Gas burner for heating furnace and heating furnace thereof

Abstract

The present invention provides a gas burner for a heating furnace and a heating furnace thereof. The gas burner for the heating furnace comprises: a smoke guide burner brick comprises a combustion chamber, a secondary air through-hole, a secondary gas through-hole and a smoke reflow hole, one end of the combustion chamber is connected to the air inlet, and the other end of the combustion chamber is connected to the combustion side; the secondary air through-hole is arranged outside the combustion chamber, one end of the secondary air through-hole is connected to the air inlet, and the other end of the secondary air through-hole is connected to the combustion side; the secondary gas through-hole is arranged outside the secondary air through-hole, one end of the secondary gas through-hole is connected to the gas inlet, and the other end of the secondary gas through-hole is connected to the combustion side; one end of the smoke reflow hole is connected to the secondary air through-hole, and the other end of the smoke reflow hole is connected to the combustion side of the smoke guide burner brick; a plurality of primary air nozzles are arranged on the air distribution disk; one end of the primary gas spray gun is connected to the gas inlet, and the other end of the primary gas spray gun can pass through the air distribution disk and be connected to the combustion side.

Description

Technical Field

[0001] The invention relates to the technical field of gas burners, and in particular to a gas burner for a heating furnace and the heating furnace thereof. Background Art

[0002] Steel rolling heating furnaces are currently the largest emitters of atmospheric pollutants in industrial furnaces due to their high furnace temperature and large production capacity. The increasingly stringent pollutant emission standards make the development of clean and green industrial heating and combustion equipment of great significance.

[0003] Usually, the design of steel rolling heating furnace focuses on production capacity, but the actual production capacity is too small; or it is designed to heat carbon steel, but it is actually used to heat alloy steel; or the composition and calorific value of the fuel gas on site fluctuate greatly, which deviates from the burner design conditions, resulting in the design parameters not matching the on-site conditions. However, the commonly used low-nitrogen combustion technology has a narrower range of use than conventional combustion technology. If it exceeds the range, the adaptability of the combustion equipment will be difficult to meet, which indirectly makes it difficult for the low-nitrogen combustion technology to operate within a reasonable range. Summary of the invention

[0004] The present invention provides a gas burner for a heating furnace and a heating furnace thereof, so as to achieve the purpose of adapting to the low pollution emission requirements under the circumstances of load change, calorific value fluctuation or steel type replacement.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a gas burner for a heating furnace, comprising: a flue gas guide burner brick, which is a cylindrical structure, the flue gas guide burner brick comprises a combustion chamber, a secondary air through-hole, a secondary gas through-hole and a flue gas reflow hole, the combustion chamber is coaxially arranged with the flue gas guide burner brick and penetrates the flue gas guide burner brick, one end of the combustion chamber is connected to the air inlet, and the other end of the combustion chamber is connected to the combustion side of the flue gas guide burner brick; the secondary air through-hole is arranged at intervals on the outside of the combustion chamber in parallel along the radial direction of the flue gas guide burner brick, one end of the secondary air through-hole is connected to the air inlet, and the other end of the secondary air through-hole is connected to the combustion side of the flue gas guide burner brick side; a secondary gas through cavity is arranged outside the secondary air through cavity in parallel and at intervals along the radial direction of the flue gas guide burner brick, one end of the secondary gas through cavity is connected to the gas inlet, and the other end of the secondary gas through cavity is connected to the combustion side; one end of the flue gas reflow hole is connected to the secondary air through cavity, and the other end of the flue gas reflow hole is connected to the combustion side of the flue gas guide burner brick; an air distribution disk is coaxially arranged in the combustion chamber, and a plurality of primary air nozzles are arranged on the air distribution disk; a primary gas spray gun is coaxially arranged in the combustion chamber, one end of the primary gas spray gun is connected to the gas inlet, and the other end of the primary gas spray gun can pass through the air distribution disk and be connected to the combustion side.

[0006] Furthermore, there are at least four secondary air through-cavities, which are evenly distributed on the outside of the combustion chamber along the circumference of the combustion chamber, and the distance between the axis of each secondary air through-cavity and the axis of the combustion chamber is the same.

[0007] Furthermore, a nozzle is provided in each secondary air through-hole, and one end of the smoke reflow hole is located between the nozzle and the combustion side.

[0008] Furthermore, the nozzle is a cylindrical structure, and is provided with two symmetrically arranged arcuate through holes, and the planes corresponding to the chord sides of the two arcuate through holes are opposite.

[0009] Furthermore, there are multiple smoke reflow holes, and the multiple smoke reflow holes are connected to at least four secondary air through-cavities in a one-to-one correspondence.

