Double-heat-storage low-nitrogen flat flame burner and method

Abstract

The double-heat-storage low-nitrogen flat flame burner comprises two heat storage chambers, two rotational flow channels, a mixing channel, a flat flame channel, a secondary fuel gas channel and a secondary fuel gas nozzle, the upper ends of the two heat storage chambers are provided with an air inlet and a primary fuel gas inlet respectively, the bottoms of the two heat storage chambers are connected with the two rotational flow channels respectively, and the two rotational flow channels are communicated with the mixing channel. The two rotational flow channels are communicated with the mixing channel together, an outlet of the mixing channel is a flared flat flame channel, the secondary gas channel and the secondary gas nozzle are arranged on the outer circumference of the flat flame channel in the circumferential direction, the secondary gas nozzle is a tangential outlet, and the secondary gas channel is externally connected with a secondary gas pipe. The double regenerative chambers and the flat flame combustion technology are perfectly fused, fuel gas and air can be preheated to 1000 DEG C or above, the fuel gas after heat storage and combustion-supporting air are cooperatively matched to achieve high rotational flow strength to form flat flame, and meanwhile the generation amount of nitric oxide can be controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of heating furnace burners, and in particular to a double-heat storage low-nitrogen flat flame burner and a method thereof. Background Art

[0002] With the increasing demand for energy efficiency and environmental protection in the industrial heating sector, burner performance optimization, as a core component of high-temperature heating equipment, has become a key area of ​​technological research and development. Traditional burners generally suffer from low thermal efficiency, high pollutant emissions (such as NOx and CO), and poor fuel adaptability. This is particularly evident in intermittent high-temperature heating applications (such as metallurgy, mechanical heating and heat treatment, glass melting furnaces, and ceramic sintering). In recent years, regenerative combustion technology has gained widespread application due to its efficient waste heat recovery capabilities.

[0003] Traditional flat flame regenerative burners all use a single regenerative body design, which recovers the waste heat of the flue gas by periodically switching the combustion gas, air and exhaust mode. However, the combustion efficiency of burners in this mode is lower than that of double regenerative burners. For example, the theoretical combustion temperature of blast furnace gas with single regenerative heat generally does not exceed 1800°C, which will cause the furnace to heat up slowly. In order to increase the theoretical combustion temperature, some manufacturers have to mix high calorific value natural gas, which increases fuel costs. In addition, although the above-mentioned high-temperature combustion mode can improve thermal efficiency, it will significantly increase NOx generation (>200mg / m 3 However, existing flat flame low nitrogen combustion technologies (such as simple staged combustion and flue gas recirculation) are less compatible with thermal storage structures, making it difficult to achieve ultra-low emissions while efficiently storing heat. Summary of the Invention

[0004] The present invention provides a dual-heat storage low-nitrogen flat flame burner and method, which perfectly integrates dual heat storage chambers with flat flame combustion technology. The gas and air can be preheated to above 1000°C respectively, and the heat-stored gas and combustion-supporting air can be coordinated to achieve high swirl intensity to form a flat flame, while the amount of nitrogen oxides generated can be controlled.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A double regenerative low-nitrogen flat flame burner comprises two regenerative chambers, two swirl channels, a mixing channel, a flat flame channel, a secondary gas channel, and a secondary gas nozzle. The upper ends of the two regenerative chambers are respectively provided with an air inlet and a primary gas inlet. The bottoms of the two regenerative chambers are respectively connected to two swirl channels, which are connected to the mixing channel. The outlet of the mixing channel is a bell-mouthed flat flame channel. The secondary gas channel and the secondary gas nozzle are circumferentially arranged on the outer circumference of the flat flame channel. The secondary gas nozzle is a tangential outlet. The secondary gas channel is externally connected to a secondary gas pipe.

[0007] Preferably, an inner swirl tube is provided in the mixing channel, the inner hole of the inner swirl tube is communicated with the swirl channel I, and the outer circumferential annular channel formed by the inner swirl tube and the mixing channel is communicated with the swirl channel II.

[0008] Preferably, the flat flame channel is a Laval nozzle structure.

[0009] Preferably, an observation hole is provided at the other end of the mixing channel.

[0010] Preferably, a flame monitor and an ignition burner are provided at the flat flame channel.

