Secondary air nozzle structure for garbage incinerator

Abstract

The secondary air nozzle structure comprises a nozzle body, concave surfaces are arranged on the upper side and the lower side of one end of the nozzle body respectively, convex surfaces are arranged on the left side and the right side of one end of the nozzle body respectively, and the two concave surfaces are connected with the two convex surfaces respectively to form a bow tie type nozzle. The axial penetrating power and the transverse divergence angle range of secondary air can be increased, the secondary air can be fully mixed with flue gas in the channel, and therefore combustible pollutants can be better burnt out, and the temperature in the furnace can be controlled to be evenly distributed. Meanwhile, the bow tie type nozzle structure not only ensures the transverse diffusion range, but also compresses and accelerates secondary air through a concave gradually-shrinking structure to ensure sufficient outlet air speed, so that the bow tie type nozzle structure has higher momentum to sufficiently disturb the interior of an incineration hearth, and CO emission is effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of nozzles for waste incinerators, and in particular to a secondary air nozzle structure for a waste incinerator. Background Art

[0002] At present, with the rapid advancement of urbanization, the living standards of residents are constantly improving, and the amount of urban and rural domestic waste has increased significantly. Waste incineration technology has become the inevitable development direction for China to deal with domestic waste. But inevitably, waste incineration is also accompanied by the generation of air pollutants, which brings environmental pollution. In the context of environmental governance, ultra-low emissions of air pollutants are an inevitable trend, which poses a higher challenge to the waste incineration industry.

[0003] The function of the secondary air system of a garbage incinerator is to enhance the mixing disturbance in the incinerator through secondary air, provide appropriate oxygen, improve the combustion conditions in the furnace, achieve complete combustion of combustibles such as CO, and control the residence time of dioxin decomposition, thereby meeting the emission requirements of pollutants such as CO and dioxins in the back-end flue gas.

[0004] In the relevant technology, one of the keys to realize the effect of secondary air is the secondary air nozzle. The secondary air is sent to the secondary air duct through the fan, and then sent into the furnace through the secondary air nozzle to fully mix and disturb the flue gas to achieve complete combustion. The secondary air nozzle has different structures, sizes and materials due to different incinerator design capabilities and working conditions. The performance of this type of secondary air nozzle is intended to achieve low investment and low operating costs under conditions with low secondary air input, while meeting relevant flue gas emission indicators (CO≤50mg / Nm 3 wait).

[0005] With respect to the above-mentioned related technologies, the inventors believe that: in the related technologies, the secondary air nozzles used in waste incinerators mostly use cylindrical and conical nozzle forms. Although this nozzle form has higher penetration performance when the secondary air volume is high, it can have better disturbance and mixing effect and effectively reduce CO emissions; but under the condition of low secondary air input, due to structural performance limitations, the air jet lacks penetration strength, and has poor diffusion performance on the lateral surface of a flue, which easily forms an insufficiently mixed area, and does not meet the requirements of sufficient mixing in the "3T+E" process of waste incineration. The combustibles and harmful substances in the flue gas, such as CO and dioxins, cannot be completely burned and decomposed. Utility Model Content

[0006] The purpose of the present application is to provide a secondary air nozzle structure for a waste incinerator, so as to solve the problem that the secondary air nozzles used in waste incinerators in the related art mostly use cylindrical and conical nozzle forms. Although this nozzle form has high penetration performance when the secondary air volume is high, it can have a good disturbance mixing effect and effectively reduce the CO emission value; but under the condition of low secondary air input, due to the limitation of structural performance, the air jet lacks penetration strength, and has poor diffusion performance on the lateral surface of a flue, which easily forms an insufficiently mixed area, does not meet the requirements of sufficient mixing in the "3T+E" process of waste incineration, and the combustibles and harmful substances in the flue gas, such as CO and dioxins, cannot be completely burned and decomposed.

[0007] The secondary air nozzle structure for a waste incinerator provided in this application adopts the following technical solution:

[0008] A secondary air nozzle structure for a waste incinerator comprises a nozzle body, wherein the upper and lower sides of one end of the nozzle body are both provided with concave surfaces, the left and right sides of one end of the nozzle body are both provided with convex surfaces, and the two concave surfaces are respectively connected to the two convex surfaces to form a bowtie-type nozzle.

[0009] Furthermore, one side of the two convex surfaces is an arc-shaped structure that bulges outwards.

[0010] Furthermore, one side of the two concave surfaces is an arc-shaped structure that tapers inwards.

[0011] Furthermore, the arc angles of the two concave surfaces are both 90°.

[0012] Furthermore, the angles between the arc edges of the two concave surfaces and the central axis of the nozzle body are both 9°.

[0013] Furthermore, the radii of the two convex surfaces are the same as the radius of the nozzle body, and the length of the nozzle body is 70 / 11 times the radius of the nozzle body.

[0014] Furthermore, the vertical distance between the upper and lower endpoints of the arc edges of the two convex surfaces is 14 / 11 times the radius of the nozzle body.

