JPH0221105A - Burner - Google Patents

Abstract

PURPOSE:To obtain combustion gas which is free of NOX and unburnt substances by laying out a return flow passage within a forward flow passage so that they may be connected with each other in a folding manner separated by a cylinder-shaped wall, and installing a main stream inlet which is adapted to connect a fuel mixer with the upper stream side of said forward flow passage and auxiliary stream inlet which connects a pilot burner to said forward flow passage, and connecting the outlet of combustion gas with the downstream side of said forward flow passage. CONSTITUTION:Combustion gas is adapted to flow into a forward flow passage 3 of a burner from an auxiliary flow inlet 6 by operating a pilot burner 12 so as to heat an outer cylinder 1 and an inner cylinder 2 on the upper stream side. At the time when this portion is heated to about 900 deg.C and over, a fuel mixer 11 is made to operate so that fuel mixed air may flow to the upper stream side of the forward passage 3. At that time, the pilot burner 12 is adapted to come to a halt. The fuel mixed gas which has flown into the upper stream side from the fuel mixer 11 by way of a main stream inlet 5 under this condition is brought into contact with the side walls of the outer cylinder and the inner cylinder on the upper stream side of the heated forward flow passage and starts combustion. The combustion gas is discharged from an outlet 7, passing through a return flow passage 4 from the forward flow passage 3. Therefore, the fuel contained in the fuel mixed gas which has been introduced from the fuel mixer 11 can be burnt to a satisfactory extent until it has reached the outlet of the return flow passage 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustor for obtaining high-temperature combustion gas.

[Conventional technology]

It is desirable that the combustion gas obtained in the combustor be free of pollutants, ie, NOx and unburned materials, and be completely combusted and have a low residual O2 content.

In conventional combustors of this type, (1) air and fuel are mixed at a concentration within the explosion limit, ignited by means such as an electric spark to form a flame; A combustor configured to continuously burn the above-mentioned mixed gas of air and fuel, (2) a combustor configured to mix fuel into preheated air and combust it using a combustion catalyst, (3) the inventor of the present application As previously proposed in Japanese Unexamined Patent Publication No. 1808/1983, the outside of the heating tube of the main combustor is constantly heated above the ignition temperature of the fuel in the auxiliary combustor, and the above-mentioned heating is performed in the main combustor. There are known combustors that continue combustion by bringing fuel into contact with heated tubes.

[Problem to be solved by the invention]

Among the above-mentioned conventional combustors, the one in (1) has a partially high-temperature portion to form a flame, and therefore the generation of NOx is unavoidable. Furthermore, since the mixing and combustion of air and fuel are carried out within an extremely short period of time, there are problems such as a large amount of unburned matter and residual O2 in the combustion gas.

In addition, in the case of (2) above, combustion is possible at low temperatures, but if the combustion temperature exceeds 1300°C, the life of the combustion catalyst is short, and long-term operation is impossible, and the combustion catalyst In this case, fuel containing sulfur, which poisons the catalyst, cannot be used.

Furthermore, in the case of (3) above, in addition to the main combustor, the auxiliary combustor must be kept burning at all times, so combustion control must be performed for both the main combustor and the auxiliary combustor. It was rather troublesome. Further, even with this conventional example, NOx in the combustion gas could not be completely eliminated.

The present invention was conceived in view of the above, and an object of the present invention is to provide a combustor that can obtain combustion gas free of pollutant NOx and unburned substances.

[Means to solve the problem]

In order to achieve the above object, the combustor according to the present invention has a cylindrical outgoing flow path and a return side flow path connected in a folded manner across a cylindrical wall. A main inlet connected to a fuel mixer and an auxiliary inlet connected to a pilot burner are provided on the upstream side of the flow path, and a combustion gas outlet is connected to the downstream side of the return flow path.

In addition, a honeycomb-shaped passage having a cylindrical shape and a passage in the axial direction is rotatably provided in the frame cylinder having a cylindrical cross-sectional shape, and a partition wall is provided on one side in the axial direction of the frame cylinder. An inflow chamber and an outflow chamber partitioned in the diametrical direction are provided on the other side, and a combustion gas chamber is provided on the other side facing the axial end surface of the honeycomb-shaped passage, and a fuel mixed gas inlet and a pilot burner are provided in the inflow chamber. Further, the outflow chambers are each provided with an outlet for combustion gas, and the supporting shaft of the honeycomb-shaped passage is connected to a rotating device.

Furthermore, a combustion catalyst may be supported on the wall surface of the honeycomb-shaped passage.