[0011] A method for using a double heat storage low nitrogen flat flame burner, comprising:

[0012] 1) Regenerative process: Primary gas and air enter the two regenerators through the primary gas inlet and air inlet respectively for preheating. The preheated primary gas and air enter the two swirl channels respectively for swirl, and then enter the mixing channel together. The ignited mixed swirling gas forms a flat flame under the bell mouth and wall effect of the bell mouth flat flame channel. At the same time, the secondary gas swirlingly ejected from the secondary gas nozzle and the mixed combustion flat flame undergo secondary combustion;

[0013] 2) Reversing is performed under the set cycle, the primary gas, secondary gas and air are cut off, and the high-temperature flue gas in the furnace is sucked into the mixing channel through the flat flame channel by negative pressure, and then enters the two heat storage chambers through two swirl channels to heat the heat storage body. After heating to the set temperature, the negative pressure is cut off, and the supply of primary gas, secondary gas and air is restored. The flue gas is switched with the gas and air to complete a heat storage and heat release cycle.

[0014] The preheating temperature of the heat storage chamber is not less than 1000°C.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The burner has dual heat storage functions for gas and combustion air, which can preheat the gas and air to above 1000°C. The difficulty lies in coordinating the heat-stored gas and combustion air to achieve a high swirl intensity to form a flat flame, while also controlling the amount of nitrogen oxides generated.

[0017] 2) The dual heat storage low nitrogen flat flame burner of the present invention can be applied to heating furnaces to increase the theoretical combustion temperature of low calorific value gas (such as blast furnace gas) to above 2000°C. There is no need to mix natural gas when burning low calorific value fuels. For example, if pure blast furnace gas is burned, a heating furnace at 1250°C can use both air and gas to store heat, and the theoretical combustion temperature can reach 2300°C. This can effectively complete the heating process for the heating furnace, greatly reduce fuel consumption, improve combustion efficiency, and achieve the purpose of energy conservation and carbon reduction. The gas is injected twice for graded swirl combustion, which reduces the generation of nitrogen oxides and achieves low nitrogen emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of embodiment 1 of the present invention.

[0019] Figure 2 It is a schematic diagram of embodiment 2 of the present invention.

[0020] Figure 3 yes Figure 2 AA cross-section diagram.

[0021] In the figure: 1. Air inlet; 2. Primary gas inlet; 3. Steel shell; 4. Refractory insulation material; 5. Regenerator; 6. Swirl channel; 7. Mixing channel; 8. Ignition burner; 9. Flame monitor; 10. Secondary gas pipe; 11. Secondary gas nozzle; 12. Flat flame channel; 13. Inner swirl channel; 14. Inner swirl pipe; 15. Outer swirl channel; 16. Observation hole; 17. Secondary gas channel. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further described below with reference to the accompanying drawings:

[0023] like Figure 1-Figure 3As shown, a double regenerative low-nitrogen flat flame burner includes two regenerative chambers 5, two swirl channels 6, a mixing channel 7, a flat flame channel 12, a secondary gas channel 17, and a secondary gas nozzle 11. A regenerative body is installed in the regenerative chamber 5. The upper ends of the two regenerative chambers 5 are respectively provided with an air inlet 1 and a primary gas inlet 2. The bottoms of the two regenerative chambers 5 are respectively connected to two swirl channels 6, which are connected to the mixing channel 7. The outlet of the mixing channel 7 is a bell-shaped flat flame channel 12. The secondary gas channel 17 and the secondary gas nozzle 11 are circumferentially arranged on the outer circumference of the flat flame channel 12. The secondary gas nozzle 11 is a tangential outlet. The secondary gas channel 11 is externally connected to a secondary gas pipe 10.

[0024] Preferably, an inner swirl tube 14 is provided in the mixing channel 7, the inner hole of the inner swirl tube 14 is connected with the swirl channel 6 for introducing air to form an inner swirl channel 13, and the outer circumferential annular channel formed by the inner swirl tube 14 and the mixing channel 7 is connected with the swirl channel 6 for introducing gas to form an outer swirl channel 15.

[0025] Preferably, the flat flame channel 12 is a Laval nozzle structure.

[0026] Preferably, an observation hole 16 is provided at the other end of the mixing channel 7 .

[0027] Preferably, a flame monitor 9 and an ignition burner 8 are provided at the flat flame channel 12 .

[0028] The burner body is composed of a steel shell 3 and a heat-insulating refractory material 4, with a gas channel formed inside. The heat storage chamber 5 is provided with a retaining brick and a heat storage body, which is generally made of a porous structure of ceramic material.

[0029] A method for using a double heat storage low nitrogen flat flame burner, comprising:

[0030] 1) Regenerative process: Primary gas and air enter the two regenerators 5 through the primary gas inlet 2 and air inlet 1, respectively, for preheating. The preheated primary gas and air enter the two swirl channels 6, undergo swirl, and then enter the mixing channel 7 together. The ignited mixed swirling gas forms a flat flame with the assistance of the bell-shaped flat flame channel 12. Simultaneously, the secondary gas ejected tangentially from the secondary gas nozzle 11 and the mixed flat flame undergo secondary combustion.

