Low air fuel ratio kiln burner

Abstract

The low air-fuel ratio kiln burner of the present application, the stable flame axial air jet generated by the stable flame axial air jet conveying port interacts with the radial gas jet generated by the radial gas jet conveying port, the jet velocity is slowed down and fully mixed with the gas for combustion, forming a flame stable structure with wider adaptability; the axial gas jet generated by the axial gas jet conveying port starts to contact the flame formed by the radial gas jet at a suitable position, and fully mixes the unburned gas with the already burned flame part before the outlet of the combustion chamber, realizing the full combustion of the residual oxygen in the flue gas in the furnace by the entraining capacity of the high-speed flame, thereby greatly widening the working range of the burner, allowing the burner to work normally within the air excess coefficient range of 0.4-1.5, maintaining a certain flame shape and rigidity, maintaining stable heat exchange capacity, fully utilizing the residual oxygen in the furnace, reducing energy consumption and harmful gas emission.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of burners, and particularly relates to a low air-fuel ratio kiln burner. BACKGROUND

[0002] During the operation of a ceramic tunnel kiln, due to the negative pressure caused by high-temperature heat absorption and conveying in the initial upstream high-temperature section, external air enters the kiln from the gap outside the tunnel kiln, so that the flue gas conveyed from the upstream high-temperature section to the preheating section contains a large amount of oxygen. Therefore, a combustion mode for reducing the oxygen content of flue gas is usually adopted in the combustion chamber of the preheating section to consume the excess oxygen in the flue gas and reduce the flue gas emission. At present, the kiln burners used in the kiln of the ceramic industry are mostly designed according to the normal air-fuel ratio (i.e., the air excess ratio adjustment ratio >= 1.0), specifically the ability to control the proportion of flue gas conveyed from the upstream high-temperature section and the amount of supplied fuel gas for combustion, but when the air excess ratio of the kiln is controlled to be much less than 1 (even less than 0.5) in actual operation, it will deviate from the design working range of the kiln burner and cannot work normally, resulting in flameout, flameout, reduced heat exchange capacity, and increased energy consumption. SUMMARY

[0003] The present application aims to overcome the problem that the existing kiln burner has a small range of ability to control the proportion of air and fuel gas for combustion and cannot achieve low air-fuel ratio adjustment, and to provide a low air-fuel ratio kiln burner capable of controlling low air-fuel ratio combustion.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] The low air-fuel ratio kiln burner comprises a burner body, the burner body comprising an igniter, a combustion-supporting gas delivery part and a fuel gas delivery part; the combustion-supporting gas delivery part is located at the peripheral part of the burner body and is provided with a plurality of circumferentially arranged stable flame axial air jet delivery ports; the fuel gas delivery part is located at the middle part of the burner body and extends outside the combustion-supporting gas delivery part, and is provided with a plurality of circumferentially arranged axial fuel gas jet delivery ports on the front side and a plurality of circumferentially arranged radial fuel gas jet delivery ports on the outer side; the plurality of axial fuel gas jet delivery ports are inclinedly arranged outward along the central axis direction of the fuel gas delivery part; and the plurality of radial fuel gas jet delivery ports and the plurality of stable flame axial air jet delivery ports are correspondingly arranged in the same radial direction.

[0006] Compared with the prior art, the low air-fuel ratio kiln burner of the present application has the following advantages: the stable flame axial air jet delivery ports are arranged in the combustion-supporting gas delivery part, the stable flame axial air jet generated by the stable flame axial air jet delivery ports and the radial gas jet generated by the radial gas jet delivery ports are alternately arranged, the jet velocity is slowed down and the gas is fully mixed and combusted, forming a flame stable structure with a wider range; the axial gas jet generated by the axial gas jet delivery ports starts to contact the flame formed by the radial gas jet at a suitable position, and fully mixes the unburned gas with the partially combusted flame before the outlet of the combustion chamber, thereby realizing the full combustion of the residual oxygen in the flue gas in the furnace by the entraining capacity of the high-speed flame, thereby greatly widening the working range of the burner, allowing the burner to work normally in the range of 0.4-1.5 of the air excess coefficient, maintaining a certain flame shape and rigidity, maintaining stable heat exchange capacity, fully utilizing the residual oxygen in the furnace, reducing energy consumption and harmful gas emission.

