TWI685632B - Burner, boiler and burning method - Google Patents

Abstract

A primary fuel nozzle 37 is provided on the axis 100 of the throat 33 of the combustion device 31. The flame stabilizer 41 is arranged on the inner peripheral side of the throat 33 and around the primary fuel nozzle 37. A plurality of secondary fuel nozzles 52 are spaced apart from each other on the outer circumferential side of the supply throat 33 on an annular area centered on the primary fuel nozzle 37. A secondary air nozzle 62 is provided on the annular area. The plurality of secondary air nozzles 62 and the plurality of secondary fuel nozzles 52 are arranged alternately.

Description

Combustion device, boiler and combustion method

The present invention is an amount of reduction of nitrogen oxides with the exhaust gas after combustion (hereinafter referred to as the combustion gases) of (hereinafter referred to as NO _x) about the combustion apparatus.

From the previous start, is required to reduce the combustion apparatus for the combustion gas boiler or the like in an amount of NO _x in exhaust, now it has the NO _x in the combustion gas oxygen concentration is reduced to 0% in terms of the degree of 60ppm. However, for example, in a regional heating and cooling equipment of deep urban air pollution in the desired discharge amount of NO _x in an oxygen concentration of 0% in terms of 40ppm or less (refer to Patent Document 1).

In Non-Patent Document 1, the fuel is supplied in two stages, the primary fuel is rapidly mixed and burned at a high air ratio, and then the secondary gas injected from the surroundings is slowly released by the combustion gas containing a low concentration of residual oxygen combustion, and the secondary gas jet at high speed of the combustion gas recirculated to reduce NO _x.

Advanced technical literature

Patent Literature

[Patent Document 1] Japanese Patent Laid-Open No. 9-60811

Non-patent literature

Issued on July 1, 2012 (Issued by the Japan Energy Conservation Center) "New Theory and Practice of Air Combustion" pages 206-207

In Non-Patent Document 1, the disadvantage of two-stage fuel combustion is that although the NO _x reduction effect is higher than that of air two-stage combustion, it is also pointed out that unburned parts are likely to be generated, and vibration combustion is prone to occur. Make the degree of matching with the combustion chamber becomes very important.

Further, by the burner configuration (FIG. 8.23) Non-Patent Document 1 and the NO _x emission characteristics (FIG. 8.24) may be presumed to have the following problems and the like, i.e.,

‧The NO _x emission value of Non-Patent Document 1 is 40 ppm (O ₂ =5%) under the combustion conditions of O ₂ =3% (air-to-air ratio 1.17), that is, the NO _x emission value converted from the oxygen concentration of 0% 52.5ppm, NO _x emissions are still high.

‧In Non-Patent Document 1, the high air ratio of the primary fuel is performed using the entire amount of air necessary for combustion. ‧ Rapid mixed combustion, the flow rate of the main fuel becomes more than the flow rate of the secondary fuel. Turndown ratio (TDR: Turn Down Ratio) is very difficult.

‧Non-patent document 1 supplies all the air required for combustion to the pre-combustion port (primary fuel area), so the air supply pressure loss is large.

In order to solve the above technical problems, the object of the present invention to provide apparatus which can effectively achieve a low NO _x combustion of.

In order to achieve the above object, the combustion device of the present invention includes: a primary fuel nozzle arranged on the axis of the combustion air supply throat; and a flame stabilized on the inner circumference side of the combustion air supply throat and around the primary fuel Device; spaced apart from each other in the circumferential direction A plurality of secondary fuel nozzles on the outer circumferential side of the combustion air supply throat and the annular area centered on the axis; a plurality of spaced apart from each other on the outer circumferential side of the combustion air supply throat and the annular area Secondary air nozzles, wherein the plurality of secondary fuel air nozzles and the plurality of secondary fuel nozzles are arranged alternately.

In the above configuration, the secondary air nozzle and the plurality of secondary fuel nozzles are alternately arranged on the annular area centered on the axis, so the high-speed jet effect of the secondary fuel nozzle and the secondary air nozzle, recirculating combustion gases and a low NO _x state. Moreover, since the secondary air nozzles and the plurality of secondary fuel nozzles are spaced apart from each other, the mixing of the secondary air and the secondary fuel gas becomes slow, and maintaining them in the divided state for a long time can obtain an effective slow combustion state. Thus, generation of NO _x combustion can be suppressed by this slow.

Effect of the Invention According to the present invention for a number of slow-burning can be achieved by a sufficient effect of low NO _x. Other aspects and advantages of the present invention will be disclosed in the accompanying drawings showing examples of technical ideas of the present invention and the following description.

201‧‧‧One flame

202‧‧‧Second flame

203‧‧‧recirculation flow

204‧‧‧ Recirculation flow

21‧‧‧Boiler

22‧‧‧combustion chamber

31‧‧‧Combustion device

32‧‧‧Blowbox

321‧‧‧Front wall

33‧‧‧Combustion air supply throat (throat)

34‧‧‧ First Air Supply Room

35‧‧‧ Front opening

36‧‧‧Central fuel supply pipe

37‧‧‧primary fuel nozzle

38‧‧‧ nozzle hole

41‧‧‧ Flame stabilizer

42‧‧‧vent

43‧‧‧Convex

44‧‧‧Ventilation gap

45‧‧‧Eye

51‧‧‧Outside fuel supply pipe

52‧‧‧Secondary fuel nozzle

53‧‧‧ nozzle hole

61‧‧‧Connecting port

62‧‧‧Secondary air nozzle

621‧‧‧ Front opening

622‧‧‧Side wall

623‧‧‧Bottom wall

63‧‧‧Second air supply room

100‧‧‧Axis

A-A~G-G‧‧‧Cross section

θ11‧‧‧Angle

θ12‧‧‧Angle

d‧‧‧Specified length

Fig. 1 is a cross-sectional view of a combustion device of a first embodiment.

Fig. 2 is a side view of the combustion device of Fig. 1.

Fig. 3(a) is a cross-sectional view of the primary fuel nozzle, and Fig. 3(b) is a left side view thereof.

FIG. 4(a) is a cross-sectional view of the secondary fuel nozzle, and FIG. 4(b) is a left side view thereof.

Fig. 5 is a plan view of a secondary air nozzle.

Fig. 6 is a cross-sectional view showing the operation state.

7 is a cross-sectional view showing the operation state.

8 is a cross-sectional view of a combustion device of a second embodiment type.

9 is a left side view of the combustion device.

10 is a side view of a combustion device of a third embodiment type.

Fig. 11 is a perspective view of a combustion device of a first embodiment.

Fig. 12 is a left side view of the combustion device of Fig. 11.

Fig. 13 is a right side view of the combustion device of Figs. 1 and 8.

Fig. 14 is a cross-sectional view taken along line A-A in Fig. 12.

15 is a perspective view of the combustion device of FIG. 8.

16 is a left side view of the combustion device of FIG. 15.

Fig. 17 is a cross-sectional view taken along line B-B of Fig. 16.

