Multi-coal blending combustion system
By designing a multi-coal blending system, using components such as the diversion cylinder, diversion ring, blower duct and reversing valve, the problems of coal powder not being flammable and the fly ash being high in high load operation of the boiler are solved, and the carbon content of the fly ash is high is achieved. The full combustion of coal powder and the reduction of the carbon content of fly ash have reduced production costs.
Patent Information
- Application Number
- CN202411673018.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-21
- Publication Date
- 2025-02-11
AI Technical Summary
During high load operation of boilers, due to the low weighted calorific value of coal types in the furnace, the coal powder is not easy to burn out, the fly ash has a high carbon content, and the coal powder has too high moisture content, which increases the heat of the coal powder, further aggravates the Carbon content problem of fly ash.
A multi-coal blending system is designed to ensure the full combustion of coal powder through the combination of boiler, feed pipe and feed line. The system includes a flow guide cylinder, a flow guide ring, a blower duct and a reversing valve. By adjusting the combustion path of the coal powder and increasing the movement path of the coal powder in the furnace, it can achieve full combustion and preheating and drying through the reverse channel to reduce the The carbon content of fly ash.
Effectively ensure the full combustion of coal powder, meet the heating needs of boilers, significantly reduce the carbon content of fly ash, and reduce production costs.
Smart Images
Figure CN119412714A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of thermal power generation, and in particular to a multi-coal blending system. Background Art
[0002] With the continuous development of the economy, electricity consumption has increased year by year, but the supply of coal for power generation has not increased synchronously. As the boiler's designed coal types are in short supply and coal costs increase, the supplied coal types include mixed coal from the coal blending center, coal slime, market mixed coal, lean coal, and out-of-province railway coal. These coal types seriously deviate from the designed coal types when blended. When the boiler is operating at high load, due to the low weighted calorific value of the coal entering the furnace, the supply of coal powder must be guaranteed. At this time, the pulverizer is overloaded, the fineness of the coal powder increases, the combustion is delayed, and the coal powder is not easy to burn out, resulting in a high carbon content in the fly ash. Due to the deterioration of the quality of the fly ash (the particle size is too large and the carbon content is too high), the cooperative units refuse to accept it, resulting in difficulties in the disposal of the fly ash and increased production costs. In addition, some coal powder has too high moisture content during combustion, and the ignition heat of the coal powder increases, which is not conducive to the combustion of the coal powder, further aggravating the problem of carbon content in the fly ash. Summary of the invention
[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.
[0004] To this end, an embodiment of the present invention proposes a multi-coal blending system, which can ensure the full combustion of coal powder to meet the heating demand of the boiler when coal powder is blended, and effectively reduce the carbon content of fly ash and reduce production costs.
[0005] The multi-coal blending system of the embodiment of the present invention comprises:
[0006] A boiler, wherein the boiler has a furnace and is provided with a feed pipe connected to the furnace, the feed pipe is used to transport pulverized coal with a moisture content not exceeding a set standard, a guide tube is provided in the furnace, an open end of the guide tube is arranged toward the bottom of the furnace and has a set distance from the bottom of the furnace;
[0007] A material delivery pipe, the material delivery pipe comprising a connecting section and a vertical section which are connected to each other, one end of the connecting section protruding from the boiler and used to deliver pulverized coal with a moisture content exceeding a set standard, at least a portion of the vertical section being arranged in the guide cylinder, the diameter of the vertical section being smaller than the diameter of the guide cylinder so as to limit a reverse channel between the vertical section and the guide cylinder, and both ends of the reverse channel being respectively connected to the furnace and the inner cavity of the vertical section;
[0008] A plurality of feeding line bodies, wherein the feeding line bodies include a coal bunker, a first feeding line, a coal mill, a moisture meter, a second feeding line and a reversing valve which are arranged in sequence. The plurality of coal bunkers are used to store a plurality of types of coal. The first feeding line is used to transport the type of coal corresponding to the coal bunker to the coal mill. The moisture meter is used to measure the moisture content of the coal powder discharged from the coal mill. The reversing valve is arranged on the second feeding line and the two discharge ports of the reversing valve are respectively connected to the feed pipe and the connecting section.
[0009] The multi-coal blending system of the embodiment of the present invention can ensure the full combustion of pulverized coal to meet the heating demand of the boiler when pulverized coal is blended, and effectively reduce the carbon content of fly ash and reduce production costs.
