the response speed is greatly improved.

[0017] The present invention realizes the above-mentioned transfer through a closed two-way coal feeder. The two-way coal feeder is internally provided with a two-way belt conveyor. For a plurality of coal bins arranged side by side, it can adjust the rotation angle according to needs, so as to realize the transfer of coal transportation from left to right or from right to left. Compared with the form of scraper conveying that can only transport unidirectionally, its adjustment method is more flexible. And compared with scraper conveying, belt conveying has higher stability, higher transportation carrying capacity and lower cost.

[0018] The present invention designs multiple outlets for the two-way coal feeder. Through a number of corresponding two-way discharge devices, the coal on the conveyor belt is automatically discharged to one outlet and received by a corresponding coal feeder. Compared with the traditional belt conveyor that only discharges at the end, the discharge during transportation in the present invention can greatly improve the flexibility of transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic structural diagram of the present invention.

[0021] Figure 2 It is a schematic diagram of the effect of the present invention.

[0022] Figure 3 It is a simplified front view of the present invention.

[0023] Figure 4 It is a simplified front view of the present invention.

[0024] Figure 5 It is a schematic structural diagram of the external hanging bin structure of the present invention.

[0025] Figure 6 It is a simplified internal structural diagram of the two-way coal feeder of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will describe in detail the embodiments of the present utility model in conjunction with the drawings and embodiments.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Usually, the components of the embodiments of the present utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present utility model provided in the drawings is not intended to limit the scope of the present utility model to be protected, but merely represents the selected embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model.

[0029] It should be noted that like reference numerals and letters refer to like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of the present utility model, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship in which the product of the present utility model is habitually placed during use. It is only for the convenience of describing the present utility model 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 cannot be construed as a limitation to the present utility model.

[0031] In addition, if terms such as "first", "second", etc. are only used for distinguishing descriptions, they cannot be understood as indicating or implying relative importance.

[0032] It should be noted that, without conflict, the features in the embodiments of the present utility model can be combined with each other.

[0033] The traditional coal feeding system of coal-fired machines is difficult to adjust the coal feeding quality according to the load, resulting in insufficient flexibility. There are some designs with transfer mechanisms arranged between the coal bunker and the coal feeder, but the mechanisms for distributing coal mostly use scraper conveyors, belt conveyors, etc. These devices can only transfer in one direction. More importantly, these devices can only unload at the end of transportation. Therefore, when there are many coal bunkers, multiple independent transfer mechanisms often need to be designed, bringing pressure to design and manufacture as well as operation and use.

[0034] For this reason, the present invention provides a flexible coal feeding system for coal-fired units, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, which mainly includes a coal bunker 1, an external bin 2, a coal feeder 3, a two-way coal feeder 4 and a two-way discharger 5.

[0035] Among them, the coal bunker 1 and the coal feeder 3 are the inherent equipment of the traditional coal feeding system. Generally speaking, there are multiple coal bunkers 1 and multiple coal feeders 3. In the present invention, the calorific values of the coal loaded in each coal bunker 1 are not exactly the same. The discharge ports of each coal bunker 1 are respectively connected to at least one coal feeder 3, and coal is supplied to the combustion system through each coal feeder 3.

[0036] The external bin 2, the two-way coal feeder 4 and the two-way discharger 5 are important features of the present invention. Among them, the number of the external bins 2 is preferably the same as the number of the coal bunkers 1, that is, one external bin 2 is respectively arranged in each coal bunker 1, and the feed inlet of the external bin 2 communicates with the side wall of the corresponding coal bunker 1.

[0037] The external bin 2 is equivalent to a discharge branch of the coal bin 1, but it also has a certain storage function to be able to supply the coal in the corresponding coal bin 1 to the double-direction coal feeder 4 as soon as possible when receiving an instruction.

[0038] The double-direction coal feeder 4 is a transfer mechanism between the external bin 2 and the coal feeder 3. It is designed below the discharge port of each external bin 2 to receive the coal output from the external bin 2.

[0039] The double-direction discharger 5 is used to discharge the coal transported on the double-direction coal feeder 4 to a coal feeder 3. It is arranged above the conveyor belt of the double-direction coal feeder 4 and above the inlet of a coal feeder 3. The double-direction discharger 5 can contact the coal being transported to guide the coal on the transported belt to the corresponding coal feeder 3.

[0040] According to the above structure, on the one hand, each coal bin 1 of the present invention supplies materials to the coal feeder 3 fixedly connected thereto, and on the other hand, it can also supply materials to the double-direction coal feeder 4 through its external bin 2. Through the double-direction discharger 5 on the double-direction coal feeder 4, the coal being transported can be introduced into the required coal feeder 3, thereby completing the mixing or separate use of the coal.