FIG 18 is a graph showing the comparison of NO _x emission values both technical and NO _x in the first embodiment and the emission values of patterns.

Fig. 19 is a cross-sectional view of a combustion device of a fourth embodiment.

Fig. 20 is a side view of the combustion device of Fig. 19.

21 is a cross-sectional view showing the operating state of the combustion device of FIG. 19.

22 is a cross-sectional view showing the operating state of the combustion device of FIG. 19.

23 is a cross-sectional view of a combustion device of a fifth embodiment type.

24 is a cross-sectional view of a combustion device of a sixth embodiment type.

25(a) and (b) are a cross-sectional view and a left side view showing a combustion device of a seventh embodiment.

26(a) and (b) are a partial cross-sectional view and a left side view showing an eighth embodiment mode.

27(a) and (b) are a partial cross-sectional view and a left side view showing a ninth embodiment mode.

Fig. 28 is a partial cross-sectional view showing a modified example.

29(a) and (b) are a partial cross-sectional view and a left side view showing other modified examples.

30(a) and (b) are a partial cross-sectional view and a left side view further showing other modified examples.

Fig. 31 is a perspective view of the combustion device of Fig. 19.

FIG. 32 is a left side view of the combustion device of FIG. 31. FIG.

33 is a right side view of the combustion device of FIG. 31.

Fig. 34 is a cross-sectional view taken along line C-C of Fig. 32.

Fig. 35 is a perspective view of the combustion device of Fig. 24.

36 is a left side view of the combustion device of FIG. 35.

Fig. 37 is a cross-sectional view taken along the line D-D in Fig. 36.

FIG. 38 is a perspective view of the combustion device of FIG. 25. FIG.

39 is a left side view of the combustion device of FIG. 38.

FIG. 40 is a cross-sectional view taken along the line E-E of FIG. 39. FIG.

Fig. 41 is a perspective view of the combustion device of Fig. 26.

42 is a left side view of the combustion device of FIG. 41.

Fig. 43 is a sectional view taken along line F-F of Fig. 42;

FIG. 44 is a perspective view of the combustion device of FIG. 27. FIG.

FIG. 45 is a left side view of the combustion device of FIG. 44. FIG.

46 is a cross-sectional view taken along line G-G in FIG. 45.

Fig. 47 is a perspective view of a combustion device of a modified example of Fig. 30.

FIG. 48 is a left side view of the combustion device of FIG. 47. FIG.

FIG. 49 is a cross-sectional view taken along line H-H in FIG. 48. FIG.

[First Embodiment]

The first embodiment will be described. As shown in FIG. 1, a horizontal combustion chamber 22 is formed on the boiler 21, and a combustion device 31 of the first embodiment is installed on the combustion chamber 22.

As shown in FIGS. 1 and 11-14, a tubular combustion air supply throat 33 (hereinafter referred to as throat 33) is arranged on the horizontal axis 100 in the central portion of the air box 32 of the combustion device 31. This throat 33 is connected to the rear first blast chamber 34 in the air box 32, and thereby the first blast chamber 34 sends primary air into the throat 33, and the primary air is passed through the front opening 35 of the throat 33 to the combustion chamber 22 sprayed forward. In addition, in the first embodiment, the left side of FIG. 1 is the front.

As shown in FIGS. 1 and 2, the central fuel supply pipe 36 having an opening at the front end is disposed on the axis 100 in the throat 33 in a penetrating manner. A primary fuel nozzle 37 is attached to the front end of the central fuel supply pipe 36, and a plurality of (six in the first embodiment) nozzle holes 38 are attached to the outer periphery of the front end at equal intervals. As shown in FIGS. 3(a) and 3(b), the nozzle hole 38 is arranged on a radius line centered on the axis 100 when viewed from the axis 100 direction, and viewed from a direction perpendicular to the axis 100, the nozzle hole 38 is The central angle θ1 to the axis 100 is about 30 degrees to 80 degrees (60 degrees in the first embodiment). Next, the fuel gas made of gas is supplied into the primary fuel nozzle 37 through the central fuel supply pipe 36, The fuel gas is injected into the combustion chamber 22 from the nozzle hole 38 in a radial direction, that is, diagonally forward toward the outer peripheral side in the combustion chamber 22.

In addition, an ignition burner (not shown) for ignition is provided on the rear side of the primary fuel nozzle 37 in the throat 33.

As shown in FIGS. 1 and 3 (a) and (b), a rear side adjacent to the nozzle hole 38 and an outer peripheral surface of the primary fuel nozzle 37 are installed between the outer peripheral surface and the inner peripheral surface of the throat 33 'S flame stabilizer 41. As shown in FIG. 2, the convex portions 43 toward the outer side in the radial direction are formed at six positions on the outer peripheral portion of the flame stabilizer 41 at equal intervals (six positions in the embodiment). The concave portion divided between these convex portions 43 forms a vent 42, and a narrow vent space 44 is formed between the front end of the convex portion 43 and the inner peripheral surface of the throat 33. The convex portion 43 is located between the corresponding nozzle holes 38. Next, the primary air in the throat 33 is ejected into the combustion chamber 22 along the axis 100 through the vent 42 and the vent gap 44. The air vent 42 and the air gap 44 defined by the flame stabilizer 41 and the throat 33 function as a primary air nozzle for ejecting primary air into the combustion chamber 22. The front surface of the flame stabilizer 41 is a certain length behind the front end surface of the throat 33.

As shown in FIGS. 1, 2, 4 (a ), and 4 (b ), there are a plurality (six in the first embodiment) of outer fuel supply tubes 51 at equal intervals around the throat 33 The ground penetrates the front wall 321 of the bellows 32. The secondary fuel nozzle 52 located in the annular area centered on the axis 100 is fixed to the front end of the outer fuel supply pipe 51. A single nozzle hole 53 is formed in the front end of the secondary fuel nozzle 52. The nozzle hole 53 is located on the radius line centered on the axis 100 and passing through the vent 42 of the flame stabilizer 41. As shown in FIG. 6, the nozzle hole 53 opens toward the axis 100 toward the axis 100 at an angle of about 5 degrees to 30 degrees (15 degrees in the first embodiment) toward the axis 100. The front end portion of the primary fuel nozzle 37 is arranged at the same position as the front end opening of the throat 33. Secondly, through the outer fuel supply pipe 51 is supplied by The gaseous fuel gas is injected into the secondary fuel nozzle 52, and the fuel gas is injected obliquely forward from the nozzle hole 53 toward the center of the combustion chamber 22.

