CN201106847Y - Burner device for cement kiln - Google Patents

Abstract

The utility model discloses a burner (1) used for cement kilns having a plurality of flow routes which are separated into a plurality of concentric-circle barrel-shaped components. The burner comprises a solid powder fuel flow route (2) used for arranging a revolving device (2a) of the solid powder fuel flow, a fist air flow route (3), adjacent to the solid powder fuel flow route, arranged outside and filled with an air-flow revolving mechanism (3a), a second air flow route (4) adjacent to the solid powder fuel flow route and arranged outside, a third air flow route (5) adjacent to the solid powder fuel flow route and arranged inside and filled with an air-flow revolving mechanism (5a). The revolving angle of the solid powder fuel flow at the front end of the solid powder fuel flow route is less than half of revolving angles of all air flows at the front ends of the first air flow route and the second air flow route. The revolving angle of the solid powder fuel flow can be ranged from 3 degrees to 15 degrees, and the revolving angles of the first air flow and the second air flow can be ranged from 30 degrees to 50 degrees, so that the plurality of control factors of the burner can be optimized in the cement kiln in a short time.

Description

Burner device for cement kiln

technical field

The utility model relates to a cement kiln burner device which takes solid fuel such as pulverized coal as the main fuel, strengthens the adjustment function of the flame, improves the change of the fuel type and the adaptability of the furnace to the operating environment.

Background technique

Conventionally, in a kiln for cement sintering (hereinafter referred to as "cement kiln"), a burner device in which a fuel flow path and an air flow path are concentrically arranged is used to distribute the air volume and Rotate the strength to adjust the combustion state in the cement kiln.

For example, the pulverized coal burner device described in Patent Document 1 is equipped with a plurality of concentric flow paths for the purpose of improving the flame holding function and suppressing the generation of nitrogen oxides. The coal flow path and the inner and outer air flow paths adjacent to the pulverized coal flow path are equipped with a mechanism for rotating the air flow in the inner air flow path.

On the other hand, Patent Document 2 discloses a burner device for a rotary kiln, the purpose of which is to reduce the amount of primary air and expand the adjustment range of the flame, thereby contributing to energy saving and suppressing the generation of nitrogen oxides. Equipped with a plurality of flow paths in a circular shape, and equipped with: a first air flow path arranged outside adjacent to the flow path for solid powder fuel, equipped with a rotating device for air flow, adjacent to the first air flow path The second air flow path arranged on the outside and the third air flow path arranged on the inside are adjacent to the flow path for solid powder fuel.

However, even with the above-mentioned conventional burner device for cement kiln (hereinafter referred to as "burner device" as appropriate), it is difficult to use various fuels, ensure the quality of various clinkers, and reduce the nitrogen oxides produced. , it is difficult to obtain a burner device that can perform satisfactorily.

Therefore, the present applicant has developed a burner device capable of reducing the amount of nitrogen oxides produced while maintaining the quality of fired clinker, and obtained a patent on the device (see Patent Document 3). As shown in FIG. 1 and FIG. 2, the burner device 1 includes: a solid powder fuel flow path 2 equipped with a solid powder fuel rotating blade 2a, which is arranged on the outside adjacent to the solid powder fuel flow path 2, and is equipped with The first air flow path 3 of the rotating blade 3a of the air flow, the second air flow path 4 arranged on the outside adjacent to the first air flow path 3, is arranged on the inside adjacent to the flow path 2 for solid powder fuel, and is equipped with The third air flow path 5 of the rotating blade 5a of the air flow.

By using this burner device 1, the combustibility of the solid powder fuel can be improved, and the amount of nitrogen oxides produced can be reduced without deteriorating the quality of the clinker fired in the rotary kiln. The amount of air is changed independently, thereby making it easy to perform adjustments for obtaining an optimum flame according to the type of solid powder fuel used and the like.

