JPS6339801B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) This invention has a combustor main body formed of an integral structure of ceramic honeycomb, which enables heat exchange between exhaust gas, combustion air, and fuel. ,and,
This invention relates to a ceramic honeycomb combustor that uniformly heats a heated object through surface combustion.

(Prior art) In order to efficiently heat an object to be heated by a combustor, exhaust heat recovery is performed, that is, heat exchange is performed between the exhaust gas from the combustor and the air and fuel supplied to the combustor. It is better to let

On the other hand, if fuel and air are uniformly supplied throughout the combustion section from multiple passages, resulting in so-called surface combustion, the combustion area will be much lower compared to normal combustion where fuel and air are supplied from a single passage. In addition to being able to uniformly heat the heating element, the area of the flame becomes larger and the amount of heat radiated from the flame increases, which has the advantage of lowering the maximum flame temperature.

Therefore, in order to efficiently and uniformly heat the object to be heated, it is found that it is better to carry out surface combustion while recovering exhaust heat. However, in order to do so, the following problems have conventionally occurred.

In other words, waste heat recovery improves heating efficiency, but (1) in conventional combustors that recover waste heat, the burner section and heat exchange section are separate, so the entire combustor In addition to being large in size, manufacturing and assembly is troublesome and productivity is poor.

(2) Conventional combustors that perform surface combustion (for example, Schwank gas burners) use a premix combustion method in which fuel and air are mixed in advance and then supplied to the combustion section. When added, the air temperature rises and flashback occurs,
Combustion cannot continue. In other words, the conventional surface combustion becomes impossible, and it becomes difficult to uniformly heat the object to be heated.

On the other hand, surface combustion allows for uniform heating, but
(1) As mentioned above, due to the need to premix fuel and air, it is not possible to raise the air temperature to prevent flashback, and as a result, sufficient exhaust heat recovery is not possible. Heating efficiency decreases.

(Purpose of the Invention) This invention was made in view of the above-mentioned conventional problems.It is small and lightweight, has excellent productivity, and performs surface combustion while preheating the air with exhaust gas, thereby heating the heated object. It is an object of the present invention to provide a ceramic honeycomb combustor that has excellent characteristics such as high efficiency and uniform heating.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention forms a combustor main body with a ceramic integral structure having a honeycomb-shaped cross section in which a large number of linear passages extending in the axial direction are gathered together, and a first row of passages extending in the axial direction and opening at the front and rear end surfaces of the combustor body; and a closing member provided in the passage, one end of which is provided on one side surface of the combustor body. a second row of passages that communicate with the through holes and whose other ends are open to the front end surface of the combustor body; and a through hole in which the passages are provided with closing members and whose one ends are provided on the other side of the combustor body. a third row of passages communicating with the holes and having the other end opening at the front end surface of the combustor body; A heated body is arranged to cover the openings of the three passage rows, and each of the first to third passage rows is a passage row through which any one of the fluids consisting of exhaust gas, air, or fuel flows, and A passage row through which air flows is arranged on both sides of a passage row through which fuel flows, and a passage row through which exhaust gas flows is arranged adjacent to this passage row through which air flows.

As a result, the burner part and the heat exchange part are integrated, making it smaller and lighter.Furthermore, after making the combustor body by extrusion molding of ceramic honeycomb,
Prior to combustion of the ceramic honeycomb, the combustor can be obtained by simply performing secondary processing on the combustor body, thereby improving productivity. In addition, fuel and air are separately supplied to the combustion section through many passages to achieve surface combustion, thereby achieving both sufficient air preheating by exhaust gas and uniform heating. Furthermore, the above-mentioned special arrangement of the three rows of passages prevents the fuel from carbonizing due to the high heat of the exhaust gas, and increases the efficiency of heat exchange between the air and the exhaust gas.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a combustor body made of an integral structure of ceramics, which has a honeycomb shape in cross section as shown in FIG. There is. The combustor body 11 is made by extruding a clay-like ceramic material through a honeycomb-shaped die.

Here, the honeycomb shape is triangular, quadrilateral,
and more polygons viewed from the axial direction 12,
It refers to a shape in which a large number of squares are arranged vertically and horizontally, and in this example, a large number of quadrangles are arranged adjacent to each other. Furthermore, the term "integral structure" refers to something that is formed as a single piece from the beginning, such as by extrusion molding, and does not include something that is integrated by laminating a plurality of parts later.

As shown in FIG. 1, the numerous passages 13 are as follows:
A first passage row 16 that opens to the front and rear end surfaces 14 and 15 of the combustor main body 11, a second passage row 19 that opens to the upper surface 17 of the combustor main body 11 and the front end surface 14, and a combustor main body 11 and a third passage row 21 opening to the front end surface 14.