[0010] Furthermore, each flue gas recirculation hole includes an axial hole section and a radial hole section, the axis of the axial hole section is parallel to the axis of the flue gas guide burner brick, the axis of the radial hole section is arranged along the radial direction of the flue gas guide burner brick, and one end of the axial hole section is connected to one end of the radial hole section, the other end of the radial hole section is connected to the secondary air through cavity, and the other end of the axial hole section is connected to the combustion side.

[0011] Furthermore, there are at least two secondary gas through-cavities, which are symmetrically arranged on the outside of at least four secondary air through-cavities along the circumference of the combustion chamber, and the distance between the axis of each secondary gas through-cavity and the axis of the combustion chamber is the same, and a secondary gas spray gun is arranged in each secondary gas through-cavity.

[0012] Furthermore, a nozzle is provided in each secondary gas through-hole, and the nozzle is located at the outlet of the corresponding secondary gas spray gun. The nozzle is a cylindrical structure, and the nozzle is provided with two symmetrically arranged arched through-holes, and the planes corresponding to the chord sides of the two arched through-holes are opposite.

[0013] Furthermore, the gas burner for the heating furnace also includes a secondary gas pipe, the inlet end of which is connected to one end of the primary gas spray gun and communicated with the gas inlet, and a gas switching valve is provided at the connection between one end of the primary gas spray gun and the inlet end of the secondary gas pipe, and the outlet end of the secondary gas pipe is communicated with the secondary gas through-hole.

[0014] The present invention also provides a heating furnace, including a heating furnace gas burner, an air pipeline and a gas pipeline. The heating furnace gas burner is the above-mentioned heating furnace gas burner, the air pipeline is connected to the air inlet, and the gas pipeline is connected to the gas inlet.

[0015] The beneficial effect of the present invention is that, through the Venturi effect of high-speed injection of air and gas, dual internal circulation of combustion-supporting air and flue gas and fuel and flue gas is realized in the furnace. The flue gas inside the furnace is remixed by high-speed injection through the secondary gas through-hole cavity, and the combustion temperature is reduced by reducing the calorific value of the fuel, thereby reducing the formation of thermal nitrogen oxides. At the same time, the flue gas inside the furnace is remixed by injection through the secondary air through-hole cavity, and the mixed flue gas reduces the partial pressure of oxygen, which will weaken the process of oxygen and nitrogen generating thermal nitrogen oxides, thereby reducing the generation of nitrogen oxides, thereby achieving the purpose of adapting to the low-pollution emission requirements under conditions such as load changes, calorific value fluctuations or steel grade changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A-direction view;

[0019] Figure 3 for Figure 1 B-direction view;

[0020] Figure 4 Schematic diagram of the structure of the nozzle in the embodiment of the present invention.

[0021] Reference numerals in the figure: 1. air inlet; 2. gas inlet; 3. gas switching valve; 4. secondary gas pipe; 5. secondary air through-hole; 6. air distribution disk; 7. primary gas spray gun; 8. combustion chamber; 9. flue gas reflow hole; 10. flue gas guide burner brick; 11. secondary gas through-hole; 12. nozzle. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] like Figures 1 to 4As shown, an embodiment of the present invention provides a gas burner for a heating furnace, including a flue gas guide burner brick 10, an air distribution plate 6 and a primary gas spray gun 7. The flue gas guide burner brick 10 is a cylindrical structure, and the flue gas guide burner brick 10 includes a combustion chamber 8, a secondary air through cavity 5, a secondary gas through cavity 11 and a flue gas reflow hole 9. The combustion chamber 8 is coaxially arranged with the flue gas guide burner brick 10 and penetrates the flue gas guide burner brick 10. One end of the combustion chamber 8 is connected to the air inlet 1, and the other end of the combustion chamber 8 is connected to the combustion side of the flue gas guide burner brick 10; the secondary air through cavity 5 is arranged parallel to and spaced apart from the outside of the combustion chamber 8 along the radial direction of the flue gas guide burner brick 10. One end of the secondary air through-hole 5 is connected to the air inlet 1, and the other end of the secondary air through-hole 5 is connected to the combustion side; the secondary gas through-hole 11 is arranged parallel and spaced outside the secondary air through-hole 5 along the radial direction of the smoke guide burner brick 10, one end of the secondary gas through-hole 11 is connected to the gas inlet 2, and the other end of the secondary gas through-hole 11 is connected to the combustion side; one end of the smoke reflow hole 9 is connected to the secondary air through-hole 5, and the other end of the smoke reflow hole 9 is connected to the combustion side of the smoke guide burner brick 10. The air distribution plate 6 is coaxially arranged in the combustion chamber 8, and a plurality of primary air nozzles are arranged on the air distribution plate 6. The primary gas spray gun 7 is coaxially arranged in the combustion chamber 8, one end of the primary gas spray gun 7 is connected to the gas inlet 2, and the other end of the primary gas spray gun 7 can pass through the air distribution plate 6 and be connected to the combustion side.

