EP0780631B1 - Method and burner for combustion of hydrogen - Google Patents

Description

The invention relates to a method for burning hydrogen and a burner to carry out the procedure.

Hydrogen (H2) as fuel for all types of burners, for example for combustion chambers for gas turbines, is characterized by a particularly high reactivity and thus by an extraordinary great stability of the combustion, even with excess air, such as in combustion chambers modern gas turbines occur. Through publications by Heywood and Mikus it is known in combustion technology that in the area with sufficiently high excess air Increasing the degree of mixing leads to a reduction in the formation of nitrogen oxide (NOx). there there is a minimum of NOx formation with completely homogeneous fuel-air mixtures, such as they can be achieved, for example, by premixing in front of the actual firing zone. A corresponding one Pratt & proposes a homogeneously premixed combustion of hydrogen Whitney of Canada. Despite the advantages of premixing in terms of NOx reduction offers, a major disadvantage of this measure is that a repulsion of the Flame in the mixing area is possible in principle.

Technical solutions from corresponding burners with premixing show a relatively simple one Construction. Here, for example, a distribution chamber of plate-like shape for the hydrogen transverse to the flow direction of the air, hereinafter referred to as the main flow direction, in a Combustion chamber used, the distribution chamber in the main flow direction of a variety of Air ducts with an inlet opening and an outlet opening is penetrated. Every air pipe stands with small holes, which are located near the inlet opening, with the distribution chamber in connection. If H2 is now introduced into the distribution chamber, it flows across Main flow direction to the individual holes and thus reaches the air ducts. Will now at the same time Air is blown through the air guide pipes into the combustion chamber, so both gases mix within the air pipes. The mixture produced in this way then enters the combustion chamber and is ignited. The arrangement of the distribution chamber makes the structure of the burner essential Simplified, as this enables individual hydrogen lines to the individual air ducts or Burning zones can be avoided.

Taking into account the importance of the degree of mixing in terms of NOx formation in the Combustion of H2 have become known hydrogen burners and combustion chambers without Premixing, i.e. working with diffusion combustion, an increased number of H2 injection nozzles on. These are usually conventional swirl nozzles. Appropriate solutions were presented in Russia by TRUD / Kusnetzov and in Germany by MTU. When using This principle, for example using TRUD, allows the number of firing zones to be reduced by a factor Increase five or larger, so the number of burn zones for a given combustion chamber from Z. B. 30 can be increased to 150 or more. The individual firing zones show diameter of approx. 20 mm.

A further reduction in the size of the firing zones and thus an increasing number of injection nozzles stands in the way of the large number of individual hydrogen lines required.

In addition, the two publications: "US-A 1,968,359" and "EP-A 0 334 736" are known to the experts, which are considered to be the closest prior art from which the invention is based.

A plate-shaped gas burner is known from US-A 1,968,359. According to FIGS. 1 and 3 This publication has 24 air channels, four channels for each of these air channels flow the fuel so that a total of 96 individual combustion zones are created. According to these orders of magnitude one skilled in the art will recognize that these firing zones used are by no means something with micro-burning zones in the respective areas of the bores of a distribution channel from one Burner for burning hydrogen, the exemplary embodiment of which he added from the FIGS. 18 and 19 and 20 and 21 including their correlating exemplary explanations below may have to do. This person skilled in the art becomes familiar with one of these FIG Granted attentive gaze also note that at least one hole is on either side a so-called roof edge is provided, with a side on these sides of the roof edge Variety of these holes are taken into account. The US-A 1,968,359 miss. In addition, this publication contains no information on the problem of nitrogen oxides directed notes. The introduction of a fuel into an air environment is specialist common. However, it can be assumed that the diagonal introduction of the Hydrogen into a combustion chamber along the lines of Figure 19 and also Providence a measure according to which the air and hydrogen supply take place at a mixing angle in combination with the selection of micro-combustion zones (microcombustion flames per square inch) a significant nitrogen oxide reduction compared to known burners with diffusion combustion implemented, will not be common.

