JPH09178128A - Method and burner for burning hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of NOx significantly while lowering cost involved in manufacturing technique by using air as oxidizing agent in a method of burning hydrogen by diffusion combustion to create a lateral flow that allows the generation of a minute distribution into a plurality of individual fine combustion areas. SOLUTION: Gaseous hydrogen is introduced into a distribution chamber comprising perforated plates 2 and 3 and air is admitted into a combustion chamber through a guide pipe 4. In this process, the hydrogen flows in a distribution chamber laterally to the direction of the main stream to be finely distributed in a local range of the porous perforated plate 3 made of sintered metal or the like and enters the combustion chamber through the perforated plate 3 to form ambient hydrogen. In this process, a turning occurs with a disc 9 at an outlet of each guide tube 4 to form an air flow taking the shape of a conical outer circumferential wall. The air flow enters a mixed gas forming process together with the ambient hydrogen to produce a rotation-symmetrical diffusion flame. The shapes of air guide pins 6 in the guide tube 4 are selected so that a specified flame shape is developed when the guide pins are inserted into respective stoppers 6a.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for burning hydrogen and a burner for carrying out this method.

[0002]

2. Description of the Prior Art Hydrogen (H ₂ ) as a fuel for all types of burners, for example gas turbine combustion chambers, is
It is characterized by extremely high reactivity and combustion stability, and even in the case of excess air, such as in the combustion chambers of modern gas turbines. Heywood
And the publication of Maikasu (Mikus), by increasing the degree of mixing in the excess air is sufficiently large range, to reduce the generation of nitrogen oxides (NO _x) are known in combustion technology. At that time, for example, completely homogeneous fuel such as achieved by premixed before the actual combustion zone - air - in the case of mixture, generation of the NO _x is minimized. A corresponding proposal for homogeneous premixed combustion of hydrogen has been made by Pratt & Whitney of Canada. NO _x Despite this advantage caused by premixing in terms of reduction, this means, there is an important drawback flame revert to mixing range.

The technical solution of the burner with premixing is relatively simple in construction. In this case, for example, a plate-shaped distribution chamber for hydrogen is inserted into the combustion chamber laterally with respect to the air flow direction (hereinafter referred to as the main flow direction). A number of air guide tubes with inlets and outlets pass through this distribution chamber. Each air guide tube is connected to the distribution chamber via a hole located near the inlet. When H ₂ is introduced into the distribution chamber, H ₂ flows into the individual holes transversely to the main flow direction, reaches the air guide tube. At the same time, when air is blown into the combustion chamber through the air guide tube, both gases are mixed in the air guide tube. The air-fuel mixture thus generated reaches the combustion chamber and is ignited. By arranging the distribution chamber, the structure of the burner is greatly simplified. This is because this eliminates the need for individual air guide tubes or individual hydrogen tubes leading to the combustion zone.

Considering the importance of the degree of mixing from the viewpoint of NO _x generation during H ₂ combustion, known hydrogen burners and hydrogen combustion chambers that operate without premixing, that is, with diffusion combustion, have many hydrogen injection nozzles. Is equipped with. This nozzle is usually a conventional swirl vortex nozzle. A similar solution was announced at TRUD / Kusnetzov in Russia and MTU in Germany.
For example, if this principle of Trad is applied, the number of fuel regions increases five times or more, so that 30 combustion regions increase to 150 or more in a given combustion chamber. The individual combustion zones then have a diameter of approximately 20 mm. If the combustion area is further reduced and the number of injection nozzles is increased, a large number of individual hydrogen tubes are required.

[0005]

Therefore, the problem underlying the present invention is to increase the fuel area significantly.
It is an object of the present invention to provide a method for diffusive combustion of hydrogen and a burner for carrying out this method, which can significantly reduce NO _x generation as compared with conventional burners of diffusive combustion.

[0006]

This object is achieved in the method and burner mentioned at the outset by the features of claims 1, 4 and 10.

In this case, in particular, the production engineering costs remain low, despite the considerable increase in the combustion area. Advantageous embodiments of the invention are described in the dependent claims.

An advantage of the embodiment of claim 2 is that hydrogen has a very good cooling effect on the structure.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in the drawings. Next, this embodiment will be described in detail.

