JPH0116888Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a burner that can smoothly burn fuels of different phases, such as solid, liquid, and gas, individually or co-fired. Coal is being reconsidered as an alternative to costly petroleum-based fuels such as heavy oil, but the coal used as such alternative fuel is usually used in the form of pulverized coal, which is finely ground to increase its combustion rate. is normal. However, even when used as pulverized coal, stable combustion cannot be obtained by using it alone, so pulverized coal is injected into the combustion furnace using air or other gas as a carrier gas, and liquid fuel such as heavy oil and/or Combustion aids such as various gaseous fuels are injected and co-combusted with these. However, since the pulverized coal injected into the combustion furnace scatters, it is difficult to obtain a stable flame, and a large amount of nitrogen oxides and unburned substances are generated.Furthermore, molten ash adheres to the furnace wall or the area around the burner. Not only does the so-called clinker phenomenon occur, which interferes with the operation of the combustion furnace, but it also impairs turndown performance, making it impossible to achieve continuous and stable combustion. Since fuels with significantly different combustibility are co-combusted, there are disadvantages such as a tendency to blow out, misfire, backfire, explosion, etc. during the combustion process. The present invention was developed in view of the above circumstances, and its purpose is to arrange one or more air introduction pipes concentrically with a plurality of concentrically arranged fuel injection pipes outside the plurality of fuel injection pipes, A crater is faced in front of the fuel injection pipe, and in front of the outermost air introduction pipe, a fume region, a fume adjustment region, and a fume regulation region are alternately arranged along the outer periphery of the crater. A hole is opened in the circumferential wall of the jet injection adjustment area, and an air flow rate regulator can be inserted into and removed from the injection adjustment area through this hole, and the airflow amount adjustment device can be inserted into and removed from the injection adjustment area according to the type of combustion fuel and the mixture ratio. The flow rate of high-temperature combustion gas from inside the combustion furnace to the crater side is adjusted to appropriately promote the decomposition and gasification of the fuel injected from the crater, thereby reducing unburned matter and reducing Our goal is to provide a burner that enables NO _x combustion. Hereinafter, the present invention will be specifically explained based on drawings showing embodiments thereof. Figure 1 is a schematic cross-sectional view showing the burner according to the present invention (hereinafter referred to as the product);
The figure is a front view taken along the - line in Figure 1. In the figure, 1 is the furnace wall of the combustion furnace, 1a is the iron shell, 1b is the refractory brick, 1c is the hole 2 drilled in the furnace wall 1, and 3 is the crater member. The burner body is shown. The crater member 2 includes a burner tile 21 , a guide tube 22 for secondary air arranged outside the burner tile 21 , and an airflow regulator 2 installed between the burner tile 21 and the guide tube 22 .
3. Consists of a blocker 24 and the like. The burner tile 21 is made of a refractory material and is formed into a disk shape with the same thickness as the furnace wall 1, and the diameter increases from one side, that is, the outer surface of the furnace, to the other side, that is, the inner surface of the furnace. A protective iron shell 21b is provided over the outer peripheral surface and one side, and is disposed concentrically with a hole 1c bored in the furnace wall 1. On the other hand, the guide tube 22 has a cylindrical shape, its inner diameter is set slightly larger than the outer diameter of the protective iron skin 21b, and a flange 22a is provided on the outer periphery of the base end.
In addition, insertion guides 22b for inserting and removing the ventilation amount adjuster 23 are provided on the intermediate circumferential wall in the axial length direction at six equally spaced positions in the circumferential direction and are inclined so as to intersect each other at an angle θ with respect to the axial center line. It is arranged. The insertion guide 22b is formed of a cylindrical body, and one end penetrates the front end circumferential wall of the guide tube 22 and opens on the inner circumferential surface of the guide tube 22 adjacent to the position where the blocking device 24 is disposed.
