Wall-attached self-preheating low-nitrogen high-efficiency combustor
By introducing specially designed nozzles, swirl vanes, and heat exchange turbulence conductors into the burner, the problems of uneven flame and excessive NOx emissions in traditional burners have been solved, achieving a more efficient and uniform combustion process and reducing furnace wall temperature gradient and nitrogen oxide emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DAQING HUAKAI PETROCHEMICAL DESIGN ENG CO LTD
- Filing Date
- 2024-11-11
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional wall-mounted burners are prone to flameout, have excessively long flames, and poor wall adhesion, resulting in uneven furnace wall temperatures, excessive NOx and CO levels, and difficulty in fuel grading and adjustment, making it difficult to effectively suppress the generation of nitrogen oxides.
It employs specially designed nozzles, swirl blades, and heat exchange turbulence conductors to improve fuel-air mixing efficiency, expand the flame area, and reduce the furnace wall temperature gradient by preheating the combustion air. The flame shape is also controlled by the specially designed nozzles to reduce heat loss.
It improves the thermal efficiency of the burner, reduces the unevenness of furnace wall temperature, reduces NOx and CO emissions, and achieves more uniform combustion and more efficient fuel utilization.
Smart Images
Figure CN119468210B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of burner technology, specifically to a wall-mounted self-preheating low-NOx high-efficiency burner. Background Technology
[0002] With increasing environmental awareness and ever-increasing requirements for air quality, reducing nitrogen oxide (NOx) emissions has become an important task. During combustion, the generation of NOx has many negative impacts on the environment and human health. Traditional burners often produce high concentrations of NOx during combustion. To address this issue, low-NOx burners have emerged. Low-NOx burners employ advanced combustion technologies and design concepts to reduce the amount of NOx generated during combustion. In ethylene plants, the cracking furnace is the largest energy-consuming device, and the burner is a crucial part of the fuel consumed by the cracking furnace.
[0003] However, traditional wall-mounted burners are prone to flameout, have excessively long flames, and poor wall adhesion. During combustion, most of the flames are too concentrated, adhering to the furnace wall around the burner and failing to spread. This results in the flame adhering to the wall in the center, with the furnace wall temperature being much higher than other areas. Consequently, the furnace wall temperature around the burner is high, leading to significant heat loss and a large temperature gradient around the burner nozzle. The temperature distribution in the radiant furnace is uneven. In some burners, the nozzle distribution ratio for fuel grading is difficult to adjust. After adjusting the operating conditions, it is not easy to suppress NOx generated by the burner, and NOx or CO exceed the standard. Some side-wall burners using premixed fuel methods have limited means and effectiveness in controlling the flame range and suppressing nitrogen oxide generation due to limitations in flame shape, safety, and adjustment range. Summary of the Invention
[0004] This invention provides a wall-mounted self-preheating low-NOx high-efficiency burner, which solves the problems existing in the prior art through a specially designed nozzle and swirl blades.
[0005] The technical solution of this invention is as follows:
[0006] A wall-mounted self-preheating low-NOx high-efficiency burner includes: a shell, a burner duct fire basin brick fixedly connected to the shell, a nozzle gun body installed at the center of the shell, the nozzle gun body passing through the shell and the burner duct fire basin brick, a burner shroud installed outside the shell, a main damper valve and a fine-tuning damper valve respectively provided on the shell and the burner duct fire basin brick, the main damper valve and the fine-tuning damper valve being able to open the communication channel between the shell and the burner duct fire basin brick and the burner shroud, a fuel pipe installed at the center of the nozzle gun body, a swirl ring, a vortex blade and a grid corner post sequentially arranged on the fuel pipe, the swirl ring being slidably connected to the fuel pipe, the grid corner post being fixedly connected to the fuel pipe, a special nozzle being installed at one end of the fuel pipe located inside the burner duct fire basin brick, and the grid corner post being close to the special nozzle.
[0007] Preferably, the nozzle body includes an arc-shaped tube one, a straight tube one, an arc-shaped tube two, and a straight tube two arranged in sequence. The straight tube two has multiple rows of ventilation holes, and a venturi tube is installed at one end of the arc-shaped tube one.
[0008] Preferably, a heat exchange turbulence conductor is provided inside the burner shroud, the heat exchange turbulence conductor is an elastic steel wire mesh, and an air inlet is provided on the burner shroud, the air inlet is annular and the notch is 15cm.
[0009] Preferably, a rain shield is provided on the upper part of the burner shroud.
