JP7161639B1 - Gas burner and combustion equipment - Google Patents

Abstract

A gas burner capable of further suppressing the generation of NOx when using a gas fuel containing hydrogen is provided.
A gas burner for burning gas fuel containing hydrogen includes a nozzle formed with an ejection port for ejecting the gas fuel, and surrounding the ejection port in a front view viewed along the axial direction of the nozzle. In addition, a primary air flow path portion formed with a primary air outlet through which the primary air flows out, and a secondary air outlet through which the secondary air flows out from the primary air outlet in the radial direction outside the nozzle in a front view are formed. at least one secondary air flow path portion, the gas burner including at least one recirculation region in which an imaginary line extending radially from the center of the nozzle does not intersect the secondary air outlet when viewed from the front.
[Selection drawing] Fig. 2

Description

The present disclosure relates to gas burners and combustion equipment for burning gaseous fuels containing hydrogen.

Combustion equipment such as a boiler is equipped with a burner and employs a technique for suppressing the generation of nitrogen oxides (NOx) due to combustion of fuel. For example, Patent Literature 1 discloses a combustion facility that circulates part of exhaust gas discharged from a furnace to a burner as combustion air according to the amount of combustion air supplied to the burner. Further, Patent Document 2 describes a burner (two-stage combustion type combustion) configured to mix primary air with fuel and burn it, and then mix secondary air to burn unburned fuel. equipment) are disclosed.

Efforts to break away from fossil fuels (decarbonization) are underway for the purpose of reducing emissions of carbon dioxide, which is a typical greenhouse gas. For this decarbonization, a gas fuel containing hydrogen is sometimes applied as the burner fuel. Compared to other gases such as methane and propane, hydrogen has characteristics that are significantly different from those of other gases, such as a faster burning speed and a higher flame temperature. Patent Literature 1 suggests setting the amount of exhaust gas to be circulated to the burner in consideration of the respective characteristics of hydrogen, propane, and the like.

JP 2020-118359 A JP 2011-149676 A

However, according to the present inventors, when burning a gas fuel containing hydrogen, the generation of NOx can be significantly reduced by using a gas burner designed in consideration of the characteristics of hydrogen instead of a conventional gas burner. was found to be suppressible to

The present disclosure has been made in view of the above problems, and aims to provide a gas burner that can further suppress the generation of NOx when using gas fuel containing hydrogen.

In order to achieve the above object, a gas burner according to the present disclosure is a gas burner for burning gas fuel containing hydrogen, comprising: a nozzle formed with an ejection port for ejecting the gas fuel; A primary air flow path portion in which a primary air outlet for discharging the primary air is formed and which surrounds the jet outlet in a front view viewed along the main air flow path, and a diameter of the nozzle from the primary air outlet in the front view and at least one secondary air flow path portion formed with a secondary air outlet through which the secondary air flows out from the outside of the direction, and the gas burner extends in the radial direction from the center of the nozzle in the front view. A recirculation region is included in which an imaginary extending line does not intersect said secondary air outlet.

According to the gas burner of the present disclosure, since the characteristics of hydrogen are taken into consideration when designing, the generation of NOx can be further suppressed when gas fuel containing hydrogen is used.

It is a figure showing roughly composition of combustion equipment concerning one embodiment. 1 is a schematic diagram (front view) when the configuration of a gas burner according to a first embodiment is viewed from a combustion space; FIG. It is a figure showing roughly composition of a gas burner concerning a 1st embodiment. FIG. 4 is a diagram for explaining a recirculation region according to the first embodiment; FIG. It is a test result of the gas burner according to the first embodiment. 4 is a graph showing the relationship between the concentration of NOx contained in exhaust gas discharged from a furnace and time. FIG. 10 illustrates a configuration of a recirculation region according to some embodiments; It is a schematic diagram (front view) when the gas burner which concerns on 2nd Embodiment is seen from combustion space. It is a figure which shows roughly the structure of the gas burner which concerns on 2nd Embodiment. FIG. 10 illustrates a configuration of a recirculation region according to some embodiments; It is the figure which looked the internal structure of the furnace of the combustion equipment which concerns on one Embodiment from the perpendicular direction. It is the figure which expanded a part of wall surface of the furnace of the combustion equipment which concerns on another one embodiment.

Gas burners and combustion equipment according to embodiments of the present disclosure will be described below with reference to the drawings. Such an embodiment shows one aspect of the present disclosure, does not limit the present disclosure, and can be arbitrarily changed within the scope of the technical idea of the present disclosure.

(Configuration of combustion equipment)
FIG. 1 is a diagram schematically showing the configuration of combustion equipment 100 according to one embodiment. As illustrated in FIG. 1, the combustion facility 100 includes a tubular furnace 102 having a combustion space 104 formed therein, and a gas burner 1 for burning a gaseous fuel F containing hydrogen in the combustion space 104. Prepare. The gas burner 1 is provided in a throat portion (not shown) that opens the furnace wall 106 of the furnace 102 . Such a combustion facility 100 is, for example, a boiler, and forms a flame 101 in a combustion space 104 to burn gas fuel F to generate high-temperature exhaust gas G, and recover heat from this high-temperature exhaust gas G. to generate steam. The heat of the exhaust gas G may be recovered by a heat exchanger provided inside the furnace 102 or may be recovered by a heat exchanger provided outside the furnace 102 .

