JP2971423B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus applied to a boiler for a thermal power plant or a chemical plant or a chemical industrial furnace.

[0002]

FIG. 8 shows a furnace 1 such as a boiler. As shown in the figure, in the furnace 1, four burners 5 are installed on the front wall 2 of the furnace and four places on the rear wall 3 of the furnace. Of these burners 5, four burners 5 installed on the right side in the figure
Is set so that the in-furnace ejection direction axis 8 which is the direction of the fuel and combustion air ejected from the burner is in contact with the circumference of a virtual circle 6 in which a circle having a certain diameter is imagined in the furnace. The four burners 5 installed on the middle left also set the virtual circle 6 in the same manner. The fuel and combustion air ejected from the burner 5 move along the direction axis 8 in the furnace 1a.
The flame 7 is formed by being ejected and burning, and two swirling combustion flame vortices 9 having different center positions are formed inside the furnace 1. In the prior art, as described above, all of the burners 5 are arranged on a pair of opposed furnace front wall 2 and furnace back wall 3 and the diameter of the virtual circle 6 is appropriately selected,
A stable and appropriate swirling combustion flame vortex 9 was formed.

[0003]

However, as shown in FIG. 9, as the capacity of the boiler increases and the size of the burner increases, the size of the burner wind box 10 attached to the furnace 1 also increases. It was feared that they would be close to each other and the space for maintenance would be short. For the same reason, the size of the burner panel 12 projecting outward from the furnace front wall 2 toward the outside of the furnace 1 has been increased. As a result, the size of the boiler as a whole becomes unnecessarily large, and the flame 7 is affected by the effect of the combustion gas 13 flowing along the inner wall surface of the burner panel 12, and the swirling combustion is caused. It was feared that the stable flow of the flame vortex 9 might be disturbed.

As shown in FIG. 9, a rear flue 14 and a gas duct 15 and various boiler auxiliary equipment (not shown) are arranged near the furnace rear wall 3 as compared with the furnace front wall 2. Have been. For this reason, the space outside the furnace rear wall 3 is extremely narrow, and the burner 5
There are also concerns that the boiler's overall size will be unnecessarily large due to the lack of space for maintenance that has been improved due to the arrangement of four locations. Was done. The present invention has been made in view of the above problems, and has as its object to provide a combustion device that can provide a space for facilitating maintenance outside a furnace rear wall.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a furnace having a rectangular cross section, wherein a plurality of burners are provided on one opposing wall of the furnace. Either fuel or air gushing from the
Alternatively, a burner is arranged such that the axis of the ejection direction of both or an extension line thereof is in contact with a virtual circle set in the furnace of the furnace, and at least two or more virtual circles having different center positions are set in the furnace. In the apparatus, at least one or more of the burners are arranged on the other opposite wall of the furnace.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a combustion apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a furnace 1 of a combustion apparatus according to the present invention. As shown in the figure, a burner 5 is installed in a rectangular furnace 1 so as to be in contact with two virtual circles 6 having different center positions. That is, on the front wall 2 of the furnace, burners 5a are installed at two places at the center, burners 5b are installed at two places on the outside, burners 5c are installed at two places on the rear wall 3 of the furnace, and burners are provided at two places on the side wall 4 of the furnace. 5d are provided, and four burners 5a to 5d are set as one set so as to be in contact with one virtual circle 6. And four burners 5 in one set
Two sets a to 5d are symmetrically arranged in the furnace 1a.

The furnace 1 according to the present embodiment is different from the furnace described in the prior art mainly in that the four burners 5 installed on the rear wall 3 of the furnace are two and the furnace rear wall of both furnace side walls 4 is provided. Burners 5d should be installed at one location on each side. Also, the diameter D of the virtual circle 6 in the furnace 1a is increased. Then, as the diameter D of the virtual circle 6 increases, two burners 5 installed in the center of the furnace front wall 2.
a are both displaced to the outside thereof. In the present embodiment, the size of the diameter D of the virtual circle 6 is 25% of the sum of the half of the furnace width and the length of the furnace depth [virtual circle diameter = (furnace width / 2 + furnace) Depth) × 0.25], which is larger than in the past.

Next, the operation of the first embodiment of the present invention will be described. As shown in FIG. 1, two of the burners 5 are arranged on the furnace side wall 4 as shown by 5d. As a result, the number of installation locations of the burners 5 arranged in a narrow space near the outside of the furnace rear wall 3 is reduced by half from four to two. By this action, the space occupied by the main air duct for supplying combustion air to the burner 5 can be reduced in the vicinity of the outside of the furnace rear wall 3, and at the same time, the effect of reducing the number of installation points of the burner itself is reduced. In addition, a sufficient space can be secured.