[0007] Further, the combustion-supporting gas delivery part is provided with a plurality of annularly arranged inclined air jet delivery ports inside the stable flame axial air jet delivery ports, the inclined air jet delivery ports are arranged obliquely to the outside, and the normal line of the inclined air jet delivery ports and the normal line of the radial gas jet delivery ports are arranged alternately; by such arrangement, the inclined air jet generated by the inclined air jet delivery ports and the radial gas jet generated by the radial gas jet delivery ports are arranged alternately, which generates a plurality of small vortex stable flame structures, and uses the entraining capacity to deliver the gas along the radial periphery, and the multiple, annular, outwardly extending jets form a larger central backflow area, improving the flame stability.

[0008] Further, the air and gas delivery ratio of the stable flame axial air jet delivery ports and the radial gas jet delivery ports is 0.8 to 1.2; by such arrangement, the radial gas jet generated by the radial gas jet delivery ports is kept stable and fully combusted under the designed air excess coefficient, which ensures stable flame and stable combustion of the burner in the low air-fuel ratio design range.

[0009] Further, the combustion-supporting gas delivery part is provided with a plurality of annularly arranged rotating air jet delivery ports outside the stable flame axial air jet delivery ports, and the plurality of rotating air jet delivery ports are arranged obliquely along one side of the circumferential direction; by such arrangement, the rotating air jet generated by the rotating air jet delivery ports strengthens the mixing of air and gas and promotes full combustion.

[0010] Further, the combustion-supporting gas delivery part is also provided with a plurality of annularly arranged peripheral axial air jet ports; the peripheral axial air jet ports are arranged in the same circumferential direction as the rotating air jet delivery ports, and one peripheral axial air jet port is arranged at a distance of at least one rotating air jet delivery port; through such arrangement, although the rotating air jet has the effect of strengthening the mixing of air and gas and promoting combustion, strong rotation flow is easy to cause hollow flame, which reduces the volumetric heat intensity of the combustion chamber and leads to poor flame stability; therefore, the axial air jet delivered by the axial air jet port in proper proportion can increase the turbulence degree, fill the hollow phenomenon caused by rotation flow, strengthen combustion, and increase the volumetric utilization rate of the combustion chamber.

[0011] Further, the combustion-supporting gas delivery part is also provided with a plurality of annularly arranged peripheral axial air jet ports; the peripheral axial air jet ports are arranged in the same circumferential direction as the rotating air jet delivery ports, and one peripheral axial air jet port is arranged at a distance of at least one rotating air jet delivery port; through such arrangement, although the rotating air jet has the effect of strengthening the mixing of air and gas and promoting combustion, strong rotation flow is easy to cause hollow flame, which reduces the volumetric heat intensity of the combustion chamber and leads to poor flame stability; therefore, the axial air jet delivered by the axial air jet port in proper proportion can increase the turbulence degree, fill the hollow phenomenon caused by rotation flow, strengthen combustion, and increase the volumetric utilization rate of the combustion chamber.

[0012] Further, the combustion-supporting gas delivery part is also provided with a plurality of annularly arranged peripheral axial air jet ports; the peripheral axial air jet ports are arranged in the same circumferential direction as the rotating air jet delivery ports, and one peripheral axial air jet port is arranged at a distance of at least one rotating air jet delivery port; through such arrangement, although the rotating air jet has the effect of strengthening the mixing of air and gas and promoting combustion, strong rotation flow is easy to cause hollow flame, which reduces the volumetric heat intensity of the combustion chamber and leads to poor flame stability; therefore, the axial air jet delivered by the axial air jet port in proper proportion can increase the turbulence degree, fill the hollow phenomenon caused by rotation flow, strengthen combustion, and increase the volumetric utilization rate of the combustion chamber.

[0013] Further, the combustion-supporting gas delivery part is also provided with a plurality of annularly arranged peripheral axial air jet ports; the peripheral axial air jet ports are arranged in the same circumferential direction as the rotating air jet delivery ports, and one peripheral axial air jet port is arranged at a distance of at least one rotating air jet delivery port; through such arrangement, although the rotating air jet has the effect of strengthening the mixing of air and gas and promoting combustion, strong rotation flow is easy to cause hollow flame, which reduces the volumetric heat intensity of the combustion chamber and leads to poor flame stability; therefore, the axial air jet delivered by the axial air jet port in proper proportion can increase the turbulence degree, fill the hollow phenomenon caused by rotation flow, strengthen combustion, and increase the volumetric utilization rate of the combustion chamber.

[0014] Further, the axial gas jet generated by the plurality of axial gas jet delivery ports accounts for 25-75% of the total gas amount; the radial gas jet generated by the plurality of radial gas jet delivery ports accounts for 25-75% of the total gas amount.