Even if a person skilled in the art from EP-A 0 334 736 furthermore the straightforward introduction of the Hydrogen through an opening in a combustion chamber, as in the example of the figure attached 20 provided, may be known, the spaced arrangement of a bore, which (next to a Numerous other holes) is embedded in a hydrogen-emitting distribution channel a perforated perforated plate, which is assigned to the respective hole in the perforated plate is (are), for the intended purpose, the formation (of a multitude) of micro-combustion zones seems to him not to be common. In any case, the disclosure content of EP-A 0 334 736 cannot Clearly remove process step after the readable "when starting up the burner after injecting hydrogen and air into the combustion chamber with an air environment Fine distribution to a large number of micro-combustion zones in the respective areas of the holes is formed.

The gas burner which has become known from EP-A 0 334 736 and which passes through several nozzles the combustion of a flame generated in the air combustible compressed gas includes one Air chamber, one wall of which is perforated with a large number of openings close together, where the flame is generated.

With the opening of the (individual) nozzle, the gas burner emits a gas jet in the direction of the air stream surrounding this jet will deflect, but - with a glance at the figure 7 of this publication - due to a mechanical obstacle across the central area the exit of each opening in the axis extension of a corresponding needle is blown straight into the combustion chamber. According to the teaching of EP-A 0 334 736 will certainly trained several burning zones, but achieving micro-burning zones provided that just a jet of hydrogen through the narrow bore of a perforated plate in an air jet within the Combustion chamber is injected, can not be found in print.

Accordingly, the invention is based on the object of a method for the diffusion combustion of H2 and a burner to carry out this procedure so that by a drastic Increase in the burning zones a significant reduction in NOx formation compared to previous ones Burners with diffusion combustion is achieved.

This object is achieved by the measures specified in claims 1 and 2. In the Further claims are appropriate further developments and refinements of the measures Claim 2 specified.

It is particularly advantageous here that the manufacturing outlay is considerable in spite of considerable Increase in the number of firing zones remains small. Another advantage is that by the hydrogen has a particularly good cooling effect on the structure.

Fig. 1

eine Ansicht eines Brenners in Matrix-Bauart für eine Brennkammer,

Fig. 2

den Schnitt II - II nach Fig. 1,

Fig. 3

einen Leitbolzen,

Fig. 4

den Schnitt IV-IV nach Fig. 3,

Fig. 5

ein Führungsrohr mit einem Leitbolzen,

Fig. 6

eine Ansicht eines Brenners in zweidimensionaler Bauart,

Fig. 7

den Schnitt VII-VII nach Fig. 6,

Fig. 8

eine Ansicht eines weiteren Brenners in Matrix-Bauart,

Fig. 9

den Schnitt IX-IX nach Fig. 8,

Fig. 10

ein Führungsrohr nach Fig. 9 mit einem Leitbolzen,

Fig. 11

die Ansicht XI nach Fig. 10,

Fig. 12

den Schnitt XII-XII nach Fig. 10,

Fig. 13

die Einzelheit XIII nach Fig. 10,

Fig. 14

eine Darstellung nach Fig. 13 mit einer veränderten axialen Stellung des Leitbolzens,

Fig. 15

eine Darstellung nach Fig. 14 mit einer veränderten Winkelstellung des Leitbolzens,

Fig. 16

eine Ausgestaltung einer Führungsrohr-Leitbolzen-Anordnung mit Leitkanälen,

Fig. 17

den Schnitt XVII-XVII nach Fig. 16,

Fig. 18

eine Ansicht eines weiteren Brenners in zweidimensionaler Bauart,

Fig. 19

den Schnitt XIX-XIX nach Fig. 18,

Fig. 20

einen Brenner mit einteiliger Lochplatte,

Fig. 21

die Ansicht XXI nach Fig. 20,

Fig. 22

einen Brenner mit gekrümmtem Verteilerkanal und

Fig. 23

den Schnitt XXIII-XXIII nach Fig. 22.

