Ammonia-fired wall burner

Abstract

Two-stage combustion produces NO X To provide an ammonia combustion wall burner capable of efficiently and stably burning ammonia by reducing the generation of fumes. [Solution] The ammonia combustion wall burner 10 of the present invention comprises a cylindrical combustion tip 30 attached to the tip of the wall burner body 20, and the combustion tip 30 is characterized by comprising: ammonia fuel injection holes 38 that are connected to the ammonia fuel passage of the wall burner body 20 and open at intervals on the circumferential surface of the outer circumferential surface to inject ammonia fuel; front and rear primary combustion air injection holes 40, 42 that are connected to the primary combustion air passage of the wall burner body 20 and inject combustion air from the outer circumferential surface of the combustion tip and are arranged on either side of the ammonia fuel injection hole in the circumferential direction of the outer circumferential surface of the combustion tip; and secondary combustion air injection holes 54 that are connected to the secondary combustion air passage of the wall burner body and are located at a predetermined distance from the combustion tip 30 on the outer circumferential surface of a circular member 52 that extends from the tip surface of the combustion tip and inject combustion air.

Description

[Technical Field]

[0001] The present invention relates to an ammonia-fired wall burner that burns ammonia (NH3) fuel. [Background technology]

[0002] Naphtha cracking furnaces, which thermally crack naphtha to produce basic petrochemical products, have traditionally emitted tens of millions of tons of CO2 annually. In recent years, technological developments have been underway to reduce CO2 emissions by switching the fuel used in naphtha cracking furnaces from hydrocarbon fuels to ammonia fuel. Ammonia fuel does not contain carbon, so it does not emit carbon dioxide when burned, and has advantages such as increased energy density when liquefied and efficient transportation and storage. However, ammonia fuel produces large amounts of NO when burned. X However, there are problems with the emission of CO2 and the drawback of low combustion stability.

[0003] Patent Document 1 describes a conventional ammonia combustion furnace that is equipped with a furnace body having a first combustion chamber in which fuel containing ammonia is burned in a reducing atmosphere at 1400°C or higher, and a second combustion chamber in which unburned fuel is burned at 1300°C or lower, and that achieves ignition and flame stability and low NO X A technology that achieves both high efficiency and low power consumption has been disclosed. However, the technology of Patent Document 1 is configured to achieve ignition and flame-stabilization of ammonia in the entire combustion furnace of the first and second combustion chambers, and therefore requires the installation of a new combustion furnace, and therefore cannot be applied to existing combustion furnaces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-178082 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a method for producing NO by two-stage combustion in consideration of the above-mentioned problems of the prior art. X To provide an ammonia combustion wall burner capable of efficiently and stably burning ammonia by reducing the generation of HCl. [Means for solving the problem]

[0006] As a first means for solving the above problems, the present invention provides: The wall burner has a cylindrical combustion tip attached to the tip of the wall burner body. the combustion tip has ammonia fuel injection holes that are connected to the ammonia fuel passage of the wall burner body and open at intervals in the circumferential direction of the outer circumferential surface to inject ammonia fuel; The wall burner body is connected to a primary combustion air passage to inject combustion air from the outer peripheral surface of the combustion tip, and Axial direction front and rear stage primary combustion air injection holes arranged so as to sandwich the ammonia fuel injection hole therebetween; The wall burner body is connected to a secondary combustion air passage and extends from the tip end surface of the combustion tip. cross section The object of the present invention is to provide an ammonia combustion wall burner characterized in that secondary combustion air injection holes for injecting secondary combustion air are provided on the outer peripheral surface of the tip of a circular member at a predetermined distance from the combustion tip. According to the first method, the generation of NOx can be reduced and the stability and combustion efficiency of the ammonia flame can be improved. In addition, the radial injection from the outer periphery of the combustion tip can efficiently and uniformly heat the wall surface of the combustion furnace. Furthermore, it can be easily applied to existing combustion wall burners by simply replacing the combustion tip.