In the present embodiment, the diameter D of the virtual circle 6 is set to 25% of the sum of the half of the furnace width X and the length of the furnace depth Y in comparison with the prior art. Consideration is made so that the swirling combustion flame vortex 9 can be formed stably by interaction with the arrangement of the burner 5 including the burner 5d arranged on the side wall. 2 and FIG.
As can be seen from the relationship, a large distance L between the burner wind boxes 10 arranged in two places near the center of the furnace front wall 2 can be ensured.

In FIG. 3, the horizontal axis is the position in the height direction of the combustion gas generated in the furnace 1a (the height of the combustion gas from the floor / the total height in the furnace), and the vertical axis is generated in the furnace 1a. The correlation between the three components is shown with the effective swirl number Swe of the swirling combustion flame vortex 9 and the diameter D of the virtual circle 6 as a parameter. Here, the effective swirl number Swe refers to a component in the circumferential direction of the virtual circle 6, that is, a component in the turning direction in the furnace, of the flow velocity generated when the combustion gas generated in the furnace 1 a flows in the furnace 1 a by Vθ. When the ascending direction component in the furnace is Vz, the distance of the combustion gas element existing in a certain part in the furnace from the center of the virtual circle 6 is r, and the hydrodynamic equivalent radius of the furnace is R, the combustion gas element It is an index obtained by integrating the ratio between the swirling component and the ascending component over the entire horizontal sectional area A of the furnace, and is expressed by the following equation.

[0011]

(Equation 1) That is, the effective swirl number Swe is an index indicating the swirling strength of the combustion gas in a certain cross section in the furnace. As the index value is larger, the swirling force of the combustion gas is larger, that is, the swirling combustion flame vortex 9 It means that it is formed stably. In FIG. 3, the diameter D of the virtual circle 6 is 5% of the sum of the half of the furnace width X and the length of the furnace depth Y [virtual circle diameter = (furnace width / 2 + furnace depth) × 0. .0
5], 10%, and 25% are shown. It can be seen that the effective swirl number Swe can be increased as the diameter D increases.

Further, in the case of the present invention, in order to stably form the swirling combustion flame vortex 9 equal to or more than the prior art,
At least the diameter D of the virtual circle 6 exceeds 5% of the sum of the length of the furnace width X and the length of the furnace depth Y [virtual circle diameter> (furnace width / 2 + furnace depth) × 0.05. ] Needs to be larger. From the above,
According to the present invention, it is possible to increase the degree of freedom in the arrangement of the burner 5 while stably forming the swirling combustion flame vortex 9, that is, while ensuring sufficient combustion performance. In order to take up the space for maintenance, which has been done, it is possible to solve the problem of compactness of the entire boiler without unnecessarily increasing the size of the boiler.

Next, the configuration of a combustion apparatus according to a second embodiment of the present invention will be described. As shown in FIG. 4, eight burners 5 a to 5 of the furnace 1 of the second embodiment.
The location of d is provided on the same wall portions 2 to 4 corresponding to the first embodiment. Therefore, also in the present embodiment, two burners 5 d out of eight burners 5 are arranged on the furnace side wall 4, unlike the prior art shown in FIG. 8. This embodiment differs from the first embodiment in that two virtual circles having different diameters are provided in the furnace 1a. The diameter D of the outer first imaginary circle 17 is:
The length is set to 25% of the sum of the length of the furnace width X and the length of the furnace depth Y [imaginary circle diameter = (furnace width / 2 + furnace depth) × 0.25], which is larger than before. The diameter has been reduced. Inside the first virtual circle 17, a second virtual circle 18 having a diameter different from that of the first virtual circle 17 is set. The first imaginary circle 17 and the second imaginary circle 18 are imagined concentrically and are provided at two places in the furnace 1a.

Of the burners 5 disposed at eight locations, six burners 5b to 5d disposed on the outer side of the front wall 2 of the furnace and on the side wall 4 and the rear wall 3 of the furnace are ejected from the burners. The axis 8 of the direction in which the combustion and combustion air is injected into the furnace is in contact with the first virtual circle 17. Further, with respect to the burners 5 a arranged at two places near the center of the furnace front wall 2, the axis 8 a of the fuel and combustion air ejected from the burners in the furnace is in contact with the second virtual circle 18.

