Ash cleaning device for horizontal flue at hearth outlet of circulating fluidized bed boiler

Abstract

The utility model discloses a circulating fluidized bed boiler furnace outlet horizontal flue ash removal device which comprises a furnace, a horizontal flue, a cyclone separator, a high-temperature superheater, a low-temperature superheater, a coal economizer and an ash removal device, one end of the ash removal device is arranged at the bottom of the horizontal flue, and the other end of the ash removal device is arranged at the lower end of the coal economizer. The ash removal device comprises a primary air pre-heater, a conveying air pipe, a conveying air branch pipe and an ash removal module, and the ash removal module is arranged at the bottom in the horizontal flue and comprises a main air pipe, a branch air pipe, a connecting rod and a small air cap. A small part of primary air is led to the bottom of the horizontal flue at the hearth outlet through the bypass pipeline of the primary air pre-heater and enters the ash removal device, accumulated ash accumulated at the horizontal flue at the hearth outlet is loosened and fluidized through the small air cap and then enters the cyclone separator along with flue gas, and therefore the purpose of removing the accumulated ash in the horizontal flue at the hearth outlet is achieved. After accumulated ash is cleaned, the smoke flow speed of a hearth outlet is reduced, and the efficiency of the boiler is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circulating fluidized beds, in particular to a circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device. Background Art

[0002] During the operation of the circulating fluidized bed boiler, the fly ash concentration in the flue gas at the furnace outlet is high. As the boiler runs longer, the horizontal flue at the furnace outlet is prone to ash accumulation. Especially during the boiler load reduction process, the flue gas flow rate decreases, and the flue gas velocity decreases accordingly. A large number of ash particles are deposited in the horizontal flue. After the horizontal flue is accumulated, the flow area of ​​the horizontal flue at the furnace outlet is reduced, and the flue gas velocity increases, affecting the separation efficiency of the cyclone separator. At the same time, most circulating fluidized bed boilers use SNCR+SCR combined denitrification, and the SNCR spray gun is arranged in the horizontal flue at the furnace outlet. Due to the accumulation of ash at the bottom of the horizontal flue, the uniformity of ammonia atomization of the bottom spray gun is affected. At the same time, the accumulation of ash at the bottom causes the flue gas velocity to increase, resulting in an increase in the use of SNCR ammonia, an increase in the ammonia escape rate, and an increase in ash accumulation in the tail flue of the circulating fluidized bed boiler, a deterioration of the heat transfer effect, and a decrease in boiler efficiency.

[0003] The invention patent with announcement number "CN104374088B" and name "Furnace core mechanism provided with water pipe cleaning device" discloses a furnace core mechanism provided with a water pipe cleaning device. This technical solution can clean the dust in the furnace, but this technical solution requires manual operation, which is cumbersome and not suitable for large boiler equipment that cannot be entered by people. Utility Model Content

[0004] In order to solve the problem of ash accumulation in the flue, reduced heat transfer effect and decreased boiler efficiency in the above-mentioned prior art.

[0005] The utility model proposes a circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device. Its technical solution is:

[0006] A circulating fluidized bed boiler furnace outlet horizontal flue ash cleaning device, comprising a furnace, a horizontal flue is arranged at the furnace top outlet, a cyclone separator is arranged on the right side of the horizontal flue, a high-temperature superheater, a low-temperature superheater, and an economizer are arranged on the right side of the cyclone separator from top to bottom in sequence, and also comprises a ash cleaning device, one end of the ash cleaning device is arranged at the bottom of the horizontal flue, and the other end is arranged at the lower end of the economizer, the ash cleaning device comprises a primary air preheater arranged at the lower end of the economizer, and also comprises a conveying air duct, one end of the conveying air duct is connected to the primary air preheater and the other end is connected to a plurality of conveying air branch pipes, the other end of the conveying air branch pipe is connected to a ash cleaning module, the ash cleaning module is arranged at the bottom of the horizontal flue, the conveying air branch pipe passes through the horizontal flue wall and is connected to the ash cleaning module, the ash cleaning module comprises a main air duct, a plurality of branch air ducts arranged in parallel and fixedly connected to the main air duct, a plurality of connecting rods are arranged on each branch air duct, a small air hood is arranged on the top of the connecting rod, a plurality of air outlet holes are provided on the small air hood, and the middle openings at both ends of the main air duct are closed and fixedly connected to the conveying air branch pipe.

[0007] Furthermore, the cleaning device also includes a first electric isolation door arranged at one end of the conveying air duct close to the primary air preheater, a second electric isolation door arranged at one end of each conveying air branch pipe close to the conveying air duct, and a third electric isolation door arranged close to one end of the cleaning module.