In the present disclosure, "gas fuel F containing hydrogen" includes fuel containing hydrogen and fuel other than hydrogen (mixed combustion) and hydrogen only (single combustion), and further, fuel containing hydrogen and fuel other than hydrogen , hydrogen as the main fuel (50% or more by volume of hydrogen), and fuel other than hydrogen as the main fuel (less than 50% by volume of hydrogen). "Gaseous fuel F containing hydrogen" includes all of these cases.

<First Embodiment>
(Constitution)
A configuration of the gas burner 1 according to the first embodiment will be described. FIG. 2 is a schematic diagram (front view) of the configuration of the gas burner 1 according to the first embodiment when viewed from the combustion space 104. FIG. FIG. 3 is a diagram schematically showing the configuration of the gas burner 1 according to the first embodiment. In the first embodiment, as illustrated in FIG. 2, the gas burner 1 is a rectangular burner, and the shape of the end face 5 facing the combustion space 104 has a longitudinal direction along the vertical direction D1. Note that the present disclosure does not limit the gas burner 1 to a rectangular burner.

As illustrated in FIG. 2, the gas burner 1 includes a nozzle 2, a primary air flow path section 4, and a secondary air flow path section 6. As shown in FIG.

The nozzle 2 is formed with an ejection port 8 that ejects the gas fuel F into the combustion space 104 . The nozzle 2 is configured such that gaseous fuel F can flow through it, and has, for example, a cylindrical shape extending along an axis O passing through the center 3 of the nozzle 2 . Hereinafter, of the axial directions D2 in which the axis O of the nozzle 2 extends, the direction toward the combustion space 104 is defined as one axial direction D2, and the direction away from the combustion space 104 is defined as the other axial direction D2.

As exemplified in FIG. 2 , the primary air flow path portion 4 surrounds the ejection port 8 in a front view (hereinafter referred to as a front view) viewed along the axial direction D2 of the nozzle 2, A primary air outlet 10 is formed through which air A1 exits. In the first embodiment, the primary air flow path portion 4 is a sleeve having a cylindrical shape. The primary air outlet 10 has a circular shape when viewed from the front. As illustrated in FIG. 3 , the primary air flow path portion 4 extends along the axial direction D2 of the nozzle 2 . The inner diameter 11 of the primary airflow channel portion 4 is larger than the outer diameter 13 of the nozzle 2 , and the nozzle 2 is arranged within the primary airflow channel portion 4 . In the primary air flow path portion 4, a primary air flow path 12 through which the primary air A1 flows is formed between the inner wall surface of the primary air flow path portion 4 and the outer wall surface of the nozzle 2. As shown in FIG. In other words, the primary air flow path 12 is formed around the nozzle 2 .

In the first embodiment, the gas burner 1 includes a flame stabilizer 16 provided at the outlet of the primary air flow path 12 mainly for the purpose of flame stabilization. Although the primary air A1 flowing through the primary air flow path 12 is a straight flow, the flame stabilizer 16 is configured to apply a swirling force to a part or all of the primary air A1.

As exemplified in FIG. 2, the secondary air flow path portion 6 extends radially from the primary air outlet 10 around the axis O of the nozzle 2 (hereinafter simply referred to as "radial direction") in a front view. A secondary air outlet 18 is formed through which the secondary air A2 exits from the outside. That is, the secondary air outlet 18 is farther from the ejection port 8 than the primary air outlet 10 when viewed from the front. As illustrated in FIG. 3, the secondary air flow path portion 6 is formed with a secondary air flow path 14 through which the secondary air A2 flows.

Let m1 be the air ratio of the primary air A1 to the gas fuel F ejected from the ejection port 8, and let m2 be the air ratio of the secondary air A2 to the gas fuel F ejected from the ejection port 8, m1+m2≧1.0, and m1 < 0.5 is satisfied. Furthermore, in the first embodiment, 0.25<m1<0.35 is satisfied. In the present disclosure, the air ratio refers to the ratio of the amount of air when the amount of air required to completely burn the gas fuel F is set to 1.

In the first embodiment, as illustrated in FIGS. 2 and 3, the secondary air flow path portion 6 includes a first secondary air flow path portion 6A (6) and a second secondary air flow and a path portion 6B(6). The first secondary air flow path portion 6A is a first cylindrical portion 19 having an open end on one side in the axial direction D2. The opening of the first tubular portion 19 is configured as a secondary air outlet 18A (18). The second secondary air flow path portion 6B is a second tubular portion 21 having an open end on one side in the axial direction D2. The opening of the second cylindrical portion 21 is configured as a secondary air outlet 18B (18). Each of the first tubular portion 19 and the second tubular portion 21 is separate from each other.

As illustrated in FIG. 2, each of the secondary air outlet 18A of the first tubular portion 19 and the secondary air outlet 18B of the second tubular portion 21 extends in a horizontal direction D3 orthogonal to the vertical direction D1 in front view. It has a rectangular shape with a longitudinal direction along. The secondary air outlet 18A of the first tubular portion 19 and the secondary air outlet 18B of the second tubular portion 21 extend in the circumferential direction around the axis O of the nozzle 2 (hereinafter simply referred to as the “circumferential direction”) when viewed from the front. ) are spaced apart from each other. The secondary air outlet 18A of the first tubular portion 19 is located above the secondary air outlet 18B of the second tubular portion 21 in a front view. The secondary air outlet 18A of the first tubular portion 19 is located on the opposite side of the secondary air outlet 18B of the second tubular portion 21 across the primary air outlet 10 in a front view. The secondary air outlet 18A of the first cylindrical portion 19 and the secondary air outlet 18B of the second cylindrical portion 21 at least partially overlap with each other in the left-right direction D3 when viewed from the front. When viewed from the front, the secondary air outlet 18A of the first cylindrical portion 19, the ejection port 8, and the secondary air outlet 18B of the second cylindrical portion 21 are arranged in this order along the vertical direction D1 (radial direction).

