JP2802616B2 - Combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor for obtaining a high-temperature combustion gas.

[0002]

2. Description of the Related Art Combustion gas obtained from this type of combustor is:
It is desirable that there be no pollutants, that is, NO _X and unburned substances, and that the fuel be completely burned and the residual O ₂ be low.

In this type of conventional combustor, (1)
Air and fuel are mixed at a concentration within the explosion limit range, this mixed gas is ignited by means such as electric sparks to form a flame, and thereafter, the mixed gas of air and fuel is continuously burned. (2) A combustor in which a preheated mixed gas obtained by mixing fuel in preheated air is burned by a combustion catalyst (Japanese Patent Application Laid-Open No.
(Refer to JP-A-33213), (3) As proposed by the present inventor in Japanese Patent Application Laid-Open No. 62-116808, the outside of the heating tube of the main combustor is always at or above the ignition temperature of fuel by the auxiliary combustor. In the main combustor, there is known a combustor in which fuel is brought into contact with the heated heating pipe to continue combustion.

[0004]

In the conventional combustor (1), a high-temperature portion exists in the combustion gas to form a flame.
The occurrence of O _X could not be avoided. Further, since the mixing of air and fuel and the combustion of this mixed gas are performed within a very short time, there are problems such as a large amount of unburned substances and residual O _{2 in} the combustion gas. In the above (2), combustion at a low temperature is possible, but when the combustion temperature exceeds 1300 ° C., the life of the combustion catalyst is short, and long-term operation is impossible. In such a case, it is not possible to use a fuel containing sulfur or the like which is a catalyst poison.

Further, in the above (3), since the auxiliary combustor must be constantly burned in addition to the main combustor, combustion control is performed for both the main combustor and the auxiliary combustor. It had to be done and it was troublesome.
Moreover, even those of the prior art could not be completely eliminated the NO _X in the combustion gas.

[0006] The present invention has cans in the above was considered, in which an object to provide a combustion apparatus to be able to obtain the NO _X and unburned absence combustion gas is pollutant is there.

[0006]

In order to achieve the above object, a combustor according to the present invention comprises at least one inner cylinder 2, 22 arranged in parallel in an outer cylinder 1, 21; , 21 and the outer circumferential surfaces of the inner cylinders 2, 22.
3 and return passages 4, 24 inside the inner cylinders 2, 22.
And one end of the forward flow paths 3 and 23 are closed, and the other end is connected to one end of the return flow paths 4 and 24 in a folded manner. At the other end, a main inlet 5 connected to the fuel mixer 11 and an auxiliary inlet 6 connected to the pilot burner 12 are provided to face the outer peripheral surfaces of the inner cylinders 2 and 22, respectively. Roads 4, 24
Is connected to the outlet 7 at the other end.

In the above-described combustor, a honeycomb-shaped flow path member 8, 9, 26, 27 is provided in a combustion gas flow path including a forward flow path 3, 23 and a return flow path 4, 24. Has become.

Further, in the above combustor, the inner cylinders 2, 2
2 was composed of silicon carbide.

[0009]

