Arrangement structure of coal bunker in CFB boiler steel frame

Abstract

The invention discloses a coal bunker arrangement structure in a CFB (circulating fluid bed) boiler steel frame, which is characterized in that coal bunkers are arranged by adopting a boiler front coal bunker and boiler rear two-side coal bunkers, and the front coal bunker and the two-side coal bunkers are arranged in a boiler steel frame (1-1); an independent coal-bunker-free steel frame is not arranged in a boiler steel frame (1-1), coal bunkers are directly integrated in the boiler steel frame, a boiler (1-3) is arranged in the middle of the boiler steel frame (1-1), four front coal bunkers are arranged in front of the boiler (1-3), and the coal bunkers are numbered as first to fourth coal bunkers (1 # to 4 #) respectively; and two side coal bunkers are respectively arranged on two sides of the rear part of the boiler (1-3), and the serial numbers of the coal bunkers are respectively set as fifth to sixth coal bunkers (5 # and 6 #). By means of the arrangement mode, the front coal bunker and the side coal bunkers are all arranged in the boiler steel frame, a supporting structure does not need to be additionally erected, and the occupied area is saved.

Description

Technical Field

[0001] The invention relates to a steel frame inner coal bunker arrangement structure suitable for a large-scale circulating fluidized bed boiler. Background Art

[0002] At present, the common coal bunker layout of existing CFB boilers is the front coal bunker, and the coal bunker steel frame and the boiler steel frame are relatively independent, and the two are not connected by a steel frame.

[0003] like Figure 1 , Figure 2 As shown, a CFB boiler coal bunker layout structure, the furnace steel frame is set to 0-1, the coal bunker steel frame is set to 0-2, and the coal bunker steel frame is arranged in front of the boiler steel frame. The coal bunker is set in the coal bunker steel frame 0-2, see Figure 1 , Figure 2 The number of coal bunkers is set to 5, which are coal bunker A to coal bunker E. Among them, the coal bunker A and coal bunker E are set at the two ends of the coal bunker, set as side coal bunker structure, and connected to the rear wall of the boiler. The coal bunker B to coal bunker D are set in the middle of the coal bunker, set as front coal bunker structure, and connected to the front wall of the boiler.

[0004] Coal bunker A and coal bunker E are equipped with 2 return leg coal feeding mechanisms, and the maximum coal feeding capacity of a single return leg is 80t / h. Coal bunkers B to D are equipped with 2 wall-type coal feeding mechanisms, and the maximum coal feeding capacity of a single wall-type is 35t / h. The boiler design adopts 6 front wall wall-type coal feeding mechanisms + 4 rear wall return leg coal feeding mechanisms. Therefore, the total maximum coal feeding output is 530t / h, which can meet 200% of the designed coal feeding capacity (BMCR working condition 268t / h requirement).

[0005] The two return leg coal feeding mechanisms in coal bunker A and coal bunker E are respectively composed of an electronic weighing coal feeder 0-4 and a scraper feeder 0-6.

[0006] The two wall-type coal feeding mechanisms in coal bunker B to coal bunker D are respectively composed of electronic weighing coal feeders 0-5.

[0007] The boiler 0-3 is installed in the boiler steel frame 0-1, wherein the coal bunker A and the coal bunker E are connected to the rear wall of the boiler through the electronic weighing coal feeder 0-4 and the scraper feeder 0-6. The length of the electronic weighing coal feeder 0-4 in the coal bunker A and the coal bunker E is set to L1, and its value range is set to 25 to 40 meters.

[0008] Boiler 0-3 is installed in boiler steel frame 0-1, in which coal bunker B to coal bunker D are connected to the front wall of the boiler through electronic weighing coal feeder 0-5.

[0009] In the above-mentioned prior art, all coal bunkers are placed on the supporting structure between the steam engine room and the boiler room. In conjunction with the coal feeding method of the boiler, a front and rear wall combined coal feeding method is adopted. When burning inferior fuels, the amount of coal required to enter the furnace is large, and a front and rear wall combined coal feeding method is usually adopted. At this time, the coal bunkers arranged on both sides of the front wall will use a long-distance electronic weighing coal feeder + scraper to deliver the fuel to the corresponding coal feeding point on the rear wall. Since the coal bunker unloading capacity, the transportation speed of the electronic weighing coal feeder, and the material distribution uniformity of the scraper will affect the operating stability and variable load response speed of the boiler, the subsequent maintenance cost is also relatively high, and the economic benefit is low. Summary of the invention

[0010] The present invention provides a coal bunker arrangement structure in a CFB boiler steel frame, wherein the coal bunker arrangement adopts a boiler front coal bunker + boiler rear side coal bunker arrangement, and the front coal bunker and the side coal bunkers are arranged in a boiler steel frame (1-1); no independent coal bunker-free steel frame is arranged in the boiler steel frame (1-1), and the coal bunker is directly integrated in the boiler steel frame; a boiler (1-3) is arranged in the middle of the boiler steel frame (1-1), and four front coal bunkers are arranged in front of the boiler (1-3), and the coal bunkers are numbered as the first to fourth coal bunkers (1# to 4#), respectively; and one side coal bunker is respectively arranged on both sides of the rear of the boiler (1-3), and the coal bunkers are numbered as the fifth to sixth coal bunkers (5#, 6#), respectively.