As exemplified in FIG. 2, the gas burner 1 has a recirculation region in which the imaginary line X radially extending from the axis O of the nozzle 2 (the center 3 of the nozzle 2) does not intersect the secondary air outlet 18 when viewed from the front. Including R. Here, the recirculation region R will be specifically described. FIG. 4 is a diagram for explaining the recirculation region R according to the first embodiment.

The imaginary line X is a half straight line extending in any radial direction from the axis O of the nozzle 2 . As illustrated in FIG. 4, the angular position θ of the imaginary line X when the imaginary line X extends upward in the vertical direction D1 from the axis O of the nozzle 2 is assumed to be 0 degrees. This angular position θ increases as the nozzle 2 rotates in the clockwise direction (clockwise in FIG. 4) about the axis O of the nozzle 2, and the angular position θ when the imaginary line X makes one rotation is 360 degrees. and

In the first embodiment, the recirculation region R is configured such that the sum of the angular positions θ is 180 degrees or more. As illustrated in FIG. 4, the virtual line X intersects the secondary air outlet 18A of the first tubular portion 19 when the angular position θ is 0 degrees. The imaginary line X intersects the secondary air outlet 18A of the first tubular portion 19 until the angular position θ increases from 0 degrees to 30 degrees. The virtual line X intersects with the secondary air outlet 18A of the first cylindrical portion 19 and the secondary air outlet 18B of the second cylindrical portion 21 in the range where the angular position θ is greater than 30 degrees and less than 150 degrees. not The virtual line X intersects the secondary air outlet 18B of the second tubular portion 21 until the angular position θ increases from 150 degrees to 210 degrees. The virtual line X intersects with the secondary air outlet 18A of the first cylindrical portion 19 and the secondary air outlet 18B of the second cylindrical portion 21 in the range where the angular position θ is greater than 210 degrees and less than 330 degrees. not The virtual line X intersects the secondary air outlet 18A of the first tubular portion 19 until the angular position θ increases from 330 degrees to 360 degrees. That is, in the first embodiment, the sum of the angular positions θ is 240 degrees.

In the first embodiment, the recirculation region R includes a first recirculation region R1(R) formed within an angular position θ greater than 30 degrees and less than 150 degrees. The first recirculation region R1 is located on the right side of the axis O of the nozzle 2 in the horizontal direction D3. The first recirculation region R1 is defined by an imaginary line X at an angular position θ of 30 degrees and an imaginary line X at an angular position θ of 150 degrees, and is formed by these two imaginary lines X. This is the area where the primary air outlet 10 is removed from the area with the smaller angle (120 degrees).

To explain the first recirculation region R1 more specifically, the position where the virtual line X at the angular position θ of 30 degrees intersects in the secondary air outlet 18A of the first tubular portion 19 is defined as P1. Let P2 be the position where the imaginary line X at the angular position θ of 150 degrees intersects in the secondary air outlet 18B of the second tubular portion 21 . The first recirculation region R1 includes a straight line connecting the axis O of the nozzle 2 and the position P1, a straight line connecting the axis O of the nozzle 2 and the position P2, and a line connecting the position P1 and the position P2 to the right. It is a portion excluding the primary air outlet 10 from the area defined by the projecting arc-shaped curve. The line connecting the position P1 and the position P2 may be a straight line.

In the first embodiment, the recirculation region R includes a second recirculation region R2(R) formed within an angular position θ greater than 210 degrees and less than 330 degrees. The second recirculation region R2 is located on the left side of the axis O of the nozzle 2 in the horizontal direction D3. That is, the second recirculation region R2 is located on the opposite side of the axis O of the nozzle 2 from the first recirculation region R1 in the left-right direction D3. The second recirculation region R2 is defined by an imaginary line X at an angular position θ of 210 degrees and an imaginary line X at an angular position θ of 330 degrees, and is formed by these two imaginary lines X. This is the area where the primary air outlet 10 is removed from the area with the smaller angle (120 degrees).

To describe the second recirculation region R2 more specifically, the position where the virtual line X at the angular position θ of 210 degrees intersects in the secondary air outlet 18B of the second tubular portion 21 is defined as P3. Let P4 be the position where the imaginary line X at the angular position θ of 330 degrees intersects in the secondary air outlet 18A of the first tubular portion 19 . A second recirculation region R2 includes a straight line connecting the axis O of the nozzle 2 and the position P3, a straight line connecting the axis O of the nozzle 2 and the position P4, and a line connecting the position P3 and the position P4 to the left. It is a portion excluding the primary air outlet 10 from the area defined by the projecting arc-shaped curve. The line connecting the position P3 and the position P4 may be a straight line.