The other end passes through the flange 22a and is positioned outside the base end of the guide tube 22. Guide tube 2
2 is concentric with the outer periphery of the crater member 2 and is fixed to the furnace wall 1 via a flange 22a with a bolt (not shown) with a required gap between the outer periphery of the crater member 2 and the outer periphery of the crater member 2. . A ceramic fiber (not shown) is filled in the gap between the guide tube 22 and the peripheral wall of the hole 1c in the furnace wall 1.
is removably packed. As shown in FIG. 1, the ventilation amount regulator 23 includes an arc-shaped control plate 23a curved to the same curvature as the inner circumferential wall of the insertion guide 22b so as to be in surface contact therewith. The control plate 23a has an insertion guide 2 at its base end.
Plug body portion 23b having a diameter substantially equal to the inner diameter of 2b
Also, the plug portion 23b is provided with a flange 23c having a diameter larger than the inner diameter of the insertion guide 22b at its base end. Ventilation amount adjuster 2
3 is a mode in which the control plate 23a is inserted from the base end of the insertion guide 22b, and the control plate 23a blocks the gap for secondary air circulation formed between the protective iron skin 21b and the guide tube 22. The plug body portion 23b is integrally fixed to the insertion guide 22b by a set screw 22c. Various types of ventilation amount regulator 23 are available with different width dimensions of the control plate 23a, so that the most suitable ventilation amount adjustment device 23 preset according to the type of fuel and the mutual mixture ratio of fuels is selected. It's getting old. Note that the shape of the control plate 23a is not particularly limited, and it goes without saying that it may be a simple flat plate, a cylindrical body, or the like. The blocker 24 is made of a fire _- resistant material and is formed into a pentagonal shape in plan view as shown in FIG. 3 to 10%, and the thickness d is set approximately equal to the gap between the protective iron skin 21b and the guide tube 22, and the front and back surfaces are set to be approximately equal to the gap between the protective iron skin 21b and the guide tube 22.
1b and the guide tube 22, and is curved to have the same curvature as the guide tube 22 so as to be in surface contact with them. Each of the blocking devices 24 is arranged at six equal positions in the circumferential direction within the gap between the protective iron shell 21b and the guide tube 22, and overlaps with the formation position of the insertion guide 22b in the axial direction of the crater member 2. The protective iron skin 21b is installed by passing the bolts 24b through the holes 24a from the outer peripheral surface of the guide tube 22 and screwing them into nuts embedded in the burner tile 21. and the guide tube 22 in a manner that closes the gap therebetween. As shown in FIG. 2, the gap between the protective iron skin 21b and the guide tube 22 is located in the fumarole area A (circumferential length w ₁ ) and the insertion and removal of the ventilation amount regulator 23 or the control plate 2 in the ventilation amount adjustment tool 23.
3a, where the amount of jet is adjusted (maximum length w ₂ in the circumferential direction), and jet regulation region C (circumferential maximum length w 2 ) where no jet is generated due to the presence of the blocker 24. The length in the direction w ₃ ) is formed alternately. In the front facing these areas, that is, in the furnace, a film of secondary air is supplied from an air introduction pipe 34, which will be described later, to the part facing the fumarole area A, and to the part facing the fumarole regulation area C. is a break in the secondary air film, and the ventilation amount adjuster 23 has its control plate 2.
A cut in the secondary air film having a maximum width of W ₂ is formed in accordance with the width dimension of 3a, and the length of the cut in the secondary air film in the circumferential direction as a whole is adjusted by the ventilation amount regulator 23. The Rukoto. The burner body 3 has a liquid fuel spray pipe 30 in the center.