[0011] Preferably, the first to fourth coal bunkers (1#~4#) are respectively provided with 2 return leg coal feeding mechanisms, and the maximum coal feeding capacity of a single return leg is 80t / h; the fifth to sixth coal bunkers (5#, 6#) are respectively provided with 4 return leg coal feeding mechanisms, and the maximum coal feeding capacity of the return leg is 80t / h; the boiler design adopts 8 front wall return legs + 8 rear wall return legs for coal feeding, so the total maximum coal feeding output is 1280t / h, which can meet 200% of the designed coal feeding amount.

[0012] Preferably, the eight return leg coal feeding mechanisms in the first to fourth coal bunkers 1# to 4# are respectively composed of the second electronic weighing coal feeder (1-5); and the eight return leg coal feeding mechanisms in the fifth to sixth coal bunkers 5# and 6# are respectively composed of the first electronic weighing coal feeder (1-4).

[0013] Preferably, the fifth to sixth coal bunkers (5#, 6#) are connected to the rear wall of the boiler via a first electronic weighing coal feeder (1-4); wherein the length of the first electronic weighing coal feeder (1-4) in the fifth to sixth coal bunkers (5#, 6#) is set to L2, and its numerical range is set to 5 to 8 meters; the boiler (1-3) is arranged in a boiler steel frame (1-1), wherein the first to fourth coal bunkers (1# to 4#) are connected to the front wall of the boiler via a second electronic weighing coal feeder (1-5).

[0014] Compared with the prior art, the present invention has the following beneficial effects: the present invention discloses a coal bunker arrangement structure in a boiler steel frame, and the coal bunker arrangement adopts a front coal bunker + two side coal bunker arrangement. With this arrangement, the front coal bunker and the side coal bunker are both arranged in the boiler steel frame, and no additional supporting structure is required, thus saving floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Front view of conventional coal bunker layout of existing CFB boiler.

[0016] Figure 2 Top view of conventional coal bunker layout of existing CFB boiler.

[0017] Figure 3 Front view of the coal bunker layout in a new CFB boiler steel frame.

[0018] Figure 4 A top view of the coal bunker arrangement within a new CFB boiler steel frame.

[0019] Figure 5 Diagram of a new CFB boiler return feeder.

[0020] Figure numerals: boiler steel frame 1-1, boiler 1-3, first electronic weighing coal feeder 1-4, second electronic weighing coal feeder 1-5, first to fourth coal bunkers 1#~4#, fifth to sixth coal bunkers 5#, 6#. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods, but the present invention is not limited to the following embodiments.

[0022] A coal bunker arrangement structure in a CFB boiler steel frame, the coal bunker arrangement adopts a front coal bunker + two side coal bunker arrangement, and the front coal bunker and the two side coal bunkers are arranged in the boiler steel frame (see Figure 3 , Figure 4 ).

[0023] The boiler steel frame is set as 1-1, and there is no coal bunker steel frame in the boiler. Among them, the boiler 1-3 is arranged in the middle of the boiler steel frame 1-1. In this embodiment (see Figure 3 , Figure 4 ), there are 4 front coal bunkers in front of boiler 1-3, and the coal bunkers are numbered as 1# to 4# for the first to fourth coal bunkers. There are 1 side coal bunkers on both sides of the rear of boiler 1-3, and the coal bunkers are numbered as 5# and 6# for the fifth to sixth coal bunkers.

[0024] The first to fourth coal bunkers 1#~4# are respectively equipped with 2 return leg coal feeding mechanisms, and the maximum coal feeding capacity of a single return leg is 80t / h. The fifth to sixth coal bunkers 5# and 6# are respectively equipped with 4 return leg coal feeding mechanisms, and the maximum coal feeding capacity of the return leg is 80t / h. The boiler design adopts 8 front wall return legs for coal feeding + 8 rear wall return legs for coal feeding. Therefore, the total maximum coal feeding output is 1280t / h, which can meet 200% of the designed coal feeding amount (BMCR working condition 524t / h requirement).

[0025] The eight return leg coal feeding mechanisms in the first to fourth coal bunkers 1#~4# are all composed of the second electronic weighing coal feeder 1-5.

[0026] The eight return leg coal feeding mechanisms in the fifth to sixth coal bunkers 5# and 6# omit the scraper feeding mechanism and are all composed of the first electronic weighing coal feeder 1-4.