(action/effect)
Actions and effects of the gas burner 1 according to the first embodiment will be described. FIG. 5 shows test results of the gas burner 1 according to the first embodiment, showing concentrations of nitrogen oxides (NOx) contained in the exhaust gas G emitted from the furnace 102. FIG. FIG. 5 shows, as a comparative example, the test results of a gas burner with no recirculation region R, ie a gas burner in which the secondary air outlet surrounds the primary air outlet all the way around.

According to the present inventors, as shown in FIG. 5, after mixing primary air A1 with gas fuel F and combusting (generating primary combustion gas), secondary air A2 is further mixed to produce unburned When the gas fuel F is burned (secondary combustion gas is generated), the primary combustion gas and the secondary combustion are provided in a region where the gas fuel F and the primary air A1 are mixed and burned (hereinafter referred to as the primary region Ra). It has been found that the generation of NOx can be greatly suppressed by generating entrainment so that the gas flows in. In the test results of the gas burner 1 shown in FIG. 5, the concentration of NOx is 1/5 or less compared to the comparative example. Note that the primary region Ra includes the primary air outlet 10 when viewed from the front.

The reason why the generation of NOx can be greatly suppressed is that the primary region Ra is a strong reduction region where the gas fuel F is excessive with respect to the primary air A1. Since there is a gap between the primary air flow path and the secondary air flow path 14 in the primary region Ra, a condition is formed in which the primary combustion gas and the secondary combustion gas, which are recirculated gases, easily flow in. . It is conceivable that the NOx contained in the gas in the combustion process and the primary combustion gas and the secondary combustion gas is reduced by allowing the primary combustion gas and the secondary combustion gas to flow into the primary region Ra. Therefore, according to the first embodiment, the primary combustion gas and the secondary combustion gas are caused to flow into the primary region Ra via the recirculation region R, thereby further suppressing the generation of NOx.

According to the first embodiment, since m1+m2≧1.0 and m1<0.5 are satisfied (m1 is the air ratio of the primary air A1, and m2 is the air ratio of the secondary air A2), the combustion temperature in the primary region Ra can be suppressed, and the generation of NOx can be suppressed. In addition, since the primary region Ra is a strong reduction region in which the gas fuel F is excessive with respect to the primary air A1, as described above, the NOx contained in the exhaust gas G that has flowed into the primary region Ra is reduced, and the concentration of NOx is reduced. can be reduced.

By reducing m1, a strong reduction region is formed and the generation of NOx can be suppressed, but the ignitability and combustibility of the gas fuel F may be reduced. FIG. 6 is a graph showing the relationship between the concentration of NOx contained in the exhaust gas G discharged from the furnace 102 and time. The graph in FIG. 6 is set to m1=0.3. A solid line 20 in FIG. 6 indicates the concentration of NOx when the gas fuel F containing hydrogen is burned, and a dotted line 22 in FIG. 6 indicates the concentration of NOx when propane gas is burned. The horizontal axis of FIG. 6 is the time that has elapsed since the ignition process for the gas fuel F or the propane gas was performed.

According to the present inventors, as shown in FIG. 6, even if the gas fuel F is set to m1 = 0.3, it ignites quickly because it contains hydrogen, and the combustion of the gas fuel F instantaneously Although the concentration of NOx is increased, the concentration of NOx is greatly reduced as time passes. On the other hand, propane gas is not ignited when m1 is set to 0.3, and the concentration of NOx cannot be reduced. According to the first embodiment, 0.25<m1<0.35 is satisfied, so NOx is reduced by flowing the gas fuel F into the primary region Ra while ensuring the ignitability and combustibility of the gas fuel F. can be realized.

According to the first embodiment, the recirculation region R is configured so that the sum of the angular positions θ is 240 degrees. It is possible to increase the amount of exhaust gas G to be caused. According to the first embodiment, since the recirculation region R includes the first recirculation region R1 and the second recirculation region R2, the exhaust gas G can flow into the primary region Ra from both left and right sides of the primary region Ra. can be done. According to the first embodiment, the secondary air outlet 18A of the first cylindrical portion 19 and the secondary air outlet 18B of the second cylindrical portion 21 are arranged at symmetrical positions centering on the ejection port 8, so that they are asymmetrical. The amount of the exhaust gas G that flows into the primary region Ra can be increased compared to the case where it is arranged at the position.

In the first embodiment, the recirculation region R included a first recirculation region R1 and a second recirculation region R2, but the present disclosure is not limited to this form. There may be one recirculation region R, or there may be three or more.

FIG. 7 is a diagram illustrating a configuration of recirculation region R according to some embodiments. In some embodiments, as illustrated in Figure 7, the secondary air outlet 18 includes four secondary air outlets 18C, 18D, 18E, 18F. That is, in the form illustrated in FIG. 7 , the gas burner 1 includes four secondary air flow path portions 6 . Each of the four secondary air outlets 18C, 18D, 18E, 18F are spaced from each other in the circumferential direction. The recirculation regions R are, in the circumferential direction, a recirculation region R3 formed between the secondary air outlets 18C, 18D, a recirculation region R4 formed between the secondary air outlets 18D, 18E, a secondary air outlet It includes a recirculation region R5 formed between 18E and 18F and a recirculation region R6 formed between secondary air outlets 18F and 18C.

In the first embodiment, each of the secondary air outlet 18A of the first tubular portion 19 and the secondary air outlet 18B of the second tubular portion 21 has a rectangular shape, but the present disclosure is limited to this form. not. For example, each of the secondary air outlet 18A of the first tubular portion 19 and the secondary air outlet 18B of the second tubular portion 21 may be circular or elliptical.