1 to 4 show a burner for burning hydrogen (H ₂ ) which is incorporated in a combustion chamber of a gas turbine, for example. The burner has a plate-like shape and is installed in the combustion chamber transversely to the main flow direction. The connecting portion of the burner between the edge area of the burner and the combustion chamber casing (not shown) is not shown and can be arbitrarily formed. The burner comprises a first perforated plate 2 and a second perforated plate 3. The two perforated plates are held by a large number of guide tubes 4 at regular intervals d. The holes can then be arranged according to a predetermined matrix pattern. The perforated plate 2 is made of, for example, a suitable metal and is impermeable to gas. The second perforated plate 3, on the other hand, is permeable to gas and consists of a suitable porous material, for example sintered metal. The holes of the two perforated plates 2, 3 are then congruent, so that the holes of the second perforated plate 2 together with the holes of the second perforated plate 3 form a pair of holes. The holding of the burners against disengagement is essentially effected by the guide tubes 4 being inserted and fixed as spacers in each pair of holes. The guide tube 4 has a circumferential groove 5 formed by rolling outward. The fixing of the guide tube 4 in the perforated plate 2 is carried out, for example, by brazing or welding, whereas the perforated plate 3 is fixed.
The fixing of the guide tube inside can be done by rolling or edge bending. At that time, in cooperation with the circumferential groove 5, a shape-complementary connection is respectively established between the guide tube 4 and the perforated plate 3.
Thereby, the perforated plates 2, 3 together with the guide tube 4 form a distribution chamber. An air guide pin 6 is inserted in each of the guide tubes 4 as shown in FIGS. This air guide pin is basically a stopper 6a, a guide portion 6
b, a holding member 8 and a circular plate 9 are provided. The outer diameter of the guide portion 6b is approximately equal to the inner diameter of the guide tube 4, and in the illustrated embodiment it is provided with four axial guide passages 7. The holding member 8 is attached to the guide portion on the right side in FIG. 3 and has a reduced diameter. This area supports a concentrically mounted disc 9. The outer diameter of this disc is approximately equal to the outer diameter of the guide portion 6b. The stopper 6a is formed by a short range in the axial direction, and its outer diameter is larger than the outer diameter of the guide portion 6b. A guide pin 6 is inserted into each guide tube 4 from the air side of the burner until the stopper 6a contacts the perforated plate 2, and is permanently fixed at this position. Each such structural group forms an injector.
To start up the burner, gaseous hydrogen is introduced into the distribution chamber consisting of perforated plates 2,3. In addition, air is introduced into the combustion chamber through the guide tube. At that time, hydrogen flows laterally in the distribution chamber with respect to the main flow direction and is finely distributed in the local area of the porous perforated plate 3, through which the hydrogen enters the combustion chamber, To form ambient hydrogen. At the outlet of each guide tube 4, an air flow in the form of a conical outer peripheral wall is generated due to the deflection by the disc 9. This air flow in the form of a conical outer wall, together with the surrounding hydrogen, enters the mixture formation process and forms a rotationally symmetrical diffusion flame. Here, the interaction of adjacent conical flames that collide with each other due to the activation of the mixing process is promoted. The shape of the guide pin 6 is selected so that a predetermined deflection, that is, a predetermined flame shape is generated when the guide pins 6 are inserted up to the respective stoppers 6a. The stopper 6a can be omitted for reasons of weight. In this case, the insertion of the guide pin 6 into the guide tube 4 up to a predetermined axial position is performed by the manufacturing device.
Due to the extremely simple structure of the injector, the injector can be miniaturized so that a large number of injectors can be attached to each combustion chamber. Due to the miniaturization of the above order, the combustion region formed according to the present invention is called a fine combustion region.

6 and 7 show another embodiment of the burner according to the present invention. This burner is for U
It comprises elongated individual distribution channels 11 of V-shaped cross section.
The distribution passage has a wall 12 made of porous sintered metal on the combustion chamber side.
Has been closed by. The channels 11 are connected to each other by means of perforated sections 13 having a chevron-shaped cross section, the free longitudinal edges of the perforated sections 13 being fixed to the longitudinal edges of two adjacent distribution channels 11, respectively. At this time, the holes 14 are formed in the strip-shaped leg portions of the perforated frame member 13 at regular intervals. Gaseous hydrogen is introduced into the distribution passage 11 in order to start the operation of this burner. At the same time,
Air enters the combustion chamber through holes 14. At that time, hydrogen flows laterally in the distribution passage 11 with respect to the main flow direction, and is distributed to the local region of the porous wall 12 by fine distribution. Hydrogen passes through this porous wall into the combustion chamber where it forms ambient hydrogen. The air supply creates a stoichiometric region within each hole 14. This area creates an inherent flame upon ignition of the burner. The burner is very simple to make and can be manufactured as a thin plate structure. In that case, for example, the U-shaped distribution passage 11 is made by bending a thin plate,
Each leg of the U-shape is integrally connected to a diagonally bent perforated strip. After inserting the porous wall 12, the adjacent passages 11 are connected to each other along the free edge of the perforated strip, for example by welding. This burner can be miniaturized so that thousands of combustion zones can be obtained in the combustion chamber.