[0027] The boiler 1-3 is arranged in the boiler steel frame 1-1, wherein the fifth to sixth coal bunkers 5# and 6# are connected to the boiler rear wall through the first electronic weighing coal feeder 1-4. The length of the first electronic weighing coal feeder 1-4 in the fifth to sixth coal bunkers 5# and 6# is set to L2, and its value range is set to 5 meters to 8 meters.

[0028] The boiler 1-3 is arranged in the boiler steel frame 1-1, wherein the first to fourth coal bunkers 1#~4# are connected to the boiler front wall through the second electronic weighing coal feeder 1-5.

[0029] The present invention discloses a coal bunker arrangement structure in a boiler steel frame. The coal bunker arrangement adopts a front coal bunker + two side coal bunker arrangement. With this arrangement, the front coal bunker and the side coal bunker are both arranged in the boiler steel frame, and no additional supporting structure is required, thus saving floor space.

[0030] The present invention discloses a coal bunker arrangement structure within a boiler steel frame. The length of the first electronic weighing coal feeder 1-4 in the coal bunkers on both sides, i.e., the fifth to sixth coal bunkers 5# and 6#, is L2. Compared with the CFB boiler with previous coal bunker arrangement, the length of the electronic weighing coal feeder is L1. The length of L2 is one-fifth of the length of L1, and the length of the mechanism is reduced, which improves the stability of the boiler and the speed of variable load response. The later maintenance cost is low and the economic benefit is high. The front coal bunker and the side coal bunker in the present invention both adopt a single-stage electronic weighing and conveying method that eliminates the scraper feeder. The overall coal conveying path length tends to be consistent, which is more suitable for the rapid variable load operation requirements of the boiler. With the combined coal bunker design, the coal input on the entire bed surface tends to be uniform, making the boiler operation more stable.

[0031] The present invention discloses a new coal bunker arrangement structure in a CFB boiler steel frame. The coal bunker arrangement adopts a front coal bunker + two side coal bunkers arrangement. The coal feeding system is designed with 8 returners, so 16 coal feeding ports can be set, which improves the coal feeding uniformity and coal quality adaptability of the boiler, and is particularly suitable for low calorific value fuel mixed with coal gangue.

[0032] Figure 5 This is a diagram of a new CFB boiler return feeder. The return feeders in the figure are numbered as: 1-6-1#~1-6-8# (8 in total), and the coal feeding ports in the figure are numbered as: 1-7-1#~1-7-16# (16 in total).

[0033] The selection of coal feeding system for large circulating fluidized bed boilers needs to be determined according to the coal burning conditions of the project and the geographical conditions of the project. For fuels with low calorific value, the boiler fuel consumption is large. At the same time, for CFB boilers above 300MW, the furnace width is wide and the number of coal feeding ports for each furnace is large. In the actual operation process, due to the influence of various factors, the deviation of the amount of fuel fed into each coal feeding port is very large. In order to reduce the impact of coal feeding on furnace combustion, the front and rear walls are combined for feeding, that is, the coal bunker layout adopts the front coal bunker + two-side coal bunker layout, and the first to fourth coal bunkers 1#~4# are connected to the front wall of the boiler through an electronic weighing coal feeder to realize the function of boiler front wall feeding. The fifth to sixth coal bunkers 5# and 6# are connected to the rear wall of the boiler through an electronic weighing coal feeder to realize the function of boiler rear wall feeding.

[0034] In addition, the combined coal feeding of the front and rear walls is conducive to improving the uniformity of the furnace, and the coal feeding of the rear wall (coal feeding by the return feeder) can completely avoid the coal blockage of the front wall coal drop pipe in rainy and humid areas. In view of the advantages of coal feeding by the return feeder, a new CFB boiler disclosed in the present invention innovatively adopts a combined coal feeding design structure of the front and rear walls in the coal feeding method, and the coal feeding methods of the front and rear walls also adopt coal feeding by the return feeder, which is used to improve the reliability and stability of the coal feeding system.

[0035] The new CFB boiler disclosed in the present invention innovatively adopts a front and rear wall combined coal feeding design structure in the coal feeding method. Both the front and rear wall coal feeding methods also use a return feeder to feed coal. Compared with other coal feeding methods, for CFB boilers, since there is a large amount of high-temperature circulating material in the return feeder, feeding coal from the return feeder has the following advantages: 1. The feed coal and circulating materials are fully mixed in the return device before entering the furnace, making the furnace combustion temperature more uniform; 2. The flow rate of circulating materials in each return feeder is much larger than the coal feeding amount. Therefore, the coal feeding amount of a single return feeder can be much larger than the conventional wall-type coal feeding amount. Therefore, the coal feeding amount of a single return feeder coal feeding point can be larger than the coal feeding amount of the conventional wall-type coal feeding point while ensuring the uniformity of the bed temperature. 3. Feeding coal with the return feeder can avoid coal blockage in the feed pipe. Since the feed pipe is basically a straight pipe, it can reduce or even prevent coal blockage. 4. It can reduce or even eliminate the wear of the coal drop pipe. For wall-type coal feeding, due to the design of the elbow, the wear of the coal drop pipe is very serious. For power plants burning coal gangue, the wear is particularly serious. Therefore, wall-type coal feeding is not recommended in the design of ultra-supercritical CFB boilers.

