FIR direct-fired low-nitrogen burner

Abstract

The utility model discloses an FIR (Finite Impulse Response) direct-fired low-nitrogen burner, which comprises a burner fire tube, an FIR (Finite Impulse Response) direct-fired low-nitrogen burner, an FIR (Finite Impulse Response) direct-fired low-nitrogen burner and an FIR direct-fired low-nitrogen burner, the fuel supply pipeline is fixedly arranged on the burner fire tube so as to supply fuel to the burning end of the burner fire tube; the primary air supply area is located in the central area of the burner fire tube, and primary air flows to the burning end of the burner fire tube; the secondary air supply area is close to the inner wall of the burner fire tube, and secondary air flows to the burning end of the burner fire tube; the swirler is fixedly arranged at the combustion end of the combustor fire tube and right faces the primary air supplied by the primary air supply area, the combustor can achieve internal circulation of flue gas, and the generation amount of NOx in the flue gas is reduced under the condition that the FGR is not increased; by optimizing the original combustion head part, the equipment emission is reduced, the energy efficiency of the boiler is improved, and the equipment cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of boiler combustion equipment, and specifically relates to a FIR direct-fired low-nitrogen burner. Background Art

[0002] Oxygen-enriched combustion is an emerging combustion technology. With the advancement of oxygen production methods, especially the progress of oxygen-enriched membrane technology, oxygen-enriched combustion technology has been gradually promoted in recent years. Moreover, oxygen-enriched combustion technology has been realized by transformation on boilers, and has a foreseeable development prospect. At present, oxygen-enriched combustion is mainly used in foreign countries and industrial furnaces and is relatively mature. In addition, oxygen-enriched combustion technology has also appeared in the aviation field and ship combustion. The so-called oxygen-enriched combustion technology refers to the combustion in which the oxygen content in the air used for combustion exceeds 20.94%. The increase in oxygen content in the air reduces the inert gas in the air accordingly. In theory, the combustion temperature is increased. The increase in oxygen content in the air reduces the amount of smoke produced by combustion, and the heat carried away by the corresponding smoke temperature is reduced. This not only increases the combustion temperature, but also improves the purpose of energy conservation and emission reduction.

[0003] To achieve oxygen-enriched combustion, one feasible path is to reduce the amount of nitrogen oxides generated. At present, most low-nitrogen burner manufacturers mainly use flue gas recirculation (FGR) to achieve low-nitrogen combustion. The basic principle is to introduce part of the low-temperature flue gas (inert gas) discharged from the smoke pipe of the boiler into the burner and mix it with the combustion air to reduce the combustion speed and absorb the combustion heat, thereby controlling the flame temperature at a low level, so that the flame energy is insufficient for the nitrogen in the combustion air to react with oxygen to generate nitrogen oxides, thereby achieving the purpose of controlling the concentration of nitrogen oxides. With the advancement of social science and technology and the continuous enhancement of people's energy-saving awareness, although The FGR flue gas external circulation technology is mature and runs relatively stably, but the problems with this technical solution are: first, it increases the furnace resistance, resulting in increased power consumption of the combustion-supporting fan; second, the relatively low-temperature flue gas (generally below 180°C) produced by combustion is sucked into the combustion-supporting fan through the flue outside the furnace, mixed with the air at normal temperature, and cooled by the air. The water vapor in the flue gas will condense into liquid water and flow out of the burner, polluting the working environment and increasing energy consumption. In addition, liquid water will cause unreliable burner ignition and insulation failure of electronic components; third, it is necessary to establish a flue gas channel between the furnace body (boiler outlet flue) and the burner fan inlet, which increases the workload of burner installation.

[0004] Based on the above technical problems existing in the prior art, the utility model proposes a FIR direct-fired low-nitrogen burner. Utility Model Content

[0005] The utility model aims to provide a FIR direct-fired low-nitrogen burner in view of the deficiencies in the prior art.

[0006] The utility model adopts the following technical solutions:

[0007] An FIR direct-fired low-nitrogen burner, comprising:

[0008] A burner fire tube is embedded in the front wall of the boiler, and the combustion end of the burner fire tube extends into the combustion chamber of the boiler;

[0009] a fuel supply pipeline, fixedly disposed on the burner fire tube to supply fuel to the combustion end of the burner fire tube;

[0010] A primary air supply area is located in the central area of ​​the burner fire tube, and the primary air flows toward the combustion end of the burner fire tube;

[0011] A secondary air supply area is close to the inner wall of the burner fire tube, and the secondary air flows toward the combustion end of the burner fire tube;

[0012] The swirler is fixedly arranged at the combustion end of the burner fire tube, facing the primary air supplied by the primary air supply area.

[0013] Furthermore, the burner fire tube also includes a fire tube extension section, which is fixed to the middle of the burner fire tube by welding, and the length of the fire tube extension section is 50-100 mm.

[0014] Furthermore, the fuel supply pipeline includes a center fire tube fixedly arranged at the axis of the burner fire tube and an edge fire tube connected to the center fire tube, a primary combustion fire tube is arranged in the area of ​​the center fire tube close to the combustion end, and a secondary combustion fire tube is arranged in the area of ​​the edge fire tube close to the combustion end.