[0010] Preferably, the grate ring is located between the straight pipe one and the arc-shaped pipe two, and the grate ring is conical with the same arc as the arc of the arc-shaped pipe two.
[0011] Preferably, the special nozzle includes a primary combustion head and a secondary combustion head installed at the head of the fuel pipe. The primary combustion head is equipped with a flame stabilizing plate. The two ends of the secondary combustion head are fixedly connected to the fuel pipe and the flame stabilizing plate, respectively, and pass through the fuel pipe and the flame stabilizing plate. The secondary combustion head is arc-shaped and has multiple rows of flame holes. The flame holes are located on the side of the flame stabilizing plate away from the secondary combustion head. The flame stabilizing plate has multiple return holes.
[0012] Preferably, a flame nozzle is fixedly connected to the secondary combustion head at the flame hole, and the flame nozzle forms a certain angle with the secondary combustion head.
[0013] Preferably, the specially designed nozzle extends out of one end of the burner duct fire basin brick.
[0014] Compared with the prior art, the present invention has the following beneficial effects:
[0015] This invention incorporates a heat exchange turbulence conductor within the burner shroud. This conductor, made of elastic wire mesh packing, adheres to the furnace wall panel. Simultaneously, it exchanges heat from the superheated area outside the furnace wall panel, preheating the combustion air. The heated combustion air mixes more thoroughly with the fuel, thus reducing localized high temperatures on the furnace wall panel and minimizing heat loss from the pyrolysis furnace, thereby improving the thermal efficiency of the heating furnace. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the installation of the burner of the present invention;
[0017] Figure 2 This is a perspective view of the burner of the present invention;
[0018] Figure 3 This is a three-dimensional cross-sectional view of the burner of the present invention;
[0019] Figure 4 This is a perspective view of the front of the fuel pipe structure of the present invention.
[0020] In the picture:
[0021] 1. Outer shell; 2. Burner duct fire basin brick; 3. Nozzle gun body; 31. Arc-shaped tube one; 32. Straight tube one; 33. Arc-shaped tube two; 34. Straight tube two; 35. Venturi tube; 36. Venturi tube; 4. Burner hood; 41. Heat exchange turbulence conductor; 42. Air inlet; 43. Rain baffle; 5. Main damper valve; 6. Damper fine-tuning valve; 7. Fuel pipe; 8. Roar ring; 9. Swirl blades; 10. Grille corner post; 11. Special nozzle; 111. Primary combustion head; 112. Secondary combustion head; 113. Flame stabilizer plate; 114. Flame hole; 115. Return hole; 116. Flame hole nozzle; 12. Furnace wall panel. Detailed Implementation
[0022] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Example
[0023] like Figure 1-3As shown, this invention provides a wall-mounted self-preheating low-NOx high-efficiency burner, comprising: a shell 1, and a burner duct fire basin brick 2 fixedly connected to the shell 1. The burner is mounted on a furnace wall panel 12 via the burner duct fire basin brick 2. A nozzle gun body 3 is installed at the center of the shell 1, and the nozzle gun body 3 passes through the shell 1 and the burner duct fire basin brick 2. A burner hood 4 is installed outside the shell 1. A main damper valve 5 and a damper fine-tuning valve 6 are respectively provided on the shell 1 and the burner duct fire basin brick 2. The main valve 5 and the damper fine-tuning valve 6 can open the communication channel between the outer shell 1 and the burner duct fire basin brick 2 and the burner hood 4. The nozzle body 3 is equipped with a fuel pipe 7 at its center. The fuel pipe 7 is sequentially equipped with a grate ring 8, a swirl vane 9 and a grid corner post 10. The grate ring 8 is slidably connected to the fuel pipe 7, and the grid corner post 10 is fixedly connected to the fuel pipe 7. A special nozzle 11 is installed at one end of the fuel pipe 7 inside the burner duct fire basin brick 2, and the grid corner post 10 is close to the special nozzle 11.
[0024] Combustion air is introduced naturally through the burner shroud 4. The main air valve 5 is opened, allowing most of the combustion air to enter the outer casing 1 and flow into the nozzle body 3. A large amount of combustion air enters the nozzle body 3 and is delivered to the special nozzle 11. The special nozzle 11 sprays fuel from the fuel pipe 7, which comes into contact with the combustion air in the nozzle body 3 and is ignited by the igniter. The air damper fine-tuning valve 6 is adjusted to allow a small portion of the combustion air to enter the burner duct fire basin brick 2 and be delivered to the special nozzle 11 for air distribution. During the transmission of the combustion air in the nozzle body 3, the flow rate of the combustion air is controlled by the duct ring 8, and the combustion air is vortex-guided by the swirl blades 9 to ensure that the combustion air and fuel are fully mixed.