[Patent Document 1]: Japanese Patent Publication No. 4-74603

[Patent Document 2]: European Patent No. 421903

[Patent Document 3]: Japanese Patent No. 3914448

As mentioned above, the burner device 1 described in Patent Document 3 is a four-pass burner device equipped with three air flow paths 3 to 5 in addition to the flow path 2 for solid powder fuel, which can be respectively Independently control the amount of air flowing in each of the flow paths 2 to 5, and since the rotating vane 2a of the solid powder fuel flow and the first air flow path 3 and the third air flow path 5 are also equipped with respective rotating The blades 2a, 3a, and 5a can also adjust the rotation angle of these rotating blades, and there are many control elements. Therefore, the above effects can be fully enjoyed as long as the control elements can be optimized according to the type of solid powder fuel used, etc., but it may take a long time to achieve the optimization.

When the above-mentioned control elements are optimized, a certain degree of information can be obtained by simulation, but in the end, it is necessary to confirm the shape of the burner flame, the amount of NOx generation, etc. in the operation of the cement kiln in the atmosphere of the actual cement kiln. Conditions, the quality of the fired clinker, etc. to judge whether the optimization is achieved.

Contents of the invention

Therefore, the inventors of the present invention found the basic limited area for optimizing the control elements of the burner device for a cement kiln described in Patent Document 3 based on the above-mentioned simulation results, the verification results of the actual machine, and the like. In a cement kiln, control elements are optimized in a short time.

In order to achieve the above object, the utility model is equipped with a burner device for a cement kiln equipped with a plurality of flow paths divided into a plurality of concentric cylindrical parts, and is characterized in that it is equipped with a solid powder fuel flow rotation mechanism. The flow path for powdered fuel is arranged on the outside adjacent to the flow path for solid powder fuel, the first air flow path equipped with the rotation mechanism of the air flow, and the second air flow path is arranged on the outside adjacent to the first air flow path. A flow path, and a third air flow path equipped with an air flow rotation mechanism arranged on the inner side adjacent to the flow path for solid powder fuel; the rotation of the flow of solid powder fuel at the front end of the flow path for solid powder fuel The angle is one-half or less of the rotation angle of the air flow at the tip of the first air flow path and the rotation angle of the air flow at the tip of the second air flow path.

Moreover, according to the present invention, since the rotation angle of the solid powder fuel flow ejected from the solid powder fuel flow path is set to the rotation angle of the air flow ejected from the first air flow path and the second air flow path Therefore, the solid powder fuel and the primary air injected from each flow path can be fully mixed, and at the same time, the flame shape can be easily controlled while keeping the firing zone at a high temperature, and NOx generation The amount can also be kept very low.

In the burner device for a cement kiln, the rotation angle of the solid powder fuel flow at the front end of the solid powder fuel flow path may be set to 3° or more and 15° or less.

In addition, in the burner device for a cement kiln, the rotation angle of the air flow at the tip of the first air flow path and the second air flow path may be set to 30° or more and 50° or less.

Furthermore, in the burner device for a cement kiln, a flow path for combustible waste may be provided inside the third air flow path.

As described above, according to the present invention, by providing a basic limited area for optimizing the control elements of the burner device for a cement kiln, the control elements can be optimized in a short time in each cement kiln.

Description of drawings

Fig. 1 is a front view showing an example of the conventional art and the burner device of the present invention.

Fig. 2 is a longitudinal sectional view of the burner device in Fig. 1 (in order to clarify the cross-sectional structure, the thickness of the burner parts and the refractories drawn in Fig. 1 are omitted).

Fig. 3 is a flowchart showing an example of a combustion system including the burner device in Fig. 1 .

Fig. 4 is a schematic diagram for explaining the rotation angle of the rotary blades of the burner device.

Fig. 5 is a flowchart showing another example of a combustion system including the burner device in Fig. 1 .

Explanation of reference signs

1 Burner device for cement kiln

2 flow path for solid powder fuel

2a Rotating blades

3 The first air flow path

3a Rotating blades

4 Second air flow path

5 third air flow path

5a Rotating blades

6 oiler

7 Flow path for combustible waste

8 cylindrical parts

9 Axial direction (of burner unit 1)

10 (of the rotating blade 2a) center line

11 Combustion system

12～14 fans

15 Pulverized coal delivery piping

16～19 Air piping

22 baffle

23 baffle

31 Combustion system

32 Combustion Flow Roots Blower

33 primary air fan

34 Pulverized coal delivery piping

35～38 Air piping

39～42 baffles

Detailed ways

Hereinafter, embodiments of the present utility model will be described with reference to the accompanying drawings.