In order to facilitate an understanding of the invention, further embodiments of a burner for burning hydrogen are explained and described below with reference to FIGS. 1 to 17 and 22 to 23, which a person skilled in the art assigns to the prior art on the basis of his knowledge and experience becomes. The invention is explained and described in more detail below with reference to exemplary embodiments according to FIGS. 18 to 21. Show it

Fig. 1

2 shows a view of a burner in a matrix design for a combustion chamber,

Fig. 2

the section II - II of FIG. 1,

Fig. 3

a guide pin,

Fig. 4

the section IV-IV of Fig. 3,

Fig. 5

a guide tube with a guide pin,

Fig. 6

a view of a burner in two-dimensional design,

Fig. 7

the section VII-VII of FIG. 6,

Fig. 8

a view of another burner in matrix design,

Fig. 9

the section IX-IX of FIG. 8,

Fig. 10

9 with a guide pin,

Fig. 11

the view XI of FIG. 10,

Fig. 12

the section XII-XII of FIG. 10,

Fig. 13

the detail XIII of FIG. 10,

Fig. 14

13 with a changed axial position of the guide pin,

Fig. 15

14 with a changed angular position of the guide pin,

Fig. 16

an embodiment of a guide tube-guide pin arrangement with guide channels,

Fig. 17

the section XVII-XVII of Fig. 16,

Fig. 18

a view of another burner in two-dimensional design,

Fig. 19

the section XIX-XIX according to Fig. 18,

Fig. 20

a burner with a one-piece perforated plate,

Fig. 21

the view XXI of FIG. 20,

Fig. 22

a burner with a curved distribution channel and

Fig. 23

the section XXIII-XXIII of FIG. 22.

Figures 1 to 4 show a burner for burning H2 for installation, for example, in the Combustion chamber of a gas turbine. The burner has a plate-like shape and is transverse to the main flow direction built into the combustion chamber. The edge area of the burner and its connection with the combustion chamber housing, not shown, is not shown and can be designed as desired his. The burner consists of a first perforated plate 2 and a second perforated plate 3 passing through a plurality of guide tubes 4 are kept at a constant distance d. The Holes can be arranged according to certain matrix mustem. The first perforated plate 2 is, for example made of a suitable metal and is gas impermeable.

In contrast, the second perforated plate 3 is gas-permeable and consists of a suitable porous Material, for example made of a sintered metal. The holes in both plates 2, 3 are congruent attached so that each hole in the first plate 2 with the associated hole of the second plate 3 forms a pair of holes. The cohesion of the burner is essentially due to this made that a guide tube 4 is used as a spacer and fixed in each pair of holes. The guide tubes 4 have peripheral beads 5 which are rolled outwards.

The guide tubes 4 are fixed in the perforated plate 2, for example by soldering or Welding, whereas the fixation in the plate 3, for example by rolling or flanging can be done. This results in cooperation with the bead 5 between the guide tubes 4 and the perforated plate 3 each have a positive connection. This essentially forms the perforated plates 2, 3 with the guide tubes 4 a distribution chamber. In each guide tube 4 there is an air guide pin 6 used, as shown enlarged in Figures 3 and 4. The guide pin consists of Basically a cylindrical rotating body with a stop 6a, a guide part 6b, a holder 8 and a disk 9. The outer diameter of the guide part 6b corresponds to in about the inner diameter of the guide tube 4 and has in the example embodiment shown four axial guide channels 7. The bracket 8 is attached to the right of the guide part in Figures 3 and 5 and practically represents an area with a reduced diameter, which concentrically Disc 9 carries, whose outer diameter corresponds approximately to that of the guide part 6b. The Stop 6a is formed by a region which is short in the axial direction and whose outer diameter is larger than that of the guide part 6b. In each guide tube 4 is from the air side of the burner A guide pin 6 is inserted until the stop 6a abuts the perforated plate 2 and is in this position permanently fixed. Such an assembly forms an injector. To start up the Brenners is gaseous hydrogen in the existing between the perforated plates 2, 3 distribution chamber initiated. Air is also blown into the combustion chamber through the guide tubes. The hydrogen flows in the distribution chamber across the main flow direction and distributes thereby in a fine distribution on the local areas of the porous perforated plate 3, through which it in the combustion chamber enters and forms a hydrogen environment here. Everybody emerges at the exit Guide tube 4 as a result of the deflection by the disk 9, an air flow in the manner of a conical jacket, which enters a process of mixture formation with the surrounding hydrogen and forms a rotationally symmetrical diffusion flame. Beneficial for the activation of the mixing process here is the interaction of colliding neighboring cone flames. The geometry the guide pin 6 is selected so that when it is inserted up to the respective stop 6a a predetermined redirection, d. H. gives a predetermined flame shape. It is also conceivable that the stops 6a are omitted for reasons of weight. In this case the insertion takes place the guide pin 6 in the guide tubes 4 in a predetermined axial position by means of a Manufacturing device. The extremely simple structure of the injectors enables them to be miniaturized that a much larger number of them can be installed per combustion chamber. As a result of Miniaturization in the specified order of magnitude becomes the firing zones micro-firing zones called.