<Second embodiment>
A gas burner 1 according to a second embodiment of the present disclosure will be described. The gas burner 1 according to the second embodiment differs from the first embodiment in that the recirculation region R is configured by the blocking portion 32 . In the second embodiment, the same reference numerals are given to the same components as those of the first embodiment, and detailed description thereof will be omitted.

(Constitution)
FIG. 8 is a schematic diagram (front view) when the gas burner 1 according to the second embodiment is viewed from the combustion space 104. FIG. FIG. 9 is a diagram schematically showing the configuration of the gas burner 1 according to the second embodiment.

In the second embodiment, as illustrated in each of FIGS. 8 and 9, the secondary air flow path portion 6 includes one annular secondary air flow path portion 6C(6). The annular secondary air flow path portion 6C includes a tubular portion 30 that is open at one end on one side in the axial direction D2 and is arranged to surround the entire periphery of the primary air outlet 10; and a blocking portion 32 that blocks a portion of the opening 36 of the . The remainder of the opening 36 is configured as the secondary air outlet 18 and the closed portion 32 is configured as the recirculation region R.

In the second embodiment, the tubular portion 30 has a cylindrical shape. As illustrated in FIG. 9 , this cylindrical portion 30 extends along the axial direction D2 of the nozzle 2 . The inner diameter 31 of the tubular portion 30 is larger than the outer diameter 33 of the primary air flow path portion 4, and the primary air flow path portion 4 is arranged within the annular secondary air flow path portion 6C. In the gas burner 1 according to the second embodiment, the secondary air channel 14 is formed between the inner wall surface of the tubular portion 30 and the outer wall surface of the primary air channel portion 4 . The opening 36 of the tubular portion 30 has a circular shape when viewed from the front. The primary air outlet 10 is located in the center of the circular opening 36, and the outlet of the secondary air channel 14 is ring-shaped.

In the second embodiment, as illustrated in FIG. 8, the closing portion 32 includes a first closing portion 32A (32) and a second closing portion 32B (32). The second closing portion 32B is provided separately from the first closing portion 32A, and is spaced from the first closing portion 32A in the circumferential direction. Each of the first closing portion 32A and the second closing portion 32B is arranged at the outlet of the secondary air flow path 14 of the annular secondary air flow path portion 6C. Each of the first blocking portion 32A and the second blocking portion 32B has a plate shape, the first blocking portion 32A blocking a part of the outlet of the secondary air flow path 14, and the second blocking portion 32B A part of the remainder of the outlet of the next air flow path 14 is further blocked. Thus, in the second embodiment, the secondary air outlets 18 include a first secondary air outlet 18G (18) and a second secondary air outlet 18H (18). That is, a first secondary air outlet 18G and a second secondary air outlet 18H are formed in one annular secondary air flow path portion 6C.

As illustrated in FIG. 8, the first secondary air outlet 18G is located above the second secondary air outlet 18H in front view. The first secondary air outlet 18G is located on the opposite side of the primary air outlet 10 from the second secondary air outlet 18H when viewed from the front. The first secondary air outlet 18G and the second secondary air outlet 18H at least partially overlap each other in the left-right direction D3 when viewed from the front. When viewed from the front, the first secondary air outlet 18G, the ejection port 8, and the second secondary air outlet 18H are arranged in this order along the vertical direction D1 (radial direction).

As exemplified in FIG. 8, the gas burner 1, in front view, has a recirculation flow formed by arranging the first closing portion 32A at the outlet of the secondary air flow path 14 of the annular secondary air flow path portion 6C. It includes a region R11(R) and a recirculation region R12(R) formed by the second blocking portion 32B being arranged at the outlet of the secondary air channel 14 of the annular secondary air channel portion 6C. The recirculation region R11 is located on one side (combustion space 104 side) in the axial direction D2 of the first blocking portion 32A, and is a region that includes the first blocking portion 32A in a front view. The recirculation region R12 is located on one side (combustion space 104 side) in the axial direction D2 of the second closing portion 32B, and is a region including the second closing portion 32B in a front view.

(action/effect)
Actions and effects of the gas burner 1 according to the second embodiment will be described. According to the second embodiment, the two recirculation regions R11 and R12 are separated by providing the first closing portion 32A and the second closing portion 32B at the outlet of the secondary air flow path 14 (the opening 36 of the cylindrical portion 30). It can be easily formed.

In the second embodiment, the annular secondary air flow path portion 6C included two recirculation regions R11, R12, but the present disclosure is not limited to this form. There may be one recirculation region R, or there may be three or more.

FIG. 10 is a diagram illustrating a configuration of recirculation region R according to some embodiments. In the form illustrated in FIG. 10, the closing portion 32 includes four closing portions 32C, 32D, 32E and 32F. Each of the four closing portions 32C, 32D, 32E, and 32F is arranged with a space therebetween in the circumferential direction. The recirculation region R is formed by arranging a recirculation region R13 formed by arranging a blocking portion 32C at the outlet of the secondary air flow channel 14 and a blocking portion 32D at the outlet of the secondary air flow channel 14. a recirculation region R14 formed by placing a block 32E at the outlet of the secondary air flow channel 14; and a recirculation region R15 formed by placing a block 32F at the outlet of the secondary air flow channel 14. includes a recirculation region R16 that is

A combustion facility 100 including a gas burner 1 according to an embodiment of the present disclosure will be described. FIG. 11 is a vertical view of the internal configuration (combustion space 104) of the furnace 102 of the combustion facility 100 according to one embodiment.