[For production]

The upstream wall surface of the outgoing flow path is heated to 90° C. or higher with combustion gas from the pilot burner, and then the fuel mixture gas is allowed to flow into the upstream side of the outgoing flow path from the main stream inlet. This fuel mixture gas comes into contact with the heated wall surface and is combusted, and this combustion gas flows back from the outgoing flow path through the return flow path and flows out to the outlet, and is then combusted by the wall that separates the outbound flow path and the return flow path. is heated from both sides facing both channels. The pilot burner operates only while the upstream side of the outgoing flow path is heated to a predetermined temperature.

In addition, in a combustor in which a honeycomb-shaped passage is rotated within the outer cylinder, by rotating the honeycomb-shaped passage, the fuel mixture that is heated by the combustion gas and sequentially flows into the inlet chamber is heated on the side of the honeycomb-shaped passage. The gases come into contact and are combusted. The honeycomb-shaped passage is heated by the combustion of the fuel mixture gas that flows in from the inflow chamber and the combustion gas flowing from the combustion gas chamber to the outflow chamber, and the portion heated by the combustion gas from the combustion gas chamber sequentially flows into the inflow chamber as it rotates. faced.

By supporting a combustion catalyst on the wall surface of the honeycomb-shaped passage, the fuel mixture gas comes into contact with the combustion catalyst and is combusted, and even the fuel mixture gas whose preheating temperature is low is combusted.

〔Example〕 Embodiments of the present invention will be described based on the drawings.

1 and 2 show a first embodiment of the present invention,
In the figure, 1 is an outer cylinder, and 2 is an inner cylinder arranged approximately concentrically inside the outer cylinder 1, and these are made of ceramics. The two cylinders 1 and 2 constitute a ring-shaped outgoing flow path 3 and a cylindrical return flow path 4 disposed within the outgoing flow path 3, and the upstream end of the outgoing flow path 3 is closed, and its downstream end communicates with the upstream end of the return flow path 4 in a folded manner in a space formed by the end of the outer cylinder 1. A main stream inlet 5 and an auxiliary inlet 6 are opened in the side wall at the upstream end of the outgoing flow path 3, and an outlet 7 is opened at the downstream end of the return flow path 4. Further, a cam-shaped flow path 8.9 made of ceramics and formed in a donut shape and a plug shape is interposed at the downstream end of the outgoing flow path 3 and the downstream end of the return flow path 4, respectively. .

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 outgoing flow path 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 main fuel mixer 11, and the air and fuel flowing in from both inflow pipes 13 and 14 are mixed in an air-fuel mixing section 15. The mixed gas is then flowed into the upstream side of the outgoing flow path 3 as a fuel mixed gas. The pilot burner 12 also has an air inlet pipe 16.
A fuel inlet pipe 17 is connected to the pilot burner 12 so that the fuel gas from the pilot burner 12 is allowed to flow into the upstream side of the outgoing flow path 3.

In the above configuration, first, the pilot burner 12 is operated to cause future combustion gas to flow into the outgoing flow path 3 of the combustor, thereby heating the outer cylinder 1 and the inner cylinder 2 on the upstream side of the outgoing flow path 3. . When this portion is heated to about 900° C. or higher, the fuel mixer 11 is operated to cause the fuel mixed air to flow into the upstream side of the outgoing flow path 3. At this time, the pilot burner 12 is stopped immediately or with some overlap.

In the above state, the fuel mixture gas flowing from the fuel mixer 11 through the main stream inlet 5 contacts the heated side walls of the outer cylinder 1 and inner cylinder 2 on the upstream side of the outgoing flow path 3 and starts combustion. The combustion gas passes from the outgoing flow path 3 to the return flow path 4 and is discharged from the outlet 7. During this time, the side walls of both the flow paths 3 and 4 are sequentially heated, and as a result, the fuel mixture is heated. The fuel in the fuel mixture gas that has flowed in from the vessel 11 is sequentially combusted and flows into the return side flow path 4.
completely burnt out by the time it reaches the outlet. In this case, the fuel in the fuel mixer 11 has a combustion gas temperature of 1200 to 1
Mix in air preheated to 400°C.

During the above-mentioned combustion operation, the combustion started at the upstream part of the outgoing flow path 3 continues from the outgoing flow path 3 to the return side flow path 4, and the inner cylinder 2 is Heated from both sides. Further, the combustion gas is completely combusted while passing through the honeycomb-shaped channels 8.9 provided at the downstream end of the outgoing channel 3 and the downstream end of the returning channel 4, respectively. Also, at this time, by applying a paint with a high absorption rate of infrared rays to the inner surface of the outer cylinder 1, the absorption rate of infrared rays emitted from the outer surface of the inner cylinder 2 becomes high, and the inner temperature of the outer cylinder 1 becomes high. Therefore, the inner surface of the outer cylinder 2 can also be used as a heat generating surface for burning the fuel mixture gas.