As clearly shown in FIG. 3, the first passage row 16 extends in the axial direction 12 of the combustor main body 11 and opens into the front and rear end surfaces 14 and 15 of the combustor main body 11.

Further, as clearly shown in FIG. 4, in the second passage row 19, a closing member 22 is provided in the middle of the passage 13, and this closed end 19a is attached to the upper side 17 of the combustor main body 11. It communicates with the provided through hole 23, and the other end 19b opens to the front end surface 14 of the combustor main body 11. The closing member 22 may be provided not in the middle of the passage 13 but at the rear end 13a.

As clearly shown in FIG. 5, the third passage row 21 has a closing member 22 provided at the rear end 13a of the passage 13, and one end 21a provided on the lower surface 20 of the combustor main body 11. It communicates with the through hole 24, and the other end 21b opens to the front end surface 14 of the combustor main body 11.

The first to third passage rows 16, 19, 21
Each of these is a passage row through which one of the fluids consisting of exhaust gas, air, or fuel flows, and the fluids flowing through the three passage rows 16, 19, and 21 are different from each other. In this embodiment, as shown in FIG. 1, exhaust gas 25 is directed to the first passage row 16, fuel 26 is directed to the second passage row 19, and air 27 is directed to the third passage row 21, as indicated by the arrows. flowing in the direction.

Further, on the front end side of the combustor main body 11, a sixth
Space 29 for holding the flame as shown in the figure
A plate-shaped heated body 30 is arranged to cover the openings of the three passage rows 16, 19, and 21, and this heated body 30 is inserted into the combustor main body 11 through the bracket 31 so that there is no leakage. Fixed.

By the way, the three passage rows 16, 19, 21
may be combined in any way, but in this embodiment, the second passage row 1 through which the fuel 26 flows
A third passage row 21 through which air 27 flows is arranged on both sides of the exhaust gas 25 adjacent to the third passage row 21.
A first row of passages 16 through which fuel flows is arranged, thereby preventing the fuel 26 from being carbonized due to the high heat of the exhaust gas 25 while allowing heat exchange to occur between the exhaust gas 25 and the air 27. The air 27 is preheated.

Further, in this embodiment, the front end edge 33a of the passage wall 33 that partitions the second passage row 19 through which the fuel 26 flows and the third passage row 21 through which the air 27 flows is located between the other passage rows, that is, between the air 27 The third passage row 21 through which the gas flows and the first passage row 1 through which the exhaust gas 25 flows
6 and the front edge 34a of the passage wall 34 that partitions the
It is set backwards. Thereby, the fuel 26 and the air 27 are sufficiently mixed before entering the space 29, improving combustion efficiency. Further, the front end edge 33a of the passage wall 33 is crushed to form a slightly swollen bulge, and this bulge disturbs the air 27 and functions to stabilize the flame.

When actually using the combustor 35 obtained in this way, it is preferable to connect the fuel header 36 and fuel pipe 37 to the air header 38 and air pipe 39, respectively, as shown in FIG.

Next, an example of a method for manufacturing the combustor main body 11 shown in FIG. 1 will be described.

First, by extruding a clay-like ceramic material through a honeycomb-shaped die,
The combustor main body 11 shown in Figure A is manufactured. Such ceramic honeycomb structures have already been widely used as catalyst carriers in three-way catalyst devices for exhaust purification in automobiles.

Next, as shown in FIG. 8B, the combustor main body 1
A through hole 23 is cut from the upper side 17 of the
A closing member 22 made of the same ceramic material as the combustor main body 11 is packed behind the through hole 23 to form a second passage row 19.

Furthermore, as shown in FIG. 8C, the combustor main body 1
A through hole 24 is cut from the lower side 20 of the
A closing member 22 made of the same ceramic material as the combustor main body 11 is packed behind the through hole 24 to form a third passage row 21.

Among the many passages 13 in FIG. 8A, the passage row that is not blocked is the first passage row 16.

Finally, the entire body is fired to complete the combustor main body 11 shown in FIG. 8D.

The combustor 35 of the present invention has the above-described configuration, and fuel 26 and air 27 are supplied to the space 2 through the second passage row 19 and the third passage row 21 shown in FIG.
9 and after combustion, the exhaust gas 25 enters the first
is discharged through a row of passages 16.

Here, a burner part is formed at the front end of the combustor main body 11, and a heat exchange part is formed over the entire length of the combustor main body 11, including the burner part. Since these are integrally formed, the entire combustor 35 becomes smaller and lighter, and manufacturing and assembly becomes easier, improving productivity.

In addition, each passage row 1 composed of a large number of passages 13
6, 19, 21, exhaust gas 25, fuel 26, air 2
7, the heat of the exhaust gas is effectively recovered, surface combustion by diffusion combustion is possible, the heat flux is made uniform, and hot spots are not generated on the heated body 30. Here, the above fuel 2
6 and air 27 are mixed only after entering the space 29 which is the combustion part, that is, the premixing method is not used as in the conventional case, so no flashback occurs at all.