[0025] like Figure 3 As shown, the nozzle body 3 includes an arc-shaped tube 31, a straight tube 32, an arc-shaped tube 33, and a straight tube 34 arranged sequentially. These three tubes form a Venturi tube shape. When combustion air flows from the relatively large arc-shaped tube 31 through the narrow straight tube 32, the flow rate decreases and the velocity increases. According to Bernoulli's principle, the increased velocity leads to a decrease in pressure, thus creating a low-pressure zone at the straight tube 32. This creates a pressure difference between the two ends of the straight tube 32, increasing the pressure of the combustion air and allowing for more complete contact between the combustion air and the fuel. Figure 3 As shown, a ventilation hole 35 is provided on the straight pipe 2 34, allowing a small amount of combustion air to enter from the gap between the burner duct fire basin brick 2 and the nozzle body 3, and flow through the ventilation hole 35 to the special nozzle 11 to finely adjust the flame; as Figure 3 As shown, a venturi tube 36 is installed at one end of the arc-shaped tube 31, so that the combustion air entering from the burner shroud 4 is pressurized and accelerated through the venturi tube 36 and enters the nozzle body 3. The Reynolds number can be adjusted within a suitable range according to the local air pressure conditions.
[0026] like Figure 1 As shown, a heat exchange turbulence conductor 41 is provided inside the burner hood 4. The heat exchange turbulence conductor 41 is made of elastic steel wire mesh filler and can be adsorbed on the furnace wall plate 12. At the same time, the heat exchange turbulence conductor 41 absorbs and stores the heat from the outside of the furnace wall plate 12, and preheats the combustion air entering the burner hood 4, so that the inside of the burner hood 4 is in a thermal equilibrium state. The heated combustion air then enters the nozzle body 3 to assist combustion. This can reduce the local high temperature of the furnace wall plate 12 and reduce the heat loss of the pyrolysis furnace, greatly improving the thermal efficiency of the heating furnace.
[0027] An air inlet 42 is provided on the burner shroud 4. The air inlet 42 is a ring with a notch of 15cm, which creates a negative pressure and draws the external gas into the burner shroud 4, thereby preheating the air.
[0028] A rain shield 43 is provided on the upper part of the burner shroud 4 to prevent rainwater from entering the burner shroud 4.
[0029] like Figure 3 As shown, the grate ring 8 is located between the straight pipe 32 and the arc-shaped pipe 33. The grate ring 8 is conical and its curvature is the same as that of the arc-shaped pipe 33. This allows the combustion air to flow towards the edge of the arc-shaped pipe 33 when it flows out from the gap between the grate ring 8 and the arc-shaped pipe 33. Because of the Venturi principle, the flow pressure between the straight pipe 32 and the arc-shaped pipe 33 is greater, so the combustion air has greater power to flow towards the edge from this point, thus making the combustion air and fuel more fully contacted.
[0030] like Figure 4 As shown, the special nozzle 11 includes a primary combustion head 111 and a secondary combustion head 112 installed at the head of the fuel pipe 7. A flame stabilizer plate 113 is installed on the primary combustion head 111. The two ends of the secondary combustion head 112 are fixedly connected to the fuel pipe 7 and the flame stabilizer plate 113 respectively and pass through the fuel pipe 7 and the flame stabilizer plate 113. The secondary combustion head 112 is arc-shaped and has multiple rows of flame holes 114. The flame holes 114 are located on the side of the flame stabilizer plate 113 away from the secondary combustion head 112. Multiple return holes 115 are provided on the flame stabilizer plate 113.
[0031] Fuel in fuel pipe 7 flows out from primary burner head 111 and secondary burner head 112 respectively, and comes into contact with combustion air flowing in from the gap between straight pipe 2 34 and flame stabilizer plate 113. The fuel is ignited by igniter to achieve heating. The secondary burner head 112 is set in an arc shape, which expands the flame area attached to the wall of the burner by 30% to 40% compared with the traditional area, and the flame is more powerful. At the same time, it reduces the temperature gradient around the flame area of the burner, reducing heat loss. The flue gas generated by combustion flows from return hole 115 to grid corner column 10. The grid corner column 10 returns the flue gas to the inner wall of straight pipe 2 34. It is carried by the combustion air and re-enters the combustion zone on one side of flame stabilizer plate 113 for complete combustion, thereby reducing the generation of oxygen-containing nitrogen oxides. The combustion air is evenly distributed by the grid corner column 10, so that the combustion air and fuel are more fully mixed.