As shown in FIGS. 1, 2 and 5, a plurality of communication ports 61 are formed at equal intervals between the outer fuel supply tubes 51 at the front wall 321 of the air box 32 (six locations in the first embodiment) At each communication port 61, the secondary air nozzles 62 are mounted on the front wall 321 at equal intervals from each other. The secondary air nozzle 62 is connected to the second air blowing chamber 63 of the air box 32 through the communication port 61. Then, the air from the second air blowing chamber 63 is discharged from the front end opening 621 of the secondary air nozzle 62 as secondary air into the combustion chamber 22 in the direction of the axis 100. The front end opening 621 of the secondary air nozzle 62 is formed in a rectangular long shape. Next, the front end opening 621 is located on a radius line centered on the axis 100 passing through the convex portion 43, and its long side extends along the radius line. The front end opening 621 of the secondary air nozzle 62 protrudes forward by a certain length toward the front end opening of the throat 33. As shown in FIG. 5, the side wall 622 of the secondary air nozzle 62 is inclined so as to converge toward the front end opening 621. In addition, the front end opening 621 of the secondary air nozzle 62 approaches the throat 33 by tilting the bottom wall 623.

Next, the secondary air nozzle 62 and its front end opening 621 are arranged in a concentric annular area centered on the axis 100, and the secondary fuel nozzle 52 are alternately arranged at equal intervals with the secondary fuel nozzle 52.

In the first embodiment, the front end opening 621 of the secondary air nozzle 62 is extended in the direction of the radius line centered on the axis 100, and the length in the radius line direction may be longer than the length in the direction perpendicular to the radius line. Therefore, the shape of the front end opening 621 is not limited to a rectangular long shape, and may be implemented in various shapes such as an oblong shape, an elliptical shape, and a weight shape in which both ends of the radial direction expand.

Next, the operation of the combustion device 31 constructed as described above will be described.

As shown in FIG. 6 or FIG. 7, during the combustion operation of the combustion device 31, the primary fuel gas is ejected toward the combustion chamber 22 from the nozzle hole 38 around the axis 100 of the primary fuel nozzle 37 toward the oblique outer peripheral direction to form a primary flame 201, At this time, around the primary fuel nozzle 37, primary air is injected into the combustion chamber 22 from the vent 42 of the flame stabilizer 41 and the vent gap 44 along the direction in which the axis 100 extends. At this time, since the flame stabilizer 41 is located in the throat 33, a small recirculation flow 204 is formed in front of the convex portion 43 of the flame stabilizer 41, so the primary flame 201 can be stably burned at a high air ratio, and the primary The flame 201 becomes a divided state, and the surface area increases, so that the temperature of the primary flame 201 decreases.

On the other hand, the secondary fuel gas is ejected from the nozzle hole 53 of the secondary fuel nozzle 52 in an oblique direction toward the axis 100, and this secondary fuel gas is supplied near the front end of the primary flame 201. Therefore, the primary flame 201 serves as an ignition flame, and the secondary flame 202 is formed at the front end of the primary flame 201. By discharging secondary fuel gas, the fuel gas flows from the upstream side of the secondary fuel nozzle 52 and is recycled to the secondary fuel gas mixture recycle stream 203, the secondary flame 202 becomes slow combustion state to reduce NO _x production . In other words, since the secondary fuel from the nozzle hole 53 is burned at a position away from the nozzle hole 53, the combustion becomes slow.

Next, at this time, the secondary air is injected into the combustion chamber 22 from the front end opening 621 of the secondary air nozzle 62 between the secondary fuel nozzles 52. Therefore, the temperature of the secondary flame 202 is reduced by the secondary air. It is accompanied by the opening of the front end of the secondary air nozzle 62, forming a recirculation flow 203 spiraling around the secondary flame 202, its outside, and the base end of the secondary flame air nozzle 62, affected by the recirculation flow 203. The combustion gas caused by the jet of secondary air, secondary fuel gas and two gases circulates, and the mixing of the above materials achieves slow combustion, and the secondary flame can be stably burned.

The secondary fuel nozzle 52 and the secondary air nozzle 62 are alternately arranged at equal intervals around the throat 33. As shown in FIG. 2, the recirculation flow 203 passes through the secondary fuel nozzle 52 and the secondary air nozzle 62 The space between. Therefore, the combustion gas and the secondary air are in a divided state, and their mixing becomes slow. Furthermore, the slow combustion is achieved by the recirculation flow of the space between the secondary fuel nozzle 52 and the secondary air nozzle 62.

In addition, since the secondary air nozzle 62 protrudes forward from the front end of the secondary fuel nozzle 52, the secondary air is carried out in front of the recirculation flow, that is, on the downstream side of the recirculation flow with the secondary flame 202 upstream bus, therefore the oxygen supply of the secondary flame 202 becomes slow, can effectively suppress the NO _X.

As described above, since the secondary fuel nozzle 52 is configured to protrude into the combustion chamber 22 in the first embodiment, the combustion gas flows in from the upstream side of the secondary fuel nozzle 52 and is recirculated for mixing to become a slow combustion state and reduce NO The generation of _X.

In addition, the secondary air nozzles 62 are arranged at intervals between the secondary fuel nozzles 52 so that the high-speed jet effect caused by both the secondary fuel from the secondary fuel nozzle 52 and the secondary air from the secondary air nozzle 62, promoting recirculation of combustion gas in the combustion chamber 22, and the obtained low NO _X. Further, the first flame 201 only needs to have an intensity that can stabilize the degree of combustion in consideration of the relationship of the secondary flame 202. Thus, it is possible to reduce the amount of primary fuel gas and primary air, ensuring high derating ratio (TDR) is also capable of achieving low NO _X.

In addition, in the conventional fuel two-stage combustion method, the entire amount of necessary combustion air is supplied to the primary field. However, since the secondary air is divided and supplied by the secondary air nozzle 62, the two-stage combustion is realized. Therefore, the primary gas fuel can be reduced while reducing the air supply pressure loss.

Figure 18 shows a comparison of NO _X configuration information previously described in Non-Patent Document 1, the first embodiment and the NO _X data patterns. At O ₂ = 3% (air ratio Genki 1.17) in the combustion conditions, NO _X emissions the first embodiment is 30ppm (O ₂ = 0% conversion value), with respect to the past to achieve the effect of reducing 22ppm. Further, the predetermined value corresponding to the amount of NO _X emissions regional air-conditioning apparatus certain city district (in terms of 0% and an oxygen concentration of 40ppm or less) can be sufficiently correspond.

The first embodiment has the following effects.

(1) Since the secondary fuel nozzle 52 protrudes from the front end of the throat 33 into the combustion chamber 22, the combustion gas serves as a recirculation flow on the upstream side of the throat 33 and the secondary fuel nozzle 52 from the outer periphery side to the center side Inflow. Thus, the fuel gas from the secondary fuel nozzle 52 is gradually mixed into the recycle stream, and thus slow combustion, thereby reducing NO _X. In addition, the recirculation generated by the high-speed jet flow from the secondary fuel nozzle 52 can be smoothly performed.