Furthermore, since the entire front surface of the combustor main body 11 can be used as the flame area, the flame area becomes large, and the front end surface 14 of the combustor main body 11, which is a burner section, can be orthogonally approached to the heated body 30. Since the impingement effect can be utilized, heat transfer from the flame to the object to be heated 30 is improved.

Furthermore, since the flame temperature is lowered by the improvement in heat transfer, the thermal load on each structural member is reduced, and the amount of nitrogen oxide emissions and heat radiation loss are reduced.

Furthermore, since the combustor main body 11 is made of an integral structure with a honeycomb cross section, it is homogeneous and there are no joints between passage walls, so heat transfer is uniform, heat exchange efficiency is improved, and fuel consumption rate is improved. In addition to improving
Fluid resistance is reduced, and in addition, it is advantageous in terms of strength. Moreover, since it is an integral structure made of ceramics, it maintains high strength while maintaining the passage walls 33, 3.
4 can be made thinner, which improves heat transfer.
Heat exchange efficiency is further improved. As a result, exhaust gas 2
5 and air 27 are sufficiently preheated, if necessary, the flame temperature can be raised to burn a low-calorie fuel that is difficult to burn.

Here, since each passage row 16, 19, 21 has a honeycomb structure, the exhaust gas 25
The rate of heat recovery from the fuel to the air 27 and the fuel 26 is improved, and the fuel 26 and the air 27 are no longer unevenly distributed, allowing efficient surface combustion.

That is, as shown in FIG. 12A, each passage 1
6, 19, 21, horizontal walls 16a, 19a, 21
Since there is a, heat transfer from the exhaust gas 25 to the air 27 first occurs from both the passage 34 and the side wall 16a, as shown by arrows a ₁ and a ₂ , respectively, from the exhaust gas 25 to the air 27.
5 is absorbed, and then this heat is transferred from both the passage wall 34 and the side wall 21a, respectively in the directions indicated by the arrows.
It is applied to the air 27 as shown by b ₁ and b ₂ . In other words, a large amount of heat is transferred due to the large heat transfer area. In other words, the lateral wall 16a acts as a heat transfer fin for the passage 16 of the exhaust gas 25, and the lateral wall 21a acts as a heat transfer fin for the passage 21 of the air 27, resulting in a significant increase in the amount of heat transfer. That's what I do.

This phenomenon can be easily understood when compared with the case where simple longitudinal passages 16A, 19A, and 21A are formed as shown in FIG. 12B, for example. This twelfth
In Figure B, the heat transfer areas between exhaust gas and air and between air and fuel are only passage walls 34A and 33A, respectively, so for example, the heat transfer paths from exhaust gas to air are only a ₁ and b ₁ , and the Compared to the case in Figure 12A, the amount of heat transfer is only a fraction.

The amount of heat transferred from the air 27 to the fuel 26 in FIG. 12A also increases for the same reason.

In addition, in the configuration of FIG. 12A, the fuel 26 and air 27 are dispersed vertically and horizontally, so the fuel 26 and air 27 are distributed in the combustor body 1 of FIG.
Since the fuel flows from the front end surface 14 of 1 into the space 29, which is the combustion section, in a two-dimensionally uniform distribution without deviation, efficient surface combustion is possible.

On the other hand, in the passage configuration shown in FIG. 12B, the flow of fuel 26 and air 27 is likely to be concentrated in the vertical direction, for example, concentrated in the upper part of passages 19A and 21A. Even when used in a type of combustor, it has the disadvantage that uniform surface combustion cannot be achieved.

In addition, the combustor main body 11 is made by extrusion molding of ceramic honeycomb, and the combustor main body 11 is subjected to simple secondary processing, that is, cutting with a cutter and stuffing the closing member 22 into the combustor main body 11. Since the main body 11 can be manufactured, productivity is extremely high.

FIG. 9 shows a second embodiment of the present invention, in which a breathable incandescent body 41 made of foamed ceramic is attached to the front end surface 14 of the combustor main body 11, and a heated body 30 is attached. . In this way,
As shown in FIG. 10, mixing of the fuel 26 and air 27 is promoted inside the breathable incandescent body 41, improving combustion efficiency. In addition, the breathable incandescent body 41 emits a large amount of radiant heat, and the object to be heated 30 is effectively heated, and the breathable incandescent body 41 also absorbs heat from the exhaust gas 25 and emits radiant heat, so that the object to be heated 30
A more uniform heating to 0 is achieved. Furthermore, flame holding is achieved by the breathable incandescent body 41, and combustion is stabilized.

