A porous medium injection type flue gas heating low nitrogen burner

Abstract

The present invention relates to a porous medium ejection type flue gas heating low nitrogen burner, comprising an ejector body, a gas nozzle and a porous plate, the ejector body comprising an intake chamber, a mixing chamber and a pressure diffuser connected in sequence, the cross-sectional area of ​​the intake chamber gradually decreases, and the cross-sectional area of ​​the pressure diffuser gradually increases; the gas nozzle is installed in the intake chamber; the porous plate is installed in the pressure diffuser, the four sides of the porous plate are fixed to the inner wall of the pressure diffuser, and a metal fiber layer is laid on the side of the porous plate away from the mixing chamber; the present invention arranges a porous plate laid with a metal fiber layer in the pressure diffuser, utilizes the surface combustion technology of the porous medium, so that the temperature distribution in the combustion process is more uniform, and at the same time effectively reduces the thermal nitrogen oxides generated in the combustion process, so that the combustion is more low-nitrogen and environmentally friendly; in addition, the ejector body can be installed in the flue, and the flue gas to be heated is used to directly assist combustion, so as to effectively reduce the CO content in the flue gas.

Description

Technical Field

[0001] The invention relates to the technical field of induced-ejection burners, and in particular to a porous medium induced-ejection flue gas heating low-nitrogen burner. Background Art

[0002] The ejector is a fluid mixing device with no moving parts and only a simple nozzle and pipe. It is mainly used for the mutual mixing and momentum exchange of two fluids with different pressures. Its principle is to use the high-pressure fluid flowing through the nozzle to produce the Venturi effect, that is, after the working fluid passes through the nozzle, the pressure energy is converted into kinetic energy to form a high-speed jet, and the negative pressure in the suction chamber is generated to entrain the surrounding ejected fluid, and then mixed in the mixing chamber to form a single uniform mixed fluid, and finally the mixed fluid is decelerated and pressurized through the diffuser section so that it has a certain back pressure and is ejected.

[0003] With the increasing improvement of environmental protection standards, it is required to reduce NOx emissions to 30mg / Nm 3 For natural gas, a common fuel for industrial burners, the types of NOx generated by combustion are mainly rapid NOx and thermal NOx, of which thermal NOx accounts for more than 90% of total NOx emissions. Therefore, reducing thermal NOx generated during combustion has become the main research direction for achieving low-nitrogen combustion. Summary of the invention

[0004] Based on the above description, the present invention provides a porous medium injection type flue gas heating low-nitrogen burner, which arranges a porous plate provided with a metal fiber layer in the diffuser port and utilizes the surface combustion technology of the porous medium to make the temperature distribution in the combustion process more uniform, while effectively reducing the thermal nitrogen oxides generated in the combustion process, thereby making the combustion more low-nitrogen and environmentally friendly.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a porous medium injection type flue gas heating low-nitrogen burner, comprising an injector body, a gas nozzle and a porous plate, the injector body comprising an intake chamber, a mixing chamber and a diffuser; the outlet of the intake chamber is connected to the inlet of the mixing chamber, and the cross-sectional area of ​​the intake chamber gradually decreases from the inlet to the outlet; the outlet of the mixing chamber is connected to the inlet of the diffuser, and the cross-sectional area of ​​the diffuser gradually increases from the inlet to the outlet; the gas nozzle is installed in the intake chamber, for spraying high-pressure fuel gas into the injector body; the porous plate is installed in the diffuser, the four sides of the porous plate are fixed to the inner wall of the diffuser, and a metal fiber layer is laid on the side of the porous plate away from the mixing chamber.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the ejector body is installed in the flue, and the suction chamber, the mixing chamber and the diffuser port are arranged in sequence along the moving direction of the flue gas, so as to directly utilize the flue gas to be heated to assist combustion.

[0008] Furthermore, the center of the porous plate protrudes in a direction away from the mixing chamber, so that the porous plate is in a spherical crown shape.