Next, the operation of the second embodiment of the present invention will be described. Compared to the first embodiment shown in FIG. 1, in the present embodiment, of the eight burners 5 shown in FIG.
a is the burners 5b to 5d arranged in the other six places
Unlike this, the fuel and the combustion air are ejected in the tangential direction of the second virtual circle 18. The stable formation of the swirling combustion flame vortex 9 in the furnace 1a is less likely to be disturbed by the burner 5a. Therefore, since the majority of the swirling combustion flame vortices 9 are controlled by the influence of the burners 5b to 5d disposed at the other six places, it is possible to secure a sufficiently stable swirling combustion flame vortex 9. Further, for this reason, the direction in which the fuel and combustion air ejected from the burner 5a are ejected into the furnace can be selected with a relatively greater degree of freedom than in the prior art. As a result, as shown in FIG. 5, similarly to the case of the first embodiment, the distance L between the burners 5a arranged at two places near the center of the furnace front wall 2 is determined.
Can be largely secured.

Furthermore, a burner 5a at the center of the furnace front wall 2
The relationship between the angle of the axis 8a of the direction in which the fuel and combustion air ejected from the furnace is ejected into the furnace and the diameter d of the second virtual circle 18 can be appropriately adjusted and selected. Therefore, the size of the burner panel 12 can be reduced, and the combustion gas 13 that tends to flow along the inner wall surface of the burner panel 12 can be formed.
However, it is possible to minimize the turbulence exerted on the stable formation of the swirling combustion flame vortex 9. From the above, it is possible to further increase the degree of freedom in arrangement of the burner 5 while stably forming the swirling combustion flame vortex 9, and as a result, the performance of the furnace 1 which has been a problem of the prior art At the same time as securing the space for maintenance and maintenance, it becomes possible to solve the problem of the compactness of the physique of the boiler as a whole.

Next, the configuration of a third embodiment of the combustion apparatus of the present invention will be described. As shown in FIG.
The locations of the burners 5a to 5d of the furnace 1 according to the second embodiment are the same as the wall portions 2 to 4 corresponding to the first embodiment.
It is provided in. Therefore, also in the present embodiment, unlike the prior art shown in FIG. 8, two burners 5 d of the eight burners 5 are arranged on the furnace side wall 4. And, among the burners 5 arranged at eight locations, the burners 5b to 5d arranged at the outer side of the furnace front wall 2 and at the furnace side wall 4 and the furnace rear wall 3 blow out from the burners. The combustion and combustion air ejection direction axis 8 in the furnace is brought into contact with the first virtual circle 17, and the fuel and combustion air ejection direction axis 8 in the furnace are ejected from the burners 5 b to 5 d. ~ 5d
Is at right angles to the wall of the furnace where it is located.

With respect to the burners 5a arranged at two places near the center of the furnace front wall 2, the axis 8a of the fuel and combustion air ejected from the burners is injected into the furnace 8a.
It is in contact with the virtual circle 18. The diameter D of the first virtual circle 17
Is the length of 25% of the sum of the length of the furnace width X and the length of the furnace depth Y [imaginary circle diameter = (furnace width / 2 + furnace depth) × 0.25], which is larger than before. The diameter has been reduced. The diameter of the second virtual circle 18 inside the first virtual circle 17 is set smaller than the diameter of the first virtual circle 17.

Next, the operation of the third embodiment of the present invention will be described. FIG. 9 shows two burners 5 a arranged near the center of the furnace front wall 2, while FIG. 7 shows two burners 5 c arranged near the center of the furnace rear wall 3. Except that 9 is according to the prior art and that FIG. 7 has a new effect according to the invention, two burners 5a arranged near the center of the furnace front wall 2 and 2 placed near the center of the furnace rear wall 3
There is no difference in basic configuration between the two burners 5c.

However, as described above, according to the present invention, since the ejection direction axes 8 of the plurality of burners 5b to 5d are arranged at right angles to the furnace wall, as shown in FIG. The space occupied by the box 10 can be minimized, and the excess amount of the conventional technology can be reduced. This is not the only effect that can be said only for the two burners 5c arranged near the center of the furnace rear wall 3 shown in FIG. 7, but as shown in FIG. 6 of the third embodiment, the furnace rear wall 3 Burners 5c placed in two places
And burners 5d arranged at two places on the furnace side wall 4,
And the burners 5b to 5d arranged in two of the four places on the furnace front wall 2 with the effect that the ejection direction axes of the burners 5b to 5d are provided for all six burners arranged at right angles to the furnace wall. is there.