In the form illustrated in FIG. 11, the furnace 102 has a rectangular cylindrical shape with its longitudinal direction along the vertical direction D1. The combustion space 104 is formed by being surrounded by the furnace wall 106 of the furnace 102, and in a top view of the furnace 102 viewed from above in the vertical direction D1 (hereinafter simply referred to as "top view"), It has a rectangular shape. The furnace wall 106 includes a gas burner furnace wall 107 having an inner peripheral surface corresponding to one side of the rectangular shape of the combustion space 104, and the gas burner 1 extends in the width direction (horizontal direction) of the gas burner furnace wall 107. It is provided at one end on one side. The gas burner 1 is provided in the furnace 102 so that the axis O of the nozzle 2 is deviated from the center 109 of the combustion space 104 of the furnace 102 when viewed from above. In the form illustrated in FIG. 11, the gas burner 1 is provided on the gas burner furnace wall 107 so that the flame 101 is not included in the center 109 of the combustion space 104 when viewed from above.

According to the configuration illustrated in FIG. 11, it is possible to promote swirling combustion in which the flame 101 swirls in the combustion space 104, and increase the amount of the exhaust gas G flowing into the primary region Ra via the recirculation region R. Note that the combustion facility 100 may be provided with a plurality of gas burners 1 . In this case, the gas burner 1 is provided at each of the four corners of the furnace wall 106, for example.

A combustion facility 100 according to another embodiment will be described with reference to FIG. 12 . FIG. 12 is an enlarged view of part of the furnace wall 106 of the furnace 102 of the combustion facility 100 according to another embodiment. In the form illustrated in FIG. 12, the furnace wall 106 of the furnace 102 includes a plurality of furnace wall tubes 108 extending along the vertical direction D1. The plurality of furnace wall tubes 108 includes one side furnace wall tube 108A (108) and the other side furnace wall tube 108B (108) adjacent to each other. The furnace wall tube 108A on one side is positioned to the left of the furnace wall tube 108B on the other side. The furnace wall tube 108 is configured to allow water and steam to flow therethrough, and the heat generated by the combustion of the gas fuel F is heat-exchanged with the water and steam flowing through the furnace wall tube 108, A temperature rise of the furnace wall 106 is suppressed.

The one-side furnace wall tube 108A includes a left projection 111 that projects leftward. The one-side furnace wall tube 108A is obtained by constructing a left projection 111 on a portion of the linear furnace wall tube 108 (the portion indicated by the dotted line in FIG. 12). The furnace wall tube 108B on the other side includes a right protrusion 110 that protrudes to the right. The furnace wall tube 108B on the other side is formed by constructing a rightward projecting portion 110 on a portion of the linear furnace wall pipe 108 (the portion indicated by the dotted line in FIG. 12).

At least a portion of the left protruding portion 111 and the right protruding portion 110 overlap each other in the vertical direction D1. A gap 115 between the left protruding part 111 and the right protruding part 110 corresponds to another gap 117 (gap 115) is wide compared to

In the embodiment illustrated in FIG. 12, the plurality of furnace wall tubes 108 are a straight first straight furnace wall tube 108C (108) arranged adjacent to the left side of the one side furnace wall tube 108A, and the other side furnace wall tube 108C (108). It further includes a straight second straight furnace wall tube 108D (108) positioned adjacent to the right of wall tube 108B.

The gas burner 1 is provided on the furnace wall 106 of the furnace 102 so that the primary air outlet 10 and the secondary air outlet 18 are arranged side by side along the vertical direction D1 when viewed from the front. In the form illustrated in FIG. 12, the secondary air outlets 18 are composed of an upper secondary air outlet 40 (18) positioned above the primary air outlet 10 and a lower secondary air outlet 40 (18) positioned below the primary air outlet 10. side secondary air outlets 42 (18); The primary air outlet 10 , the upper secondary air outlet 40 , and the lower secondary air outlet 42 are located within the gap 115 . The primary air outlet 10, the upper secondary air outlet 40, and the lower secondary air outlet 42 are wider than the other gaps 117 in the lateral direction D3.

In order to arrange the primary air outlet 10 and the secondary air outlet 18 side by side along the left-right direction D3, not only the construction of the one-side furnace wall pipe 108A and the other-side furnace wall pipe 108B but also the construction of the first linear furnace Installation of wall tube 108C and second straight furnace wall tube 108D may be required. On the other hand, according to the configuration illustrated in FIG. 12, the primary air outlet 10 and the secondary air outlet 18 are arranged side by side along the vertical direction D1. Construction of the second linear furnace wall pipe 108D becomes unnecessary, and the construction range of the furnace wall pipe 108 for installing the gas burner 1 can be reduced.

In the first embodiment, the one-side furnace wall is configured such that the one-side furnace wall tube 108A includes the left projecting portion 111, and the other-side furnace wall tube 108B includes the right projecting portion 110. Although both the tube 108A and the other furnace wall tube 108B were installed, the disclosure is not limited to this configuration. In some embodiments, either one of the one side furnace wall tube 108A and the other side furnace wall tube 108B is installed. Further, when the primary air outlet 10 and the secondary air outlet 18 are narrower than the other gap 117 in the left-right direction D3, construction of the one side furnace wall pipe 108A and the other side furnace wall pipe 108B is unnecessary. be.