[0036] 5. The front and rear wall coal feeding methods adopt the return feeder to feed coal, and various coal bunker layout structures can be adopted, which is easy to arrange.

[0037] For large-capacity, ultra-supercritical circulating fluidized bed boilers, fuel consumption increases, and the front and rear wall combined coal feeding method is usually used to meet the operation needs. In addition, the furnace width is wider, and the layout of a single front wall or single side coal bunker will have problems such as long transportation routes and slow response speeds. However, current policies require generators to have the ability to deeply adjust peak loads and quickly change loads, which requires a simpler coal bunker layout with a short transportation route.

[0038] The present invention discloses a coal bunker arrangement structure within a boiler steel frame, in which the length of the electronic weighing coal feeder in the coal bunkers on both sides is L2. Compared with the CFB boiler with the previous coal bunker arrangement structure, the length of the electronic weighing coal feeder is L1, and the length of L2 is one-fifth of the length of L1, that is, shortened from the conventional 25-40 meters to 5-8 meters, and the length is reduced by about 80%. The length of the mechanism is reduced, which improves the stability of the boiler and the response speed of variable load, with low maintenance costs and high economic benefits. The front coal bunker and the side coal bunker in the present invention both adopt a single-stage electronic weighing and conveying method that eliminates the scraper feeder, and the overall coal conveying path length tends to be consistent, which is more suitable for the rapid variable load operation requirements of the boiler. With the combined coal bunker design, the coal input on the entire bed surface tends to be uniform, making the boiler operation more stable.

[0039] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and improvements can be made without departing from the principles of the present invention. These improvements and improvements are also regarded as the protection scope of the present invention. The protection scope of the present invention shall be based on the definition of the claims.

Claims

1. A coal bunker arrangement structure in a CFB boiler steel frame, characterized in that: The coal bunker layout adopts the boiler front coal bunker + boiler rear two side coal bunker layout, and the front coal bunker and the two side coal bunkers are arranged in the boiler steel frame (1-1); An independent coal bunker-free steel frame is not provided in the boiler steel frame (1-1), and the coal bunker is directly integrated into the boiler steel frame. A boiler (1-3) is provided in the middle of the boiler steel frame (1-1), and four front coal bunkers are provided in front of the boiler (1-3), and the coal bunkers are numbered as the first to fourth coal bunkers (1# to 4#), respectively; and one side coal bunker is provided on both sides of the rear of the boiler (1-3), and the coal bunkers are numbered as the fifth to sixth coal bunkers (5#, 6#), respectively.

2. The coal bunker arrangement structure in a CFB boiler steel frame according to claim 1, characterized in that: The first to fourth coal bunkers (1#~4#) are respectively equipped with two return leg coal feeding mechanisms, and the maximum coal feeding capacity of a single return leg is 80t / h; The fifth and sixth coal bunkers (5# and 6#) are respectively provided with 4 return leg coal feeding mechanisms, and the maximum coal feeding capacity of the return legs is 80t / h; the boiler design adopts 8 front wall return legs + 8 rear wall return legs for coal feeding, so the total maximum coal feeding output is 1280t / h, which can meet 200% of the designed coal feeding capacity.

3. The coal bunker arrangement structure in a CFB boiler steel frame according to claim 2 is characterized by: The eight return leg coal feeding mechanisms in the first to fourth coal bunkers 1# to 4# are respectively composed of second electronic weighing coal feeders (1-5); The eight return leg coal feeding mechanisms in the fifth to sixth coal bunkers 5# and 6# are respectively composed of the first electronic weighing coal feeder (1-4).

4. The coal bunker arrangement structure in a CFB boiler steel frame according to claim 3 is characterized by: The fifth and sixth coal bunkers (5#, 6#) are connected to the rear wall of the boiler via a first electronic weighing coal feeder (1-4); wherein the length of the first electronic weighing coal feeder (1-4) in the fifth and sixth coal bunkers (5#, 6#) is set to L2, and its value range is set to 5 to 8 meters; The boiler (1-3) is arranged in a boiler steel frame (1-1), wherein the first to fourth coal bunkers (1#-4#) are connected to the front wall of the boiler via a second electronic weighing coal feeder (1-5).

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