[0007] As a second means for solving the above problems, the present invention provides a method for manufacturing a semiconductor device according to the first means, The ammonia fuel injection holes are arranged in a plurality of rows in the circumferential direction, and are inclined at an acute angle between the axis of the combustion tip and a center line perpendicular to the axis of the combustion tip, and are injected so as to be mixed at a predetermined distance with the primary combustion air injected from the primary combustion air injection holes in the front and rear stages. According to the second means, the combustion air is injected radially and uniformly with the combustion tip as the axis, thereby improving the flame stability and NOx reduction in ammonia combustion. X The generation of can be reduced.

[0008] The present invention provides, as a third means for solving the above-mentioned problems, the second means, wherein the first stage and latter stage The primary combustion air injection holes are: The aforementioned Radiating from the axis of the combustion tip arrangement The object of the present invention is to provide an ammonia combustion wall burner characterized by the above. According to the third means, combustion air can be uniformly supplied to the ammonia fuel injected from the ammonia fuel injection holes, thereby making it possible to stabilize the flame in ammonia combustion and reduce the generation of NOx. [Effects of the Invention]

[0009] According to the present invention, NO is produced by two-stage combustion. X This reduces the generation of unburned ammonia and enables efficient and stable combustion of ammonia fuel. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of the configuration of an ammonia combustion wall burner of the present invention. [Figure 2] FIG. 2 is a side cross-sectional view of the combustion tip. [Figure 3] Cross section AA of Figure 2 [Figure 4] 3 is a cross-sectional view of FIG. 2 taken along line B-B. [Figure 5] FIG. 2 is a partial development view of the outer peripheral surface of the combustion tip. [Figure 6] 1 is a graph showing a comparison of NOx values ​​between equivalence ratios. [Figure 7] FIG. 1 is an analytical diagram of NOx value distribution in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip without circular member). [Figure 8] FIG. 1 is an analytical diagram of NOx value distribution in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip with a 100 mm circular member). [Figure 9] FIG. 1 is an analytical diagram of NOx value distribution in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip with a 300 mm circular member). [Figure 10] FIG. 1 is an analytical diagram of unburned NH3 distribution in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip without circular element). [Figure 11] FIG. 11 is an analysis of the distribution of unburned NH3 in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip with a 100 mm circular member). [Figure 12] FIG. 11 is an analysis of the distribution of unburned NH3 in the cross-sectional area of ​​an ammonia-fired wall burner (combustion tip with a 300 mm circular element). DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ammonia-fired wall burner according to the present invention will now be described in detail with reference to the accompanying drawings.

[0012] [Ammonia Combustion Wall Burner 10] Fig. 1 is a schematic diagram of the configuration of an ammonia combustion wall burner of the present invention. Fig. 2 is a side cross-sectional view of a combustion tip. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 4 is a cross-sectional view taken along line BB in Fig. 2. Fig. 5 is a partial development view of the outer peripheral surface of the combustion tip.

[0013] The ammonia combustion wall burner 10 of the present invention comprises a cylindrical combustion tip 30 attached to the tip of the wall burner body 20, and the combustion tip 30 comprises ammonia fuel injection holes 38 that are connected to the ammonia fuel passage 22 of the wall burner body 20 and open at intervals in the circumferential direction of the outer peripheral surface to inject ammonia fuel, front and rear primary combustion air injection holes 40, 42 that are connected to the primary combustion air passage of the wall burner body 20 and inject combustion air from the outer peripheral surface of the combustion tip 30 and are arranged on either side of the ammonia fuel injection hole 38 in the circumferential direction of the outer peripheral surface of the combustion tip 30, and a secondary combustion air injection hole 54 that is connected to the secondary combustion air passage 50 of the wall burner body 20 and injects combustion air at a predetermined distance from the combustion tip 30 on the outer peripheral surface of a circular member 52 that extends from the tip surface of the combustion tip 30.