[0009] Furthermore, a blunt body is provided at the center of one side of the porous plate close to the mixing chamber. The blunt body is conical, and the end of the blunt body is rounded and extends into the outlet end of the mixing chamber.

[0010] Furthermore, the porosity of the porous plate is 25% to 50%.

[0011] Furthermore, the pressure diffuser is provided with at least one hollow air ring, and the air rings are all arranged on a side of the porous plate away from the mixing chamber, and the air rings are arranged in sequence along the axial direction of the pressure diffuser.

[0012] Furthermore, the cross-sectional area of ​​the mixing chamber gradually decreases and then increases from the inlet to the outlet.

[0013] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0014] 1. The present invention arranges a porous plate with a metal fiber layer in the diffuser port, and utilizes the surface combustion technology of the porous medium to make the temperature distribution more uniform during the combustion process, and effectively reduce the thermal nitrogen oxides generated during the combustion process, thereby making the combustion more low-nitrogen and environmentally friendly;

[0015] 2. By using the flue gas to be heated to directly assist combustion, the CO content in the flue gas can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a porous medium injection type flue gas heating low nitrogen burner provided in an embodiment of the present invention;

[0017] Figure 2 for Figure 1 A partial enlarged schematic diagram of the middle A area;

[0018] Figure 3 This is the isotherm diagram of the combustion test when the porous plate is not laid with a metal fiber layer;

[0019] Figure 4 Isotherm diagram of the combustion test when laying a metal fiber layer on a porous plate;

[0020] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0021] 1. Ejector body; 11. Suction chamber; 12. Mixing chamber; 13. Diffuser; 14. Air ring; 2. Gas nozzle; 3. Perforated plate; 31. Metal fiber layer; 32. Blunt body; 4. Flue. DETAILED DESCRIPTION

[0022] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0024] It will be appreciated that spatial relationship terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It will be appreciated that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0025] A porous medium ejector type flue gas heating low nitrogen burner comprises an ejector body 1, a gas nozzle 2 and a porous plate 3. The ejector body 1 is installed in a flue 4, and the flue gas to be heated in the flue 4 is directly used for combustion, which not only saves the combustion cost, but also effectively reduces the CO content in the flue gas.

[0026] The ejector body 1 includes an inlet chamber 11, a mixing chamber 12 and a pressure diffuser 13, which are arranged in sequence along the flow direction of the smoke in the flue 4. The inlet of the inlet chamber 11 is connected to the outlet of the mixing chamber 12, and the outlet of the mixing chamber 12 is connected to the inlet of the pressure diffuser 13. The smoke enters the ejector body 1 from the inlet chamber 11 and is finally discharged from the pressure diffuser 13. In the direction from the inlet to the outlet, the cross-sectional area of ​​the inlet chamber 11 gradually decreases, the cross-sectional area of ​​the mixing chamber 12 first slowly decreases and then slowly increases, and the cross-sectional area of ​​the pressure diffuser 13 gradually increases.

[0027] The gas nozzle 2 is installed at the suction chamber 11 , extends into the suction chamber 11 along the axis of the suction chamber 11 , and sprays high-pressure gas into the ejector body 1 .

[0028] The porous plate 3 is installed in the pressure diffuser 13, and the edges of the porous plate 3 are fixed to the inner wall of the pressure diffuser 13. In this embodiment, the porosity of the porous plate 3 is 25% to 50%. The center of the porous plate 3 is raised in the direction away from the mixing chamber 12, so that the porous plate 3 is spherical, so that the smoke can be more evenly ejected from the pores of the porous plate 3. In addition, a blunt body 32 is provided at the center of one side of the porous plate 3 close to the mixing chamber. The blunt body 32 is conical, and the end of the blunt body 32 is rounded and extends into the outlet end of the mixing chamber 12.

[0029] A metal fiber layer 13 is also laid on the side of the porous plate 3 away from the mixing chamber 12 .

