Tangent circle combustion boiler air supply system based on quartered-bin air preheater

Abstract

The utility model discloses a tangential combustion boiler air supply system based on a quartered air preheater. The tangential combustion boiler air supply system comprises a boiler, a coal mill, the quartered air preheater, a secondary air bellow, a burnout air bellow, a primary air fan, a primary air duct, a secondary air fan, a secondary air duct, a burnout air fan and a burnout air duct. The primary air duct penetrates through the quartered air preheater and then is connected with the coal mill; the secondary air duct penetrates through the quartered air preheater and then is connected with the secondary air bellow; and the over-fire air duct penetrates through the quartered air preheater and then is connected with the over-fire air bellow. The air supply system has the advantages that the adjustment of the over-fire air in the over-fire air bellow is controlled by the independent over-fire fan, the adjustment of the over-fire air does not influence a primary air system, the controllability of air pressure is good, and the risk that a unit is not stopped due to the fact that the running state of the fan is unstable when the over-fire air is greatly adjusted is further prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of coal-fired boilers, in particular to an air supply system for a tangential combustion boiler based on a four-compartment air preheater. Background Art

[0002] The three main engines of coal-fired power generation units include coal-fired boilers, steam turbines and generators. Coal-fired boilers can generally be divided into pulverized coal boilers and circulating fluidized bed boilers. The combustion methods generally used in pulverized coal boilers are tangential combustion with direct current burners, counter-compression combustion with swirl burners arranged on the front and rear walls, and W-type flame combustion. Among them, tangential combustion boilers are a widely used type of boiler.

[0003] For tangentially fired boilers, due to their unique combustion method, the flame in the furnace rotates at a high speed, and the smoke temperature and smoke volume at the furnace outlet have large deviations. In order to reduce the smoke deviation at the furnace outlet, tangentially fired boilers are equipped with burnout air. The burnout air uses secondary hot air. By adjusting the angle and air volume of the burnout air entering the furnace, the angle at which the secondary hot air enters the furnace is opposite to the direction of flame rotation, thereby achieving the purpose of reverse tangential derotation and controlling the smoke deviation to a certain extent.

[0004] For example, the Chinese utility model patent document with publication number CN216244252U discloses a tangential coal-fired boiler system, which uses a primary fan and an adjustable air duct baffle door to adjust the wind pressure and output wind speed, thereby ensuring the derotation effect on the rotating flame and reducing the temperature and volume deviation of the flue gas at the furnace outlet. Its technical effect is to improve combustion efficiency and stability and reduce flue gas emissions. However, in this patent, the primary air is not only supplied to the coal mill, but also to the burnout wind box. The primary air pressure is relatively high and needs to be throttled, which makes the system economical. Moreover, when the burnout air is greatly adjusted, the operating state of the primary fan is unstable, and there is a risk of non-stop unit operation. Utility Model Content

[0005] The technical problem to be solved by the utility model is how to improve the burnout wind pressure while avoiding the risk of unit non-stopping caused by the unstable operating state of the primary fan when the burnout wind is greatly adjusted using the primary air solution.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0007] A tangential combustion boiler air supply system based on a four-compartment air preheater comprises a boiler, a coal mill, a four-compartment air preheater, a secondary air box, a burnout air box, a primary fan, a primary air duct, a secondary fan, a secondary air duct, a burnout fan, and a burnout air duct;

[0008] The boiler is connected to the coal mill, the flue gas output end of the boiler is connected to the four-compartment air preheater, a secondary wind box and a burnout wind box are fixed on the boiler, the air outlets of the secondary wind box and the burnout wind box are both arranged in the boiler, and the air outlet direction is opposite to the flame rotation direction in the boiler;

[0009] The output end of the primary air fan is connected to the primary air duct, and the primary air duct passes through the four-compartment air preheater and is connected to the coal mill;

[0010] The output end of the secondary fan is connected to the secondary air duct, and the secondary air duct passes through the four-compartment air preheater and is connected to the secondary air box;

[0011] The output end of the burnout fan is connected to the burnout air duct, and the burnout air duct passes through the four-compartment air preheater and is connected to the burnout wind box.

[0012] The burnout air regulation in the burnout air box of the air supply system is controlled by a separate burnout fan. The burnout air regulation does not affect the primary air system, and the wind pressure is well controllable, thereby preventing the risk of unit non-stopping caused by drastic fluctuations in fan current when the burnout air is drastically adjusted.