[0041] The number of discharge ports of each coal bin 1 of the present invention can be any number, set according to requirements. A first valve 11 needs to be installed at each of its discharge ports. As Figure 4 shown, the first valve 11 is used to open upon receiving an instruction to supply the coal in the corresponding coal bin 1 to its coal feeder 3, or to close to stop supplying the coal in the corresponding coal bin 1 to its coal feeder 3.

[0042] A structure of the external bin 2 of the present invention, as Figure 5 shown, mainly includes a square pyramid hopper 21 in the upper part and a conical hopper 22 in the lower part. The square pyramid hopper 21 means that its cross-section is square and the cross-sectional area decreases from top to bottom. The reason for adopting this structure is to facilitate processing. The conical hopper 22 means that its cross-section is circular and the cross-sectional area decreases from top to bottom. The reason for adopting this structure is to facilitate discharging and to facilitate the installation of the rotary anti-blocking machine 25. Among them, the inlet of the square pyramid hopper 21 is the inlet of the external bin 2. A square-to-round blanking device 23 can be installed in the conical hopper 22 to achieve rapid and uniform blanking. The outlet of the conical hopper 22 is the discharge port of the external bin 2. A second valve 26 needs to be installed at the discharge port. The second valve 26 is configured to open upon receiving an instruction to send the coal in the corresponding external bin 2 into the double-direction coal feeder 4, or to close to stop sending the coal in the corresponding external bin 2 into the double-direction coal feeder 4.

[0043] Since the inner diameter of the external bin 2 is generally not very large, there may be problems of material blockage or wall sticking. Therefore, the present invention designs a blockage clearing mechanism for it. Specifically, a pneumatic blockage clearing device 24 is installed on the side walls of the square cone hopper 21 and the conical hopper 22 to clean the coal adhered to the side walls of the hopper in a pneumatic manner. Specifically, holes are opened on the side walls of the hopper and blocked by a pneumatic mechanism. This device is a conventional blockage clearing mechanism. Further, a rotary anti-blocking machine 25 is installed in the conical hopper 22. The rotary anti-blocking machine 25 is also a conventional device and can scrape the materials on the inner wall with a rotary scraper. By installing the rotary anti-blocking machine 25 and the pneumatic blockage clearing device 24, the external bin 2 can be prevented from caking during long-term shutdown. When it resumes operation, the external bin 2 will not be blocked. The hopper cylinder can be made of stainless steel material to prevent wall sticking.

[0044] In the present invention, the external bin 2 is added at the middle position on the side of the coal bunker 1, which can avoid the phenomenon of uneven coal distribution in the coal bunker 1. A relatively large intersection cut is used between the external bin 2 and the coal bunker 1 to prevent the problem of insufficient coal supply from the bin.

[0045] The two-way coal feeder 4 of the present invention includes a bin 41 and a two-way belt conveyor 42, as Figure 6 shown. Among them, a plurality of coal inlets 43 are provided at the top of the bin 41. Each coal inlet 43 is connected to the discharge port of an external bin 2. Through the aforementioned second valve 26, the corresponding fuel passage is controlled. A plurality of coal outlets 44 are provided at the bottom of the bin 41. Each coal outlet 44 is connected to the inlet of a coal feeder 3. A third valve is designed at the coal outlet 44 or the inlet of the coal feeder 3 to control the corresponding fuel passage.

[0046] The two-way belt conveyor 42 is installed in the bin 41 and includes a conveyor belt and two drive wheels. Each drive wheel is connected to a motor. When one motor is turned on, it can control the forward rotation of the conveyor belt, and when the other motor is turned on, it can control the reverse rotation of the conveyor belt, so as to achieve two-way transportation.

[0047] In the present invention, in addition to being designed at the end of the conveying direction of the two-way belt conveyor 42, the coal outlet 44 can also be designed between the two conveying direction ends. The conveying can only discharge materials at the end. In the present invention, by designing a two-way discharger 5 on the two-way belt conveyor 42 and corresponding the two-way discharger 5 above the coal outlet 44, discharging during transportation can be achieved. Compared with the existing conveying equipment, the two-way belt conveyor 42 has a large output and low failure rate in the later stage.