[Operation] The combustion gas from the pilot burner 12 flowing from the auxiliary inflow port 6 causes the upstream side of the forward passages 3, 23, particularly, the inner cylinders 2, 22 of this part where the pilot burner 12 faces. The outer peripheral surface is heated. Then, when this portion is heated to a predetermined temperature, for example, about 900 ° C. or higher, the fuel mixed gas from the fuel mixer 11 is caused to flow from the main flow inlet 5 to the upstream side of the forward flow paths 3 and 23.
At this time, the fuel mixed gas is supplied to the pilot burner 12.
The combustion gas is heated by contacting the wall surfaces of the inner cylinders 2 and 22 which are heated by the combustion gas, and the combustion gas flows from the forward flow path to the return flow path, returns to the outlet, and flows out to the outlet. Road 3,
The walls separating the flow path 23 and the return flow paths 4 and 24 are heated from both sides facing the flow paths. The pilot burner 12 operates only while the upstream sides of the forward flow paths 3 and 23 are heated to a predetermined temperature. The honeycomb-shaped flow path member 8,
When 9, 26 and 27 are installed, the combustion gas is further completely burned while passing therethrough.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes an outer cylinder, and 2 denotes an inner cylinder which is disposed substantially concentrically inside the outer cylinder 1. Is made of ceramics. A ring-shaped outward flow path 3 is formed between the inner peripheral surface of the outer cylinder 1 and the outer peripheral surface of the inner cylinder 2, and a cylindrical backward flow path 4 is formed inside the inner cylinder 2. It is configured. One end side (upstream side) of the forward side flow path 3 is closed, and the other end side (downstream side) is one end side (upstream side) of the cylindrical backward flow path 4 formed by the inner cylinder 2. )
It is connected in a folded shape in a space defined by the end of the outer cylinder 1. A main inlet 5 and an auxiliary inlet 6 are respectively opened on the side wall of the upstream end of the outward flow path 3 so as to face the outer peripheral surface of the inner cylinder 2, and the downstream end of the return flow path 4. Is open to the outlet 7. The downstream end of the forward flow path 3 and the downstream end of the return flow path 4 each have a donut shape.
Ceramic honeycomb flow path members 8 and 9 formed in a plug shape are provided. The outer cylinder 1 is supported by an outer frame 10a via a heat insulating material 10.

A fuel mixer 11 is connected to the main inlet 5 provided on the upstream side of the forward passage 3, and a pilot burner 12 is connected to the auxiliary inlet 6. A preheated air inflow pipe 13 and a fuel inflow pipe 14 are connected to the fuel mixer 11, and the air and fuel flowing from the two inflow pipes 13 and 14 are mixed in an air-fuel mixing section 15. Outgoing flow path 3 through main flow inlet 5 as fuel mixed gas
And flows toward the outer peripheral surface of the inner cylinder 2. An air inflow pipe 16 and a fuel inflow pipe 17 are connected to the pilot burner 12, and the combustion gas generated by the pilot burner 12 is upstream of the forward flow path 3 via the auxiliary inflow port 6, and The fluid flows toward the outer peripheral surface of the inner cylinder 2.

In the above configuration, first, the pilot burner 12 is operated to cause the combustion gas to flow into the forward passage 3 of the combustor, and the outer cylinder 1 and the inner cylinder 2 on the upstream side of the forward passage 3 are arranged. Heat. Then, when this portion is heated to a predetermined temperature, for example, about 900 ° C. or more, the fuel mixer 11 is operated to flow the fuel mixed gas from the main flow inlet 5 to the upstream side of the forward flow path 3. At this time, the pilot burner 1
The combustion gas from 2 is sprayed on the outer peripheral surface of the cylinder 2,
This part is particularly heated, and the fuel mixture gas from the main injection port 5 is sprayed on this part, and this fuel mixture gas is ignited and burnt well in this part. The operation of the pilot burner 12 is stopped immediately or with some overlap.

In the above state, the fuel mixed gas flowing from the fuel mixer 11 through the main flow inlet 5 is supplied to the inside and outside of the heated upstream outer cylinder 1 and inner cylinder 2 of the outward flow path 3. Combustion is started by contacting the side walls, and the combustion gas is discharged from the forward flow path 3 through the return flow path 4 through the outlet 7, and during this time, the side walls forming the two flow paths 3 and 4 are sequentially turned off. As the fuel mixture gas is heated, the fuel mixed gas flowing from the fuel mixer 11 is sequentially burned and completely burned before reaching the outlet of the return flow path 4. In this case, the fuel supplied to the fuel mixer 11 is mixed with the preheated air supplied from the preheating air inlet pipe 13 in the fuel mixer 11 so that the temperature of the combustion gas becomes 1200 to 1400 ° C. . When the fuel is gaseous, the air may be at room temperature.