[0030] In this embodiment, the high-pressure gas sprayed from the gas nozzle 2 is used as the induced gas to draw the smoke in the flue 4 into the suction chamber 11. The high-pressure gas and the smoke enter the mixing chamber 12 and are mixed and accelerated, further drawing the smoke in the flue 4. Afterwards, the mixed gas of the high-pressure gas and the smoke passes through the bluff body 32 and is accelerated for a second time, and finally passes through the pores of the porous plate 3 and is ignited.

[0031] Preferably, at least one hollow air ring 14 is provided on the diffuser 13 , and the air rings 14 are all arranged on the side of the porous plate 3 away from the mixing chamber 12 , and the air rings 14 are arranged in sequence along the axial direction of the diffuser 13 to achieve secondary suction of the flue gas in the flue 4 .

[0032] Figure 3 This is the isotherm diagram of the combustion test when the porous plate is not laid with a metal fiber layer. Figure 4 Isotherm diagram of combustion test when metal fiber layer is laid on porous plate. It can be seen from the figure that after laying metal fiber, due to its porous medium characteristics, the gas will be evenly distributed on the surface of the material, the high temperature area of ​​combustion will be more dispersed, the maximum temperature will be lower, thus reducing the generation of thermal nitrogen oxides. In addition, the flame is relatively shorter and the flame rigidity is stronger. The combustion state is more stable during the combustion process and is not easy to extinguish.

[0033] Therefore, the present invention arranges a porous plate 3 with a metal fiber layer in the pressure diffuser 13, and utilizes the surface combustion technology of the porous medium to make the temperature distribution during the combustion process more uniform, and effectively reduce the thermal nitrogen oxides generated during the combustion process, thereby making the combustion more low-nitrogen and environmentally friendly. In addition, by directly using the flue gas to be heated to support combustion, not only can the cost of supporting combustion be saved, but also the content of CO in the flue gas can be effectively reduced.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A porous medium induced flue gas heating low nitrogen burner, characterized in that: The invention comprises an ejector body (1), a gas nozzle (2) and a porous plate (3), wherein the ejector body (1) comprises a suction chamber (11), a mixing chamber (12) and a diffuser (13); the outlet of the suction chamber (11) is connected to the inlet of the mixing chamber (12), and the cross-sectional area of ​​the suction chamber (11) gradually decreases from the inlet to the outlet; the outlet of the mixing chamber (12) is connected to the inlet of the diffuser (13), and the cross-sectional area of ​​the diffuser (13) gradually increases from the inlet to the outlet; the gas nozzle (2) is installed in the suction chamber (11) and is used to inject high-pressure gas into the ejector body (1); the porous plate (3) is installed in the diffuser (13), the four sides of the porous plate (3) are fixed to the inner wall of the diffuser (13), and a metal fiber layer (31) is laid on the side of the porous plate (3) away from the mixing chamber (12); The ejector body (1) is installed in a flue (4); the suction chamber (11), the mixing chamber (12) and the diffuser (13) are arranged in sequence along the moving direction of the flue gas, and are used to directly utilize the flue gas to be heated to assist combustion; the diffuser (13) is provided with at least one hollow air ring (14); the air rings (14) are all arranged on a side of the porous plate (3) away from the mixing chamber (12), and the air rings (14) are arranged in sequence along the axial direction of the diffuser (13).

2. The porous medium injection type flue gas heating low nitrogen burner according to claim 1 is characterized in that: The center of the porous plate (3) protrudes in a direction away from the mixing chamber (12), so that the porous plate (3) is in the shape of a spherical crown.

3. The porous medium injection type flue gas heating low nitrogen burner according to claim 1 is characterized in that: A blunt body (32) is provided at the center of one side of the porous plate (3) close to the mixing chamber (12); the blunt body (32) is conical, and the end of the blunt body (32) is rounded and extends into the outlet end of the mixing chamber (12).

4. The porous medium injection type flue gas heating low nitrogen burner according to claim 1 is characterized in that: The porosity of the porous plate (3) is 25% to 50%.

5. The porous medium injection type flue gas heating low nitrogen burner according to claim 1 is characterized in that: The cross-sectional area of ​​the mixing chamber (12) gradually decreases and then gradually increases from the inlet to the outlet.

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