[0014] (Wall burner body 20) The wall burner body 20 is a cylindrical burner with a secondary combustion air passage arranged along its axis, an ammonia fuel passage 22 arranged around the secondary combustion air passage, and a primary combustion air passage 28 arranged around the ammonia fuel passage 22. The secondary combustion air passage is arranged at the center of the wall burner body 20 and is a circular pipe through which secondary combustion air passes, and the flow rate can be adjusted as desired using a throttle valve (not shown). The ammonia fuel passage 22 has a double-pipe structure, with a medium- or high-pressure gas passage (medium-high-pressure gas passage 24) for hydrocarbons (such as LPG or LNG) arranged inside and a low-pressure ammonia gas passage (low-pressure gas passage 26) arranged outside the medium-high-pressure gas passage 24. The medium-high-pressure gas passage 24 and the low-pressure gas passage 26 each have a throttle valve (not shown) that allows the flow rate to be adjusted as desired. The primary combustion air passage 28 is a passage through which primary combustion air passes, and the flow rate can be adjusted as desired using a throttle valve (not shown). Such a wall burner body 20 is arranged so that the combustion tip 30 protrudes into the chamber from the wall surface of the combustion chamber (see Figure 1). Ammonia combustion starts first with a high hydrocarbon fuel mixture ratio, and when combustion reaches a predetermined stable temperature, the ammonia fuel mixture ratio is increased.

[0015] (Combustion chip 30) The combustion tip 30 is a cylindrical tip disposed at the tip of the wall burner body 20 and equipped with a circular member 52 extending axially from the tip. The interior of the combustion tip 30 is partitioned in the cross-sectional direction from the wall burner body 20 side toward the tip into a front-stage primary combustion air chamber 32, an ammonia fuel chamber 34, and a rear-stage primary combustion air chamber 36 in that order. The combustion tip 30 also has ammonia fuel injection holes 38 connected to the ammonia fuel passage 22 of the wall burner body 20, which are open at intervals in the circumferential direction of the outer circumferential surface and inject fuel such as hydrocarbons or ammonia from the outer circumferential surface, and front-stage and rear-stage primary combustion air injection holes 40, 42 connected to the primary combustion air passage 28 of the wall burner body 20, which are open at intervals in the circumferential direction of the outer circumferential surface so as to sandwich the ammonia fuel injection hole 38 therebetween, which are open at intervals in the circumferential direction of the outer circumferential surface and inject combustion air from the outer circumferential surface.

[0016] The front-stage primary combustion air chamber 32 is connected to the primary combustion air passage 28 of the wall burner body 20. The secondary combustion air passage 50 and ammonia fuel passage 22 run through the center of the front-stage primary combustion air chamber 32. The ammonia fuel passage 22 is separated from the adjacent ammonia fuel chamber 34 by a wall, preventing the ammonia fuel from mixing with the ammonia fuel within the tip. This differs from premixed combustion, in which fuel gas and air (oxidizer) are uniformly mixed in advance and then ignited to combust. The front-stage primary combustion air chamber 32 has front-stage primary combustion air injection holes 40 on its side, i.e., on the outer circumferential surface of the combustion tip 30. The front-stage primary combustion air injection holes 40 are holes spaced apart circumferentially around the outer circumferential surface of the combustion tip 30. The front-stage primary combustion air injection holes 40 are arranged in multiple rows (two rows in this embodiment) circumferentially around the outer circumferential surface of the combustion tip 30, allowing combustion air from the primary combustion air passage 28 and the front-stage primary combustion air chamber 32 to be injected radially from the outer circumferential surface (the tip axis) of the combustion tip 30. The primary combustion air injection holes 40 in the front stage inject combustion air to form combustion on the surface of the refractory (burner tile) that forms the flame, parallel to the refractory surface, in other words, perpendicular to the outer peripheral surface of the combustion burner.