As mentioned above, the utility model has found the basic limited area for optimizing the control elements of the cement kiln burner device shown in Fig. 1 and Fig. 2. The composition of the combustion system 11 of the burner device 1 shown in FIG. 3 and the burner device 1 shown in FIG. 3 .

This burner device 1 is equipped with a plurality of flow paths concentrically, and is equipped with a total of four flow paths, that is, the flow path 2 for solid powder fuel, and the first air flow path arranged outside adjacent to the flow path 2 for solid powder fuel. The flow path 3 , the second air flow path 4 arranged outside adjacent to the first air flow path 3 , and the third air flow path 5 arranged inside adjacent to the flow path 2 for solid powder fuel. In addition, an oiler 6 , a flow path 7 for combustible waste, and the like are arranged inside the third air flow path 5 . Among the four flow paths 2 to 5 , the flow path 2 for solid powder fuel, the first air flow path 3 , and the third air flow path 5 are respectively fixed with rotating blades 2 a , 3 a , and 5 a as rotation mechanisms.

FIG. 3 shows an example of a combustion system including the above-mentioned burner device 1 . The combustion system 11 is a system configured with emphasis on ease of control, and is equipped with three fans 12 to 14 , namely, first to third. The pulverized coal C supplied to the pulverized coal delivery pipe 15 is supplied to the flow path 2 for solid pulverized fuel by the first fan 12 . Air from the second fan 13 is supplied to the first air flow path 3 and the third air flow path 5 of the burner device 1 through the air pipes 16 , 17 , and 18 . Air from the third fan 14 is supplied to the second air passage 4 of the burner device 1 through the air pipe 19 .

In addition, since the damper 22 for controlling the air volume is provided in the air pipe 18 and the damper 23 is provided in the air pipe 17, the volume of air flowing in each of the passages 2 to 5 can be independently controlled. Accordingly, it is possible to easily perform adjustments to obtain the most suitable flame according to the types of solid powder fuels such as pulverized coal, petroleum coke, and other alternative fuels, and the operating environments of various furnaces. In addition, it is also possible to supply heavy oil or the like from the oiler 6 and use it when the burner device 1 is ignited, or to co-combust pulverized coal, heavy oil and other liquid fuels during normal operation, and to supply oil sludge from the flow path 7 for combustible waste. , waste plastics, meat and bone meal, etc.

As described above, the burner device 1 is a four-pass type burner device 1 equipped with three air flow channels 3 to 5 other than the flow channel 2 for solid powder fuel, and is configured so that when the burner device 1 is used, Three fans 12-14 are running, and the two baffles 22, 23 are controlled to control the amount of air flowing in each flow path 2-5. On this basis, before using the burner device 1, the solid powder can also be adjusted There are various control elements for the rotation angles of the rotary blades 2a, 3a, and 5a of the fuel flow path 2, the first air flow path 3, and the third air flow path 5.

Therefore, the inventors of the present invention analyzed the NOx production amount, the flame shape, the temperature distribution in the cement kiln, etc. based on the combustion simulation of the burner device 1, and analyzed the burner flame shape in the actual machine. The observation of the cement kiln when using the burner device 1 (NOx, O ₂ , CO concentration in the kiln tail, temperature of the kiln tail, etc.) The basic bounded area to optimize the control elements. Table 1 summarizes the basic limited areas found in this way into a list.

Table 1

Flow path number (Figure 1) Rotation angle (°) Front wind speed (m/s) Primary air ratio (%) fuel flow 2 3～15 30～60 3～6 spin outflow 3 30～50 60～80 1～3 Straight in and out 4 0 120～180 3～7 swirling internal flow 5 30～50 60～160 1～3

In this table, the rotation angles (°) of the rotary blades 2a, 3a, and 5a of the above-mentioned solid pulverized fuel flow path 2, the first air flow path 3, and the third air flow path 5, and the front ends are listed as basic limited areas. Wind speed (m/s), primary air ratio (%). Among them, the angle of rotation (°) is also a particularly important substantially defined region. One of the reasons is that the swirling flow generated by the swirling blades 2a, 3a, 5a forms an internal circulation having the stability of ignition of the burner device 1 and the flame holding function. Another reason is that since the rotating blades 2a, 3a, 5a are usually fixed on the burner device 1, adjustments cannot be made during the use of the burner device 1. Although the rotation angles of the rotating blades 2a, 3a, 5a can also be configured to be variable, there is a problem in the reliability of mechanical operation parts because the rotating blades 2a, 3a, 5a are exposed to high temperatures. In addition, the above-mentioned rotation angle refers to the axial direction 9 of the burner device 1 when the cylindrical member 8 shown in FIG. The angle θ formed by the center lines 10 of the rotating blades 2 a corresponds to the rotation angle of the solid powder fuel flow F at the front end 2 b of the solid powder fuel flow path 2 .