Figures 6 and 7 show a further embodiment of a burner, consisting of individual for the hydrogen provided elongated distribution channels 11 of U-shaped cross section, the to the combustion chamber are closed off by walls 12 made of a porous sintered metal. The Channels 11 are connected to one another by perforated profiles 13 of an angular cross section, that in each case the free longitudinal edges of a perforated profile 13 on the longitudinal edges of two neighboring ones Distribution channels 11 are attached. The holes 14 are in the strip-shaped legs the perforated profiles 13 attached at a uniform distance. To start up this burner gaseous hydrogen is introduced into the distribution channels 11. At the same time, air gets through the holes 14 are blown into the combustion chamber. The hydrogen flows within the distribution channels 11 transverse to the main flow direction and is distributed finely to the local areas the porous walls 12 through which it enters the combustion chamber and here one Hydrogen environment forms. As a result of the air supply, a stoichiometric one forms in the region of each bore 14 Zone that forms its own flame when the burner is ignited. This burner is particularly simple and can be manufactured as a sheet metal structure. You can For example, proceed so that the U-shaped distribution channels 11 are bent from sheet metal, wherein each U-leg is connected in one piece with an obliquely angled punched tape. To the insertion of the porous walls 12 through adjacent channels 11, for example Welded together along the free edges of the paper tape. This burner is can be miniaturized in such a way that several thousand combustion zones are reached within one combustion chamber become.

In the case of the fine distribution taking place in the burners described above, the H2 is passed through the distribution chamber or distributed over the distribution channels to thousands of micro-combustion zones, so to speak microdiffusion combustion of the hydrogen takes place. The fact that with the above Burners form a hydrogen environment within the combustion chamber Air jets are injected, there is an inverse diffusion combustion, which results in the resulting Can stabilize mixing zones with a mostly turbulent course. The main advantage of this Inverse hydrogen diffusion combustion consists of good cooling of the structure that H2 is reached.

With the aforementioned burners, other porous metallic ones can also be used instead of the porous sintered metals Materials are used. This is how porous materials based on metallic come Fibers into consideration, such as are known, for example, under the name "felt metal". It is also conceivable that the porous material consists of a ceramic material. To the Limit the effects of inhomogeneities possibly present in a porous material, can be a perforated plate with a defined fine hole pattern of a relatively thin layer of a porous material or used alone.

Figures 8 to 11 show a further embodiment of a burner, but in contrast to the previous one does not work with inverse but with regular diffusion combustion. That burner again consists essentially of two congruent perforated plates, here with the numbers 15 and 16 are designated. The two perforated plates are via guide tubes 17, each of which has an inlet opening and have an outlet opening, firmly connected to each other, so that again Distribution chamber is formed. Several holes 18 in are in the vicinity of the outlet openings the same angular pitch attached to the guide tubes 17.

In each guide tube 17 is a guide pin 19, consisting of a stop 20, a guide part 21 and a free jet part 22, the free jet part practically having an axial section with a reduced diameter. The stop 20 and the guide part 21 have a Number of axially extending grooves 23, the depth of which extends to the outside diameter of the free jet part 22 can be enough. The number of bores 18 corresponds to that of the grooves 23. When starting up of the burner, air is blown through the guide tubes 17 into the combustion chamber. At the same time, H2 is introduced into the distribution chamber so that it passes through the individual bores 18 injected into the guide tubes and carried here by the air arriving through the grooves 23 becomes. In each case, a micro-combustion zone is formed downstream of a bore 18, in which there is ignition a flame stabilizes the combustion chamber. Since the guide tubes 17 in the example embodiment shown each have six bores 18, there are six micro-combustion zones per guide tube. This results in a further increase in the number of firing zones. An application of this principle the number of combustible zones that can be installed would be based on the TRUD combustion chamber mentioned at the beginning increase to about 5000. This in turn causes a very high level even without premixing Degree of mixing is achieved, which has the consequence that the formation of NOx is largely reduced becomes. By rotating and / or axially displacing the guide pins 19 with respect to the guide tubes 17 various burner settings can be made. Here too there is the possibility to omit the stops 20 and the axial position of the air guide bolts based on a appropriate device to adjust.