[0010] In some embodiments, it includes a guide ring and a blowing pipe, wherein the guide ring is coaxially sleeved on the vertical section and located below the guide tube, the diameter of the guide ring increases in a direction away from the guide tube, the blowing pipe is arranged at the bottom of the furnace, and the distance between the blowing pipe and the axis of the vertical section is greater than the diameter of the guide tube.
[0011] In some embodiments, the minimum diameter of the guide ring is equal to the diameter of the vertical section, the maximum diameter of the guide ring is greater than the diameter of the guide tube, the top surface of the guide ring is an arc surface, and the tangent of the vertical cross section of the guide ring is parallel to the axis of the vertical section.
[0012] In some embodiments, the distance between the feed pipe and the bottom of the furnace is greater than the distance between the connecting section and the bottom of the furnace, and the distance between the feed pipe and the bottom of the furnace is greater than the distance between the open end of the guide tube and the bottom of the furnace.
[0013] In some embodiments, the discharge port of the boiler is provided with an electric separator, and the electric separator is provided with a first outlet and a second outlet, the first outlet is used to discharge fly ash, and the second outlet is used to discharge flue gas, and a heat exchanger is connected upstream of the connecting section, the air inlet of the heat exchanger is connected to the second outlet, and the outlet of the heat exchanger is connected to the flue gas treatment unit.
[0014] In some embodiments, the end of the feed pipe is connected to a first feed pipe, one of the discharge ports of the reversing valve is connected to the first feed pipe, a second feed pipe is provided at the end of the connecting section, the heat exchanger is sleeved on the second feed pipe, and the other discharge port of the reversing valve is connected to the second feed pipe.
[0015] In some embodiments, a first fan is disposed at the other end of the first feeding pipe, and a second fan is disposed at the other end of the second feeding pipe.
[0016] In some embodiments, the second feeding line includes a third feeding pipe and a third fan, the two ends of the third feeding pipe are respectively connected to the coal mill and the reversing valve, the moisture meter is arranged on the third feeding pipe, and the third fan is arranged on the third feeding pipe and is used to transport air into the third feeding pipe to transport coal powder along the third feeding pipe.
[0017] In some embodiments, the feed line body includes a filter box, which is arranged on the third feed pipe and downstream of the third fan. The filter box includes a box body and a filter screen. The filter screen is used to intercept coal powder with a diameter larger than the mesh diameter of the filter screen. The filter box is connected to a return pipe, and the other end of the return pipe is connected to the coal mill. The position where the return pipe is connected to the filter box is located on the side of the filter screen close to the third fan.
[0018] In some embodiments, the feed line body includes multiple third feed lines, in one of the feed line bodies, one end of the multiple third feed lines is arranged under the corresponding coal bin, and the other ends of the multiple third feed lines respectively correspond to the coal mills in another plurality of the feed line bodies. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic structural diagram of a multi-coal blending system according to an embodiment of the present invention.
[0020] Reference numerals:
[0021] Boiler 1; furnace 11; feed pipe 12; guide tube 13; guide ring 14; blowing pipe 15;
[0022] Feed pipe 2; connecting section 21; vertical section 22;
[0023] Feeding line body 3; coal bunker 31; first feeding line 32; coal mill 33; moisture meter 34; second feeding line 35; third feeding pipe 351; third fan 352; reversing valve 36; filter box 37; return pipe 38; third feeding line 39;
[0024] Back channel 4;
[0025] Electric separator 5; first outlet 51; second outlet 52;
[0026] Heat exchanger 6;
[0027] Flue gas treatment unit 7;
[0028] First feeding pipe 8; first fan 81;
[0029] Second feeding pipe 9; second fan 91. DETAILED DESCRIPTION
[0030] 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.