A gas fuel injection pipe 32, a primary air introduction pipe 33, and a secondary air introduction pipe 34 are arranged concentrically on the outer periphery of the pulverized coal injection pipe 31, which can be removably attached to the pulverized coal injection pipe 31, and between them. A gap is formed through which fuel or air can flow, and the pipe is constructed to form a five-ply pipe as a whole. Spray pipe 30, injection pipe 3
1, 32 and the introduction tubes 33, 34 are set to shorten the length in the axial direction in this order, and the diameter of the tip gradually decreases concentrically except for the introduction tube 34, so that the inner diameter of the introduction tube 33 is reduced. The spray pipe 30, the injection pipes 31, 32, and the introduction pipe 33 are opened concentrically facing the fire pit 21a, and the inner diameter of the introduction pipe 34 is approximately equal to the diameter of the outer opening of the fire pit 21a. With the introduction pipe 34 made equal to the inner diameter of the cylinder 22 and facing the gap between the protective shell 21b and the guide cylinder 22, the flange 34a provided at the tip thereof is attached to the flange of the guide cylinder 22 using bolts and nuts 34b. It is fixed at 22a. In addition, the base end of each spray pipe 30 etc. is closed, and the connecting pipe 30a, which is connected to the vicinity thereof,
It is connected to a liquid fuel supply pipe 30b, a pulverized coal supply pipe 31b, a gas fuel supply pipe 32b, and air supply pipes 33b and 34b via 31a, 32a, 33a, and 34a, respectively, as shown by imaginary lines. The liquid fuel supply pipe 30b is connected to a heavy oil or other petroleum fuel tank, the pulverized coal supply pipe 31b is connected to a pulverized coal hopper and a carrier gas tank or blower, and the gas fuel supply pipe 32b is connected to a hydrocarbon gas tank. , further air supply pipe 33b,
34b are both connected to a blower (not shown), and appropriate flow rates are blown into the furnace through the burner body 3 and the nozzle member 2 by a flow control valve and a damper, respectively. 35 is the outer peripheral surface on the tip side of the gas fuel injection pipe 32;
A swirling vane formed between the inner circumferential surface on the tip side of the air introduction pipe 33, which swirls the air supplied through the air introduction pipe 33 in the circumferential direction and injects it into the crater 21a, thereby injecting the auxiliary combustion material. The self-circulation effect of combustion and exhaust gas promotes thermal decomposition and gasification, and the collision with pulverized coal causes rapid mixed combustion of these, promoting the combustibility of pulverized coal and reducing the generation of NO _x . As a matter of fact. The area of the opening at the tip of the spray pipe 30, the injection speed of pulverized coal, the injection amount, etc., should be determined experimentally and empirically as appropriate to obtain the necessary amount of heat as a combustion furnace and to obtain the highest possible combustion rate. It can be determined according to the In the case of the product thus configured, there is of course no obstruction in the fume adjustment area B when the ventilation amount regulator 23 is not inserted;
Since secondary air is ejected from the area, a film of secondary air is formed in front of these areas, and since no secondary air is ejected from the fume restriction area C where the blocker 24 exists, there is no air in front of this area. A break in the film of secondary air is formed, and a film of secondary air with a width of w ₁ + w ₂ in the circumferential direction is formed in front of the crater 21a.
This results in alternating cuts in the secondary air film over a width of w ₃ . On the other hand, when the ventilation amount adjuster 23 is inserted into the jet air adjustment region B through the insertion guide 22b, secondary air is not injected from the region where the control plate 23a of the ventilation amount adjustment tool 23 is located in the jet air adjustment region B. Therefore, the control board 23
If the width dimension of a is l (however, l≦w ₂ ), the crater 2
A state in which a film of secondary air that spans a width of w ₁ + (w ₂ - l) and a cut in the film of secondary air that spans a width of w ₃ + (w ₂ - l) alternate in the circumferential direction in front of 1a. Then,
The width of the cut is increased by the width dimension of the control plate 23a. When a film of secondary air as described above and a cut are formed in the front circumferential direction of the crater 21a, the pressure at the cut part is lower than that of the film, so that the high temperature combustion gas existing in the outer periphery flows into the cut part. After passing through the crater 2
The fuel flows into the area facing the fuel 1a, mixes with the fuel injected from the crater 21a, heats the fuel, and appropriately promotes its decomposition and gasification. Since the amount of backflow of high-temperature combustion gas to the region facing the crater 21a naturally changes depending on the width of the cut, the ventilation amount regulator 23 can be inserted or removed in advance according to the type of combustion fuel, the mixing ratio, etc. Adjust by exchange. The ventilation amount adjuster 23 can be easily replaced by loosening the set screw 22c and pulling it out. Ventilation amount adjuster 2
3 is not used, it goes without saying that the proximal end of the insertion guide 22c is closed. The relationship between the type of combustion fuel and the width of the control plate 23a with or without the ventilation amount regulator 23, or when using it, can be determined experimentally in advance, and test results showing the relationship between the two may be determined experimentally. An example is as follows.