Figures 12 to 15 show different settings of the burner described above. In Fig. 12 the guide pin with the grooves 23 is set relative to the guide tube 17 with the bores 18, that the injection of hydrogen through the holes 18 into the gaps between the air jets takes place, which arrive through the grooves 23. 13 shows the guide pin in a position in which the guide part 21 reaches close to the holes 18. This allows the hydrogen jet can only be diverted downstream. However, if the guide part 21 is in the guide tube 17 fixes that there is a somewhat greater distance from the bores 18, as shown in FIG. 14, can there is some recirculation. Fig. 15 finally shows a configuration in which the by Grooves 23 incoming air jets exactly on the hydrogen jets entering through the holes to meet.

In all of these cases, fine hydrogen jets are emitted into an air environment by means of the bores 18 initiated so that there is a regular diffusion combustion, the individual combustion zones only have a diameter of the order of 2 mm. This stabilize itself the flames in many cases at the holes 18. It should be mentioned that the free jet 22 in another Embodiment can also be omitted, especially with air injection according to FIG. 15.

Figures 16 and 17 show a configuration according to which the hydrogen jets and the air jets be kept separate until they enter the combustion chamber. For this, the ones described above Guide tubes 17 are used with the holes 18. These are back in the perforated plates 15 and 16 are used, of which only the number 16 is shown here. The one used here Guide pin 24 again has the grooves 23, but is otherwise with two major changes Mistake. On the one hand, the bolt with a constant diameter is approximately up to the outlet cross section guided. On the other hand, are centered on the material areas located between the grooves 23 small axially extending guide channels 25 attached. The respective guide pin 24 is in the relevant Guide tube 17 used that each bore 18 opens into a guide channel 25. hereby is the beginning of the diffusion between hydrogen and air to an area downstream from the perforated plate 16 laid, for example, to avoid excessive thermal structural loads. at In these solutions, the flames stabilize at the mouths of the guide channels 25.

Figures 18 and 19 show an embodiment of a burner according to the invention for regular Diffusion combustion of the two-dimensional type. This burner again consists of individual provided for the H2 elongated distribution channels 26, but in contrast to the Distribution channels 11 according to Figures 6 and 7 have a closed cross section. This Cross-section is essentially determined by a flat rectangular shape, but in its im The right area (FIG. 19) has a roof edge 26a. Are on both sides of the roof edge 26a fine holes 27 attached in a staggered arrangement. The individual distribution channels 26 held by a bracket, not shown, at a mutual distance so that they are a grid form, which can be flowed through from left to right according to FIG. 19 by the air. The burner 18 further comprises a perforated plate 28, which is integrated from strip-shaped gap plates is, in the longitudinal edges gaps 29 are incorporated. The gap plates are between two Distribution channels 26 are fixed in the area of the bores 27 by a bracket, not shown, that each hole 27 is assigned a gap 29. Instead of the one drawn hole 27 also several finer holes can be arranged. When starting this burner Air according to the arrows 30 through the gaps 29 and H2 through the holes 27 according to the Arrows 31 are blown into the combustion chamber, creating an air environment within the combustion chamber formed with a plurality of micro-combustion zones in the respective areas of the bores 27 becomes. After ignition of the combustion chamber, the flames stabilize at the bores 27.