[0031] like Figure 1 As shown, the multi-coal blending system of the embodiment of the present invention includes a boiler 1, a feed pipe 2 and a plurality of feed lines 3. The boiler 1 has a furnace 11 and is provided with a feed pipe 12 connected to the furnace 11. The feed pipe 12 is used to transport pulverized coal with a moisture content not exceeding a set standard. A guide tube 13 is provided in the furnace 11. The open end of the guide tube 13 is arranged toward the bottom of the furnace 11 and has a set distance from the bottom of the furnace 11. The feed pipe 2 includes a connecting section 21 and a vertical section 22 that are connected. One end of the connecting section 21 extends out of the boiler 1 and is used to transport pulverized coal with a moisture content exceeding the set standard. At least a part of the vertical section 22 is arranged in the guide tube 13, and the diameter of the vertical section 22 is smaller than that of the guide tube 13. The diameter is used to limit a reverse channel 4 between the vertical section 22 and the guide tube 13. The two ends of the reverse channel 4 are respectively connected to the inner cavity of the furnace 11 and the vertical section 22. The feeding line body 3 includes a coal bunker 31, a first feeding line 32, a coal mill 33, a moisture meter 34, a second feeding line 35 and a reversing valve 36 arranged in sequence. The multiple coal bunkers 31 are used to store multiple types of coal. The first feeding line 32 is used to transport the coal type in the corresponding coal bunker 31 to the coal mill 33. The moisture meter 34 is used to measure the water content of the coal powder discharged from the coal mill 33. The reversing valve 36 is arranged on the second feeding line 35 and the two discharge ports of the reversing valve 36 are respectively connected to the feed pipe 12 and the connecting section 21.
[0032] The working principle of the multi-coal blending system of the embodiment of the present invention is as follows: the coal bunker 31 is opened, and the first feeding line 32 conveys the coal discharged from the coal bunker 31 to the corresponding coal mill 33. The coal mill 33 grinds the coal to produce coal powder, and the coal powder enters the second feeding line 35 under the action of gravity. The water content of the coal powder is measured. When the water content of the coal powder is lower than the set standard, the reversing valve 36 is switched, and the coal powder directly enters the furnace 11 through the feed pipe 12 for combustion. When the water content of the coal powder is higher than the set standard, the reversing valve 36 is switched, and the coal powder enters the vertical section 22 through the connecting section 21, and is preheated and dried through the reverse channel 4 by heat exchange with the gas in the furnace 11, and finally moves from the bottom of the furnace 11 to the top of the furnace 11 and starts to burn.
[0033] The multi-coal blending system of the embodiment of the present invention adjusts the combustion path of the coal powder by the water content of the coal powder, and increases the movement path and movement time of the coal powder in the furnace 11 by the setting of the reverse channel 4, so as to offset the combustion lag time of the coal powder, ensure that the coal powder can be fully and completely burned after entering the furnace 11, meet the heating demand of the boiler 1, and effectively reduce the carbon content of the fly ash, thereby reducing the production cost.
[0034] It should be noted that the setting standard of the moisture content depends on the working load of the boiler 1. Under the set working load, when the moisture content of the pulverized coal is lower than or equal to the set standard, the pulverized coal can be fully and completely burned after entering the furnace 11 through the feed pipe 12 and when being discharged from the furnace 11, thereby avoiding the occurrence of excessive carbon content in the fly ash.
[0035] It should be noted that multiple coal bins 31 are used to store multiple types of coal, which means that when the number of coal bins 31 is less than the number of coal types, some coal bins 31 store one type of coal, and some coal bins 31 store two, three or more types of coal; or, when the number of coal bins 31 is equal to the number of coal types, each coal bin 31 stores one type of coal; or, when the number of coal bins 31 is greater than the number of coal types, multiple coal bins 31 store one type of coal, and some coal bins 31 store only one type of coal.
[0036] Optionally, the first feeding line 32 is a coal powder conveyor belt.
[0037] In some embodiments, Figure 1 As shown, it includes a guide ring 14 and a blowing pipe 15. The guide ring 14 is coaxially sleeved in the vertical section 22 and is located below the guide tube 13. The diameter of the guide ring 14 increases in the direction away from the guide tube 13. The blowing pipe 15 is arranged at the bottom of the furnace 11, and the distance between the blowing pipe 15 and the axis of the vertical section 22 is greater than the diameter of the guide tube 13.
[0038] The guide ring 14 is provided to guide the direction of the coal powder discharged from the reverse channel 4 to prevent the coal powder from falling directly on the bottom of the furnace 11, and the blowing pipe 15 is provided to assist the coal powder discharged from the reverse channel 4 to change direction, so as to facilitate the movement and combustion of the coal powder in the furnace 11. The position of the blowing pipe 15 is restricted to prevent the blowing pipe 15 from blowing the coal powder in the reverse channel 4 back into the tube cavity of the vertical section 22, thereby ensuring smooth circulation of the coal powder.