[0015] Furthermore, the primary combustion fire tube is provided with a plurality of fuel nozzles, and the fuel nozzles are arranged in a ring array at the combustion end of the primary combustion fire tube.

[0016] Furthermore, the fuel injection direction of the fuel nozzle is perpendicular to the direction of the primary combustion fire tube.

[0017] Furthermore, the central fire tube is connected to a plurality of the edge fire tubes, and the edge fire tubes are arranged in a ring array on the central fire tube.

[0018] Furthermore, the diameter of the edge fire tube is smaller than the diameter of the center fire tube.

[0019] Furthermore, the central fire tube is connected to 3-4 edge fire tubes, and the diameter of the edge fire tubes is greater than 1 / 2 of the diameter of the central fire tube.

[0020] Furthermore, the combustion end of the burner fire tube is connected to a fire tube reduced diameter portion, and the angle between the outer wall of the burner fire tube and the outer wall of the fire tube reduced diameter portion is 120-135 degrees.

[0021] The beneficial effects of the utility model are:

[0022] The FIR direct-fired low-nitrogen burner of the utility model can realize internal circulation of flue gas by coordinating the arrangement of burner fire tubes, fuel supply pipelines, primary air supply areas, secondary air supply areas and cyclones, thereby reducing the generation of flue gas NOx without increasing FGR; and can reduce equipment emissions by optimizing the original combustion head part, thereby improving boiler energy efficiency and reducing equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the FIR direct-fired low-nitrogen burner described in an embodiment of the present invention;

[0024] In the figure, 1-burner fire tube, 11-combustion end, 12-fire tube extension section, 13-fire tube reduction section;

[0025] 2-fuel supply pipe, 21-center fire tube, 211-primary combustion fire tube, 2111-fuel nozzle, 22-edge fire tube, 23-butt flange;

[0026] 3-Primary air supply area;

[0027] 4- Secondary air supply area;

[0028] 5- Cyclone. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above-mentioned purposes, features and advantages of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] Example

[0031] like Figure 1 As shown, the FIR direct-fired low-nitrogen burner comprises:

[0032] A burner fire tube 1 is embedded in the front wall of the boiler, and a combustion end 11 of the burner fire tube 1 extends into the combustion chamber of the boiler;

[0033] a fuel supply pipeline 2, fixedly arranged on the burner fire tube 1, to supply fuel to the combustion end 11 of the burner fire tube 1;

[0034] A primary air supply area 3 is located in the central area of ​​the burner fire tube 1, and the primary air flows toward the combustion end 11 of the burner fire tube 1;

[0035] The secondary air supply area 4 is close to the inner wall of the burner fire tube 1, and the secondary air flows toward the combustion end 11 of the burner fire tube 1;

[0036] The swirler 5 is fixedly arranged at the combustion end 11 of the burner fire tube 1, facing the primary air supplied by the primary air supply area 3, so as to evenly mix the fuel and the flame retardant air to form a disturbed rotating flame, and push the flame toward the tail of the furnace;

[0037] As a specific implementation, the burner fire tube 1 is made of 310S stainless steel;

[0038] The fuel supply pipeline 2 is made of stainless steel;

[0039] The swirler 5 is a grid-type swirling burner;

[0040] Two different air supply areas, the primary air supply area 3 and the secondary air supply area 4, are used to generate different air pressures in the combustion area;

[0041] The supply end of the fuel supply pipeline 2 is provided with a docking flange 23 to facilitate the supply of fuel.

[0042] The burner fire tube 1 further includes a fire tube extension section 12, which is fixed to the middle of the burner fire tube 1 by welding, and the length of the fire tube extension section 12 is 50-100 mm;

[0043] By providing the fire tube extension section 12, the FIR direct-fired low-nitrogen burner can provide sufficient smoke return space;

[0044] The cyclone 5 allows the burning flue gas to flow from the tail of the boiler back to the flame part of the FIR direct-fired low-nitrogen burner, and to flow over a long distance, so that the low-temperature flue gas can flow back to the burning flame part, reducing the flame peak and achieving the purpose of internal circulation to reduce nitrogen oxides. During this period, the reliance on oxygen provided by fresh air can be reduced.

[0045] The fuel supply pipeline 2 includes a central fire tube 21 fixedly arranged at the axis of the burner fire tube 1 and an edge fire tube 22 connected to the central fire tube 21. The central fire tube 21 is provided with a primary combustion fire tube 211 in an area close to the combustion end 11, and the edge fire tube 22 is provided with a secondary combustion fire tube 221 in an area close to the combustion end 11.