[0015] Further, the ratio of the flow rate of the axial gas jet generated by the axial gas jet delivery port to the flow rate of the radial gas jet generated by the radial gas jet delivery port is 65:35; the number of the axial gas jet delivery ports is 6-24, and the number of the radial gas jet delivery ports is 6-24.

[0016] Further, the opening angle of the axial gas jet delivery port with respect to the axis of the combustion-supporting gas delivery part is [5, 45] degrees.

[0017] Further, the opening angle of the inclined air jet delivery port with respect to the axis of the combustion-supporting gas delivery part is [0, 30] degrees.

[0018] Further, the ratio of the diameter of the stable flame axial air jet delivery port to the diameter of the inclined air jet delivery port is 1:9-1:1.

[0019] Further, the ratio of the flow rate of the stable flame axial air jet generated by the stable flame axial air jet delivery port to the flow rate of the rotating air jet generated by the rotating air jet delivery port is 1:1-1:10. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a lateral sectional view of the low air-fuel ratio kiln burner

[0021] Figure 2 is a front view of the low air-fuel ratio kiln burner

[0022] Figure 3 is a lateral sectional view of the low air-fuel ratio kiln burner Figure 2 is a sectional view along H-H

[0023] Figure 4 is a schematic view of the low air-fuel ratio kiln burner in the combustion chamber

[0024] Figure 5 is a graph of the change in the air excess coefficient of the low air-fuel ratio kiln burner with an increase in the combustion gas delivery amount

[0025] Figure 6 is a graph of the change in the combustion gas pressure of the low air-fuel ratio kiln burner with an increase in the flow rate

[0026] Figure 7 is a graph of the change in the air pressure of the low air-fuel ratio kiln burner with an increase in the flow rate DETAILED DESCRIPTION

[0027] The technical solutions of the present application are described below in conjunction with the drawings:

[0028] Reference is made to Figure 1 After that Figure 7The low air-fuel ratio kiln burner of the present application comprises a burner body 1, the burner body 1 comprising an igniter 2, a combustion-supporting gas delivery part 3 and a gas delivery part 4; the combustion-supporting gas delivery part 3 is located at the peripheral part of the burner body 1 and is provided with a plurality of annularly arranged stable flame axial air jet delivery ports 31; the gas delivery part 4 is located at the middle part of the burner body 1 and extends out of the combustion-supporting gas delivery part 3, and is provided with a plurality of annularly arranged axial gas jet delivery ports 41 at the front side and a plurality of circumferentially arranged radial gas jet delivery ports 42 at the outer side, the plurality of axial gas jet delivery ports 41 are inclinedly arranged outward along the central axis direction of the gas delivery part 4, and the plurality of radial gas jet delivery ports 42 are arranged in the same radial direction corresponding to the plurality of stable flame axial air jet delivery ports 31, and the air and gas delivery ratio of the stable flame axial air jet delivery ports 31 and the radial gas jet delivery ports 42 is 0.8 to 1.2.

[0029] Compared with the prior art, the low air-fuel ratio kiln burner of the present application, by arranging a plurality of annularly arranged stable flame axial air jet delivery ports 31 in the combustion-supporting gas delivery part 3 and a plurality of annularly arranged axial gas jet delivery ports 41 and radial gas jet delivery ports 42 in the gas delivery part 4, the stable flame axial air jet generated by the stable flame axial air jet delivery ports 31 and the radial gas jet generated by the radial gas jet delivery ports 42 are interacted, the jet velocity is slowed down and the gas is fully mixed and combusted, forming a flame stable structure with a wider adaptation range; in cooperation with the axial gas jet generated by the axial gas jet delivery ports 41, the flame formed by the radial gas jet starts to contact at a suitable position, and the unburned gas is fully mixed with the already burned flame part before the outlet of the combustion chamber 5, and the high-speed flame is formed by the entrainment capacity, so that the residual oxygen in the flue gas in the furnace is fully combusted, thereby greatly widening the working range of the burner, allowing the burner to work normally in the range of 0.4-1.5 of the air excess coefficient, and maintaining a certain flame shape and rigidity, maintaining stable heat exchange capacity, fully utilizing the residual oxygen in the furnace, reducing energy consumption and harmful gas emission.

[0030] Referring to Figure 1 and Figure 2 In one embodiment, the inner side of the gas delivery part 4 is provided with a gas delivery cavity 43 communicating with the axial gas jet delivery ports 41 and the radial gas jet delivery ports 42, and the combustion-supporting gas delivery part 3 and the gas delivery part 4 are integrated.