[0039] In some embodiments, Figure 1 As shown, the minimum diameter of the guide ring 14 is equal to the diameter of the vertical section 22 , the maximum diameter of the guide ring 14 is greater than the diameter of the guide tube 13 , the top surface of the guide ring 14 is an arc surface, and the tangent of the vertical section of the guide ring 14 is parallel to the axis of the vertical section 22 .
[0040] The size of the guide ring 14 is constrained, and the end of the guide ring 14 with a smaller diameter is tangent to the vertical section 22. When the coal powder is guided, the coal powder can be prevented from accumulating at the connection position between the guide ring 14 and the vertical section 22. At the same time, the top surface of the guide ring 14 is set on an arc surface, which is convenient for adjusting the direction of the coal powder entering the furnace 11 after passing through the guide ring 14, thereby facilitating the transportation and combustion of the coal powder.
[0041] In some embodiments, the distance between the feed pipe 12 and the bottom of the furnace 11 is greater than the distance between the connecting section 21 and the bottom of the furnace 11, and the distance between the feed pipe 12 and the bottom of the furnace 11 is greater than the distance between the open end of the guide tube 13 and the bottom of the furnace 11, that is, the feed pipe 12 is arranged above the connecting section 21, and the connection position between the feed pipe 12 and the furnace 11 is above the connection position between the reverse channel 4 and the furnace 11. When the coal powder is transported, the coal powder that enters the furnace 11 through the feed pipe 12 can be prevented from entering the reverse channel 4 again, thereby ensuring sufficient combustion of the coal powder.
[0042] In some embodiments, Figure 1 As shown, the discharge port of the boiler 1 is provided with an electric separator 5, and the electric separator 5 is provided with a first outlet 51 and a second outlet 52. The first outlet 51 is used to discharge fly ash, and the second outlet 52 is used to discharge flue gas. A heat exchanger 6 is connected to the upstream of the connecting section 21, and the air inlet of the heat exchanger 6 is connected to the second outlet 52, and the outlet of the heat exchanger 6 is connected to the flue gas treatment unit 7.
[0043] The electric separator 5 processes the fly ash and flue gas at the discharge port of the boiler 1, discharges the fly ash through the first outlet 51 and collects it, and discharges the flue gas through the second outlet 52. The discharged flue gas carries a certain amount of heat, and the heat carried by the flue gas is used to exchange heat with the air carrying coal powder flowing to the connecting section 21 through the heat exchanger 6 at the position of the heat exchanger 6, so that the moisture in the coal powder is volatilized by heat, thereby reducing the water content in the coal powder, so as to promote the complete combustion of the coal powder in the furnace 11.
[0044] In some embodiments, Figure 1 As shown, the end of the feed pipe 12 is connected to the first feed pipe 8, one of the discharge ports of the reversing valve 36 is connected to the first feed pipe 8, the end of the connecting section 21 is provided with a second feed pipe 9, the heat exchanger 6 is sleeved on the second feed pipe 9, and the other discharge port of the reversing valve 36 is connected to the second feed pipe 9.
[0045] Specifically, the heat exchanger 6 is a ring tube arranged on the second feeding pipe 9, and heat is transferred through the contact between the ring tube and the second feeding pipe 9. The extension direction of the ring tube is opposite to the forward direction of the coal powder in the second feeding pipe 9 to ensure the maximum heat exchange efficiency between the flue gas and the coal powder.
[0046] In some embodiments, Figure 1 As shown, a first fan 81 is provided at the other end of the first feeding pipe 8, and a second fan 91 is provided at the other end of the second feeding pipe 9. A plurality of feeding lines 3 are provided in parallel on the first feeding pipe 8 or the second feeding pipe 9. By providing fans at the ends of the first feeding pipe 8 and the second feeding pipe 9, power and sufficient oxygen are provided for the transportation of coal powder, and the transportation direction of coal powder is ensured, thereby achieving full combustion of coal powder.
[0047] In some embodiments, Figure 1 As shown, the second feeding line 35 includes a third feeding pipe 351 and a third fan 352. The two ends of the third feeding pipe 351 are respectively connected to the coal mill 33 and the reversing valve 36. The moisture meter 34 is arranged on the third feeding pipe 351. The third fan 352 is arranged on the third feeding pipe 351 and is used to convey air into the third feeding pipe 351 to transport coal powder along the third feeding pipe 351.