At the time of the above-mentioned combustion action, the combustion started in the upstream part of the forward flow path 3 is continued from the forward flow path 3 to the return flow path 4, and the inner cylinder 2 is connected to the forward flow path. The inner cylinder 2 is heated from both the return side, that is, from the inside and the outside. At this time, the cross-sectional areas of both the forward and return flow paths are smaller on the return side than on the forward side. Accordingly, the flow rate of the combustion gas is higher in the return flow path 4, the heat transfer coefficient on the inner peripheral surface of the inner cylinder 2 is increased, and the amount of heating from the inner peripheral surface of the inner cylinder 2 is increased. Further, the combustion gas is further completely burned while passing through the downstream end of the forward flow path 3 and the honeycomb flow path members 8, 9 provided at the downstream end of the return flow path 4, respectively. Also, at this time, by applying a paint having a high infrared absorptivity to the inner surface of the outer cylinder 1, the absorptivity of the infrared radiation radiated from the outer surface of the inner cylinder 2 is increased and the inner surface temperature of the outer cylinder 1 is increased. Become
The inner surface of the outer cylinder 1 can also be used more effectively as an ignition surface for burning the fuel gas mixture.

FIGS. 3 to 5 show a second embodiment of the present invention. The same components as those in the first embodiment are the same as those in the first embodiment.
The same reference numerals as those shown in FIGS. 2 and 3 denote the same parts, and a description thereof will be omitted. A plurality of ceramic inner cylinders 22 are respectively arranged at appropriate positions in a ceramic outer cylinder
Between the outer circumference of the inner cylinder and the inner peripheral surface of the outer cylinder 21, and a return-side channel 24 inside each of the inner cylinders 22.
Is configured. The upstream side of the outward flow path 23 is closed by a support wall 25 that supports the downstream side of each inner cylinder 22.
Further, honeycomb-shaped passage members 26 and 27 are provided on the downstream side of the outward flow path 23 and the downstream side of the return flow path 24. A plurality of maze baffle plates 28 are interposed in the outward passage 23.

This second embodiment is advantageous when the amount of combustion is large, and its combustion action is the same as that of the first embodiment. That is, first, the pilot burner 12 heats the upstream side of the outward flow path 23, particularly, the outer peripheral surface side of the inner cylinder 2,
After the flow path wall is heated to a predetermined temperature (900 ° C.) or higher, the fuel mixed gas flows from the fuel mixer 11 into the forward flow path 23 and is burned. At this time, the combustion gas in the outward flow path 23 flows through the maze formed by the baffle plate 28 to the downstream end thereof, and during this time, the fuel gas mixture is sufficiently stirred and burned. The combustion gas flowing to the downstream side of the forward flow path 23 enters the return flow path 24 via the honeycomb-shaped passage member 26, and further burns on the inner wall of the heated inner cylinder 22 constituting the return flow path 24. It is accelerated and discharged from the outlet 7 via the honeycomb-shaped passage member 27 on the downstream side of the passage.
And also in this embodiment, since the cross-sectional area of the backward flow path 24 is smaller than that of the forward flow path 23, the flow rate of the combustion gas in the backward flow path 24 is larger than that of the forward flow path. The heat transfer coefficient on the inner peripheral surface of each inner cylinder 22 is increased by the combustion gas passing through the return flow passage 24, and the amount of heating on the inner peripheral surface is increased.

The outer cylinders 1, 21 and the inner cylinders 2, 22 and the honeycomb-shaped passage members 8, 9, 26, 2 in each of the above embodiments.
As the material of the ceramics constituting silicon 7, silicon carbide which is excellent in strength, heat resistance temperature and heat shock resistance is used.
However, it is not limited to this, zirconia-based,
Cordierite ceramics may be used.

Further, the outer cylinders 1 and 21 may be formed of a material mainly composed of alumina fiber. In this case, it is desirable that a coating mainly composed of an oxide such as SiZrO ₄ or MnO ₂ .Cr ₂ O ₃ having a high infrared absorptivity is adhered to the inner surface of the cylinder by means such as spraying.