[0031] 2) Reversing is performed at a set cycle, the primary gas, secondary gas and air are cut off, and the high-temperature flue gas in the furnace is sucked into the mixing channel 7 through the flat flame channel 12 by negative pressure, and then enters the two heat storage chambers 5 through the two swirl channels 6 to heat the heat storage body. After heating to the set temperature, the negative pressure is cut off, and the supply of primary gas, secondary gas and air is restored. The flue gas is switched with the gas and air, completing a heat storage and heat release cycle.

[0032] The preheating temperature of the heat storage chamber 5 is not less than 1000°C.

[0033] Example 1:

[0034] like Figure 1 As shown, a dual-regenerative low-nitrogen flat flame burner includes two regenerative chambers 5, two swirl channels 6, a mixing channel 7, a flat flame channel 12, a secondary gas channel 17, and a secondary gas nozzle 11. The upper ends of the two regenerative chambers 5 are respectively provided with an air inlet 1 and a primary gas inlet 2. The bottoms of the two regenerative chambers 5 are respectively connected to two swirl channels 6, which are connected to the mixing channel 7. The outlet of the mixing channel 7 is a bell-mouth flat flame channel 12. The secondary gas channel 17 and the secondary gas nozzle 11 are circumferentially arranged on the outer circumference of the flat flame channel 12. The secondary gas nozzle 11 is a tangential outlet. The secondary gas channel 17 is externally connected to the secondary gas pipe 10.

[0035] An observation hole 16 is provided at the other end of the mixing channel 7 .

[0036] A flame monitor 9 is provided at the flat flame channel 12 .

[0037] Example 2:

[0038] like Figure 2 、 Figure 3 As shown, a dual-regenerative low-nitrogen flat flame burner includes two regenerative chambers 5, two swirl channels 6, a mixing channel 7, a flat flame channel 12, a secondary gas channel 17, and a secondary gas nozzle 11. The upper ends of the two regenerative chambers 5 are respectively provided with an air inlet 1 and a primary gas inlet 2. The bottoms of the two regenerative chambers 5 are respectively connected to two swirl channels 6, which are connected to the mixing channel 7. The outlet of the mixing channel 7 is a bell-mouth flat flame channel 12. The secondary gas channel 17 and the secondary gas nozzle 11 are circumferentially arranged on the outer circumference of the flat flame channel 12. The secondary gas nozzle 11 is a tangential outlet. The secondary gas channel 17 is externally connected to the secondary gas pipe 10.

[0039] An inner swirl tube 14 is provided in the mixing channel 7. The inner hole of the inner swirl tube 14 is connected to the swirl channel 6 for introducing air to form an inner swirl channel 13. The outer circumferential annular channel formed by the inner swirl tube 14 and the mixing channel 7 is connected to the swirl channel 6 for introducing gas to form an outer swirl channel 15.

[0040] The flat flame channel 12 is a Laval nozzle structure.

[0041] An observation hole 16 is provided at the other end of the mixing channel 7 .

[0042] A flame monitor 9 and an ignition burner 8 are provided at the flat flame channel 12 .

[0043] The burner gas heat storage process is as follows:

[0044] Gas process:

[0045] The primary gas enters the heat storage body 5 from the primary gas inlet 2 (the flow rate of the primary gas is adjustable according to the proportion of the amount of nitrogen oxides generated) for preheating. The gas can be preheated to above 1000°C (varies according to the application scenario). The preheated primary gas enters the swirl channel 6 and rotates at high speed. The high-speed rotating airflow and the high-speed rotating combustion-supporting air from the other heat storage chamber 5 are mixed in the mixing channel 7. An ignition burner 8 and a flame monitor 9 are provided at the end of the mixing channel 7 for ignition and flame monitoring. The ignited mixed rotating gas forms a flat flame with the assistance of the trumpet-shaped flat flame channel 12. The secondary gas fed into the outer edge of the trumpet-shaped mouth through the secondary gas pipe 10 is rotated and ejected from the secondary gas nozzle 11 for secondary combustion with the mixed combustion flat flame, realizing dual heat storage and staged combustion of gas and combustion-supporting air, reducing nitrogen oxide emissions, and achieving low nitrogen combustion and adjustable nitrogen oxide emission concentration by adjusting the ratio of primary fuel and secondary fuel.