In this test, the solid fuel was pulverized coal (volatile content: 30%, N: 1.8%), the liquid fuel was heavy oil (N: 0.2%), and the gaseous fuel was LPG and low-calorie M gas (blast furnace gas and When using a mixed gas calorific value of 1000 kcal/Nm ³ ) with coke oven gas and burning these separately, the combustion state when not using the ventilation amount regulator 23 and when using it
The amount of _NOx was observed. The results are shown in Table 1.

[Table] As is clear from Table 1, when the ventilation amount regulator 23 is not used, that is, when the width of the cut in the secondary air film is small, the combustion state of heavy oil and LPG is good.
The amount of NO _x generated is also small, but the combustion conditions of pulverized coal and M gas are poor, especially when pulverized coal is burned _.
The amount produced is extremely large. Conversely, when the ventilation amount regulator 23 is used, that is, when the width of the cut in the secondary air film is large, the combustion state of pulverized coal and M gas is good, and NO _x is generated for pulverized coal and M gas. Although the amount is small, heavy oil causes the burner tile to become red hot and the amount of NO _x produced increases, and LPG
The combustion conditions are poor, causing oscillatory combustion, and the amount of NO _x produced is high. Therefore, it is better not to use the ventilation amount adjuster 23 when burning heavy oil or LPG.
It is also understood that it is better to use the ventilation amount regulator 23 when pulverized coal or M gas is exclusively fired. In the above-described embodiment, the thickness of the shielding device 24 is set equal to the gap between the protective iron skin 21b and the guide tube 22, but the thickness is set slightly smaller than the gap, The state may be such that a small amount of air can be constantly ejected, and as a result, the fumarole area A
Any condition is sufficient as long as a predetermined pressure difference is formed between the fuel injection control area C and the fume regulation area C. As mentioned above, in the case of this product, in front of the outermost air introduction pipe, the fume area, the fume adjustment area, and the fume regulation area are arranged alternately along the outer periphery of the crater. Regardless of whether the fume adjustment area is adjusted, in other words, even if an erroneous operation is performed, there will always be a fume area and a fume regulation area, which will prevent blow-off, blow-off, and other abnormal increases in NO _x . It is possible to prevent significant deterioration of combustion, and by adjusting the injection adjustment range using the ventilation amount adjustment device, the length of the gap in the air film can be changed even if the fuel phase and other types are different. The present invention has excellent effects, such as allowing proper combustion.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the proposed product, and Figure 2 is a schematic cross-sectional view of the proposed product.
FIG. 3 is a front view taken along the - line in the figure, and FIG. 3 is a perspective view of the blocking device. DESCRIPTION OF SYMBOLS 1... Furnace wall, 1a... Iron shell, 1b... Refractory brick, 2... Crater member, 3... Burner body, 21...
...Burna tile, 21a... Crater, 21b... Protective iron skin, 23... Ventilation rate adjuster, 24... Blocker, 30... Spray pipe, 31, 32... Injection pipe, 3
3, 34...Introduction pipe.

Claims (1)

[Scope of utility model registration request] One or more air introduction pipes are arranged concentrically outside the plurality of fuel injection pipes arranged concentrically, and a crater is faced in front of the fuel injection pipes, and the outermost air introduction pipe is arranged concentrically with the plurality of fuel injection pipes. In front of the pipe, a fume area, a fume adjustment area, and a fume regulation area are arranged alternately along the outer periphery of the crater, and a hole communicating with the fume adjustment area is opened in the peripheral wall of the fume adjustment area. 1. A burner characterized in that an air flow rate adjustment tool can be inserted into and removed from the blast adjustment area through the hole.