[0031] Referring to Figures 1 to 4In an embodiment, the combustion-supporting gas delivery part 3 is provided with a plurality of annularly arranged inclined air jet delivery ports 32 inside the stable flame axial air jet delivery port 31, the inclined air jet delivery ports 32 are arranged to be inclined to the outside direction, the normal lines of the inclined air jet delivery ports 32 and the normal lines of the radial gas jet delivery ports 42 are arranged to be staggered with each other; by such arrangement, the inclined air jet generated by the inclined air jet delivery ports 32 and the radial gas jet generated by the radial gas jet delivery ports 42 are arranged to be staggered, which can generate a plurality of micro vortex stable flame structures, and the ejection capacity of the micro vortex stable flame structures can be used to deliver the gas along the radial periphery, and the plurality of annularly arranged and outwardly extending jet streams can form a larger central backflow area, which can improve the flame stability.

[0032] Referring to Figures 1 to 3 In an embodiment, the combustion-supporting gas delivery part 3 is provided with a plurality of annularly arranged rotating air jet delivery ports 33 outside the stable flame axial air jet delivery port 31, the rotating air jet delivery ports 33 are arranged to be inclined to one side along the circumferential direction, for example, the inclination angle is 30 to 60°; by such arrangement, the rotating air jet generated by the rotating air jet delivery ports 33 can strengthen the mixing of air and gas, and promote the combustion.

[0033] Referring to Figures 1 to 4 In a further embodiment, the combustion-supporting gas delivery part 3 is further provided with a plurality of annularly arranged peripheral axial air jet ports 34; the peripheral axial air jet ports 34 and the rotating air jet delivery ports 33 are arranged in the same circumferential direction, and at least one rotating air jet delivery port 33 is provided with one peripheral axial air jet port 34, and in this embodiment, every three rotating air jet delivery ports 33 are provided with one peripheral axial air jet port 34; by such arrangement, although the rotating air jet can strengthen the mixing of air and gas, and promote the combustion, the strong rotating flow can cause a hollow flame, which can reduce the volumetric heat intensity of the combustion chamber 5, and cause the flame stability to be poor, therefore, the axial air jet delivered by the axial air jet port in a proper proportion can increase the turbulence degree, fill the hollow phenomenon caused by the rotating flow, strengthen the combustion, and increase the volumetric utilization rate of the combustion chamber 5.

[0034] Referring to Figures 1 to 3 In an embodiment, the axial gas jet generated by the plurality of axial gas jet delivery ports 41 accounts for 25-75% of the total gas amount; the radial gas jet generated by the plurality of radial gas jet delivery ports 42 accounts for 25-75% of the total gas amount. Preferably, the axial gas jet generated by the plurality of axial gas jet delivery ports 41 accounts for 35% of the total gas amount, and the radial gas jet generated by the plurality of radial gas jet delivery ports 42 accounts for 65% of the total gas amount.

[0035] Referring to Figures 1 to 3In an embodiment, the number of axial gas jet delivery ports 41 is 6-24, and the number of radial gas jet delivery ports 42 is 6-24. Preferably, the air and gas delivery ratio of the flame stabilizing axial air jet delivery port 31 and the radial gas jet delivery port 42 is 0.9-1.0.

[0036] Referring to Figures 1 to 3 In an embodiment, the opening angle of the axial gas jet delivery port 41 and the gas delivery portion 4 axis is [5, 45] degrees, and preferably, the opening angle of the axial gas jet delivery port 41 and the gas delivery portion 4 axis is 35 degrees.

[0037] Referring to Figures 1 to 3 In an embodiment, the opening angle of the inclined angle air jet delivery port 32 and the combustion-supporting gas delivery portion 3 axis is [0, 30] degrees, and preferably, the opening angle of the inclined angle air jet delivery port 32 and the combustion-supporting gas delivery portion 3 axis is 15 degrees.

[0038] In an embodiment, the diameter ratio of the flame stabilizing axial air jet delivery port 31 and the inclined angle air jet delivery port 32 is 1:9-1:1, and preferably, the diameter ratio of the flame stabilizing axial air jet delivery port 31 and the inclined angle air jet delivery port 32 is 1:4.