(2) The fuel gas from the primary fuel nozzle 37 may be an amount sufficient to form a small primary flame sufficient to stably burn the secondary flame. Since a part of the total air volume required for combustion is supplied to the throat 33 as the primary air, compared with the prior art, the primary fuel gas volume can be reduced relative to the secondary fuel gas volume. For example, the ratio of (primary combustion gas amount)/(secondary combustion gas amount) is about 1/2 to 1/10, and by controlling only the amount of secondary fuel gas without changing the amount of primary fuel gas, a high TDR. Therefore, the combustion amount of the combustion device can be controlled in a wide range. In addition, since there is no need to individually control the amount of primary fuel gas and the amount of secondary fuel gas, the gas regulating valve only needs to be used for the secondary fuel gas, which can achieve cost reduction.

(3) The secondary fuel gas is ejected toward the high-air ratio primary fuel gas region formed on the axis 100, so that the secondary flame can be stabilized, and the discharge of unburned portions and carbon monoxide can also be prevented.

(4) The nozzle hole 53 of the secondary fuel nozzle 52 is a single hole arranged obliquely toward the radially inner side toward the downstream side in the axis 100 direction. Therefore, by ejecting the secondary fuel gas toward the high fuel ratio primary fuel gas region, the discharge of the unburned portion and carbon monoxide is prevented.

(5) The plurality of secondary air nozzles 62 are provided on the outer circumferential side of the throat 33 at an annular area with the axis 100 as the center, so that the secondary fuel gas can be effectively mixed on the axis 100 from the periphery The resulting combustion gas with low concentration of residual oxygen causes it to burn slowly and effectively burn the unburned portion. Therefore, even if the amount of primary fuel gas is reduced, the auxiliary effect of stabilizing the primary flame 201 can be exerted.

(6) The plurality of secondary air nozzles 62 and the plurality of secondary fuel nozzles 52 are alternately arranged on the annular area, so that the high-speed jet effect caused by both the secondary fuel nozzle and the secondary air nozzle causes the combustion gas to be regenerated Circulate and become a low NO _X state. In addition, the secondary air nozzle 62 and the plurality of secondary fuel nozzles 52 are spaced apart from each other, so that the mixing of the secondary air and the secondary fuel gas becomes slow, and it can be maintained in the divided state for a long time to obtain an effective slow combustion state.

(7) The opening of the secondary air nozzle 62 is a strip-shaped single hole extending in the radial direction with the axis 100 as the center, whereby the interval between the secondary fuel nozzle and the secondary air nozzle is ensured. Therefore, the aforementioned divided state can be formed more reliably, and a more effective slow combustion state can be obtained.

(8) Since the secondary air nozzle 62 protrudes into the combustion chamber 22, the recirculation flow 203 flows from the rear of the secondary air nozzle 62, and the secondary air flows into the downstream side of the flow direction to mix, so that the secondary air is mixed The progress of the recirculation stream 203 becomes slow. By this, a slower combustion can be obtained.

(9) Since the opening of the secondary air nozzle 62 has a strip shape and is close to the throat 33, it is possible to avoid the insufficient amount of oxygen to the primary flame 201 and suppress the occurrence of carbon monoxide.

[Second Embodiment]

Next, a description will be given focusing on the second embodiment of the present invention that is different from the first embodiment.

As shown in FIGS. 8, 9, and 15 to 25, in the second embodiment, the opening 621 of the secondary air nozzle 62 is formed in a circular shape. Next, the opening 621 is inclined toward the front of the combustion chamber 22 toward the axis 100 at an angle of about 10 degrees to 50 degrees (30 degrees in the second embodiment) toward the axis 100 at a center angle θ2.

Therefore, the second embodiment has the following effects.

(10) The opening 621 of the secondary air nozzle 62 is a single hole arranged obliquely inward in the radial direction, whereby the jet flow of the secondary air from the secondary air nozzle 62 is inward, so that the secondary air can be well mixed in In the combustion gas caused by the secondary flame 202 formed on the axis 100, while maintaining the stability of the secondary flame 202, a higher air ratio in the area of the secondary flame is also achieved. Therefore, the generation of NO _X can be effectively suppressed.

[Third Embodiment]

Next, referring to FIG. 10, the third embodiment of the present invention will be described focusing on the differences from the first embodiment.

In the third embodiment, the entire portion of the side of the throat 33 including the opening 621 of the secondary air nozzle 62 and the portion on the opposite side thereof are formed in a curved shape. Therefore, the recirculation flow 203 can be smoothly flowed between the secondary air nozzles 62 in the arrow direction.

Therefore, the third embodiment has the following effects.

(11) Since the recycle stream to the flow direction of the arrows between the secondary air nozzle 62, so that a good recycling 203 can be formed effectively of low NO _X.

[Fourth Embodiment]

The description will focus on the parts of the fourth embodiment that are different from the first embodiment.

As shown in FIG. 19, a tube-shaped combustion air supply throat (hereinafter simply referred to as a throat) 33 is arranged on the horizontal axis 100 located at the center of the inner side of the air box 32 of the combustion device 31. The throat 33 is connected to the rear first blast chamber 34 in the air box 32, and the primary air is transported from the first blast chamber 34 into the throat 33, and the primary air passes from the front opening 35 of the throat 33 into the combustion chamber 22 In front of it. In addition, in the fourth embodiment, the left side of 19 is the front.

Inside the throat 33, a central fuel supply pipe 36 whose front end is open is disposed on the axis 100 through. At the front end of the central fuel supply pipe 36, primary fuel nozzles 37 as in the first embodiment shown in FIGS. 3(a) and (b) are installed, and a plurality of front end outer peripheral portions are arranged at equal intervals (fourth embodiment)中为6) nozzle hole 38. Therefore, the throat 33 and the primary fuel nozzle 37 are arranged coaxially.

In addition, an ignition burner (not shown) for ignition is provided on the rear side of the primary fuel nozzle 37 in the throat 33.

A flame stabilizer 41 located between the outer peripheral surface of the primary fuel nozzle 37 and the inner peripheral surface of the throat 33 is attached to the rear side of the nozzle hole 38 around the primary fuel nozzle 37. As shown in FIG. 20, a plurality of (six places in the fourth embodiment) convex portions 43 facing outward in the radial direction are formed at six places on the outer peripheral portion of the flame stabilizer 41 at equal intervals. The concave portion planned between these convex portions 43 becomes the vent 42, and a narrow vent space 44 is formed between the front end of the convex portion 43 and the inner peripheral surface of the throat 33. The convex portion 43 is located between the corresponding nozzle holes 38. Next, the primary air in the throat 33 is ejected into the combustion chamber 22 along the axis 100 through the vent 42 and the vent gap 44. The ventilation port 42 and the ventilation gap 44 planned by the flame stabilizer 41 and the throat 33 function as a primary air nozzle for ejecting primary air into the combustion chamber 22.

The front end surface of the air box 32 protrudes into the combustion chamber 22. The front surface of the flame stabilizer 41 is a certain length d behind the front end surface of the front plate 321 of the bellows 32.