Figures 20 and 21 show another burner according to the invention with a one-piece perforated plate 32 with holes 32a, to which a plurality of distribution channels 33 are fastened by means of brackets 34. The distribution channels 33 have a long round cross section and have the perforated plate 32 in their facing area a plurality of holes 35. The brackets 34 can be made of wire or sheet metal. 21, each hole 32a of the perforated plate 32 has two holes 35 assigned, whereby H2 can emerge according to the arrows 37.

When this burner is started up, air is drawn in through the perforated plate 32 in accordance with the arrows 36 blown into the combustion chamber, creating an air environment with a A large number of microburning zones is formed in the respective areas of the bores 35. To Ignition of the combustion chamber, the flames stabilize at the bores 35.

Figures 22 and 23 show a further embodiment of a burner. The partial view according to Fig. 22 shows curved distribution channels 38, which are part of an annular burner and after 23 have a long round cross section. Each distribution channel forms a closed one Ring, which is connected to the hydrogen line via its own connection. The cohesion of the burner is arranged, for example, between the individual distribution channels 38 Wavy separators 39 are produced, for example, with the distribution channels 38 are connected by welding. The separators 39 are each formed from a sheet metal strip and provide a sufficient distance between the individual distribution channels 38 for the passage of air for sure. It is also conceivable that a distribution channel 38 with a separator 39 by winding is combined into a disc-shaped or ring-shaped burner, so that the distribution channel 38 gets a spiral shape. To create a variety of micro-burning zones are on the distribution channel 38 again drilled holes, which are designated here with number 40. Cross here two hydrogen jets 41 at one point. Common feature of the annular and of the spiral manifolds is that they have a curved shape. These burners work in principle according to the same mode of operation as that already used in connection with FIGS. 18 to 21 described.

Claims (4)

1. Method for the diffusion combustion of hydrogen in a burner inside a combustion chamber of a gas turbine, in which the hydrogen and air are injected into the burner, wherein the main flow direction is defined by the primary flow direction of the air in the combustion chamber and the hydrogen present in a distribution channel flows out into the latter through a multiplicity of channel bores and, together with an air flow surrounding the distribution channel, is injected through one opening in each case of a perforated plate, and wherein the hydrogen is essentially subjected to a distribution over individual combustion zones in a transverse flow directed perpendicularly to the main flow direction, characterized in that, when the burner is started up, hydrogen and air are injected through the bores of the perforated plate into the combustion chamber, as a result of which an air environment having a multiplicity of microcombustion zones is formed inside the combustion chamber in the respective regions of the bores and, after the ignition of the combustion chamber, the flames stabilize at the bores.
2. Burner for the combustion of hydrogen that has at least one distribution channel (26, 33) that has a closed cross section of flat rectangular or oval shape and comprises a perforated plate (28, 32) that is disposed next to a combustion chamber, wherein the individual distribution channel (26, 33) is provided with a multiplicity of bores (27, 35) that are directed towards the combustion chamber, and wherein the perforated plate (28, 32) is disposed in such a way that each bore (27, 35) of a plurality of distribution channels (26, 33) that are disposed next to one another is assigned to an opening (29, 32a) multiply inset in it, characterized in that each of the distribution channels (26) having a flat rectangular shape has a ridged edge (26a) in the region directed towards the perforated plate (28), in both sides of which ridged edge fine bores (27) are provided in an offset arrangement and wherein the burner comprises strip-shaped sheets with gaps in whose longitudinal edges gaps (29) are incorporated in such a way that there is assigned to each bore (27) a gap (29) through which the hydrogen can escape, or that the distribution channels (33) having an oval cross section have a multiplicity of bores (35) in their region facing the perforated plate (32), wherein two bores (35) through which the hydrogen can escape are assigned to each hole (32a) of the perforated plate (32).
3. Burner according to Claim 2, characterized in that each bore (35) of the distribution channel (33) having the oval cross section is assigned to an opening (32a) designed as a hole.
4. Burner according to Claim 2, characterized in that, inside the combustion chamber, an air environment is present that comprises a multiplicity of microcombustion zones in the respective regions of the bores (27, 35), which multiplicity is formed by injecting, when the burner is started up, air through the opening (29, 32a) that surrounds the individual distribution channel (26, 33) and hydrogen through the bore (27, 35) that is present in the individual distribution channel (26, 33) into the combustion chamber.

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