3 to 5 show a second embodiment of the present invention, and the same constituent members as in the first embodiment are designated by the same reference numerals as those shown in FIGS. 1 and 2. omitted.

A plurality of inner cylinders 22 made of ceramic are arranged inside an outer cylinder 21 made of ceramic, and an outgoing flow path 2 is formed around the inner cylinder 22.
3, and a return side flow path 24 is configured inside the inner cylinder 22. The upstream side of the outgoing flow path 23 is closed by a branch wall 25 that supports the downstream side of each inner cylinder 22, and the downstream side of the outgoing flow path 23 and the downstream side of the return side flow path 24 are closed. In this case, honeycomb-like passages 26 and 27 are interposed. Further, a plurality of baffle plates 28 for a maze are interposed in the outgoing passage 23.

This 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 burns the outgoing flow path 23.
After heating the flow passage wall on the upstream side of the
3 and burn it. At this time, the outgoing flow path 23
The combustion gas within flows to the downstream end of the labyrinth formed by the baffle plate 28, during which time the fuel mixture gas is sufficiently stirred and combusted. The combustion gas that has flowed into the lower fluid of the outgoing flow path 23 enters the return flow path 24 through the honeycomb-shaped passage 26, and is further combusted at the temperature of the inner wall of the heated inner cylinder 22 that constitutes the return flow path 24. It is accelerated and discharged from the outlet 7 through the honeycomb-shaped passage 27 on the downstream side.

6 and 7 show a third embodiment of the present invention,
In the figure, reference numeral 31 denotes a ceramic frame tube configured in a cylindrical shape with its axis directed in the vertical direction, and a honeycomb-shaped passage 32 made of ceramic and made of +M is coaxially located in the middle part of this frame tube 31. It is rotatably fitted to the A population chamber 34 is partitioned in the left and right direction by a partition wall 33 at the upper part of the frame cylinder 31 and at a position facing above the honeycomb-like passage 32.
a and an outlet chamber 34b. Above entrance room 3
4a has an inlet 35 for the fuel mixture gas, and an outlet chamber 34b
A combustion gas outlet 36 is opened in the opening. Also frame tube 3
A combustion gas chamber 37 is provided at the lower part of the honeycomb passageway 1 and at a position facing below the honeycomb-like passage 32 .

A support shaft 38 is provided at the axial center of the honeycomb-shaped passage 32, and the lower end of this support shaft 38 is supported by a support frame 39 and connected to a rotating device 40. Honeycomb-like passage 32
Fine passages partitioned by honeycomb walls are formed in the axial direction at all cross-sectional positions, and the upper end of each passage opens into the inlet chamber 34a or the outlet chamber 34b, and the lower end opens into the combustion gas chamber 37. .

In addition to the inlet port 35, a pilot burner 12 similar to that shown in FIG. 1 is connected to the inlet chamber 34a. Further, the frame tube 31 is surrounded by a heat insulating material 41.

In the above configuration, the honeycomb passage 32 is always rotated at a predetermined rotational speed. In this state, first, the combustion gas from the pilot burner 12 for starting is allowed to flow into the artificial chamber 34a. This combustion gas heats the inlet chamber 34a and the upstream side of the honeycomb passage 32. At this time, since the honeycomb-shaped passage 32 is rotating, the honeycomb-shaped passage 32
The entire upper end of the tube 2 is sequentially heated in the inlet chamber 34a. When this portion reaches a predetermined temperature (900° C.), heating from the pilot burner 12 is stopped and preheated fuel mixture gas is allowed to flow in from the inlet 35. The fuel mixture gas starts combustion by contacting the heated wall surface in the outgoing flow path from the inlet chamber 34a to the honeycomb-shaped passage 32, and combustion ends in this outgoing flow path up to the combustion gas chamber 37. do. The combustion gas in the combustion gas chamber 37 flows through the honeycomb-shaped passage 32.
It reaches the outlet chamber 34b through the return side flow path, which is a passageway in the portion facing the outlet chamber 34b, and flows out from there to the outlet 36. At this time, the outlet chamber 3 of the honeycomb-like passage 32
4b is heated by the combustion gas from the combustion gas chamber 37, and this portion is sequentially moved to a position on the outgoing flow path side facing the population chamber 34a by the rotation of the honeycomb-shaped passage 32. do. Therefore, the fuel mixture that has flowed into the inlet chamber 34a sequentially comes into contact with the heated wall surface of the outgoing channel of the honeycomb-shaped passage 32, and its combustion continues.