[0017] The ammonia fuel chamber 34 is connected to the ammonia fuel passage 22 of the wall burner body 20. Five primary combustion air pipes 35 arranged radially from the tip axis penetrate the ammonia fuel chamber 34 (see Figures 3 and 4), and the ammonia fuel chamber 34 is separated from the adjacent rear-stage primary combustion air chamber 36 by a wall, so that the ammonia fuel does not mix with the combustion air inside the tip. The ammonia fuel chamber 34 has ammonia fuel injection holes 38 formed on its side, in other words, on the outer peripheral surface of the combustion tip 30. The ammonia fuel injection holes 38 are holes that open at intervals from one another in the circumferential direction of the outer peripheral surface of the combustion tip 30 and inject ammonia fuel from the outer peripheral surface.

[0018] The ammonia fuel injection holes 38 are arranged in multiple rows (two rows in this embodiment) in the circumferential direction, and the angle between the axis of the combustion tip 30 and the center line perpendicular to the axis is inclined at an acute angle (for example, 20 to 30 degrees), and the ammonia fuel is injected so that it mixes with the primary combustion air injected from the front and rear primary combustion air injection holes 40, 42 at a predetermined distance. This allows combustion air to be injected radially and uniformly around the combustion tip, improving flame stability and NOx reduction in ammonia combustion. X The occurrence of this can be reduced.

[0019] The rear-stage primary combustion air chamber 36 is connected to a primary combustion air pipe 35 that penetrates the ammonia fuel chamber 34. The rear-stage primary combustion air chamber 36 has rear-stage primary combustion air injection holes 42 formed on its side surface, in other words, on the outer peripheral surface of the combustion tip 30. The rear-stage primary combustion air injection holes 42 are holes that open at intervals from one another in the circumferential direction of the outer peripheral surface of the combustion tip 30. The combustion tip 30 injects the ammonia fuel and the combustion air separately into the combustion furnace, and diffusion combustion occurs from the part where the ammonia fuel and the air reach a combustible mixture ratio through natural convection and diffusion.

[0020] The rear-stage primary combustion air injection holes 42 inject ammonia fuel and hydrocarbon fuel so that they are sandwiched between the ammonia fuel and the primary combustion air injected from the front-stage primary combustion air injection holes 40 and the primary combustion air, and therefore form an air film that is injected parallel to the formed flame front, in other words, in a direction perpendicular to the outer circumferential surface of the combustion burner. The front and rear primary combustion air injection holes 40, 42 are arranged radially and evenly from the axis of the combustion tip 30 between the injection holes of the ammonia fuel injection holes 38, adjacent to the ammonia fuel injection holes 38 (see FIG. 5). This allows combustion air to be uniformly supplied to the ammonia fuel injected from the ammonia fuel injection holes 38, improving flame stability and NOx reduction in ammonia combustion. X The occurrence of this can be reduced.

[0021] The circular member 52 is attached to the center of the tip surface of the combustion tip 30 and connects the secondary combustion air passage 50 of the combustion tip 30. The circular member 52 extends a predetermined distance (preferably 300 mm or more) from the tip surface of the combustion tip 30, sealing the tip surface and providing multiple secondary combustion air injection holes 54 on the outer circumferential surface of the tip. This circular member 52 can inject secondary combustion air vertically from the outer circumferential surface at a position a predetermined distance away from the combustion tip 30.

[0022] (action) Figure 6 shows the NO X The graph shows a comparison of the NO X The horizontal axis shows the equivalence ratio (oxygen correction concentration 15%). The methane (CH4) and ammonia (NH3) mixed fuel was set to a mixture fraction (vol%) of NH3:CH4 = 50:50, NH3:CH4 = 70:30, and NH3:CH4 = 90:10. According to this, the more the proportion of ammonia contained in the fuel increases, the more NOx is generated. X The value became smaller. And, at an equivalence ratio of around 0.8, NO X The value reaches a maximum value, and the NO X On the other hand, as the equivalence ratio increases, the amount of unburned ammonia emitted increases sharply. At equivalence ratios higher than 1.2, ammonia emissions exceed the standard value (1 ppm), so at equivalence ratios of 1.2 or higher, it is difficult to achieve efficient ammonia combustion depending on the ambient temperature.