[0048] Specifically, the third feeding pipe 351 includes a vertically arranged first section and a horizontally arranged second section. One end of the first section is connected to the coal mill 33 and is used to receive the coal powder discharged from the coal mill 33. One end of the second section is connected to the reversing valve 36. The third fan 352 is connected to the position where the first section and the second section are connected through an air duct, and is used to blow the coal powder falling in the first section into the second section, providing initial power for the movement of the coal powder in the second section, thereby ensuring the transportation of the coal powder.
[0049] In some embodiments, Figure 1 As shown, the feed line 3 includes a filter box 37, which is arranged on the third feed pipe 351 and located downstream of the third fan 352. The filter box 37 includes a box body and a filter screen. The filter screen is used to intercept coal powder with a diameter larger than the mesh diameter of the filter screen. The filter box 37 is connected to a return pipe 38, and the other end of the return pipe 38 is connected to the coal mill 33. The position where the return pipe 38 is connected to the filter box 37 is located on the side of the filter screen close to the third fan 352.
[0050] Specifically, the filter box 37 includes a box body and a filter screen. The box body is provided with a flow chamber and an ash discharge port. Both ends of the flow chamber are connected to the third feed pipe 351. The filter screen is arranged in the flow chamber and on the side of the ash discharge port away from the third fan 352. When the coal powder reaches the flow chamber in the third feed pipe 351, the filter screen screens the diameter of the coal powder. The coal powder with a diameter smaller than the mesh diameter of the filter screen passes through the filter screen and continues to move along the third feed pipe 351. The coal powder with a diameter larger than the mesh diameter of the filter screen is intercepted at the filter screen position and returns to the pulverizer 33 through the return pipe 38 for further grinding processing, thereby ensuring that the diameter of the coal powder entering the furnace 11 is below the set value, thereby ensuring the full combustion of the coal powder in the furnace 11 and avoiding the fly ash content discharged from the furnace 11 exceeding the set standard.
[0051] Optionally, the filter screen adopts a raised structure which is hemispherical or semi-elliptical. When the coal powder reaches the filter screen, the coal powder with a diameter larger than the mesh diameter of the filter screen moves along the filter screen away from the axis of the flow chamber, thereby avoiding blockage of the filter screen and ensuring the filtering effect of the filter screen.
[0052] In some embodiments, Figure 1As shown, the feeding line body 3 includes multiple third feeding lines 39. In one of the feeding line bodies 3, one end of the multiple third feeding lines 39 is arranged below the corresponding coal bin 31, and the other ends of the multiple third feeding lines 39 are respectively arranged corresponding to the coal mills 33 in another multiple feeding line bodies 3.
[0053] Optionally, the feed line body 3 is provided with three, namely the first line body, the second line body and the third line body, each feed line body 3 is provided with two third feed lines 39, the ends of the two third feed lines 39 in the first line body correspond to the coal mill 33 in the second line body and the coal mill 33 in the third line body, respectively, the ends of the two third feed lines 39 in the second line body correspond to the coal mill 33 in the first line body and the coal mill 33 in the third line body, respectively, and the ends of the two third feed lines 39 in the third line body correspond to the coal mill 33 in the first line body and the coal mill 33 in the third line body, respectively. Corresponding to the setting of the coal mill 33 in the first line body and the coal mill 33 in the second line body, when multiple coal types are blended and burned, the blending ratio of each coal type changes, and the coal supply of a single feeding line body 3 and the rated load of the coal mill 33 cannot meet the demand, the coal type in the corresponding coal bin 31 can be transported to other coal mills 33 that have not reached the rated load through the third feeding line 39, so as to ensure the requirements for the diameter of the coal powder and ensure the sufficient combustion of the coal powder in the furnace 11, thereby reducing the carbon content of the fly ash and reducing the production cost.
[0054] In the description of the present invention, it is to 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”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.
[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0059] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.