[0008] Furthermore, the number of air outlet holes provided on the small hood is 4.

[0009] Furthermore, the plurality of connecting rods have different lengths, and the small hood and the connecting rods are fixedly connected.

[0010] Furthermore, the plurality of connecting rods have the same length, the small hood is slidably connected to the connecting rod, the small hood is sleeved on the connecting rod, and a limiting protrusion is provided on the connecting rod.

[0011] Furthermore, the number of the cleaning modules is 2.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The circulating fluidized bed boiler furnace outlet horizontal flue ash cleaning device guides a small amount of primary air to the bottom of the furnace outlet horizontal flue through the primary air preheater bypass pipe, enters the ash cleaning device, and loosens and fluidizes the ash accumulated in the furnace outlet horizontal flue through the small wind cap, and then enters the cyclone separator with the flue gas to achieve the purpose of cleaning the ash accumulated in the furnace outlet horizontal flue. After the ash is cleaned, the flue gas velocity at the furnace outlet is reduced, the atomization effect of the SNCR denitrification bottom spray gun is improved, the denitrification effect is increased, the ammonia escape rate is reduced, the ash accumulation degree of the tail flue is improved, and the boiler efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1It is a schematic diagram of the overall structure of the utility model;

[0015] Figure 2 for Figure 1 Schematic diagram of the middle AA section;

[0016] Figure 3 This is a partial enlarged view of the dust cleaning module of the utility model;

[0017] Figure 4 This is a side view of the dust cleaning module of Example 1 of the utility model;

[0018] Figure 5 This is a side view of the dust cleaning module of Example 2 of the utility model;

[0019] Figure 6 This is a schematic diagram of the highest point of the dust cleaning module of Example 2 of the utility model;

[0020] Figure 7 for Figure 6 Enlarged cross-sectional view of the small and medium hoods and connecting rods.

[0021] In the figure: 1. furnace; 2. horizontal flue; 3. cyclone separator; 4. high-temperature superheater; 5. low-temperature superheater; 6. economizer; 7. ash cleaning device; 71. primary air preheater; 72. first electric isolation door; 73. conveying air duct; 74. second electric isolation door; 75. third electric isolation door; 76. ash cleaning module; 761. main air duct; 762. branch air duct; 763. small air hood; 764. connecting rod. DETAILED DESCRIPTION

[0022] The following are specific embodiments, and in combination with the accompanying drawings, further describe the technical solution of the utility model. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and are therefore only used as examples, and cannot be used to limit the protection scope of the utility model.

[0023] like Figure 1 and Figure 2As shown, the utility model provides a horizontal flue ash cleaning device at the furnace outlet of a circulating fluidized bed boiler, comprising a furnace 1, a horizontal flue 2 is arranged at the top outlet of the furnace 1, a cyclone separator 3 is arranged on the right side of the horizontal flue 2, and a high-temperature superheater 4, a low-temperature superheater 5, and an economizer 6 are arranged on the right side of the cyclone separator 3 from top to bottom. One end of the ash cleaning device 7 is arranged at the bottom of the horizontal flue 2 and the other end is arranged at the lower end of the economizer 6. The ash cleaning device 7 includes a primary air preheater 71, a conveying air duct 73, a conveying air branch pipe and a ash cleaning module 76. The primary air preheater 71 is arranged at the lower end of the economizer 6, one end of the conveying air duct 73 is connected to the primary air preheater 71 and the other end is connected to a plurality of conveying air branch pipes, and the other end of the conveying air branch pipe is connected to the ash cleaning module 76, and the ash cleaning module 76 is arranged at the bottom of the horizontal flue 2, and the conveying air branch pipe passes through the wall of the horizontal flue 2 and is connected to the ash cleaning module 76. In order to control the air volume in the air duct and adjust the dust cleaning effect, a first electric isolation door 72 is provided at one end of the conveying air duct 73 close to the primary air preheater 71, and a second electric isolation door 74 is provided at one end of each conveying air branch pipe close to the conveying air duct 73 and a third electric isolation door 75 is provided at one end close to the dust cleaning module 76. The third electric isolation door 75 can control the air volume in the air duct and prevent the dust accumulated in the horizontal flue 2 from falling into the air duct and causing blockage when the dust cleaning device 7 is not working.

[0024] like Figure 3 As shown, the dust cleaning module 76 includes a main air duct 761, a branch air duct 762, a small air cap 763, and a connecting rod 764. The main air duct 761 has two closed ends and a central opening fixedly connected to the conveying air branch duct. A plurality of branch air ducts 762 are arranged in parallel and fixedly connected to the main air duct 761. A plurality of connecting rods 764 are provided on each branch air duct 762. A small air cap 763 is provided on the top of the connecting rod 764. A plurality of air outlet holes are provided on the small air cap 763. Preferably, the number of air outlet holes provided on the small air cap 763 is 4.