[0048] The two-way discharge device 5 is equivalent to a "blocking" structure, which can "block" the coal on the conveyor belt so that it falls from both sides of the belt. For this purpose, the two-way discharge device 5 needs to be fixed in the bin chamber 41 so as to have a relative movement relationship with the conveyor belt. In the present invention, it is selected to be installed on the top of the bin chamber 41, specifically on a vertical shaft, and has a sliding structure which can move axially along the vertical shaft to approach or move away from the coal transported on the conveyor belt. To avoid pressing on the conveyor belt, the vertical movement of the two-way discharge device 5 can be realized by a motor and designed as the following rules:

[0049] The motor drives the two-way discharge device 5 to move axially along the vertical shaft through movement mechanisms such as a sliding mechanism and a rack and pinion structure. When it is lifted to the highest position, there should be a sufficient distance from the conveyor belt to prevent the two-way discharge device 5 from contacting the coal when the coal outlet 44 corresponding to the two-way discharge device 5 does not need to discharge. When it falls to the lowest position, there should be a small distance from the conveyor belt. On the one hand, this small distance prevents the two-way discharge device 5 from pressing on the conveyor belt, resulting in excessive friction and inability to transport. On the other hand, it enables the two-way discharge device 5 to play a "blocking" role at its position and discharge the coal to its corresponding coal outlet 44. It should be noted that the movement of the motor driving the two-way discharge device 5 along the vertical shaft is a typical conventional means and will not be elaborated here.

[0050] Furthermore, since in most cases only one two-way discharge device 5 needs to function, the number of two-way discharge devices 5 can be reduced. In the extreme case, only one needs to be designed. At this time, the vertical shaft is installed on a horizontal shaft parallel to the conveying direction of the two-way belt conveyor 42, and a motor is added to drive the vertical shaft to be able to move horizontally along the horizontal shaft, that is, a typical XY two-dimensional movement mechanism. Fixed moving positions are set in advance. When it is necessary to stop at a certain coal outlet 44, the corresponding moving distance can be realized by the motor. First, move horizontally and then vertically to complete the position adjustment of the two-way discharge device 5.

[0051] In the embodiments of the present invention, the two-way discharge device can be in various structural forms. The principle is that the surface facing the coal is an inclined surface with a lower part at the bottom and a higher part at the top, and this inclined surface can be an arc surface or a flat surface. And because it is a two-way discharge, generally a symmetrical structure is adopted so that no matter which side is the side facing the coal, the coal discharging task can be completed.

[0052] Exemplarily, the two-way discharge device 5 is a rhomboid structure. The long axis is projected on the midline of the transportation direction, and the length of the short axis is the same as the width of the conveyor belt. Along the long axis and the short axis of the rhomboid structure, the middle of its upper surface bulges, and both sides are slope structures, and each surface is a flat surface. That is to say, the bottom surface of this rhomboid structure is a flat surface, while the top is a tetrahedron.

[0053] For example, the two-way discharger 5 is of an arc-shaped structure, with the same width as the conveyor belt. The width direction is arc-shaped, facing the conveying direction. This arc can be a convex arc or a concave arc, and it is a slope structure with the lower part being lower and the upper part being higher. Each surface is a plane or an arc surface.

[0054] For example, the two-way discharger 5 is of an S-shaped structure, with the same width as the conveyor belt. Facing the conveying direction, its edge is in a shape of alternating convex and concave arcs, and the side opposite to the conveying direction is a slope structure with the lower part being lower and the upper part being higher. Each surface is a plane or an arc surface.

[0055] For example, the two-way discharger 5 is a triangular prism, with the length of the triangular prism being the same as the width of the conveyor belt. One inclined surface of the triangular prism faces the conveying direction, and this surface can be a plane or an arc surface in addition to being a plane.

[0056] Each valve of the present invention can adopt a two-way split hydraulic gate valve, with a fast opening and closing speed; among them, since the second valve 26 does not work frequently, a manual gate valve is considered to be adopted.

[0057] Taking the use of three coal bunkers 1 as an example, the present invention will be further described.

[0058] The three coal bunkers 1 are successively loaded with high-quality coal, ordinary coal, and inferior coal.

[0059] During ignition, the first valve 11 of the coal bunker 1 loading ordinary coal and inferior coal is closed, and the first valve 11 of the coal bunker 1 loading high-quality coal is opened. High-calorific-value coal is directly supplied to the corresponding coal feeder from this coal bunker 11 and / or through its external bin 2, so as to achieve efficient and rapid ignition.

[0060] After ignition, when the load is stable, the first valve 11 of the coal bunker 1 loading ordinary coal and high-quality coal is closed, and the first valve 11 of the coal bunker 1 loading inferior coal is opened. Low-calorific-value coal is directly supplied to the corresponding coal feeder from this coal bunker 11 and / or through its external bin 2 to reduce costs. When the external bin 2 is enabled, it is controlled by the second valve 26.