[0046] Soot process:

[0047] After the primary gas removes the heat stored in the regenerator, it reverses direction at a set cycle, shutting off the gas and air. Negative pressure is applied to the primary gas inlet 2, causing the high-temperature flue gas in the furnace to pass through the flat flame channel 12, into the mixing channel 7, and then through the swirl channel 6 into the regenerator 5, heating the regenerator. Once heated to the set temperature, the negative pressure is cut off, switching between flue gas and gas, completing a heat storage and release cycle.

[0048] Combustion air heat storage process:

[0049] The combustion-supporting air enters the heat storage body 5 from the air inlet 1 for preheating, and the air can be preheated to above 1000°C (varies according to the application scenario). The preheated air enters the swirl channel 6 for high-speed rotation. The high-speed rotating airflow and the high-speed rotating primary gas from the other heat storage chamber 5 are mixed in the mixing channel 7. An ignition burner 8 and a flame monitor 9 are provided at the end of the mixing channel 7 for ignition and flame monitoring. The ignited mixed rotating gas forms a flat flame with the assistance of the trumpet-shaped flat flame channel 12. At the outer edge of the trumpet-shaped mouth of the flat flame channel 12, the secondary gas fed in through the secondary gas pipe 10 is rotated and ejected at the secondary gas nozzle 11 for mixed combustion. In this way, dual heat storage of gas and combustion-supporting air is achieved, and the purpose of low nitrogen oxide emissions through staged combustion is achieved.

[0050] Air-smoke process: After the combustion-supporting air takes away the heat accumulated in the heat storage body, it is reversed at a set cycle, the air and gas are cut off, and negative pressure is applied at the air inlet 1. At this time, the high-temperature flue gas in the furnace enters the mixing channel 7 through the flat flame channel 12, and then enters the heat storage chamber 5 through the swirl channel 6 to heat the heat storage body. After heating to the set temperature, the negative pressure is cut off, and the flue gas and air are switched to complete a heat storage and heat release cycle.

[0051] The double heat storage low nitrogen flat flame burner achieves a heating process of combustion and heat storage reciprocating cycle by switching the modes of a pair of burners.

Claims

1. A double heat storage low nitrogen flat flame burner, characterized in that: The utility model comprises two heat storage chambers, two swirl channels, a mixing channel, a flat flame channel, a secondary gas channel, and a secondary gas nozzle. The upper ends of the two heat storage chambers are respectively provided with an air inlet and a primary gas inlet. The bottoms of the two heat storage chambers are respectively connected to two swirl channels, which are connected to the mixing channel. The outlet of the mixing channel is a bell-shaped flat flame channel. The secondary gas channel and the secondary gas nozzle are circumferentially arranged on the outer circumference of the flat flame channel. The secondary gas nozzle is a tangential outlet. The secondary gas channel is externally connected to a secondary gas pipe.

2. A double heat storage low nitrogen flat flame burner according to claim 1, characterized in that: An inner swirl tube is provided in the mixing channel, the inner hole of the inner swirl tube is communicated with the swirl channel for introducing air, and the outer circumferential annular channel formed by the inner swirl tube and the mixing channel is communicated with the swirl channel for introducing gas.

3. A double heat storage low nitrogen flat flame burner according to claim 1 or 2, characterized in that: The flat flame channel is a Laval nozzle structure.

4. A double heat storage low nitrogen flat flame burner according to claim 1, characterized in that: An observation hole is provided at the other end of the mixing channel.

5. The double heat storage low nitrogen flat flame burner according to claim 1, characterized in that: A flame monitor and an ignition burner are provided at the flat flame channel.

6. A method for using the dual heat storage low nitrogen flat flame burner according to any one of claims 1 to 5, characterized in that: include: 1) Regenerative process: Primary gas and air enter the two regenerators through the primary gas inlet and air inlet respectively for preheating. The preheated primary gas and air enter the two swirl channels respectively for swirl, and then enter the mixing channel together. The ignited mixed swirling gas forms a flat flame under the bell mouth and wall effect of the bell mouth flat flame channel. At the same time, the secondary gas swirlingly ejected from the secondary gas nozzle and the mixed combustion flat flame undergo secondary combustion; 2) Reversing is performed under the set cycle, the primary gas, secondary gas and air are cut off, and the high-temperature flue gas in the furnace is sucked into the mixing channel through the flat flame channel by negative pressure, and then enters the two heat storage chambers through two swirl channels to heat the heat storage body. After heating to the set temperature, the negative pressure is cut off, and the supply of primary gas, secondary gas and air is restored. The flue gas is switched with the gas and air to complete a heat storage and heat release cycle.

7. The method for using a dual heat storage low nitrogen flat flame burner according to claim 6, characterized in that: The preheating temperature of the heat storage chamber is not less than 1000°C.

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