[0015] Furthermore, the arc center distance between the two concave surfaces is 7 / 11 times the radius of the nozzle body, and the arc diameters of the two concave surfaces are both 1.1 times the radius of the nozzle body.

[0016] Compared with the prior art, the beneficial effect of the present application lies in that: by setting a nozzle body, a concave surface and a convex surface connected to each other to form a bowtie nozzle, compared with other nozzle structures (such as circular, conical, etc.), the axial penetration force and the lateral diffusion angle range of the secondary air can be increased, so that it can be fully mixed with the channel flue gas, thereby helping to achieve better combustion of combustible pollutants and control the uniform distribution of temperature in the furnace.

[0017] At the same time, the bow-tie nozzle structure not only ensures the lateral diffusion range, but also compresses and accelerates the secondary air through the concave tapered structure, ensuring sufficient outlet wind speed, so that it has a high momentum to fully disturb the incineration furnace and effectively reduce CO emissions.

[0018] In addition, the bowtie nozzle structure of the present application can be flexibly designed according to the different sizes of the secondary air system air ducts, and has the advantages of simple structure and easy processing; it can be designed and used in new projects, or the bowtie nozzle can be nested and installed based on the original air ducts (round tubes) of the secondary air system of existing projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a secondary air nozzle structure used in a waste incinerator according to an embodiment of the present application.

[0020] Figure 2 It is a structural schematic diagram of the characteristic description of the concave surface and the convex surface of the embodiment of the present application.

[0021] Figure 3 It is a structural schematic diagram describing the characteristics of the secondary air nozzle structure of an embodiment of the present application.

[0022] Figure 4 It is a structural schematic diagram of a velocity cloud diagram of a bowtie nozzle viewed from above under the simulated working conditions of an embodiment of the present application.

[0023] Figure 5 It is a structural schematic diagram of the velocity cloud diagram of the front view cross section of the bowtie nozzle under the simulation working conditions of the embodiment of the present application.

[0024] Figure 6 It is a structural schematic diagram of the velocity streamline diagram of the bowtie nozzle under the simulation working conditions of the embodiment of the present application.

[0025] Explanation of the accompanying drawings: 1. nozzle body; 2. concave surface; 3. convex surface; 4. tubular structure. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1-6 This application is described in further detail.

[0027] The present application embodiment discloses a secondary air nozzle structure for a waste incinerator, referring to Figure 1 In this embodiment, the secondary air nozzle structure includes a nozzle body 1, a concave surface 2 and a convex surface 3. One end of the nozzle body 1 is a circular tubular structure 4, one end of which is fixedly installed at the output end of the secondary air duct of the fan, and the nozzle body 1 is made of 1Cr 20 Ni 14 Si 12 It is made of material and can withstand high temperature environment. It has excellent anti-oxidation and anti-creep properties in high temperature environment, thereby increasing its service life.

[0028] There are two concave surfaces 2, which are respectively installed on the upper and lower sides of one end of the nozzle body 1 away from the circular tubular structure 4, and one side of the two concave surfaces 2 is an arc-shaped structure that gradually shrinks inward; at the same time, the arc angles of the two concave surfaces 2 are both 90°, and the angles between the arc edges of the two concave surfaces 2 and the central axis of the nozzle body 1 are both 9°.

[0029] In addition, two convex surfaces 3 are provided, and the two convex surfaces 3 are respectively installed on the left and right sides of one end of the nozzle body 1 away from the circular tubular structure 4, and one side of the two convex surfaces 3 is an arc-shaped structure that bulges outwards.

[0030] In this way, the two concave surfaces 2 are respectively connected to the two convex surfaces 3 to form a bowtie nozzle, which is located at the end of the nozzle body 1 away from the circular tubular structure 4. By arranging the bowtie nozzle at one end of the nozzle body 1, compared with other nozzle structures (such as circular, conical, etc.), the axial penetration force and lateral diffusion angle range of the secondary air can be increased, so that it can be fully mixed with the channel flue gas, thereby helping to achieve better combustion of combustible pollutants and control the uniform distribution of temperature in the furnace.

[0031] At the same time, the bow-tie nozzle structure not only ensures the lateral diffusion range, but also compresses and accelerates the secondary air through the concave tapered structure, ensuring sufficient outlet wind speed, so that it has a high momentum to fully disturb the incineration furnace and effectively reduce CO emissions.

[0032] In addition, the bowtie nozzle structure of the present application can also be flexibly designed according to the different sizes of the secondary air system air ducts, and has the advantages of simple structure and easy processing; it can be designed and used in new projects, or the bowtie nozzle can be nested and installed based on the original air ducts (round tubes) of the secondary air system of existing projects.

[0033] The following is a detailed description of the characteristics of the secondary air nozzle structure:

[0034] Reference Figure 1In this embodiment, the radius of the two convex surfaces 3 is the same as the radius of the nozzle body 1; and the length of the nozzle body 1 is 70 / 11 times the radius of the nozzle body 1.