Although not shown, in some embodiments, the left projection 111 is offset from the first straight furnace wall tube 108C in the axial direction D2. For example, the left protruding portion 111 is located on one side (combustion space 104 side) in the axial direction D2 of the first linear furnace wall tube 108C. With such a configuration, even when the gap between the one-side furnace wall tube 108A and the first linear furnace wall tube 108C is narrow, the gap 115 for installing the gas burner 1 can be secured. can.

The contents described in each of the above embodiments are understood as follows, for example.

[1] The gas burner (1) according to the present disclosure is
A gas burner for burning gas fuel (F) containing hydrogen,
a nozzle (2) formed with an ejection port (8) for ejecting the gas fuel;
In a front view viewed along the axial direction (D2) of the nozzle, the primary air flow path portion ( 4) and
In the front view, at least one secondary air flow path portion (6) formed with a secondary air outlet (18) through which the secondary air (A2) flows from the radially outer side of the nozzle from the primary air outlet. and
Said gas burner comprises at least one recirculation region (R), in said front view, in which said imaginary line (X) extending radially from said nozzle center (3) does not intersect said secondary air outlet.

According to the present inventors, when primary air is mixed with hydrogen-containing gas fuel and burned, and then secondary air is further mixed and unburned gas fuel is burned, gas fuel and primary air It has been found that the generation of NOx can be greatly suppressed by allowing the exhaust gas to flow into a region where it is mixed and burned (hereinafter referred to as a primary region). According to the configuration described in [1] above, the exhaust gas can be caused to flow into the primary region via the recirculation region. Therefore, generation of NOx can be further suppressed when using gas fuel containing hydrogen.

[2] In some embodiments, in the configuration described in [1] above,
Let m1 be the air ratio of the primary air to the gas fuel ejected from the ejection port, and m2 be the air ratio of the secondary air to the gas fuel ejected from the ejection port, where m1+m2≧1.0, and m1 < 0.5 is satisfied.

According to the configuration described in [2] above, it is possible to suppress the increase in the combustion temperature in the primary region and suppress the generation of NOx. In addition, since the primary region becomes a strong reduction region in which the gas fuel is excessive with respect to the primary air, NOx contained in the exhaust gas that has flowed into the primary region can be reduced and the concentration of NOx can be reduced.

[3] In some embodiments, in the configuration described in [1] or [2] above,
The angular position of the virtual line when the virtual line extends vertically upward from the center of the nozzle is assumed to be 0 degrees, and the angular position increases as it rotates clockwise around the center of the nozzle. and when the angular position when the virtual line makes one rotation is 360 degrees,
The at least one recirculation region is configured such that the sum of the angular positions is greater than or equal to 180 degrees.

According to the configuration described in [3] above, it is possible to secure a wide recirculation region in the clockwise direction and increase the amount of exhaust gas flowing into the primary region.

[4] In some embodiments, in the configuration described in [3] above,
The at least one recirculation region comprises: a first recirculation region (R1) formed within the range of the angular position greater than 30 degrees and less than 150 degrees; It includes a second recirculation region (R2) formed within it.

According to the configuration described in [4] above, the exhaust gas can be caused to flow into the primary region from both the left and right sides of the primary region.

[5] In some embodiments, in the configuration described in any one of [1] to [4] above,
The at least one secondary air flow path section,
A first secondary air flow path portion (6A) having a tubular first tubular portion (19) with one end opened, wherein the opening is configured as the secondary air outlet. When,
A second secondary air flow path portion (6B) having a second tubular portion (21) having an open end, the second tubular portion having the opening serving as the secondary air outlet. and including
The opening of the first cylindrical portion and the opening of the second cylindrical portion are spaced apart from each other in the circumferential direction of the nozzle in the front view.

According to the configuration described in [5] above, the recirculation region can be easily formed by providing the first tubular portion and the second tubular portion.

[6] In some embodiments, in the configuration described in [5] above,
In the front view, the opening of the first tubular portion, the ejection port, and the opening of the second tubular portion are arranged in this order along the radial direction.

According to the configuration described in [6] above, the opening of the first tubular portion and the opening of the second tubular portion are arranged at symmetrical positions centering on the ejection port. In comparison, a larger amount of exhaust gas can be allowed to enter the primary zone.

[7] In some embodiments, in the configuration described in any one of [1] to [4] above,
The at least one secondary air flow path section,
a tubular portion (30) having an open end and arranged to surround the primary air outlet;
a blocking portion (32) that partially blocks the opening (36);
An annular secondary air flow channel section (6C), wherein the remainder of said opening is configured as said secondary air outlet and said blockage is configured as said recirculation area.

According to the configuration described in [7] above, it is possible to easily form the recirculation region by providing the closed portion at the opening of the cylindrical portion.

[8] In some embodiments, in the configuration described in [7] above,
In the front view, the blocking portion includes a first blocking portion (32A) and a second blocking portion (32)B spaced from the first blocking portion in the circumferential direction of the nozzle. ,including.

According to the configuration described in [8] above, it is possible to easily form a plurality of recirculation regions.

[9] The combustion facility according to the present disclosure is
a furnace (102);
a gas burner according to any one of [1] to [8] above;
The gas burner is provided in the furnace so that the axis (O) of the nozzle is deviated from the center (109) of the furnace when viewed from above.