[0024] Through the Venturi effect of high-speed injection of air and gas, dual internal circulation of combustion air and flue gas and fuel and flue gas is realized in the furnace. The flue gas inside the furnace is ejected and injected at high speed through the secondary gas through-hole 11 for remixing, and the combustion temperature is reduced by reducing the calorific value of the fuel to reduce the formation of thermal nitrogen oxides. At the same time, the flue gas inside the furnace is injected and injected through the secondary air through-hole 5 for remixing. The mixed flue gas reduces the partial pressure of oxygen, which will weaken the process of oxygen and nitrogen generating thermal nitrogen oxides, thereby reducing the generation of nitrogen oxides, thereby achieving the purpose of adapting to the low pollution emission requirements under the conditions of load changes, calorific value fluctuations or steel grade changes.

[0025] It should be noted that the multiple primary air nozzles arranged on the air distribution disk 6 adopt a high-speed inclined hole structure instead of a traditional swirl plate structure, which can effectively solve the problem of flame floating under standard working conditions such as low load, gas calorific value, and steel grade changes, and ensure the stability of flame rigidity.

[0026] In this embodiment, the primary gas spray gun 7, the air distribution plate 6 and the combustion chamber 8 form a primary combustion area, the primary gas ratio is less than 20%, and the primary air ratio is less than 30%. The primary air and the primary gas form a well-mixed lean fuel combustion, and the high-speed ejection of the combustion products is conducive to the reflux of the flue gas, thereby playing a flame stabilizing role for the entire burner. At the same time, the primary combustion area is in a lean combustion state, and it is not easy to generate nitrogen oxides.

[0027] In this embodiment, there are at least four secondary air through-holes 5, which are evenly spaced outside the combustion chamber 8 along the circumference of the combustion chamber 8, and the distance between the axis of each secondary air through-hole 5 and the axis of the combustion chamber 8 is the same. Figure 3 As shown, there are six secondary air through-cavities 5, and the line connecting the axial end points of the six secondary air through-cavities 5 forms a circle with a diameter greater than the outer diameter of the combustion chamber 8, and the six secondary air through-cavities 5 are evenly spaced on the circumference of the circle.

[0028] Specifically, the secondary air through-holes 5 are distributed in a circular or fan-shaped array along the circumferential direction, the number of the secondary air through-holes 5 is at least greater than 4, and they are evenly arranged in axisymmetry, and the nozzle velocity of the secondary air through-holes 5 is 40m / s to 60m / s. The secondary air through-holes 5 of the flue gas guide burner brick 10 are sprayed into by multiple high-speed nozzles, and a part of the flue gas enters the reflow hole from the furnace due to the negative pressure of the injection, thereby diluting the oxygen concentration entering the combustion area of ​​the furnace, reducing the intensity of the combustion reaction, and inhibiting the generation of nitrogen oxides at high temperature.

[0029] Furthermore, a nozzle 12 is provided in each secondary air through-hole 5, and one end of the smoke reflow hole 9 is located between the nozzle 12 and the combustion side. Each nozzle 12 is a cylindrical structure, and the nozzle 12 is provided with two symmetrically arranged arcuate through-holes, and the planes corresponding to the chord sides of the two arcuate through-holes are opposite.

[0030] like Figure 4 As shown, the nozzles 12 all adopt double-crescent nozzles, combined with the secondary air through-cavity 5 of the flue gas guide burner brick 10, can still achieve a large flue gas reflux and produce a better flue gas and air gas premixing effect under low load, gas calorific value, steel grade change and other deviations from standard working conditions, thereby expanding the low-nitrogen combustion working range and achieving a stable low-nitrogen combustion effect within a larger adjustment range.

[0031] There are multiple smoke reflow holes 9 , and the multiple smoke reflow holes 9 are connected to at least four secondary air through-cavities 5 in a one-to-one correspondence.