As shown in FIGS. 19 and 20, on the outer peripheral side of the throat 33, a plurality of (six in the fourth embodiment mode) outer fuel supply pipes 51 penetrate the front plate of the air box 32 at equal intervals from each other 321. The front end of the outer fuel supply pipe 51 is fixed with a secondary fuel nozzle 52 located in an annular area centered on the axis 100. The secondary fuel nozzle 52 is the same as the first embodiment shown in FIGS. 4(a)(b). As shown in FIG. 21, viewed from a direction perpendicular to the axis 100, the nozzle hole 53 of the secondary fuel nozzle 52 faces the axis 100 at a center angle θ2 of about 5 to 30 degrees (15 degrees in the fourth embodiment) The angle opens inward. The front end portion of the primary fuel nozzle 37 is arranged at the same position as the front end opening of the throat 33. Next, fuel gas made of gas is supplied into the secondary fuel nozzle 52 through the outer fuel supply pipe 51, and the fuel gas is injected diagonally forward from the nozzle hole 53 toward the center of the combustion chamber 22.

As shown in FIGS. 19 and 20, between the outer fuel supply tubes 51 on the outer peripheral side of the flame stabilizer 41, communication ports 61 are formed at a plurality of positions on the front plate 321 of the wind box 32 at equal intervals (fourth embodiment mode) (6 places in the center), the secondary air nozzles 62 are attached to the front plate 321 at equal intervals on a part of each communication port 61. Each secondary air nozzle 62 protrudes forward from the front end surface of the bellows 32. The secondary air nozzle 62 is connected to the second air blowing chamber 63 of the wind box 32. Then, the first air blowing chamber 34 and the second air blowing chamber 63 are separated in the air box 32 by the throat 33, and the air from the second air blowing chamber 63 is opened as the secondary air from the front end opening 621 of the secondary air nozzle 62, It is ejected into the combustion chamber 22 in the direction along the axis 100. The front end opening 621 of the secondary air nozzle 62 is formed in a rectangular strip shape. The front end opening 621 is located on a radius line centered on the axis 100 passing through the convex portion 43, and its long side extends along the radius line. The front end opening 621 of the secondary air nozzle 62 protrudes forward by a certain length toward the front end opening of the throat 33.

Next, both the secondary air nozzle 62 and its front end opening 621 and the secondary fuel nozzle 52 are arranged in a concentric annular region centered on the axis 100, and are alternately arranged with the secondary fuel nozzle 52 at equal intervals.

In the fourth embodiment, the front end opening 621 of the secondary air nozzle 62 extends in the direction of the radius line centered on the axis 100, and the length in the radius line direction is longer than the length in the direction perpendicular to the radius line. . Therefore, the shape of the tip opening 621 is not limited to a rectangular strip shape, and can be implemented in various shapes such as an oblong shape, an elliptical shape, and a weight shape that expands at both ends in the radial direction.

Next, the operation of the fourth embodiment will be described.

As shown in FIGS. 21 and 22, in the combustion operation of the combustion device 31 of the fourth embodiment, the primary fuel gas is ejected toward the combustion chamber 22 from the nozzle hole 38 around the axis 100 of the primary fuel nozzle 37 toward the oblique outer circumferential direction to form A flame 201. At this time, around the primary combustion nozzle 37, primary air is injected into the combustion chamber 22 along the extending direction of the axis 100 from the vent 42 and the vent gap 44 of the flame stabilizer 41. In addition, at this time, since the flame stabilizer 41 is located in the throat 33, a small recirculation flow 204 is formed in front of the convex portion 43 of the flame stabilizer 41, so that the primary flame 201 can be stably burned under a high air ratio, In addition, the primary flame becomes divided, the surface area increases, and the temperature of the primary flame 201 decreases.

On the other hand, the secondary fuel gas is ejected from the nozzle hole 53 of the secondary fuel nozzle 52 in an inclined direction toward the axis 100, and the secondary fuel gas is supplied toward the vicinity of the front end of the primary flame 201. Therefore, the primary flame 201 serves as an ignition flame, and the secondary flame is formed at the front end of the primary flame 201. By the ejection of the secondary fuel gas, the combustion gas flows into and recirculates from the upstream side of the secondary combustion nozzle 52, and the secondary fuel gas is mixed into the recirculation flow 203, so that the secondary flame 202 becomes a slow combustion state. reduce the production of NO _X. That is, since the secondary fuel gas from the nozzle 53 is burned at a position away from the nozzle hole 53, the combustion becomes slow.

Next, at this time, secondary air is injected into the combustion chamber 22 from the front end opening 621 of the secondary air nozzle 62 located between the secondary fuel nozzles 52. Therefore, the secondary fire is reduced by the secondary air The temperature of Yan 202. Furthermore, the front end opening of the secondary air nozzle 62 forms a recirculation flow 203 spiraling around the secondary flame 202, the outside thereof, and the base end portion of the secondary air nozzle 62. The recirculation flow 203 causes the secondary flow The combustion gas induced by the jet of air, secondary fuel gas, and these two gases circulates, and the above-mentioned materials are mixed to achieve slow combustion and stable combustion of the secondary flame.

Since the secondary fuel nozzle 52 and the secondary air nozzle 62 are alternately arranged at equal intervals around the throat 33, as shown in FIG. 20, the recirculation flow 203 passes between the secondary fuel nozzle 52 and the secondary air nozzle 62 Space. Therefore, the combustion gas and the secondary air are in a divided state, and the mixing of the two becomes slow. Moreover, the slow combustion is achieved by the recirculation flow through the space between the secondary fuel nozzle 52 and the secondary air nozzle 62.

In addition, since the secondary air nozzle 62 protrudes forward from the front end of the secondary fuel nozzle 52, the secondary air merges in front of the recirculation flow, that is, on the downstream side of the recirculation flow with the secondary flame 202 upstream. Therefore, the oxygen supply to the secondary flame 202 becomes slow, effectively inhibit NO _X.

As described above, in the fourth embodiment, the secondary fuel nozzle 52 is configured to protrude into the combustion chamber 22 so that the combustion gas flows from the upstream of the secondary fuel nozzle 52 to be recirculated and mixed to become a slow combustion state. Reduced NO _X production.

In addition, between the secondary fuel nozzles 52, the secondary air nozzles 62 are spaced apart from each other so that the high-speed jet effect caused by both the secondary fuel from the secondary fuel nozzle 52 and the secondary air from the secondary air nozzle 62 promoting recirculation of combustion gas in the combustion chamber 22, thereby obtaining a low NO _X. Next, the primary flame 201 may be an intensity that stabilizes the secondary flame 202 to such a degree. Thus, it is possible to reduce the amount of primary fuel gas and primary air, ensure high TDR (derating ratio) and the resulting low NO _X.

In addition, in the existing fuel two-stage combustion method, the required combustion air is supplied to the primary flame area in the full amount. However, since the secondary air nozzle 62 divides and supplies the secondary air, the two-stage fuel is realized. It can reduce the pressure loss of air supply and realize the reduction of primary gas fuel.

The fourth embodiment mode displays NO _X data equivalent to the first embodiment mode shown in FIG. 18. The fourth embodiment has the following effects.