In the case of fine distribution generated by the burner described above, H ₂ is distributed to thousands of minute combustion regions through the distribution chamber or distribution passage, so to speak, minute diffusion combustion of hydrogen occurs. In the case of the burner described above, ambient hydrogen is formed in the combustion chamber, and the jet of air is injected into this ambient hydrogen, so that the opposite diffusion combustion occurs. This reverse diffusion combustion is
It is possible to stabilize almost turbulent flow in the generated minute region. An important advantage of this reverse hydrogen diffusion combustion is that H ₂ achieves good cooling of the structure.

In the case of the burner described above, other porous metal materials can be used instead of the porous sintered metal. Porous materials based on metal fibers can be used, for example as known under the name "felt metal". Furthermore, the porous material can be made from a ceramic material. A perforated plate with a given fine perforated grid of a relatively thin layer of porous material may optionally be placed in front in order to limit the effect of any inhomogeneities present in the porous material. Well, this perforated grid can be used alone.

8 to 11 show another embodiment of the burner. Unlike the burners described above, this burner does not work in reverse diffusion combustion, but in normal diffusion combustion. The burner consists essentially of two conjoined perforated plates 15,16. The two perforated plates are fixedly connected to each other via a guide tube 17 having an inlet and an outlet, so that a distribution chamber is formed. Near the outlet, the holes 18 are distributed at equal angles and the guide tube 1
7 is formed. One guide pin 1 on each guide tube 17
9 has been inserted. The guide pin comprises a stopper 20, a guide portion 21 and a free jet portion 22. In this case, the free jet portion is actually a small-diameter axial section. The stopper 20 and the guide portion 21 have a plurality of grooves 23 extending in the axial direction. The depth of this groove is 22
The outer diameter of can be reached. The number of holes 18 is then equal to the number of grooves 23. At the start of operation of the burner, air is blown into the combustion chamber through the guide pipe 17. H ₂ at the same time
Are introduced into the distribution chamber so that H ₂ is injected into the guide tube through the individual holes 18 and is entrained from this guide tube by the air passing through the groove 23. In that case, hole 1 each time
A small combustion zone occurs downstream of 8. In this small combustion region, the flame becomes stable when the burner is ignited. In the illustrated embodiment, the guide tubes 17 each have six holes 18,
Six micro-combustion zones occur in each guide tube. Thereby, the number of combustion zones is further increased. If this principle is applied to the combustion chamber of the TRUD mentioned at the beginning, the number of installable combustion regions is increased to about 5000. This achieves a very high degree of mixing without premixing and NO _x
Will be significantly reduced. Various adjustments of the burner can be made by rotating and / or sliding the guide pin 19 relative to the guide tube 17 in the axial direction. Also in this case, the stopper 20 can be omitted and the axial position of the air guide pin can be adjusted based on a suitable device.

12-15 show various adjustments of the burner described above. In FIG. 12, the groove 23 of the guide pin is adjusted with respect to the hole 18 of the guide tube 17 as follows. That is, the injection of hydrogen is adjusted so as to be performed through the holes 18 into the gap between the air jets. This air jet reaches through the groove 23. FIG. 13 shows the guide portion 21.
Shows the position of the guide pin, which is in close contact with the hole 18. This allows the hydrogen jet to be deflected only downstream. However, as shown in FIG. 14, when the guide portion 21 is fixed in the guide tube 17 so as to be slightly separated from the hole 18,
Some recirculation can occur. FIG. 15 shows a state in which the air jet coming through the groove 23 exactly hits the hydrogen jet coming from the hole. In all these cases, a free jet of hydrogen is introduced into the ambient air by means of the holes 18, so that the usual diffusion combustion takes place. In this case, the individual combustion zones have a diameter on the order of 2 mm. The flame is then often stabilized at the holes 18. As described above, the free jet portion 22 can be omitted in the embodiment of the present invention, particularly in the case of the air jet of FIG.