[0035] At the same time, the vertical distance between the upper and lower endpoints of the arc edge of the two convex surfaces 3 is 14 / 11 times the radius of the nozzle body 1. The arc center distance between the two concave surfaces 2 is 7 / 11 times the radius of the nozzle body 1, and the arc diameters of the two concave surfaces 2 are both 1.1 times the radius of the nozzle body 1.

[0036] Specifically, refer to Figure 2 and Figure 3 As shown:

[0037] The radius of the convex surface 3 and the radius of the nozzle body 1 are both R1;

[0038] The arc diameter of concave surface 2 is R2, and R2 = 1.1R1;

[0039] The arc center distance between the concave surfaces 2 is L1, and L1 = 7 / 11R1;

[0040] The vertical distance between the upper and lower endpoints of the arc edge of the convex surface 3 is L2, and L2 = 14 / 11R1;

[0041] The length of the nozzle body 1 is L3, and L3 = 70 / 11R1;

[0042] The arc angle of the concave surface 2 is A1, and A1 = 90°;

[0043] The angle between the arc edge of the concave surface 2 and the central axis of the nozzle body 1 is A2, and A2 = 9°.

[0044] Therefore, by making full use of the fully mixed disturbance of the secondary air, the combustion efficiency of the unburned components in the flue gas, such as CO, can be improved, thereby significantly reducing the CO emission value of the flue gas, and then effectively reducing it to 10mg / Nm 3 The following can meet environmental protection needs.

[0045] At the same time, the flue gas in the furnace is mixed and entrained through the diffused secondary air jet, making the flue gas flow more uniform, and the gas distribution and temperature field in the furnace more uniform, thereby improving the boiler's heat absorption efficiency and boiler performance, and effectively reducing the coking in the furnace caused by uneven burning of the furnace.

[0046] The secondary air nozzle structure is simulated and tested for verification below.

[0047] Test verification: The secondary air nozzle structure has been put into use in actual projects. Test results show that under the same secondary air flow rate, its secondary air pressure is about twice that of other equal-diameter circular nozzles.

[0048] Simulation: Reference Figure 4 , Figure 5 as well as Figure 6 Through the fluent simulation analysis of the flow field and component field of a waste incinerator with a processing capacity of 750t / d in a certain plant, it can be seen from the velocity cloud map and streamline distribution map that the secondary air volume is 18000m 3 / h, and wind temperature of 30℃, the secondary air medium passes from the air duct through the bowtie nozzle structure with the upper and lower concave surfaces 2 gradually shrinking, the bowtie nozzle speed reaches 45m / s, and the lateral diffusion range is increased by 150%, which can better achieve full mixing of the secondary air and the flue gas, thereby effectively reducing the CO concentration and dioxins.

[0049] At the same time, the injection length of its bowtie nozzle can fully cover the entire furnace width and form a better wind curtain, thereby effectively reducing the amount of fly ash, further alleviating the ash accumulation problem of the heat exchange tube bundle on the rear end heating surface of the boiler, and thus improving the thermal efficiency of the boiler.

[0050] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A secondary air nozzle structure for a waste incinerator, characterized in that: The nozzle body (1) comprises a nozzle main body (1), wherein the upper and lower sides of one end of the nozzle main body (1) are both provided with concave surfaces (2), and the left and right sides of one end of the nozzle main body (1) are both provided with convex surfaces (3), and the two concave surfaces (2) are respectively connected to the two convex surfaces (3) to form a bow tie nozzle.

2. The secondary air nozzle structure for a waste incinerator according to claim 1, characterized in that: One side of the two convex surfaces (3) is an arc-shaped structure that bulges outwards.

3. The secondary air nozzle structure for a waste incinerator according to claim 1, characterized in that: One side of the two concave surfaces (2) is an arc-shaped structure that gradually shrinks inwards.

4. The secondary air nozzle structure for a waste incinerator according to claim 3 is characterized in that: The arc angles of the two concave surfaces (2) are both 90°.

5. The secondary air nozzle structure for a waste incinerator according to claim 3 is characterized in that: The angles between the arc edges of the two concave surfaces (2) and the central axis of the nozzle body (1) are both 9°.

6. The secondary air nozzle structure for a waste incinerator according to claim 1, characterized in that: The radii of the two convex surfaces (3) are the same as the radius of the nozzle body (1), and the length of the nozzle body (1) is 70 / 11 times the radius of the nozzle body (1).

7. The secondary air nozzle structure for a waste incinerator according to claim 6, characterized in that: The vertical distance between the upper and lower end points of the arc edges of the two convex surfaces (3) is 14 / 11 times the radius of the nozzle body (1).

8. The secondary air nozzle structure for a waste incinerator according to claim 6, characterized in that: The arc center distance between the two concave surfaces (2) is 7 / 11 times the radius of the nozzle body (1), and the arc diameters of the two concave surfaces (2) are both 1.1 times the radius of the nozzle body (1).

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