[0032] Specifically, Figure 1As shown, each flue gas reflow hole 9 includes an axial hole section and a radial hole section, the axis of the axial hole section is parallel to the axis of the flue gas guide burner brick 10, the axis of the radial hole section is arranged along the radial direction of the flue gas guide burner brick 10, and one end of the axial hole section is connected to one end of the radial hole section, the other end of the radial hole section is connected to the secondary air through cavity 5, and the other end of the axial hole section is connected to the combustion side. The provision of the flue gas reflow hole 9 is conducive to the high-temperature flue gas to reflow and strongly mix with the air gas to form a uniform mixture in the concentration field, thereby realizing the stable flameless combustion of high-temperature, low-oxygen, and low-calorific value fuels in the furnace space.

[0033] like Figure 3 As shown, there are at least two secondary gas through-cavities 11, which are symmetrically arranged on the outside of at least four secondary air through-cavities 5 along the circumference of the combustion chamber 8, and the distance between the axis of each secondary gas through-cavity 11 and the axis of the combustion chamber 8 is the same.

[0034] A secondary gas spray gun is arranged in the secondary gas through cavity 11 to spray gas at high speed. The number of secondary gas spray guns is at least 2, corresponding to the number of secondary gas through cavity 11. They can be added in pairs according to power and actual needs. The nozzle flow rate of the secondary gas spray gun is 80m / s to 200m / s. High-speed gas is sprayed into the secondary gas through cavity 11 of the flue gas guide burner brick 10, so that under the action of a large amount of reflux flue gas, the calorific value of the gas entering the combustion area of ​​the furnace is greatly reduced, and the high temperature peak generated when the high calorific value fuel is burned is avoided, thereby reducing the generation of thermal nitrogen oxides.

[0035] The gas burner for a heating furnace in the embodiment of the present invention also includes a secondary gas pipe 4, an inlet end of which is connected to one end of a primary gas spray gun 7 and communicates with a gas inlet 2, and a gas switching valve 3 is provided at the connection between one end of the primary gas spray gun 7 and the inlet end of the secondary gas pipe 4, and the outlet end of the secondary gas pipe 4 is communicated with the secondary gas spray gun in the secondary gas through cavity 11.

[0036] Each secondary gas through cavity 11 is provided with a nozzle 12, and the nozzle 12 is located at the outlet of the secondary gas spray gun. The nozzle 12 is a cylindrical structure, and is provided with two symmetrically arranged arcuate through holes, and the planes corresponding to the chord sides of the two arcuate through holes are opposite. The above-mentioned nozzles 12 have the same structure and are both double-crescent-shaped. The double-crescent-shaped hollow area forms a negative pressure area, which is conducive to the reflux of high-temperature flue gas and strong mixing with air gas to form a uniform mixture in the concentration field, thereby realizing stable flameless combustion of high-temperature, low-oxygen, and low-calorific value fuels in the furnace space.

[0037] When the embodiment of the present invention is used, part of the air from the air inlet 1 passes through the air distribution plate 6 and then mixes with the gas sprayed from the primary gas spray gun 7 in the combustion chamber 8 and burns. The high-speed flue gas generated has a flame stabilizing effect and quickly enters the furnace space to entrain the flue gas in the furnace, reducing the nitrogen oxides of the primary combustion. The other part of the air is sprayed through the secondary air through-hole 5, mixed and diluted with the flue gas entering from the flue gas reflow hole 9, and then enters the furnace space. The gas enters from the gas inlet 2, and after the ratio of the primary gas and the secondary gas is adjusted by the gas switching valve 3, part of it enters the combustion chamber from the primary gas spray gun 7, and the other part is sprayed from the secondary gas through-hole 11 through the secondary gas pipe 4, mixed and diluted with the flue gas entering from the flue gas reflow hole 9, and then enters the furnace space. Secondary coal gas and secondary air are sprayed out from the nozzle 12. After being double-enhanced and diluted by the flue gas guide burner bricks 10 and the reflux flue gas, the calorific value of the coal gas decreases, the oxygen partial pressure of the air also decreases, the intensity of the mixed combustion reaction in the furnace space decreases, the combustion temperature is uniform, and low-pollution flameless combustion can be achieved.

[0038] An embodiment of the present invention also provides a heating furnace including a heating furnace gas burner, an air pipeline and a gas pipeline. The heating furnace gas burner is the above-mentioned heating furnace gas burner, the air pipeline is connected to the air inlet 1, and the gas pipeline is connected to the gas inlet 2.

[0039] It should be noted that the heating furnace in the embodiment of the present invention adopts sequential pulse combustion control to adjust the heat supply.

[0040] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the present invention can achieve stable and low-pollution combustion without the use of additional flue gas circulation fans and other pipeline equipment, and avoid the unstable low-nitrogen combustion caused by large changes in load, gas calorific value, steel type, etc. in actual industrial furnaces.

[0041] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other, and with each other.