[0032] A flame nozzle 116 is fixedly connected to the secondary combustion head 112 at the flame hole 114, and the flame nozzle 116 forms a certain angle with the secondary combustion head 112.
[0033] Due to the influence of combustion speed, backfire may occur when the heat load is low or the fuel composition changes significantly. In order to prevent backfire, the specially designed nozzle 11 correctly selects the spacing, number, angle and length of the flame holes 114 according to the load adjustment ratio, fuel composition and primary air coefficient. It can effectively control the flame to stick to the wall, and the flame is flat and round, and strong and stable.
[0034] The specially designed nozzle 11 extends out of one end of the burner duct fire basin brick 2, protruding about 20mm to 30mm longer than that of a traditional burner. The flame area attached to the wall of the burner will be expanded; the expanded flame area will reduce the temperature gradient around the burner, reduce the thermal stress on the steel structure around the burner, and make the furnace tubes heat up more evenly.
[0035] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A wall-mounted self-preheating low-NOx high-efficiency burner, comprising: The outer shell (1) and the burner duct fire basin brick (2) fixedly connected to the outer shell (1) are characterized in that: a nozzle gun body (3) is installed at the center of the outer shell (1), and the nozzle gun body (3) passes through the outer shell (1) and the burner duct fire basin brick (2); a burner hood (4) is installed outside the outer shell (1); a main damper valve (5) and a damper fine adjustment valve (6) are respectively provided on the outer shell (1) and the burner duct fire basin brick (2); the main damper valve (5) and the damper fine adjustment valve (6) can open the outer shell (1) and the burner duct. The fire pit brick (2) and the burner hood (4) are connected by a communication channel. A fuel pipe (7) is installed at the center of the nozzle body (3). A swirl ring (8), a swirl vane (9) and a grid corner post (10) are arranged on the fuel pipe (7) in sequence. The swirl ring (8) is slidably connected to the fuel pipe (7). The grid corner post (10) is fixedly connected to the fuel pipe (7). A special nozzle (11) is installed at one end of the fuel pipe (7) located in the fire pit brick (2) of the burner hood, and the grid corner post (10) is close to the special nozzle (11). The burner shroud (4) is provided with a heat exchange turbulence conductor (41), which is an elastic steel wire mesh. The burner shroud (4) is provided with an air inlet (42), which is annular and has a gap of 15cm. The special nozzle (11) includes a primary combustion head (111) and a secondary combustion head (112) installed at the head of the fuel pipe (7). A flame stabilizer (113) is installed on the primary combustion head (111). The two ends of the secondary combustion head (112) are fixedly connected to the fuel pipe (7) and the flame stabilizer (113) respectively and pass through the fuel pipe (7) and the flame stabilizer (113). The secondary combustion head (112) is arc-shaped. Multiple rows of fire holes (114) are opened on the secondary combustion head (112). The fire holes (114) are located on the side of the flame stabilizer (113) away from the secondary combustion head (112). Multiple return holes (115) are opened on the flame stabilizer (113).
2. The wall-mounted self-preheating low-NOx high-efficiency burner as described in claim 1, characterized in that: The nozzle gun body (3) includes an arc-shaped tube one (31), a straight tube one (32), an arc-shaped tube two (33), and a straight tube two (34) arranged in sequence. Multiple rows of ventilation holes (35) are opened on the straight tube two (34), and a venturi tube (36) is installed at one end of the arc-shaped tube one (31).
3. The wall-mounted self-preheating low-NOx high-efficiency burner as described in claim 1, characterized in that: The burner shroud (4) is provided with a rain shield (43) on its upper part.
4. The wall-mounted self-preheating low-NOx high-efficiency burner as described in claim 2, characterized in that: The roar ring (8) is located between the straight pipe one (32) and the arc-shaped pipe two (33), and the roar ring (8) is conical and the arc is the same as that of the arc-shaped pipe two (33).
5. The wall-mounted self-preheating low-NOx high-efficiency burner as described in claim 4, characterized in that: A flame nozzle (116) is fixedly connected to the secondary combustion head (112) at the flame hole (114), and the flame nozzle (116) forms a certain angle with the secondary combustion head (112).
6. The wall-mounted self-preheating low-NOx high-efficiency burner as described in claim 1, characterized in that: The specially designed nozzle (11) extends out of one end of the burner duct fire basin brick (2).