[0061] When the load changes, the first valve 11 of the coal bunker 1 loading ordinary coal and inferior coal is closed, and the first valve 11 of the coal bunker 1 loading high-quality coal is opened. High-calorific-value coal is directly supplied to the corresponding coal feeder from this coal bunker 11 and / or through its external bin 2 to adapt to a faster working condition adjustment rate. When the external bin 2 is enabled, it is controlled by the second valve 26.

[0062] Among them, according to different load conditions, coal can also be further mixed. Taking the mixing of ordinary coal and high-quality coal as an example, close the first valve 11 of all coal bins 1, open the second valve 26 of the external bin 2 of the coal bin 1 loaded with ordinary coal and high-quality coal, control the corresponding two-way discharger 5 of the coal feeder 3 that needs to supply materials to be in place, discharge the two kinds of coal to the two-way belt conveyor 42, after preliminary mixing is completed on the conveyor belt of the two-way belt conveyor 42, discharge it to the corresponding coal feeder 3 by the two-way discharger 5, and finally be sent into the combustion system.

Claims

1. A flexible coal supply system for a coal-fired unit, characterized in that: It comprises a plurality of coal bunkers (1) for respectively loading coal of different calorific values; each of the coal bunkers (1) is provided with an external sub-bin (2), and the feed inlet of the external sub-bin (2) is connected to the side wall of the corresponding coal bunker (1); The discharge port of each coal bunker (1) is respectively connected to at least one coal feeder (3); a two-way coal feeder (4) is arranged below the discharge port of each external sub-bin (2); and a plurality of two-way dischargers (5) are arranged on the transport belt of the two-way coal feeder (4); The bidirectional discharger (5) is configured to be arranged above the inlet of a coal feeder (3) to guide the coal transported on the transport belt to the corresponding coal feeder (3).

2. The flexible coal supply system for coal-fired units according to claim 1 is characterized in that: The discharge port of each coal bunker (1) is equipped with a first valve (11).

3. The flexible coal supply system for coal-fired units according to claim 1 is characterized in that: The external sub-bin (2) comprises an upper square cone hopper (21) and a lower conical hopper (22); the inlet of the square cone hopper (21) is the feed inlet of the external sub-bin (2); a square and round feeding device (23) is installed in the conical hopper (22); a pneumatic clearing device (24) is installed on the side walls of the square cone hopper (21) and the conical hopper (22); a rotary anti-blocking machine (25) is installed in the conical hopper (22); the outlet of the conical hopper (22) is the discharge port of the external sub-bin (2) and is provided with a second valve (26).

4. The flexible coal supply system for coal-fired units according to claim 1 is characterized in that: The bidirectional coal feeder (4) comprises a chamber (41) and a bidirectional belt conveyor (42), wherein the bidirectional belt conveyor (42) is installed in the chamber (41), and a plurality of coal inlets (43) are arranged on the top of the chamber (41), each of which is connected to a discharge port of an external sub-chamber (2); and a plurality of coal outlets (44) are arranged on the bottom of the chamber (41), each of which is connected to a feed port of a coal feeder (3).

5. The flexible coal supply system for coal-fired units according to claim 4 is characterized in that: The coal outlet (44) is located at both ends of the conveying direction of the bidirectional belt conveyor (42) and at a position between the two ends, wherein a bidirectional discharger (5) is correspondingly disposed above the coal outlet (44) disposed at the position between the two ends.

6. The flexible coal supply system for coal-fired units according to claim 4, characterized in that: The bidirectional discharger (5) is mounted on a vertical shaft and can move up and down along the vertical shaft, and its width is consistent with the width of the transport belt.

7. The flexible coal supply system for a coal-fired unit according to any one of claims 1 to 6, characterized in that: The bidirectional discharger (5) is a rhombus structure, with its long axis projected on the center line of the transport direction. Along the long axis and short axis of the rhombus structure, the middle of its upper surface is raised, the two sides are slope structures, and each surface is a plane.

8. The flexible coal supply system for a coal-fired unit according to any one of claims 1 to 6, characterized in that: The bidirectional discharger (5) is an arc-shaped structure, and the side opposite to the transport direction is a slope structure with a lower bottom and a higher top, and each surface is a plane or an arc surface.

9. The flexible coal supply system for a coal-fired unit according to any one of claims 1 to 6, characterized in that: The bidirectional discharger (5) is an S-shaped structure, and the side opposite to the transport direction is a slope structure with a lower bottom and a higher top, and each surface is a flat surface or an arc surface.

10. The flexible coal supply system for a coal-fired unit according to any one of claims 1 to 6, characterized in that: The bidirectional discharger (5) is a triangular prism, one inclined surface of the triangular prism is opposite to the transport direction, and each surface is a plane or an arc surface.

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