[0019]

According to the present invention, the combustion gas that flows back from the forward flow paths 3 and 23 to the return flow paths 4 and 24 provides
The walls separating the two passages are located on both sides of the passage, and the forward passages 3, 2
3 is heated to a temperature sufficient for the fuel mixture gas flowing into the upstream side to contact and burn, and is completely burned while passing through both passages; from 7, no NO _X and unburned substances are pollutant, also by using a combustor connected to the series in multiple stages, combustion by complete combustion of residual O ₂ to obtain the extremely low combustion gas Can be.

According to the invention, in particular, the outer cylinders 1, 21
At least one inner cylinder 2, 22 is arranged in parallel, and the outward flow paths 3, 23 are provided between the inner peripheral surface of the outer cylinder 1, 21 and the outer peripheral surface of the inner cylinder 2, 22. By configuring the return-side flow paths 4 and 24 inside the inner cylinders 2 and 22, respectively, the cross-sectional area of each of the two flow paths 3, 23, 4 and 24 is greater in the forward flow path 3 and 23. The return channels 4 and 24 are small. Accordingly, the flow velocity of the combustion gas flowing through both flow paths is higher on the return flow path side than on the forward flow path side, and the heat transfer coefficient on the inner peripheral wall surfaces of the return flow paths 4 and 24 is increased. Side channel 4, 2
The amount of heating from the inside of the inner cylinders 2 and 22 constituting the inner pipe 4 is increased, so that the combustion on the outflow passages 3 and 23 is more favorably performed.

At the closed end between the forward flow paths 3 and 23, a main flow inlet 5 connected to the fuel mixer 11 and an auxiliary flow inlet 6 connected to the pilot burner 12 are each provided with an inner cylinder. By being provided to face the outer peripheral surfaces of 2, 22
The fuel mixture gas from the fuel mixer 11 is supplied to the portion heated by the pilot burner 12, so that ignition at the start can be performed smoothly.

Further, since the honeycomb-shaped flow path members 8, 9, 26, and 27 are provided in the fuel gas flow path, the fuel gas passing through the fuel gas flow path can pass through the honeycomb-shaped flow path members 8, 9 and 26.
During passing through 9, the fuel is further completely burned.

Further, the forward flow paths 3, 23 and the return flow path 4,
By forming the inner cylinders 2 and 22 which are heated to a high temperature by partitioning the inner cylinders 24 from silicon carbide, the strength, heat resistance and heat shock resistance of the inner cylinders 2 and 22 can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a sectional view taken along the line CC in FIG. 3;

[Explanation of symbols]

1, 21 ... outer cylinder, 2, 22 ... inner cylinder, 3, 23 are forward flow paths, 4, 24 are return flow paths, 5 is a main flow inlet, 6 is an auxiliary flow inlet, 7 is an outlet, 8, 9 , 26, 27 ... honeycomb channel member, 11 is a fuel mixer, 12 is a pilot burner.

Claims (3)

(57) [Claims] At least one inner cylinder is arranged in parallel in an outer cylinder, and the inner cylinder extends between an inner peripheral surface of the outer cylinder and an outer peripheral surface of the inner cylinder. The side flow paths 3, 23,
The return channels 4 and 24 are respectively formed inside the inner cylinders 2 and 22, one end of the forward channels 3 and 23 is closed, and the other end is connected to one end of the return channels 4 and 24. The fuel mixer 11 is connected in a folded manner, and the fuel mixer 11 is
The main inflow port 5 connected to the inner cylinder 2 and the auxiliary inflow port 6 connected to the pilot burner 12 are provided to face the outer peripheral surfaces of the inner cylinders 2 and 22, respectively. A combustor, characterized in that it is connected to a combustor. 2. The combustor according to claim 1, wherein honeycomb-shaped flow path members 8, 9, 26, and 27 are provided in a combustion gas flow path including a forward flow path 3, 23 and a return flow path 4, 24. A combustor characterized by being installed. 3. The combustor according to claim 1, wherein the inner cylinders 2, 22 are made of silicon carbide.