[0046] The primary combustion fire tube 211 is provided with a plurality of fuel nozzles 2111, and the fuel nozzles 2111 are arranged in a ring array at the combustion end of the primary combustion fire tube 211;

[0047] As a specific implementation, the fuel injection direction of the fuel nozzle 2111 is perpendicular to the direction of the primary combustion fire tube 211;

[0048] The central fire tube 21 is connected to a plurality of edge fire tubes 22, and the edge fire tubes 22 are arranged in a ring array on the central fire tube 21;

[0049] The diameter of the edge fire tube 22 is smaller than the diameter of the center fire tube 21;

[0050] The central fire tube 21 is connected to 3-4 edge fire tubes 22, and the diameter of the edge fire tubes 22 is greater than 1 / 2 of the diameter of the central fire tube 21;

[0051] When there are three edge fire tubes 22, the distance between each edge fire tube 22 and the center fire tube 21 is the same;

[0052] The central fire tube 21 and the edge fire tube 22 are separated from the fuel supply pipeline 2. In actual operation, the fuel flow rate output by the edge fire tube 22 is made greater than the fuel flow rate output by the central fire tube 21. Thus, the purpose of dispersing the flame is achieved. In addition, nitrogen oxides can also be reduced.

[0053] The combustion end 11 of the burner fire tube 1 is connected to a fire tube reduction portion 13, and the angle between the outer wall of the burner fire tube 1 and the outer wall of the fire tube reduction portion 13 is 120-135 degrees;

[0054] As a result, the turbocharger effect can be smoothly formed, the internal circulation effect can be rapidly produced, the peak flame is mixed, and the furnace flame temperature is neutralized;

[0055] The secondary air outlet of the secondary air supply area 4 is contracted by the fire tube diameter reduction portion 13, producing an effect of greater wind pressure than the primary air. Under the same wind pressure, the secondary air outlet is rapidly closed, and the secondary air flows through, generating a certain pressure. The primary air reduces the wind pressure under the resistance of the cyclone 5, generating a primary and secondary air pressure difference near the combustion end 11, causing the combustion return smoke to form a phenomenon of entrainment and involution.

[0056] By setting the angle of 120-135 degrees, the internal circulating flue gas can form a rotary suction effect, which not only allows the flue gas to flow smoothly, but also can change the direction and speed of the flue gas; it can smoothly form a turbocharging effect, quickly produce an internal circulation effect, mix the peak value flame, and neutralize the furnace flame temperature.

[0057] The present invention is not limited by the above embodiments. The above embodiments and the description are only for explaining the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims.

Claims

1. A FIR direct-fired low-nitrogen burner, characterized in that: include: A burner fire tube is embedded in the front wall of the boiler, and the combustion end of the burner fire tube extends into the combustion chamber of the boiler; a fuel supply pipeline fixedly disposed on the burner fire tube to supply fuel to the combustion end of the burner fire tube; A primary air supply area is located in the central area of ​​the burner fire tube, and the primary air flows toward the combustion end of the burner fire tube; A secondary air supply area is close to the inner wall of the burner fire tube, and the secondary air flows toward the combustion end of the burner fire tube; The swirler is fixedly arranged at the combustion end of the burner fire tube, facing the primary air supplied by the primary air supply area.

2. The FIR direct-fired low-nitrogen burner according to claim 1 is characterized in that: The fuel supply pipeline includes a central fire tube fixedly arranged at the axis of the burner fire tube and an edge fire tube connected to the central fire tube. A primary combustion fire tube is arranged in the area of ​​the central fire tube close to the combustion end, and a secondary combustion fire tube is arranged in the area of ​​the edge fire tube close to the combustion end.

3. The FIR direct-fired low-nitrogen burner according to claim 1, characterized in that: The burner fire tube also includes a fire tube extension section, which is fixed to the middle of the burner fire tube by welding, and the length of the fire tube extension section is 50-100 mm.

4. The FIR direct-fired low-nitrogen burner according to claim 1 or 2, characterized in that: The combustion end of the burner fire tube is connected with a fire tube reduced diameter portion, and the angle between the outer wall of the burner fire tube and the outer wall of the fire tube reduced diameter portion is 120-135 degrees.

5. The FIR direct-fired low-nitrogen burner according to claim 2, characterized in that: The primary combustion fire tube is provided with a plurality of fuel nozzles, and the fuel nozzles are arranged in a ring array at the combustion end of the primary combustion fire tube.

6. The FIR direct-fired low-nitrogen burner according to claim 2 or 5, characterized in that: The central fire tube is connected to a plurality of edge fire tubes, and the edge fire tubes are arranged in a ring array on the central fire tube.

7. The FIR direct-fired low-nitrogen burner according to claim 6, characterized in that: The central fire tube is connected to 3-4 edge fire tubes, and the diameter of the edge fire tubes is greater than 1 / 2 of the diameter of the central fire tube.

8. The FIR direct-fired low-nitrogen burner according to claim 1, characterized in that: The combustion end of the burner fire tube is connected with a fire tube reduced diameter portion, and the angle between the outer wall of the burner fire tube and the outer wall of the fire tube reduced diameter portion is 120-135 degrees.

9. The FIR direct-fired low-nitrogen burner according to claim 5, characterized in that: The primary combustion fire tube is provided with a plurality of fuel nozzles, and the fuel nozzles are arranged in a ring array at the combustion end of the primary combustion fire tube.

10. The FIR direct-fired low-nitrogen burner according to claim 9, characterized in that: The fuel injection direction of the fuel nozzle is perpendicular to the direction of the primary combustion fire tube.

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