The rotation angle of the rotary blade 2a of the flow path 2 for solid powder fuel is set to 3° or more and 15° or less. When the rotation angle is less than 3°, the mixing of the solid powder fuel injected from the flow channel 2 for the solid powder fuel and the primary air injected from the flow channel 2 for the solid powder fuel and the air channels 3 to 5 is insufficient. If sufficient, the flame formed by the burner device 1 becomes weak and tends to become a long flame, which is not preferable. Since the clinker of ordinary Portland cement needs to keep the burning zone at a high temperature in order to generate tricalcium silicate (C ₃ S), the rotation angle of less than 3° is not suitable. In addition, when firing clinker with a low firing temperature composition, it is also an ideal situation to make the fuel flow straight (the rotation angle is 0°).

On the other hand, when the rotation angle of the rotating vane 2a exceeds 15°, due to the presence of the solid powder fuel sprayed from the solid powder fuel flow path 2 and the solid powder fuel flow path 2 and from the first air flow path 3 to 5. The mixing of the injected primary air is too intense, and the flame tends to diverge excessively. Therefore, even if the air flow rate of the internal and external flows cannot be controlled, the flame shape is not suitable.

In addition, the rotation angles of the rotating blades 3a, 5a of the air passages 3, 5 are set to be not less than 30° and not more than 50°. When these rotation angles are less than 30°, the mixing of the solid powder fuel injected from the flow channel 2 for solid powder fuel and the air streams injected from the air flow channels 3 and 5 is insufficient, and the low NOx performance cannot be exhibited. Therefore it is not suitable. On the other hand, when the rotation angle of the rotating blades 3a, 5a exceeds 50°, it is not suitable because the controllability of the flame shape deteriorates as in the case of the flow path 2 for solid powder fuel.

Regarding the wind speed at the front end of flow paths 2 to 5, the high-temperature secondary air from the clinker cooler is taken in by the high-speed straight flow from the second air flow path 4, in order to ensure combustion promotion and internal circulation of volatile components It is important to increase the temperature and ensure the generation of Volatile NOx. The main combustion performance is important, and when the high speed is set, the recirculation that takes the high-temperature combustion gas into the flame occurs, and the NOx circulation area is formed in the form of intersecting with the internal circulation. Since the combustion of Char is promoted by this recirculation, and Char NOx and Thermal NOx are produced, the wind speed at the front end of the second air flow path 4 is limited within the range shown in the table. In addition, the wind speed at the front end of the solid powder fuel flow path 2, the first air flow path 3, and the third air flow path 5 is limited for the reasons of ensuring the stability of the solid powder fuel combustion and the stability of the combustion flame shape. within the range shown in the table.

With regard to the primary air ratio of the air flowing in the flow paths 2 to 5, reducing the primary air supplied to the center of the flame formed by the burner device 1 as much as possible can stably generate reducing substances in the flame, and can continuously form a reducing region. , so it is ideal, but if the primary air volume is too low, since the combustion zone moves to the kiln tail side, there is a danger of causing the temperature behind the flame to rise, so it is limited within the range shown in the table. In addition, the primary air ratio of the air flowing in the solid powder fuel flow path 2 and the second air flow path 4 is lower than the primary air ratio of the air flowing in the first air flow path 3 and the third air flow path 5 It is high because the high-temperature secondary air is smoothly taken into the flame to rapidly increase the temperature of the fuel, thereby promoting the release of volatile components and the generation of reducing substances.