Furthermore, as a fourth embodiment, in the third embodiment, the rotating honeycomb-shaped passage 3 shown in FIGS.
A combustion catalyst is supported on each wall surface of No. 2. This combustion catalyst is made of platinum, palladium, etc., and its adhesion to the above-mentioned walls is caused by the formation of honeycomb-shaped passages in the melted combustion catalyst.
This is done by dipping 2.

According to this embodiment, wall combustion is possible even when the heating temperature of the wall surface by the pilot burner 12 is 900° C. or lower.

In other words, a fuel mixture gas is created by mixing fuel in preheated air, but if the fuel is a gas, no preheating is required, or if the fuel is a liquid, the partial pressure of the fuel in the air is lower than the dew point. Preheating to a slightly higher temperature is sufficient, and it is possible to preheat the air to an extremely low temperature.

In this embodiment, fuel containing catalyst poisons such as sulfur cannot be used.

The outer cylinders 1 and 21 and the inner cylinders 2 and 22 in each of the above embodiments,
Frame cylinder 31 and honeycomb-like passage 8°9.26, 27.3
Silicon carbide, which is excellent in strength, temperature resistance, and thermal shock resistance, is used as the material for the ceramic component 2.

However, it is not limited to this, and includes zirconia,
Cordierite-based ceramics may also be used.

Further, the outer cylinders 1, 21 and the frame cylinder 31 may be molded from materials whose main component is alumina fiber. In this case, it is desirable to apply a coating material mainly composed of 5iZr04 or an oxide such as MnO2.Cr2O3, which has a high infrared absorption rate, to the inner surface of the cylinder by means such as spraying.

〔Effect of the invention〕

According to the present invention, from the outgoing channels 3, 23 to the returning channels 4, 2
4, the wall separating both passages is heated to a temperature sufficient for the fuel mixture gas flowing into the upstream side of the outgoing passages 3 and 23 from both sides to contact and burn. , the combustion is completed while passing through both passages, and there is no pollutant NOx and unburned substances from the outlet 7 provided on the downstream side of the return flow passage 4.24, and the combustor is arranged in series in multiple stages. By connecting and using them, it is possible to obtain combustion gas with extremely low residual O2 through complete combustion.

In addition, by rotating the honeycomb-shaped passage 32, which serves as a passage for combustion gas, between the outgoing and returning passages of the combustion gas, the portion heated in the returning passage is sequentially moved to the outgoing passage. The fuel mixture gas that has flowed into the outgoing flow path is continuously combusted in a good condition by the wall surface of the flow path.

Furthermore, since a combustion catalyst is supported on the wall surface of the honeycomb-shaped passage, even a fuel mixture gas whose preheating temperature is low can be burned satisfactorily.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view showing a second embodiment of the present invention. Cross-sectional view, Figure 4 is IV-I in Figure 3.
5 is a sectional view taken along line V--V in FIG. 3, FIG. 6 is a sectional view showing the third embodiment of the present invention, and FIG. It is a cross-sectional view taken along the line ■-■ in the figure. 3.23 is the outgoing flow path, 4 and 24 are the return side flow paths, 5 is the main inlet, 6 is the auxiliary inlet, 7 is the outlet, 11 is the fuel mixer, 1
2 is a pilot burner, 31 is a frame cylinder, 32 is a honeycomb-shaped passage, 33 is a partition wall, 34a is an inlet chamber, 34b is an outlet chamber, 35 is a fuel mixed gas inlet, 37 is a combustion gas chamber, 38
is a support shaft, and 40 is a rotating device. Diagram

Claims (3)

[Claims] (1) Inside the cylindrical outgoing channels 3, 23, the returning channels 4, 24
are connected in a folded manner across a cylindrical wall, and the main inlet 5 is connected to the fuel mixer 11 on the upstream side of the outgoing channels 4 and 24, and the auxiliary inlet is connected to the pilot burner 12. 6, and the downstream ends of the return side flow paths 4 and 24 are connected to the outlet 7. (2) A honeycomb-shaped passage 32 which is cylindrical and has a passage in the axial direction is rotatably provided in the frame tube 31 having a cylindrical cross-sectional shape, and one side of the frame tube 31 in the axial direction An inflow chamber 34a and an outflow chamber 34b diametrically partitioned by a partition wall 33 are provided, and a combustion gas chamber 37 is provided on the other side facing the axial end surface of the honeycomb-shaped passage 32, respectively.
The inlet chamber 34a is provided with a fuel mixed gas inlet 35 and the pilot burner 12, and the outlet chamber 34b is provided with a combustion gas outlet 36.
8 is connected to a rotating device 40. (3) The combustor according to claim 2, wherein a combustion catalyst is supported on the wall surface of the honeycomb-shaped passage 32.