(12) Since the secondary fuel nozzle 52 protrudes into the combustion chamber 22 from the front end of the throat 33, the combustion gas flows as recirculation to the upstream side of the throat 33 and the secondary fuel nozzle 52, and flows into the center side from the outer peripheral side. Thus, the fuel gas 52 from the secondary fuel nozzle gradually mixed into the recycle stream, slow burning, reduces the NO _X. In addition, the recirculation caused by the high-speed jet flow from the secondary fuel nozzle 52 can be smoothly implemented.

(13) The fuel gas from the primary fuel nozzle 37 may be an amount sufficient to form a small primary flame that can stably burn the secondary flame. That is, since a part of the total amount of air required for combustion is supplied as primary air to the throat 33, the amount of primary fuel gas can be reduced relative to the amount of secondary fuel gas as compared with the prior art. For example, the ratio of (primary fuel gas amount)/(secondary fuel gas amount) is about 1/2 to 1/10, and high TDR can be obtained by controlling only the amount of secondary fuel gas. Therefore, the combustion amount of the combustion device can be controlled in a wide range. In addition, since there is no need to individually control the amount of primary fuel gas and the amount of secondary fuel gas, the gas regulating valve needs only the secondary fuel gas, which can save costs.

(14) By ejecting the secondary fuel gas toward the high-air ratio primary fuel gas region formed on the axis 100, the secondary flame can be stabilized, and the discharge of unburned portions and carbon monoxide can be prevented.

(15) The nozzle hole 53 of the secondary fuel nozzle 52 is a single hole disposed obliquely inward in the radial direction toward the downstream side in the axis 100 direction. Therefore, the secondary fuel gas is sprayed toward the primary fuel area with a high air ratio, and the discharge of unburned portions and carbon monoxide can be prevented.

(16) On the outer circumferential side of the throat 33, on the annular region centered on the axis 100, a plurality of secondary air nozzles 62 are spaced apart from each other, so that the secondary fuel gas is effectively mixed on the axis 100 from the periphery The combustion gas with low concentration of residual oxygen makes it burn slowly, and it also effectively burns the unburned part. Therefore, even if the amount of primary fuel gas is reduced, the auxiliary effect of stabilizing the primary flame 201 can be exerted.

(17) The plurality of secondary air nozzles 62 and the plurality of secondary fuel nozzles 52 are alternately arranged on the annular area, whereby the high-speed jet effect caused by both the secondary fuel nozzle and the secondary air nozzle makes the The combustion gas is recirculated to a low NO _X state. In addition, since the secondary air nozzle 62 and the plurality of secondary fuel nozzles 52 are spaced apart from each other, the mixing of the secondary air and the secondary fuel gas becomes slower, and the two can maintain the divided state for a long time, resulting in effective slow combustion status.

(18) The opening of the secondary air nozzle 62 is a strip-shaped single hole extending in the radial direction with the axis 100 as the center, thereby ensuring the interval between the secondary fuel nozzle and the secondary air nozzle. As a result, the aforementioned divided state can be surely formed, and a more effective slow combustion state can be obtained.

(19) The front plate 321 of the bellows 32 protrudes into the combustion chamber 22, so the recirculation flow 203 flows in from the rear of the secondary air nozzle 62, and then flows into the secondary air of the secondary air nozzle 62 along the downstream side of the flow Blend. Therefore, the mixing of the secondary air to the recirculation flow 203 becomes slower, and a slower combustion can be obtained.

(20) Since the secondary air nozzle 62 protrudes into the combustion chamber 22, the recirculation flow 203 flows into the rear of the secondary air nozzle 62, and the downstream side of the flow flows into the secondary air and mixes it. The mixing of the secondary air to the recirculation flow 203 is slowed down. Therefore, a slower combustion can be obtained.

(21) The opening of the secondary air nozzle 62 has a strip shape and is close to the throat 33. Therefore, it is possible to avoid the insufficient amount of oxygen to the primary flame 201 and suppress the generation of carbon monoxide.

(22) Since the throat 33 is provided, since the throat 33 separately supplies the primary air supplied through the flame stabilizer 41 and the secondary air supplied around the flame stabilizer 41, it can be improved compared to the existing technology. TDR.

[Fifth Embodiment]

Next, a description will be given focusing on the differences between the fifth embodiment and the fourth embodiment of the present invention.

In the fifth embodiment, as shown in FIG. 23, the portion of the outer fuel supply pipe 51 branched off by the central fuel supply pipe 36 is different from the fourth embodiment.

Next, it is explained that the fifth embodiment has the following effects.

(23) Since the outer fuel supply pipe 51 branches from the central fuel supply pipe 36, the fuel supply structure can be simplified, and the cost can be saved.

[Sixth Embodiment]

The sixth embodiment of the present invention will be described with reference to FIGS. 24 and 35 to 37.

Among the sixth embodiment, in the configuration of the fourth embodiment, the center side of the front plate 321 is inclined toward the throat 33. Thereby, the sixth embodiment has the following effects.

(24) The recirculation flow 203 of the combustion gas easily flows through the space between the secondary fuel nozzle 52 and the secondary air nozzle 62.

[Seventh Embodiment]

The seventh embodiment of the present invention will be described based on FIGS. 25(a), (b) and FIGS. 38-40.

In the seventh embodiment, the rectangular opening 21 of the secondary air nozzle 62 in the configuration of the fourth embodiment is changed to a circular opening 621. The shape of the opening 621 can be changed by using an existing exhaust pipe. The seventh embodiment has the following effects.

(25) Since the existing tube is used to form the circular opening 621, the cost can be saved. In addition, since a suitable existing exhaust pipe can be selected, the radius of the opening 621 can be arbitrarily changed. Therefore, it is possible to appropriately adjust the directivity and flow rate of the revolving circulation 203 so as to exert a low NO _X effect.

[Eighth Embodiment]

The eighth embodiment of the present invention will be described based on FIGS. 26(a), (b) and FIGS. 41-43.

In the eighth embodiment, with the configuration of the seventh embodiment, a plurality of circular openings 621 of the secondary air nozzles 62 are provided along the radial direction of the wind box 32. The opening 621 is formed by an existing exhaust pipe.

With this, the eighth embodiment has the following effects.

(26) The plurality of openings 621 are arranged in the radial direction, so that the secondary air nozzle 62 having the rectangular opening 621 can obtain a similar effect, and since the existing exhaust pipe is used, it is possible to save costs as in the seventh embodiment.

[Ninth Embodiment]

The ninth embodiment of the present invention will be described based on FIGS. 27(a), (b) and FIGS. 44-46.

In the ninth embodiment, the opening 621 of the second air nozzle 62 of the seventh embodiment shown in FIGS. 25(a) and (b) is directed toward the front of the combustion chamber 22 with respect to the axis 100 at a center angle θ2 of approximately 10 degrees to 50 degrees (30 degrees in the ninth embodiment) is inclined to the inside.

Therefore, the ninth embodiment mode has the following effects.