[0039] In an embodiment, the flow ratio of the flame stabilizing axial air jet generated by the flame stabilizing axial air jet delivery port 31 and the rotational air jet generated by the rotational air jet delivery port 33 is 1:1-1:10, and preferably, the flow ratio of the flame stabilizing axial air jet generated by the flame stabilizing axial air jet delivery port 31 and the rotational air jet generated by the rotational air jet delivery port 33 is 1:3.

[0040] Referring to Figures 5 to 7 The low air-fuel ratio kiln burner of the present application has greatly improved comprehensive performance, greatly widened the effective working range of the burner, improved the quality of ceramic products, reduced gas consumption, and improved production rate. According to test results shown in the chart, the burner can stably operate at a minimum air excess coefficient of 0.4, and the flame still maintains a certain outlet flow rate and flame rigidity, without flame-out and blow-out. At the maximum combustion-supporting air amount, the gas load can be continuously reduced from the maximum to 5% of the rated power, and the adjustment ratio of the burner is more than 1:20. The burner can adapt to low air pressure and low gas pressure on site.

[0041] Based on the disclosure and teachings of the above specification, a person of ordinary skill in the art can make modifications and changes to the above embodiments. Therefore, the present application is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present application should fall within the protection scope of the claims of the present application. In addition, although some specific terms are used in the specification, these terms are only for convenience of description and do not constitute any limitation on the present application.

Claims

1. A burner for a low excess air kiln, characterized in that The burner body comprises: an igniter; a combustion-supporting gas delivery portion located at a peripheral portion of the burner body and provided with a plurality of circumferentially arranged stable flame axial air jet delivery ports; a gas delivery portion located at a middle portion of the burner body and extending out of the combustion-supporting gas delivery portion, and provided with a plurality of circumferentially arranged axial gas jet delivery ports at a front side and a plurality of circumferentially arranged radial gas jet delivery ports at an outer side, the plurality of axial gas jet delivery ports being inclinedly arranged outward along a central axis of the gas delivery portion, and the plurality of radial gas jet delivery ports being arranged in the same radial direction as the plurality of stable flame axial air jet delivery ports; the combustion-supporting gas delivery portion is provided with a plurality of circumferentially arranged inclined air jet delivery ports inward of the stable flame axial air jet delivery ports, the inclined air jet delivery ports being inclinedly arranged outward, and normals of the inclined air jet delivery ports and normals of the radial gas jet delivery ports being staggered with each other; the combustion-supporting gas delivery portion is provided with a plurality of circumferentially arranged rotating air jet delivery ports outward of the stable flame axial air jet delivery ports, the plurality of rotating air jet delivery ports being inclinedly arranged at one side along a circumferential direction; the combustion-supporting gas delivery portion is further provided with a plurality of circumferentially arranged peripheral axial air jet ports, the peripheral axial air jet ports being arranged in the same circumferential direction as the rotating air jet delivery ports, and at least one peripheral axial air jet port being provided between two rotating air jet delivery ports.

2. The low air-fuel ratio kiln burner according to claim 1, characterized in that, An air and gas delivery ratio of the stable flame axial air jet delivery ports and the radial gas jet delivery ports is 0.8 to 1.

2.

3. The low air-fuel ratio kiln burner according to claim 1, wherein An axial gas jet generated by the plurality of axial gas jet delivery ports accounts for 25-75% of a total gas amount. A radial gas jet generated by the plurality of radial gas jet delivery ports accounts for 25-75% of the total gas amount.

4. The low air-fuel ratio kiln burner according to claim 1 or 3, characterized in that, A flow ratio of the axial gas jet generated by the axial gas jet delivery ports to the radial gas jet generated by the radial gas jet delivery ports is 65:

35. An arrangement number of the axial gas jet delivery ports is 6-24, and an arrangement number of the radial gas jet delivery ports is 6-24.

5. The low air-fuel ratio kiln burner of claim 1, wherein An opening angle of the axial gas jet delivery ports with respect to an axis of the combustion-supporting gas delivery portion is [5, 45] degrees.

6. The low air-fuel ratio kiln burner of claim 1, wherein An opening angle of the inclined air jet delivery ports with respect to the axis of the combustion-supporting gas delivery portion is [0, 30] degrees.

7. The low air-fuel ratio kiln burner of claim 1, wherein A diameter ratio of the stable flame axial air jet delivery ports to the inclined air jet delivery ports is 1:9-1:

1.

8. The low air-fuel ratio kiln burner of claim 1, wherein, A flow ratio of stable flame axial air jets generated by the stable flame axial air jet delivery ports to rotating air jets generated by the rotating air jet delivery ports is 1:1-1:10.

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