[0025] like Figure 4 As shown, it is the embodiment 1 of the utility model, in which the plurality of connecting rods 764 are of different lengths, and the small hood 763 is fixedly connected to the connecting rod 764. It can clean up dust accumulations of different heights.

[0026] like Figures 5 to 7 As shown, it is the second embodiment of the utility model, in which the plurality of connecting rods 764 are of the same length, the small hood 763 is slidably connected with the connecting rod 764, the small hood 763 is sleeved on the connecting rod 764, and the small hood 763 can slide up and down along the connecting rod 764 under the action of airflow. A limiting protrusion is provided on the connecting rod 764 to ensure that the small hood 763 will not be separated from the connecting rod 764.

[0027] Preferably, the number of the cleaning modules 76 is two.

[0028] The working principle of the utility model is:

[0029] During the operation of the circulating fluidized bed boiler, the ash content of the coal in front of the furnace determines the frequency of opening the ash blowing device 7 at the bottom of the horizontal flue 2. When the horizontal flue ash cleaning device at the furnace outlet is put into operation, the first electric isolation door 72 is opened first, and the second electric isolation door 74 and the third electric isolation door 75 are opened again. The wind passes through the primary air preheater 71, the first electric isolation door 72, the conveying air duct 73, the second electric isolation door 74, the conveying air branch pipe, the third electric isolation door 75 and the ash cleaning module 76 in sequence, and enters the horizontal flue 2 from the air outlet of the small wind cap 763 on the ash cleaning module 76 to clean and blow away the coal ash in the flue. During normal operation, the air volume of the ash cleaning module 76 is controlled by controlling the opening of the second electric isolation door 74 and the third electric isolation door 75, and the ash accumulated in the horizontal flue 2 is loosened and fluidized through the small wind cap 763, and then enters the cyclone separator 3 with the flue gas to achieve the purpose of cleaning the ash accumulated in the horizontal flue 2. The cleaning device 7 can determine the cleaning cycle according to actual operation, and can set the cleaning cycle according to days or weeks.

Claims

1. A circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device, comprising a furnace (1), a horizontal flue (2) arranged at the top outlet of the furnace (1), a cyclone separator (3) arranged on the right side of the horizontal flue (2), a high-temperature superheater (4), a low-temperature superheater (5), and an economizer (6) arranged on the right side of the cyclone separator (3) in order from top to bottom, characterized in that The invention also includes a ash cleaning device (7), one end of which is arranged at the bottom of the horizontal flue (2), and the other end is arranged at the lower end of the economizer (6). The ash cleaning device (7) includes a primary air preheater (71) arranged at the lower end of the economizer (6), and also includes a conveying air duct (73), one end of which is connected to the primary air preheater (71) and the other end of which is connected to a plurality of conveying air branch pipes. The other end of the conveying air branch pipe is connected to a ash cleaning module (76), and the ash cleaning module (76) is arranged at the horizontal flue (2). At the inner bottom, the conveying air branch pipe passes through the wall of the horizontal flue (2) and is connected to the cleaning module (76). The cleaning module (76) includes a main air duct (761), a plurality of branch air ducts (762) arranged in parallel and fixedly connected to the main air duct (761), a plurality of connecting rods (764) are arranged on each branch air duct (762), a small air cap (763) is arranged on the top of the connecting rod (764), and a plurality of air outlet holes are provided on the small air cap (763), and the two ends of the main air duct (761) are closed and the middle opening is fixedly connected to the conveying air branch pipe.

2. The circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device according to claim 1, characterized in that: The dust cleaning device (7) further comprises a first electric isolation door (72) arranged at one end of the conveying air duct (73) close to the primary air preheater (71), a second electric isolation door (74) arranged at one end of each conveying air branch pipe close to the conveying air duct (73), and a third electric isolation door (75) arranged at one end close to the dust cleaning module (76).

3. The circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device according to claim 2 is characterized by: The number of air outlet holes provided on the small wind cap (763) is 4.

4. The circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device according to claim 1, characterized in that: The plurality of connecting rods (764) have different lengths, and the small wind cap (763) and the connecting rod (764) are fixedly connected.

5. The circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device according to claim 1, characterized in that: The plurality of connecting rods (764) have the same length, the small wind hood (763) is slidably connected to the connecting rod (764), the small wind hood (763) is sleeved on the connecting rod (764), and a limiting protrusion is provided on the connecting rod (764).

6. The circulating fluidized bed boiler furnace outlet horizontal flue dust cleaning device according to any one of claims 1 to 5, characterized in that: The number of the dust cleaning modules (76) is 2.

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