(27) The opening 621 of the secondary air nozzle 62 is a single hole inclined toward the inner side in the radial direction, whereby the jet flow of the secondary air from the secondary air nozzle 62 becomes inward, so the secondary air can be well mixed and entered In the combustion gas caused by the secondary flame 202 formed on the axis 100. As a result, the stability of the secondary flame 202 can be maintained, and a further high air ratio can be achieved in the secondary flame area. Therefore, the generation of NO _X can be effectively suppressed. In addition, since the existing exhaust pipe is used, the cost can be saved.

The present invention is not limited to the aforementioned embodiment forms, and may be embodied in the following forms.

In the first embodiment and the fourth embodiment, the front end opening 621 of the secondary air nozzle 62 may be formed inward as in the second embodiment. In this way, the same effects as those described in (10) above can be obtained.

The number of secondary fuel nozzles 52 and secondary air nozzles 62 can be changed. For example, the number of secondary fuel nozzles 52 and secondary air nozzles 62 may be smaller than the illustrated example. According to this configuration, the space between the secondary air nozzle 62 and the secondary fuel nozzle 52 becomes wider, and the recirculation flow 203 flows smoothly.

The number of secondary fuel nozzles 52 and secondary air nozzles 62 may not be the same number, but may be different numbers.

The primary and secondary fuels may not be gas fuels, but may be spray liquid fuels.

The primary and secondary air may not be air containing 21% oxygen. Exhaust gas can also be mixed. In this case, it is the external exhaust gas circulation.

The secondary air nozzle 62 may be omitted.

The secondary fuel nozzle 52 may protrude forward with respect to the secondary air nozzle 62.

At least one of the secondary fuel 52 and the secondary air nozzle 62 may be retracted behind the front opening of the throat 33.

The flame holder 41 is not limited to a baffle flame stabilizer of a concave-convex shape, but may be a baffle flame stabilizer of another shape. In addition, it may be a swirler flame stabilizer 41.

The nozzle hole 38 of the secondary fuel nozzle 52 may be a strip-shaped single hole extending along a radius line centered on the axis 100. In this way, by providing the nozzle hole 38 as a strip-shaped single hole, a gap can be made between the secondary fuel nozzle 52 and the secondary air nozzle 62. Thus, combustion gas recirculation can be performed well, and thus can achieve a low of NO _X.

As shown in the modification shown in FIG. 28, the throats 33 of the fourth to ninth embodiments can be omitted. In this case, since the throat 33 does not exist, the primary air and the secondary air cannot be separated in the wind box 32, and the amount of both in the wind box 32 cannot be controlled. Therefore, in order to appropriately distribute the amount of primary air and the amount of secondary air supplied into the combustion chamber 22, it is necessary to appropriately set the opening area of the vent 42 and the like of the flame stabilizer 41 that ejects primary air. When the throat 33 does not exist, as shown in FIGS. 29(a) and (b), the front plate 321 and the flame holder 41 may be joined or integrally formed. If the front plate 321 and the flame holder 41 are joined or integrally formed, the ventilation space 44 on the front end side of the convex portion 43 of the flame stabilizer 41 cannot be formed, so it can also be as shown by the double-dotted line in FIG. 29(b) As shown, an opening can be formed as a vent space 44 at the front end of the convex portion 43.

There is not necessarily a specific length d between the front plate 321 and the front of the flame holder 41 (refer to FIGS. 19 and 28). For example, in addition to the fifth embodiment in which the front plate 321 is inclined, as shown in FIG. The front plate 321 and the flame stabilizer 41 are formed on the same surface. The examples of FIGS. 30 and 47 to 49 integrate the front plate 321 and the flame stabilizer 41 of the fourth embodiment, and a plurality of small holes 45 are provided in the portion corresponding to the flame stabilizer 41. In this way, the configuration in which the front plate 321 and the flame stabilizer 41 are integrated and provided with the small holes 45 can also be applied to the sixth to ninth embodiments.

The present invention includes the following technical ideas.

(Appendix A) The combustion device according to any one of items 1 to 6 of the patent application range, wherein the opening of the secondary air nozzle is shaped to extend along a radius line centered on the axis Single hole.

By setting the opening of the secondary fuel nozzle to a single hole of a shape extending along the aforementioned radius line, the space between the secondary fuel nozzle and the secondary air nozzle can be vacated, so the combustion gas recirculation proceeds smoothly and burns slowly , Can be further reduced to NO _X.

(Appendix B) The combustion device according to any one of items 1 to 6 of the patent application range, wherein the opening of the secondary air nozzle is a single hole arranged obliquely toward the radial downstream side in the axial direction.

According to this configuration, the jet flow from the secondary air nozzle is inward, and the secondary air is well mixed into the secondary flame, thereby maintaining the stability of the secondary flame and achieving a further high air ratio.

(Appendix C) The combustion device according to any one of items 1 to 6 of the patent application range, characterized in that the opening of the secondary fuel nozzle is a strip-shaped single hole extending in the radial direction on the virtual installation circle Nozzle for gas fuel.

With strip hole can be empty and the secondary fuel nozzle spacing of the secondary air nozzle, whereby the combustion gas recirculation can be carried out well and slow combustion, can thus be low NO _X.

(Appendix D) The combustion device according to any one of items 1 to 6 of the patent application range, wherein the opening of the secondary fuel nozzle is a single unit that is inclined toward the radial inner side toward the downstream side in the axial direction Fuel nozzle.

According to this structure, by ejecting the secondary fuel to the high air ratio (lean) primary fuel region formed on the central axis, the discharge of unburned portions and carbon monoxide can be prevented.

(Appendix E) A combustion device comprising: a primary fuel nozzle arranged on the axis of the combustion air supply throat; a flame stabilizer arranged on the inner peripheral side of the combustion air supply throat, the aforementioned Around the primary fuel nozzle; a plurality of secondary fuel nozzles are arranged at an interval on the outer circumferential side of the combustion air supply throat at an annular area centered on the primary fuel nozzle, wherein the combustion air At least one of the supply throat and the aforementioned secondary fuel nozzle is configured to protrude into the combustion chamber.

According to this configuration, the combustion gas flows from the combustion air feed throat or the upstream side of the primary fuel nozzle and recycled, thus reducing NO _X.

(Appendix F) The combustion device according to appendix E, wherein the combustion air supply throat or the secondary fuel nozzle is arranged to protrude into the combustion chamber.

According to the above configuration, combustion gas flows from the upstream side of the air supplied to the combustion throat or the secondary fuel nozzle and recycled, it is possible to further reduce the NO _X.

(Appendix G) A combustion method, as in the combustion device described in any one of the patent application scopes 1-4, the ratio of (primary fuel gas amount)/(secondary fuel gas amount) is 1/2 or less, and Only control the amount of secondary fuel gas.

In this way, compared with the existing technology, a larger TDR can be obtained. In addition, because there is no need to individually control the amount of primary fuel gas and the amount of secondary fuel gas, the gas regulating valve only needs the secondary fuel gas, which can save costs.