Claims
1. A multi-coal blending system, characterized in that: include: A boiler, wherein the boiler has a furnace and is provided with a feed pipe connected to the furnace, the feed pipe is used to transport pulverized coal with a moisture content not exceeding a set standard, a guide tube is provided in the furnace, an open end of the guide tube is arranged toward the bottom of the furnace and has a set distance from the bottom of the furnace; A material delivery pipe, the material delivery pipe comprising a connecting section and a vertical section which are connected to each other, one end of the connecting section protruding from the boiler and used to deliver pulverized coal with a moisture content exceeding a set standard, at least a portion of the vertical section being arranged in the guide cylinder, the diameter of the vertical section being smaller than the diameter of the guide cylinder so as to limit a reverse channel between the vertical section and the guide cylinder, and both ends of the reverse channel being respectively connected to the furnace and the inner cavity of the vertical section; A plurality of feeding line bodies, wherein the feeding line bodies include a coal bunker, a first feeding line, a coal mill, a moisture meter, a second feeding line and a reversing valve which are arranged in sequence. The plurality of coal bunkers are used to store a plurality of types of coal. The first feeding line is used to transport the type of coal corresponding to the coal bunker to the coal mill. The moisture meter is used to measure the moisture content of the coal powder discharged from the coal mill. The reversing valve is arranged on the second feeding line and the two discharge ports of the reversing valve are respectively connected to the feed pipe and the connecting section.
2. The multi-coal blending system according to claim 1 is characterized in that: It includes a guide ring and a blowing pipe, wherein the guide ring is coaxially sleeved on the vertical section and located below the guide tube, the diameter of the guide ring increases in the direction away from the guide tube, the blowing pipe is arranged at the bottom of the furnace, and the distance between the blowing pipe and the axis of the vertical section is greater than the diameter of the guide tube.
3. The multi-coal blending system according to claim 2 is characterized in that: The minimum diameter of the guide ring is equal to the diameter of the vertical section, the maximum diameter of the guide ring is greater than the diameter of the guide tube, the top surface of the guide ring is an arc surface, and the tangent of the vertical section of the guide ring is parallel to the axis of the vertical section.
4. The multi-coal blending system according to claim 2, characterized in that: The distance between the feed pipe and the bottom of the furnace is greater than the distance between the connecting section and the bottom of the furnace, and the distance between the feed pipe and the bottom of the furnace is greater than the distance between the open end of the guide tube and the bottom of the furnace.
5. The multi-coal blending system according to claim 1 is characterized in that: The discharge port of the boiler is provided with an electric separator, and the electric separator is provided with a first outlet and a second outlet, the first outlet is used to discharge fly ash, and the second outlet is used to discharge flue gas, a heat exchanger is connected upstream of the connecting section, the air inlet of the heat exchanger is connected to the second outlet, and the outlet of the heat exchanger is connected to the flue gas treatment unit.
6. The multi-coal blending system according to claim 5, characterized in that: The end of the feed pipe is connected to a first feeding pipe, one of the discharge ports of the reversing valve is connected to the first feeding pipe, a second feeding pipe is provided at the end of the connecting section, the heat exchanger is sleeved on the second feeding pipe, and the other discharge port of the reversing valve is connected to the second feeding pipe.
7. The multi-coal blending system according to claim 6, characterized in that: The other end of the first feeding pipe is provided with a first fan, and the other end of the second feeding pipe is provided with a second fan.
8. The multi-coal blending system according to claim 1, characterized in that: The second feeding line includes a third feeding pipe and a third fan. Both ends of the third feeding pipe are respectively connected to the coal mill and the reversing valve. The moisture meter is arranged on the third feeding pipe. The third fan is arranged on the third feeding pipe and is used to transport air into the third feeding pipe to transport coal powder along the third feeding pipe.
9. The multi-coal blending system according to claim 8, characterized in that: The feed line body includes a filter box, which is arranged on the third feed pipe and located downstream of the third fan. The filter box includes a box body and a filter screen. The filter screen is used to intercept coal powder with a diameter larger than the mesh diameter of the filter screen. The filter box is connected to a return pipe, and the other end of the return pipe is connected to the coal mill. The position where the return pipe is connected to the filter box is located on the side of the filter screen close to the third fan.
10. The multi-coal blending system according to claim 1, characterized in that: The feeding line body includes a plurality of third feeding lines. In one of the feeding line bodies, one end of the plurality of third feeding lines is arranged below the corresponding coal bin, and the other ends of the plurality of third feeding lines are respectively arranged corresponding to the coal mills in another plurality of the feeding line bodies.