Further, according to the present invention, the burner panel 1
2 can be minimized, and in addition, the turbulence of the combustion gas 13 flowing along the inner wall surface of the burner panel 12 to the stable formation of the swirling combustion flame vortex 9 can be reduced as much as possible. From the above, it is possible to secure the performance and the space for maintenance, which have been problems of the related art, and at the same time, to solve the problem of making the physique of the boiler compact.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited to these, and various modifications can be made based on the technical idea of the present invention. For example, in each of the above embodiments, two virtual circles having different center positions are provided in the furnace 1a, but three or more virtual circles may be provided.

[0023]

As described above, according to the present invention, a plurality of burners are provided only on one opposing wall of a furnace having a rectangular cross section.
Since the number of the burners is set on the other opposing wall of the furnace, the number of burners on the one opposing wall can be reduced. Therefore, a space is generated in one wall portion, and maintenance can be easily performed. Further, the diameter of the virtual circle exceeds 5% of the sum of the length of the furnace width and the length of the furnace depth [virtual circle diameter> (furnace width / 2 + furnace depth) × 0.
05], the swirling combustion flame vortex can be formed stably. Further, at least one of the fuel and the air ejected by at least one or more of the burners, or both the ejection direction axes or their extension lines may be in contact with the second virtual circle set in the virtual circle. Thus, the degree of freedom of mounting the burner with the ejection direction axis directed to the second virtual circle is improved while maintaining the stability of the swirling combustion flame vortex. Still further, the burners are arranged such that at least one of the burners ejects fuel and / or air, and / or both the ejection direction axis and the extension line thereof are perpendicular to the furnace wall surface on which the burners are arranged. In this case, the space occupied by the burner-like box can be minimized.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually showing a concept of a horizontal section of a boiler furnace employing a combustion device according to a first embodiment of the present invention and a combustion flame in the section.

FIG. 2 is an enlarged view of a burner provided on a furnace front wall of the boiler furnace of FIG.

FIG. 3 is a diagram showing the effect of the diameter of a virtual circle on the performance of a swirling combustion flame vortex in the present invention and the first embodiment.

FIG. 4 is a diagram conceptually illustrating a concept of a horizontal cross section of a boiler furnace employing a combustion device according to a second embodiment of the present invention and a combustion flame in the cross section.

FIG. 5 is an enlarged view of a burner provided on a furnace front wall of the boiler furnace of FIG. 4;

FIG. 6 is a diagram conceptually showing a concept of a horizontal cross section of a boiler furnace employing a combustion device according to a third embodiment of the present invention and a combustion flame in the cross section.

FIG. 7 is an enlarged view of a burner disposed on a furnace rear wall which is inverted by 180 degrees from FIG. 5 with a furnace rear wall side being a lower side of the drawing and a furnace front wall side being an upper side of the drawing.

FIG. 8 is a view conceptually showing a concept of a horizontal section of a boiler furnace adopting a swirling combustion system according to a conventional technique and a combustion flame in the section.

FIG. 9 is an enlarged view of a burner provided on a furnace front wall of the boiler furnace of FIG.

FIG. 10 is a conceptual diagram showing a side surface of the boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace 2 Furnace front wall 3 Furnace rear wall 4 Furnace side wall 5 Burner 6, 17, 18 Virtual circle 7 Flame 8 Direction axis of fuel and combustion air ejection into furnace 9 Rotating combustion flame vortex 10 Burner wind box 11 Furnace wall tube 12 Burner panel 13 Combustion gas 16 Burner 17 Virtual circle 1 18 Virtual circle 2

Continuation of the front page (56) References JP-A-2-197710 (JP, A) JP-A-1-312384 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23C 5 / 32

Claims (4)

(57) [Claims] 1. A furnace having a rectangular cross section, wherein a plurality of burners are provided on one opposing wall of the furnace, and one of fuel and air ejected from the burner is provided.
Alternatively, a burner is arranged such that the axis of the ejection direction of both or an extension line thereof is in contact with a virtual circle set in the furnace of the furnace, and at least two or more virtual circles having different center positions are set in the furnace. The apparatus of any of the preceding claims, wherein at least one or more of said burners is located on the other opposing wall of said furnace. 2. The diameter of the virtual circle exceeds 5% of the sum of the length of the furnace width and the length of the furnace depth [virtual circle diameter> (furnace width / 2 + furnace depth) × 0. .0
5]. The combustion apparatus according to claim 1, wherein 3. A plurality of virtual circles having different diameters, and at least one of the burners injects fuel and / or air in each of the virtual circles. 3. The combustion apparatus according to claim 1, wherein the axis or an extension thereof is in contact with the axis. 4. A burner such that at least one of the burners ejects fuel and / or air, and at least one of the ejection direction axes or an extension thereof is perpendicular to the furnace wall surface on which the burner is disposed. The combustion device according to claim 1, 2 or 3, wherein