As described above, according to the present invention, before the burner device 1 is used, that is, when the burner device 1 is manufactured, the rotation of the solid powder fuel flow path 2, the first air flow path 3 and the third air flow path 5 The rotation angles of the blades 2a, 3a, 5a are set within the range shown in Table 1. When the burner device 1 is used, three fans 12-14 are operated to adjust the air volume, and then the two dampers 22, 23 are adjusted. The opening of the baffles is used to control the amount of air flowing in each flow path 2-5, thereby adjusting the front end wind speed and primary air ratio of each flow path 2-5 to the range shown in Table 1, so that it can be set up In the cement kiln equipped with the burner device 1, the control elements are optimized in a short time.

Next, another example of a combustion system including the above-mentioned burner device 1 will be described with reference to FIG. 5 .

While the combustion system 11 shown in FIG. 3 emphasizes ease of control, the combustion system 31, which is equipped with a fuel flow Roots blower 32 and a primary air fan 33, emphasizes reduction in equipment cost. The pulverized coal C supplied to the pulverized coal delivery pipe 34 is supplied to the solid pulverized fuel flow path 2 by the Roots blower 32 , and the air from the primary air fan 33 is supplied to the first stage of the burner device 1 via the air pipes 35 to 38 . The air flow path 3, the second air flow path 4, and the third air flow path 5 are supplied. Moreover, since the air piping 35 is provided with a baffle 39 for controlling the amount of air, the air piping 37 is provided with a baffle 40 , the air piping 38 is provided with a baffle 41 , and the air piping 36 is provided with a baffle 42, so the amount of air flowing in each flow path of flow paths 2 to 5 can be independently controlled. According to this structure, compared with the apparatus structure of FIG. 3, since there are one fewer windmills, equipment costs can be reduced.

In the combustion system 31 described above, the rotation angles of the rotary blades 2a, 3a, and 5a are determined based on the basic limited area for optimizing the control elements shown in Table 1, and the fuel flow Roots blower 32 and the primary air fan 33 are operated. To adjust the air volume, and then adjust the baffle openings of the four baffles 39-42 to control the air volume flowing in each flow path 2-5, thus, the front end wind speed of each flow path 2-5 and the primary air By adjusting the ratio to the range shown in Table 1, the control elements can be optimized in a short time in the cement kiln provided with the burner device 1 .

In addition, although illustration is omitted, it is also possible to configure such a structure that, between the solid powder fuel flow path 2 and the third air flow path 5 of the above-mentioned four-pass type burner device 1 (see FIGS. 1 and 2 ), In between, a fourth air flow path capable of independently adjusting the amount of air is further added, and by independently controlling the flow rate of the air flowing in the fourth air flow path, not only the outside of the flow path for solid powder fuel, but also the inside can also be Adjusting the rotation intensity without changing the overall air flow rate flowing in the third air flow passage 5 mainly in the rotation of the air flow and the fourth air flow passage mainly in the straight flow of the air flow makes it easier to perform the operation. To obtain the most suitable flame adjustment according to the type of solid powder fuel, etc. At this time, each control element can be optimized using the basic limited area shown in Table 1 except the front end air velocity and primary air ratio of the third air flow path 5 and the front end air velocity and primary air ratio of the fourth air flow path.

Claims (4)

1. A burner device for a cement kiln, which is equipped with a plurality of flow paths divided into a plurality of concentric cylindrical parts, characterized in that it has: Flow path for solid powder fuel equipped with a rotary mechanism for solid powder fuel flow, The first air flow path provided on the outer side adjacent to the flow path for solid powder fuel and equipped with a rotation mechanism for air flow, a second air flow path arranged outside adjacent to the first air flow path, and A third air flow path provided on the inner side adjacent to the flow path for solid powder fuel and equipped with a rotation mechanism for air flow; The rotation angle of the solid powder fuel flow at the tip of the solid powder fuel flow path is the rotation angle of the air flow at the tip of the first air flow path and the rotation angle of the air flow at the tip of the second air flow path. less than half of that. 2. The burner device for a cement kiln according to claim 1, wherein the rotation angle of the flow of the solid powder fuel at the front end of the flow path for solid powder fuel is not less than 3° and not more than 15°. 3. The burner device for a cement kiln according to claim 1, wherein the rotation angle of the air flow at the tip of the first air flow path and the second air flow path is 30° or more and 50° or less. . 4. The burner device for a cement kiln according to claim 1, 2 or 3, wherein a flow path for combustible waste is provided inside the third air flow path.

Images