Claims

1. A gas burner for a heating furnace, It is characterized in that include: A flue gas guide burner brick (10) is of cylindrical structure. The flue gas guide burner brick (10) comprises a combustion chamber (8), a secondary air through cavity (5), a secondary gas through cavity (11) and a flue gas reflow hole (9). The combustion chamber (8) is coaxially arranged with the flue gas guide burner brick (10) and penetrates the flue gas guide burner brick (10). One end of the combustion chamber (8) is connected to an air inlet (1), and the other end of the combustion chamber (8) is connected to a combustion side of the flue gas guide burner brick (10). The secondary air through cavity (5) is arranged parallel to and spaced apart from the outside of the combustion chamber (8) along the radial direction of the flue gas guide burner brick (10). On the side, one end of the secondary air through-hole (5) is connected to the air inlet (1), and the other end of the secondary air through-hole (5) is connected to the combustion side; the secondary gas through-hole (11) is arranged outside the secondary air through-hole (5) in parallel and spaced along the radial direction of the flue gas guide burner brick (10); one end of the secondary gas through-hole (11) is connected to the gas inlet (2), and the other end of the secondary gas through-hole (11) is connected to the combustion side; one end of the flue gas reflow hole (9) is connected to the secondary air through-hole (5), and the other end of the flue gas reflow hole (9) is connected to the combustion side of the flue gas guide burner brick (10); An air distribution disk (6) is coaxially arranged in the combustion chamber (8), and a plurality of primary air nozzles are arranged on the air distribution disk (6); A primary gas spray gun (7) is coaxially arranged in the combustion chamber (8), one end of the primary gas spray gun (7) is connected to the gas inlet (2), and the other end of the primary gas spray gun (7) can pass through the air distribution plate (6) and be connected to the combustion side; There are at least four secondary air through-holes (5), which are evenly spaced along the circumference of the combustion chamber (8) outside the combustion chamber (8), and the distance between the axis of each secondary air through-hole (5) and the axis of the combustion chamber (8) is the same; Each of the secondary air through-holes (5) is provided with a nozzle (12), and one end of the smoke reflow hole (9) is located between the nozzle (12) and the combustion side; There are a plurality of smoke return holes (9), and the plurality of smoke return holes (9) are connected to at least four of the secondary air through-holes (5) in a one-to-one correspondence.

2. The gas burner for a heating furnace according to claim 1, It is characterized in that The nozzle (12) is a cylindrical structure, and is provided with two symmetrically arranged arcuate through holes, wherein the planes corresponding to the chord sides of the two arcuate through holes are opposite.

3. The gas burner for a heating furnace according to claim 1, It is characterized in that Each of the flue gas reflow holes (9) comprises an axial hole section and a radial hole section, the axis of the axial hole section is parallel to the axis of the flue gas guide burner brick (10), the axis of the radial hole section is arranged along the radial direction of the flue gas guide burner brick (10), one end of the axial hole section is connected to one end of the radial hole section, the other end of the radial hole section is connected to the secondary air through cavity (5), and the other end of the axial hole section is connected to the combustion side.

4. The gas burner for a heating furnace according to claim 1, It is characterized in that There are at least two secondary gas through-holes (11), which are symmetrically arranged on the outside of at least four secondary air through-holes (5) along the circumference of the combustion chamber (8), and the distance between the axis of each secondary gas through-hole (11) and the axis of the combustion chamber (8) is the same. A secondary gas spray gun is arranged in each secondary gas through-hole (11).

5. The gas burner for a heating furnace according to claim 4, It is characterized in that A nozzle (12) is arranged in each of the secondary gas through-holes (11), and the nozzle (12) is located at the outlet of the corresponding secondary gas spray gun. The nozzle (12) is a cylindrical structure, and the nozzle (12) is provided with two symmetrically arranged arched through holes, and the planes corresponding to the chord sides of the two arched through holes are opposite.

6. The gas burner for a heating furnace according to claim 4, It is characterized in that The gas burner for the heating furnace also includes a secondary gas pipe (4), the inlet end of which is connected to one end of the primary gas spray gun (7) and communicates with the gas inlet (2), a gas switching valve (3) is provided at the connection between one end of the primary gas spray gun (7) and the inlet end of the secondary gas pipe (4), and the outlet end of the secondary gas pipe (4) is communicated with the secondary gas spray gun.

7. A heating furnace, comprising a heating furnace gas burner, an air pipeline and a gas pipeline, It is characterized in that The gas burner for a heating furnace is the gas burner for a heating furnace according to any one of claims 1 to 6, the air pipeline is connected to the air inlet (1), and the gas pipeline is connected to the gas inlet (2).

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