[0023] Figure 7 shows the NO concentration in the cross-sectional area of ​​an ammonia-fired wall burner. XFig. 8 shows the NO value distribution analysis for the cross-sectional area of ​​the ammonia-fired wall burner (combustion tip without circular element). X Figure 9 shows the NO value distribution analysis for the cross-sectional area of ​​the ammonia-fired wall burner (combustion tip with a 100 mm circular element). X Analysis of value distribution (combustion tip with 300mm circular member) The results showed that compared to the combustion tip without a circular element, both the combustion tip with a 100mm circular element that injects secondary combustion air and the combustion tip with a 300mm circular element had a higher NO X This is because the combustion tip with a 100 mm circular member and the combustion tip with a 300 mm circular member have a high equivalence ratio atmosphere due to the supply of secondary combustion air. X This is because the inhibitory reaction of production was promoted.

[0024] Figure 10 is an analysis of the unburned NH3 distribution in the cross-sectional area of ​​the ammonia-fired wall burner (combustion tip without a circular member), Figure 11 is an analysis of the unburned NH3 distribution in the cross-sectional area of ​​the ammonia-fired wall burner (combustion tip with a 100 mm circular member), and Figure 12 is an analysis of the unburned NH3 distribution in the cross-sectional area of ​​the ammonia-fired wall burner (combustion tip with a 300 mm circular member). In the combustion atmosphere using a combustion tip without a circular element, the flame is short and concentrated, promoting combustion and generating little unburned ammonia near the tip. In the combustion atmosphere using a combustion tip with a 100mm circular element and a combustion tip with a 300mm circular element, an oxygen-deficient state is formed due to the high equivalence ratio atmosphere, and unburned NH3 is observed in the lower region between the flame and the tile surface. Furthermore, the unburned NH3 generated here is lost due to the high furnace temperature before being exhausted, so it is not emitted outside the furnace.

[0025] According to the present invention, NO is produced by two-stage combustion. X The generation of unburned ammonia is reduced, and the generation of unburned ammonia is reduced, allowing for efficient and stable combustion of ammonia fuel. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the present invention is not limited to the combinations shown in the embodiments, but can be implemented in various combinations. [Explanation of symbols]

[0026] 10 Ammonia-fired wall burner 20 Wall burner body 22 Ammonia fuel passage 24 Medium and high pressure gas passage 26 Low pressure gas passage 28 Primary combustion air passage 30 Burning Chips 32 Primary combustion air chamber 34 Ammonia fuel chamber 35 Combustion air pipe 36 Rear primary combustion air chamber 38 Ammonia fuel injection holes 40 Front stage primary combustion air injection hole 42 Rear stage primary combustion air injection hole 50 Secondary combustion air passage 52 Circular Members 54 Secondary combustion air injection hole

Claims

1. The wall burner has a cylindrical combustion tip attached to the tip of the wall burner body. the combustion tip has ammonia fuel injection holes that are connected to the ammonia fuel passage of the wall burner body and open at intervals in the circumferential direction of the outer circumferential surface to inject ammonia fuel; front and rear primary combustion air injection holes connected to the primary combustion air passage of the wall burner body and injecting combustion air from the outer peripheral surface of the combustion tip, and arranged on either side of the ammonia fuel injection hole in the axial direction of the outer peripheral surface of the combustion tip; An ammonia combustion wall burner characterized in that a secondary combustion air injection hole for injecting combustion air at a predetermined distance from the combustion tip is provided on the outer peripheral surface of the tip of a circular cross-section member that is connected to the secondary combustion air passage of the wall burner body and extends from the tip surface of the combustion tip.

2. 2. The ammonia-fired wall burner of claim 1, the ammonia fuel injection holes are arranged in a plurality of rows in the circumferential direction, and are inclined at an acute angle between the axis of the combustion tip and a center line perpendicular to the axis of the combustion tip, and are injected so as to be mixed at a predetermined distance with the primary combustion air injected from the primary combustion air injection holes in the front and rear stages.

3. 3. An ammonia-fired wall burner according to claim 2, 1. An ammonia combustion wall burner, wherein the front and rear primary combustion air injection holes are arranged radially from the axis of the combustion tip.

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