[0013] Preferably, the output port of the gas bellows is provided with an adjustable air duct baffle door.

[0014] Preferably, the output port of the gas bellows is provided with an adjustable small air damper.

[0015] Preferably, the number of the gas wind boxes is four and they are evenly distributed on the boiler.

[0016] Preferably, a primary air compartment, a secondary air compartment, a burnout air compartment and a flue gas compartment are arranged inside the four-compartment air preheater. The primary air duct passes through the primary air compartment and is connected to the coal mill, the secondary air duct passes through the secondary air compartment and is connected to the secondary air box, and the burnout air duct passes through the burnout air compartment and is connected to the burnout air box.

[0017] Preferably, the output end of the four-compartment air preheater is also provided with a smoke exhaust duct connected to the smoke compartment.

[0018] Preferably, the output end of the smoke exhaust duct is connected to an induced draft fan.

[0019] Preferably, a dust collector is also provided on the smoke exhaust duct.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] The burnout air regulation in the burnout air box of the air supply system is controlled by a separate burnout fan. The burnout air regulation does not affect the primary air system, and the wind pressure is well controllable, thereby preventing the risk of unit non-stopping caused by unstable fan operating state when the burnout air is drastically adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an air supply system for a tangential combustion boiler based on a four-compartment air preheater according to an embodiment of the utility model;

[0023] Figure 2 It is a partial schematic diagram of an embodiment of the utility model;

[0024] Figure 3 It is a schematic structural diagram of a four-compartment air preheater according to an embodiment of the utility model. DETAILED DESCRIPTION

[0025] In order to facilitate those skilled in the art to understand the technical solution of the utility model, the technical solution of the utility model is further explained in conjunction with the drawings in the specification.

[0026] In this application, 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 connection; it can be a mechanical connection, an electrical connection, or a communication; 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. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] In this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically limited.

[0028] See also Figures 1 to 3 The present embodiment discloses a tangential combustion boiler air supply system based on a four-compartment air preheater, comprising a boiler 1, a coal mill 2, a four-compartment air preheater 3, a secondary air box 4, a burnout air box 5, a primary fan 6, a primary air duct 7, a secondary fan 8, a secondary air duct 9, a burnout fan 10, and a burnout air duct 11.

[0029] The boiler 1 is connected to the coal mill 2, and the flue gas output end of the boiler 1 is connected to the four-compartment air preheater 3. In this embodiment, the four-compartment air preheater 3 is internally provided with a primary air compartment 31, a secondary air compartment 32, a burnt air compartment 33 and a flue gas compartment 34.

[0030] The boiler 1 is fixed with a secondary wind box 4 and a burnout wind box 5, and the air outlets of the secondary wind box 4 and the burnout wind box 5 are both arranged in the boiler 1 and the air outlet direction is opposite to the flame rotation direction in the boiler 1. In this embodiment, the number of the gas wind boxes 5 is four and they are evenly distributed on the four corners of the furnace of the boiler 1. The output ports of the gas wind boxes 5 are all provided with an adjustable air duct damper door 12 and an adjustable small air door 13.

[0031] The output end of the primary air fan 6 is connected to the primary air duct 7 , and the primary air duct 7 passes through the primary air compartment 31 in the four-compartment air preheater 3 and is connected to the coal mill 2 .

[0032] The output end of the secondary air fan 8 is connected to the secondary air duct 9 , and the secondary air duct 9 passes through the secondary air compartment 32 of the four-compartment air preheater 3 and is connected to the secondary air box 4 .

[0033] The output end of the burnout blower 10 is connected to the burnout air duct 11 , and the burnout air duct 11 passes through the tertiary air compartment 33 of the four-compartment air preheater 3 and is connected to the burnout wind box 5 .

[0034] It should be noted that the burnout wind pressure generated by the burnout fan 10 is higher than the secondary wind pressure. By adjusting the opening and closing size of the adjustable air duct baffle door 12, the pressure balance of the burnout wind box 5 at the four corners of the boiler 1 is ensured. By adjusting the output of the burnout fan 10, the number of operating layers and the opening of the adjustable small air door 13, the burnout wind volume and output wind speed are controlled, thereby ensuring the derotation effect on the rotating flame and reducing the deviation of the flue gas temperature and flue gas volume at the furnace outlet.