(Appendix H) The combustion device as described in item 4 or 5 of the patent application, characterized in that the front plate of the air box is configured to protrude toward the combustion chamber.

According to this configuration, the upstream side of the inflow and recirculation of combustion gases from the secondary air nozzle or secondary fuel nozzle, reduce NO _X.

The conditions in the implementation form and the modified examples can be appropriately combined, and the configuration of a part of an implementation form can be replaced with a part of another implementation form, or the configuration of a part of an implementation form can be added to another Implementation type. As long as the effects obtained by this replacement/addition are obtained by related companies, the effects can be understood by the description and illustrations in this case.

The invention is not limited to what is shown in the examples. For example, the illustrated features should not be interpreted as necessary for the present invention, and the subject matter of the present invention is less than all the features of the disclosed specific embodiments.

201‧‧‧One flame

203‧‧‧recirculation flow

204‧‧‧ Recirculation flow

21‧‧‧Boiler

22‧‧‧combustion chamber

31‧‧‧Combustion device

32‧‧‧Blowbox

321‧‧‧Front wall

33‧‧‧Combustion air supply throat (throat)

34‧‧‧ First Air Supply Room

35‧‧‧ Front opening

36‧‧‧Central fuel supply pipe

37‧‧‧primary fuel nozzle

41‧‧‧ Flame stabilizer

51‧‧‧Outside fuel supply pipe

52‧‧‧Secondary fuel nozzle

53‧‧‧ nozzle hole

61‧‧‧Connecting port

62‧‧‧Secondary air nozzle

621‧‧‧ Front opening

622‧‧‧Side wall

623‧‧‧Bottom wall

63‧‧‧Second air supply room

100‧‧‧Axis

Claims (21)

A combustion device comprising: a primary fuel nozzle arranged on the axis of a combustion air supply throat; a flame stabilizer arranged on the inner peripheral side of the combustion air supply throat and around the primary fuel nozzle; a plurality of two The secondary fuel nozzles are circumferentially spaced from each other on the outer circumferential side of the combustion air supply throat at an annular area centered on the axis, and are characterized by being provided on the outer circumference of the combustion air supply throat A plurality of secondary air nozzles spaced apart from each other on the side and the annular area; the plurality of secondary air nozzles and the plurality of secondary fuel nozzles are spaced apart from each other and can pass the recirculation flow of the combustion chamber Interactive configuration. The combustion device according to item 1 of the patent application range, wherein at least one of the combustion air supply throat and the secondary fuel nozzle is arranged to protrude toward the combustion chamber. The combustion device according to item 1 of the patent application range, wherein the secondary air nozzle is configured to protrude into the combustion chamber. The combustion device according to item 1 of the patent application range, wherein the opening of the secondary air nozzle is a single hole having a shape extending along a radius line centered on the foregoing axis. The combustion device according to item 1 of the patent application range, wherein the opening of the secondary air nozzle is a single hole arranged obliquely toward the radial downstream side in the axial direction. The combustion device according to item 1 of the patent application range, wherein the opening of the secondary fuel nozzle is a strip-shaped single-hole gas fuel nozzle extending in a radial direction on a virtual installation circle. The combustion device according to item 1 of the patent application range, wherein the opening of the secondary fuel nozzle is a single-hole gas fuel nozzle that is inclined toward the radial inner side toward the downstream side in the axial direction. A combustion device comprising: a primary fuel nozzle arranged on the axis of a combustion air supply throat; a flame stabilizer arranged on the inner peripheral side of the combustion air supply throat and around the primary fuel nozzle; a plurality of The secondary fuel nozzles are arranged at intervals on the outer peripheral side of the combustion air supply throat, in an annular area centered on the primary fuel nozzle, and a plurality of secondary air nozzles are arranged at intervals from each other The outer circumferential side of the combustion air supply throat and the annular area centered on the primary fuel nozzle are characterized in that at least one of the plurality of secondary air nozzles and the plurality of secondary fuel nozzles are opposed Prominent way configuration. The combustion device according to item 8 of the patent application range, wherein the combustion air supply throat or the secondary fuel nozzle is configured to protrude into the combustion chamber. A combustion device comprising: a primary fuel nozzle, which is arranged inside the wind box; a flame stabilizer, which is arranged around the aforementioned primary fuel nozzle; A plurality of secondary fuel nozzles are provided inside the bellows on the outer circumferential side of the flame stabilizer, and are circumferentially spaced apart from each other in a circular area centered on the primary fuel nozzles. A plurality of secondary air nozzles, the plurality of secondary air nozzles are arranged on the front plate of the bellows at a distance from each other on the outer circumferential side of the flame stabilizer and in the annular area, and the plurality of secondary fuel nozzles pass through the The front plate is arranged in such a manner that the plurality of secondary air nozzles and the plurality of secondary fuel nozzles are alternately arranged so as to allow the recirculation flow of the combustion chamber to pass through. The combustion device according to item 10 of the patent application scope, wherein the aforementioned wind box is configured to protrude toward the combustion chamber. The combustion device according to item 11 of the patent application scope, wherein a combustion air supply throat is provided in the bellows, the combustion air supply throat is formed coaxially with the primary fuel nozzle, and separates and passes through the flame The primary air supplied by the stabilizer and the secondary air supplied around the flame stabilizer. The combustion device according to item 10 of the patent application scope, wherein the front plate of the aforementioned wind box is configured to protrude toward the combustion chamber. The combustion device according to item 12 of the patent application range, wherein the opening of the secondary air nozzle is a single hole having a shape extending along a radius line centered on the foregoing axis. The combustion device according to item 12 of the patent application range, wherein the opening of the secondary air nozzle is a single hole arranged obliquely toward the radial downstream side in the axial direction. The combustion device according to item 12 of the patent application range, wherein the opening of the secondary fuel nozzle is a strip-shaped single-hole gas fuel nozzle extending in a radial direction on a virtual installation circle. The combustion device according to item 12 of the patent application range, wherein the opening of the secondary fuel nozzle is a single-hole gas fuel nozzle that is inclined toward the radial inner side toward the downstream side in the axial direction. The combustion device according to item 10 of the patent application range, wherein the combustion device is configured to be mountable on a boiler having a combustion chamber, and when the combustion device is mounted on the boiler, the front end portion of the wind box faces the boiler The combustion chamber protrudes, and the front end portions of the plurality of secondary air nozzles and the front end portions of the plurality of secondary fuel nozzles protrude forward of the front end portion of the wind box in the combustion chamber of the boiler. The combustion device according to item 10 of the patent application range, wherein the front end portions of the plurality of secondary air nozzles and the front end portions of the plurality of secondary fuel nozzles are not covered by the wind box. A boiler has a combustion device as described in any one of patent application scopes 1-16. A combustion method, in the combustion device as described in any one of the patent application scopes 1-16, the ratio of (primary fuel gas amount)/(secondary fuel gas amount) is 1/2 or less, and only controls two The amount of secondary fuel gas.

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