According to the configuration described in [9] above, it is possible to promote swirling combustion in which the flame swirls in the furnace, and increase the amount of exhaust gas flowing into the primary zone via the recirculation zone.

[10] The combustion facility according to the present disclosure includes
a furnace;
a gas burner according to any one of [1] to [8] above;
the furnace wall (106) of the furnace includes a vertically extending furnace wall tube (108);
The gas burner is provided on the furnace wall of the furnace so that the primary air outlet and the secondary air outlet are arranged side by side along the vertical direction in the front view.

According to the configuration described in [10] above, compared to the case where the primary air outlet and the secondary air outlet are arranged side by side along the left-right direction, the construction range of the furnace wall pipe for installing the gas burner can be made smaller.

1 gas burner 2 nozzle 3 center of nozzle 4 primary air channel portion 6 secondary air channel portion 6A first secondary air channel portion 6B second secondary air channel portion 6C annular secondary air channel portion 8 Ejection port 10 Primary air outlet 18 Secondary air outlet 19 First cylindrical portion 21 Second cylindrical portion 30 Cylindrical portion 32 Closing portion 32A First closing portion 32B Second closing portion 36 Opening 100 of cylindrical portion Combustion facility 102 Furnace 106 Furnace wall 108 Furnace wall tube 109 Furnace center

A1 primary air A2 secondary air D1 vertical direction D2 axial direction D3 lateral direction F gas fuel O nozzle axis R recirculation zone R1 first recirculation zone R2 second recirculation zone X imaginary line

Claims (12)

A gas burner for burning gas fuel containing hydrogen,
a nozzle formed with an ejection port for ejecting the gas fuel;
a primary air flow path portion that surrounds the jet outlet and is formed with a primary air outlet through which the primary air flows out, in a front view viewed along the axial direction of the nozzle;
at least one secondary air flow path portion formed with a secondary air outlet through which secondary air flows out from the radially outer side of the nozzle from the primary air outlet in the front view,
the gas burner includes at least one recirculation region in which the imaginary line extending radially from the center of the nozzle does not intersect the secondary air outlet in the front view;
The angular position of the virtual line when the virtual line extends vertically upward from the center of the nozzle is assumed to be 0 degrees, and the angular position increases as it rotates clockwise around the center of the nozzle. and when the angular position when the virtual line makes one rotation is 360 degrees,
The at least one recirculation region comprises a first recirculation region formed within the angular position greater than 30 degrees and less than 150 degrees, and an angular position within the angular position greater than 210 degrees and less than 330 degrees. comprising a second recirculation region formed;
gas burner. Let m1 be the air ratio of the primary air to the gas fuel ejected from the ejection port, and m2 be the air ratio of the secondary air to the gas fuel ejected from the ejection port, where m1+m2≧1.0, and m1 satisfying <0.5,
A gas burner according to claim 1. satisfying 0.25<m1<0.5,
A gas burner according to claim 2. The at least one secondary air flow path section,
a first secondary air flow path portion having a tubular first tubular portion with one end opened, wherein the opening is configured as the secondary air outlet;
a second secondary air flow path portion having a second tubular portion having an open end, the second tubular portion having the opening configured as the secondary air outlet;
The opening of the first cylindrical portion and the opening of the second cylindrical portion are spaced apart from each other in the circumferential direction of the nozzle in the front view,
A gas burner according to any one of claims 1 to 3. In the front view, the opening of the first cylindrical portion, the ejection port, and the opening of the second cylindrical portion are arranged in this order along the radial direction.
A gas burner according to claim 4 . The at least one secondary air flow path section,
one cylindrical tubular portion having one open end and arranged to surround the primary air outlet;
a blocking part that blocks a part of the opening,
an annular secondary air flow channel portion, wherein the remainder of the opening is configured as the secondary air outlet and the occlusion portion is configured as the recirculation region;
Gas burner according to any one of claims 1 to 5. The cylindrical portion is arranged to surround the entire periphery of the primary air outlet,
A gas burner according to claim 6 . The blocking portion includes, in the front view, a first blocking portion, and a second blocking portion that is spaced from the first blocking portion in the circumferential direction of the nozzle,
A gas burner according to claim 6 . a furnace;
A gas burner according to any one of claims 1 to 3,
The gas burner is provided in the furnace so that the axis of the nozzle is deviated from the center of the furnace in a top view of the furnace from above.
Combustion equipment. a furnace;
A gas burner according to any one of claims 1 to 3,
The furnace wall of the furnace includes a furnace wall tube extending along the vertical direction,
The gas burner is provided on the furnace wall of the furnace so that the primary air outlet and the secondary air outlet are arranged side by side along the vertical direction in the front view.
Combustion equipment. a furnace;
A gas burner according to any one of claims 1 to 3,
the furnace wall of the furnace includes a pair of furnace wall tubes that extend along the vertical direction and are adjacent to each other;
The gas burner is provided in a gap formed between the pair of furnace wall tubes so that the primary air outlet and the secondary air outlet are arranged side by side along the vertical direction in the front view. is being
Combustion equipment. One furnace wall tube of the pair of furnace wall tubes includes a projecting portion projecting to the opposite side of the other furnace wall tube of the pair of furnace wall tubes,
the gap is located between the projecting portion of the one furnace wall tube and the other furnace wall tube,
Combustion equipment according to claim 11 .

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