[0035] In addition, the burnout air regulation in the burnout air box 5 of this embodiment is controlled by a separate burnout fan 10, the wind pressure is well controllable, and the regulation of the burnout air does not affect the primary air system, thereby preventing the risk of unit non-stopping caused by the unstable operating state of the fan when the burnout air is drastically adjusted.

[0036] The output end of the four-compartment air preheater 3 is also provided with a smoke exhaust duct 14 connected to the smoke compartment 34 for exhausting smoke. The output end of the smoke exhaust duct 14 is connected to an induced draft fan 15 to improve the smoke exhaust effect. Furthermore, a dust collector 16 is also provided on the smoke exhaust duct 14 to remove dust and filter the exhausted smoke to reduce pollution to the environment.

[0037] The working principle of this embodiment is as follows: when the boiler 1 is burning, the primary fan 6, the secondary fan 8, the burnout fan 10 and the induced draft fan 13 are turned on at the same time, the primary air input by the primary fan 6 passes through the primary air duct 7 and is heated by the primary air compartment 31 in the four-compartment air preheater 3 before entering the coal mill 2, and the pulverized coal ground by the coal mill 2 is sent to the boiler 1; the secondary air input by the secondary fan 8 passes through the secondary air duct 9 and is heated by the secondary air compartment 32 in the four-compartment air preheater 3 before entering the boiler 1 through the secondary wind box 4, so as to provide oxygen for combustion in the boiler 1 and ensure the boiler Combustion effect in furnace 1; the burnout air input by burnout fan 10 is heated by tertiary air compartment 33 of quadrant air preheater 3 through burnout air duct 11 and then sent to boiler 1 through burnout wind box 5; by adjusting the opening and closing size of the adjustable wind duct baffle door 12, the pressure balance of burnout wind box 5 at the four corners is ensured, and the air volume and output wind speed of burnout air are controlled by adjusting the output of burnout fan 10, the number of layers and opening of adjustable small air door 13, thereby ensuring the de-rotation effect of rotating flame and reducing the deviation of flue gas temperature and flue gas volume at furnace outlet. At the same time, induced draft fan 15 sucks the flue gas generated by combustion and passing through flue gas compartment 34 of quadrant air preheater 3, and removes dust and filters through dust collector 16.

[0038] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0039] The above-described embodiments merely represent implementation methods of the utility model, and the protection scope of the utility model is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the utility model, and all of these belong to the protection scope of the utility model.

Claims

1. A tangential combustion boiler air supply system based on a four-compartment air preheater, characterized in that: Including boiler, coal mill, four-compartment air preheater, secondary air box, burnout air box, primary fan, primary air duct, secondary fan, secondary air duct, burnout fan, burnout air duct; The boiler is connected to the coal mill, the flue gas output end of the boiler is connected to the four-compartment air preheater, a secondary wind box and a burnout wind box are fixed on the boiler, the air outlets of the secondary wind box and the burnout wind box are both arranged in the boiler, and the air outlet direction is opposite to the flame rotation direction in the boiler; The output end of the primary air fan is connected to the primary air duct, and the primary air duct passes through the four-compartment air preheater and is connected to the coal mill; The output end of the secondary fan is connected to the secondary air duct, and the secondary air duct passes through the four-compartment air preheater and is connected to the secondary air box; The output end of the burnout fan is connected to the burnout air duct, and the burnout air duct passes through the four-compartment air preheater and is connected to the burnout wind box.

2. According to claim 1, a tangential combustion boiler air supply system based on a four-compartment air preheater is characterized in that: The output port of the burnout wind box is provided with an adjustable air duct baffle door.

3. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 1 is characterized by: The output port of the burnout wind box is provided with an adjustable small air door.

4. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 1 is characterized by: The number of the burnout wind boxes is four and they are evenly distributed on the boiler.

5. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 1 is characterized by: The four-compartment air preheater is internally provided with a primary air compartment, a secondary air compartment, a burnout air compartment and a flue gas compartment. The primary air duct passes through the primary air compartment and is connected to the coal mill. The secondary air duct passes through the secondary air compartment and is connected to the secondary air box. The burnout air duct passes through the burnout air compartment and is connected to the burnout air box.

6. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 5 is characterized in that: The output end of the four-compartment air preheater is also provided with a smoke exhaust duct connected to the smoke compartment.

7. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 6 is characterized by: The output end of the smoke exhaust duct is connected to the induced draft fan.

8. The tangential combustion boiler air supply system based on the four-compartment air preheater according to claim 6 is characterized by: A dust collector is also provided on the smoke exhaust duct.

Images