16 and 17 show another embodiment. In this case, the hydrogen jet and the air jet are guided separately until they enter the combustion chamber. For that purpose, the above-mentioned guide tube 17 with holes 18 is used. This guide tube has a perforated plate 15,
16 has been inserted. Only the perforated plate indicated by 16 of the perforated plates is visible. Guide pin 24 used here
Has a groove 23, but with two important modifications. First
The modification is that the pin has a constant diameter up to approximately the exit cross section. The second modification consists in the formation of a small axially extending guide channel 25 in the center of the material area between the grooves 23. Each guide pin 24 is inserted into the corresponding guide tube 17 so that each hole 18 opens into the guide passage 25. Thereby, for example, diffusion between hydrogen and air is initiated in the area downstream of the perforated plate 16 in order to avoid excessive structural heat loads. With this solution, the flame stabilizes at the opening of the guide passage 25.

18 and 19 show an embodiment of a burner for normal diffusion combustion of the two-dimensional type. The burner is provided with elongated individual distribution passages 26 for H ₂ . This distribution channel differs from the distribution channel 11 in FIGS. 6 and 7 and has a closed cross section. This cross section is a substantially flat rectangle, but is provided with a roof-shaped edge 26a in the area to the right of the figure. On both sides of this roof edge,
The free holes 27 are formed in a staggered manner. Individual passage 26
Are held at a distance from each other by a holding member (not shown), thereby forming a grid. Air can flow through this grid from left to right in FIG.
The burner further comprises a strip-shaped gap plate 28. A gap 29 is formed at the vertical edge of this gap plate. The gap plate 28 has two distribution passages 2 in the range of the holes 27.
6 is fixed by a holding member (not shown). At that time, each hole 27 is fixed so that one gap 29 is attached. At that time, the illustrated one hole 2
Instead of 7, a plurality of fine holes can be provided.
At the start of operation of the burner, air is blown into the combustion chamber through the gap 29 corresponding to the arrow 30, and H ₂ is discharged into the hole 2
It is blown into the combustion chamber through arrow 7 according to arrow 31. As a result, in the combustion chamber, ambient air is formed in each area of the holes 27 by a large number of minute combustion regions. After ignition of the combustion chamber, the flame stabilizes at the holes 27.

20 and 21 show a burner having an integral perforated plate 32 having a hole 32a. A plurality of distribution passages 33 are fixed to the perforated plate by holding members 34. The distribution passage 33 has an oval cross section and is provided with a number of holes 35 in its area near the perforated plate 32.
The holding member 34 may be formed of a wire rod or a thin plate. As shown in FIG. 21, each hole 32 a of the perforated plate 32 is provided with two small holes 35. Thereby, H ₂ can flow out according to arrow 37.

At the start of operation of the burner, air is blown into the combustion chamber through the perforated plate 32 according to the arrow 36. As a result, in the combustion chamber, ambient air is formed in each area of the hole 35 by a large number of minute combustion regions. After ignition of the combustion chamber, the flame stabilizes at the holes 35.

22 and 23 show another embodiment of the burner. The partial view of FIG. 22 shows a curved distribution passage 3
8 is shown. This distribution passage is a component of an annular burner and has an oval cross section according to FIG. In this case, each distribution channel forms a closed ring. This ring is connected to the H ₂ tube via its own connecting tube. The holding of the burners against disengagement is effected, for example, by corrugated separators 39 arranged between the individual distribution channels 38. The separator is connected to the distribution passage 38 by welding, for example.
The separators 39 are each formed of thin strips,
There is sufficient spacing between the individual distribution passages 38 for the passage of air. The distribution passage 38 can be integrated with a separator 39 into a disc-shaped or ring-shaped burner by winding. Thereby the distribution passage 38
It has a spiral shape. Holes are formed in the distribution passage 38 in order to form a large number of minute combustion regions. This hole is shown here at 40. Two hydrogen jets 41 each time
Intersect at one point. A common feature of disc-shaped and spiral-shaped distribution passages is that they have a curved shape. This burner operates in principle according to the same effect as already described in connection with FIGS.

[Brief description of the drawings]

1 shows a matrix burner for a combustion chamber, FIG.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a view showing a guide pin.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a view showing a guide tube provided with a guide pin.

FIG. 6 is a diagram showing a burner having a two-dimensional structure.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a diagram showing another burner having a matrix structure.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 8;

FIG. 10 shows the guide tube of FIG. 9 with a guide pin.

FIG. 11 is a view as seen in the direction of the arrow XI in FIG. 10;

12 is a sectional view taken along line XII-XII in FIG.

13 is a detailed view of a portion 13 of FIG.

FIG. 14 is a view similar to FIG. 13 in which the axial position of the guide pin is changed.

15 is a view similar to FIG. 12 in which the angular position of the guide pin is changed.

FIG. 16 is a view showing an embodiment of a guide tube-guide pin-device having a guide passage.

17 is a sectional view taken along line XVII-XVII in FIG.

FIG. 18 is a diagram showing another burner having a two-dimensional structure.