Further, as a third embodiment, it is preferable to use the breathable incandescent body 41 shown in FIG. 9 impregnated with an oxidation catalyst. For example, the front surface 41a of the breathable incandescent body 41
is immersed in a melt of an oxidation catalyst such as platinum or palladium to adhere the oxidation catalyst to the front surface 41a. According to this, ignition is facilitated, combustion efficiency is improved, and since combustion can be performed at a low temperature, nitrogen oxides are reduced.

Furthermore, since the above-mentioned ignition becomes easier,
Without using a conventional plug as an ignition device, the first
As shown in Figure 1, air 27 is heated using a heater 43.
It is possible to ignite by simply heating the ignition device, which simplifies the ignition device.

(Effects of the Invention) As explained above, according to the present invention, since the burner section and the heat exchange section are integrally formed, the entire combustor becomes smaller and lighter, and manufacturing and assembly becomes easier. Improves sex.

In addition, while increasing the heating efficiency by recovering exhaust heat, surface combustion by diffusion combustion is possible, the flame temperature is lowered, the heat flux is made uniform, and hot spots are not generated on the heated object. Moreover, since the honeycomb structure has a large heat transfer area, the efficiency of exhaust heat recovery is improved. In addition, because the row of passages through which air flows are placed on both sides of the row of passages through which fuel flows, carbonization of the fuel due to the high heat of exhaust gas is prevented, and the row of passages through which exhaust gas flows is placed adjacent to the row of passages through which air flows. Therefore, the air is efficiently preheated by the heat of the exhaust gas. Furthermore, since heat transfer to the heated object is improved and the flame temperature is lowered, the thermal load on each structural member is reduced, and the amount of nitrogen oxide emissions is reduced.
A reduction in heat radiation loss is achieved.

In addition, since the combustor body has a honeycomb cross-section and is made of an integral ceramic structure, it is homogeneous and seamless, and the passage walls can be made thinner.
Heat exchange efficiency is improved, fuel consumption rate is improved, fluid resistance is reduced, and strength is also advantageous. Furthermore, the combustor body can be efficiently manufactured by extrusion molding of ceramic honeycomb, and the combustor can be obtained by simply performing a simple secondary process on the combustor body, resulting in extremely high productivity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the same embodiment, FIGS. 3 to 5 are cutaway perspective views showing essential parts of the same embodiment, and FIG. 6 is a plan sectional view of the same embodiment, and FIG. 7 is a schematic sectional view showing an example of a combustion system using the same embodiment.
FIG. 8 is a process diagram showing the manufacturing process of the same example, and FIG.
The figure is a perspective view showing the second embodiment, FIG. 10 is a cross-sectional view showing the main parts of the same embodiment, and FIG. 11 is a schematic configuration diagram showing the ignition device when using the third embodiment.
FIG. 12 is a cross-sectional view showing the operation of the present invention. 11... Combustor main body, 12... Axial direction, 13...
... Passage, 14... Front end surface, 15... Rear end surface, 16
...first aisle row, 17...one side, 19...
...Second passage row, 19a...One end, 19b...
Other end, 20...Other side, 21...Third passage row, 20a...One end, 20b...Other end, 22
...Closing member, 23, 24...Through hole, 25...
Exhaust gas, 26...Fuel, 27...Air, 33,3
4... Passage wall, 29... Space, 30... Heated object.

Claims (1)

[Claims] 1. A combustor that exchanges heat between exhaust gas discharged from the combustor and air and fuel supplied to the combustor, and then mixes and burns the air and fuel, It has a combustor main body made of an integral structure of ceramics and has a honeycomb cross-sectional shape in which a large number of straight passages extending in the axial direction are arranged vertically and horizontally overlapping each other when viewed from the axial direction. A first row of passages extending in the axial direction and opening at front and rear end surfaces of the combustor main body, and a closing member provided in the passage, one end communicating with a through hole provided on one side surface of the combustor main body. a second passage row whose other end opens at the front end surface of the combustor main body; a closing member is provided in the passage; and one end communicates with a through hole provided on the other side of the combustor main body. , and a third passage row whose other end opens at the front end surface of the combustor main body,
A heated body is disposed on the front end side of the combustor body to cover the openings of the three passage rows through a space for holding flame, and each of the first to third passage rows is connected to the exhaust gas. , a row of passages through which either air or fuel flows, and rows of passages through which air flows are arranged on both sides of the row of passages through which fuel flows,
A ceramic honeycomb combustor characterized in that a row of passages through which exhaust gas flows is arranged adjacent to a row of passages through which air flows. 2 The front end edge of the passage wall that partitions the passage row in which fuel flows and the passage row in which air flows is set further back than the front end edge of the passage wall between the other passage rows. Ceramic honeycomb combustor.