19 is a cross-sectional view taken along line XIX-XIX in FIG.

FIG. 20 shows a burner with an integral perforated plate.

FIG. 21 is an arrow view in the XXI direction of FIG. 20.

FIG. 22 shows a burner with curved distribution passages.

23 is a cross-sectional view taken along the line XXIII-XXIII of FIG.

[Explanation of symbols]

 2 1st perforated board 3 2nd perforated board 4 Guide tube 6,19,24 Air guide pin 6a, 20 Stopper 7,23 Guide passage 8 Holding member 9 Disc 11,26,33,38 Distribution passage 12 Wall 13 Perforated material 15, 16 Perforated plate 21 Guide part 22 Free jet part 25 Guide passage 27 Hole 28 Gap plate 29 Gap 32 Perforated plate 34 Holding member 35 Hole 39 Separator

Claims (21)

[Claims] 1. Hydrogen and an oxidant are introduced into a burner, the main flow direction is the flow direction of the oxidant, and hydrogen is distributed to each combustion region in a lateral flow that is oriented substantially perpendicular to the main flow direction. In a method of burning hydrogen by diffusion combustion, air is used as an oxidant and the lateral flow results in a fine distribution into a number of individual fine combustion zones. 2. A method according to claim 1, characterized in that air is introduced into the ambient hydrogen in the individual micro-combustion zones. 3. The method according to claim 1, characterized in that hydrogen is introduced into the ambient air in the individual micro-combustion zones. 4. A burner for carrying out the method for burning hydrogen according to claim 1, wherein the burner comprises a distribution chamber in the form of a substantially plate. ) And a second perforated plate (3), both perforated plates being held at regular intervals by a number of guide tubes (4), each of the guide tubes (4) having a plurality of axial guides. Burner, characterized in that an air guide pin (6) having passages (7, 23) is inserted. 5. Burner according to claim 4, characterized in that the second perforated plate (3) is made of a gas-permeable porous material. 6. Burner according to claim 4, characterized in that the perforated plates (15, 16) are made of a gas-impermeable material. 7. Burner according to any one of claims 4 to 6, characterized in that the air guide pin (6) comprises a retaining member (8) having a disc (9). 8. Burner according to any one of claims 4 to 6, characterized in that the air guide pin (6, 19) comprises a guide part (21) and a free jet part (22). 9. An air guide pin (6, 19, 24) extends from the inlet to the outlet of the guide tube in question and has a constant diameter and is axially centered in the material range between the grooves (23). Burner according to any one of claims 4 to 6, characterized in that a guide passage (25) extending to the is formed. 10. Burner for carrying out the method for burning hydrogen according to claim 1, wherein the burner comprises at least one distribution passage, the distribution passage (11) having a U-shaped cross section. Closed on the combustion chamber side by a wall (12) of porous material, such that the longitudinal free edge of the perforated profile (13) is fixed to the longitudinal edge of the adjacent distribution passage (11), Burner, characterized in that the distribution channel (11) is connected to an adjacent distribution channel by means of a perforated profile (13) having an angled cross section. 11. Burner for carrying out the method for burning hydrogen according to claim 1, wherein the burner comprises at least one distribution passage.
Burner characterized in that 6) has a substantially flat rectangular closed cross section and has a number of holes (27) on the combustion chamber side. 12. A crevice plate (28) is fixed in the area of the hole (27) between each of the two distribution passages (11, 26) so that a gap (29) is provided in each hole (27). The burner according to claim 11, wherein the burner is provided. 13. The burner comprises an integral perforated plate (32) to which a plurality of distribution passages (33) are fixed by holding members (34), each of the perforated plates (32) being provided with a plurality of distribution passages (33). One hole per hole (35) or group of holes (35)
The burner according to claim 11, wherein the burner is attached. 14. Distribution passages (11, 26, 33, 38)
10. The curved shape of claim 10
The burner according to any one of 12. 15. Burner corrugated separator (39)
The burner according to claim 14, further comprising: 16. The burner according to claim 5, wherein the porous material is a sintered metal. 17. The burner according to claim 5, wherein the porous material is a ceramic material. 18. The burner according to claim 5, wherein the porous material is a metal fiber-based material. 19. A burner according to claim 5, wherein a perforated plate having a predetermined fine hole grid is arranged in front of the porous material. 20. Burner according to any one of claims 5 to 15, characterized in that the porous material is replaced by a perforated plate with a defined fine hole grid. 21. Burner according to any one of claims 4 to 9, characterized in that the air guide pins (6, 19) are provided with stoppers (6a, 20).