JPH09310818A - Method and apparatus for suppressing pulsation of flame and pressure in combustion facilities - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent pulsation of flame and pressure having an intolerable amplitude by supplying fluid into a combustion chamber in such a manner that the fluid enters from outside of an annular vortex formed in an outer region of flame. SOLUTION: Air 11 having an ambient temperature is introduced into a combustion chamber 3 through gas outlets 10. The gas outlets 10 are arranged in a wall 9 of the combustion chamber 3 in such a manner as to be uniformly dispersed around an axis 6. Then, the air 11 is sucked by a converging slit 8 in a tangential direction with regard to the annular vortex 7 and replaces high temperature flue gas. At the same time temperature of the annular vortex decreases and the content of fuel decreases correspondingly. The gas outlets 10 have an effect of appropriately cooling the annular vortex 7 in a whole circumference of the flame 2, and by providing the gas outlets 10 with an appropriate inclination with regard to the axis 6 of the flame, outlet opening portions of the outlets 10 are directed as near as possible to an area where the annular vortex 7 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing a flame and pressure pulsation in a combustion equipment including a burner for generating a flame and a combustion chamber in which the flame is adjusted, and to realize the method. Of the corresponding device.

[0002]

2. Description of the Related Art In the case of industrial combustion equipment such as a gas turbine combustion chamber, a blast heater, a residue incineration facility, or an industrial furnace, or a small combustion chamber such as a gas boiler or a heat boiler in the domestic use area. Unstable operating conditions occur under certain conditions determined by operating parameters on combustion technology, such as thermal efficiency and air equivalent ratio. This unstable operating condition is characterized in particular by the temporal fluctuations of the flame, especially in the combustion chamber and in the sections immediately before and after the combustion chamber, which occur with static pressure fluctuations. Compared with the static operation of combustion equipment, the instability of combustion often changes the operating state of the equipment, increasing the noise level,
Increased mechanical and / or thermal stress on the combustion chamber or the lining of the combustion chamber. Under such an inconvenient situation,
Such flame and pressure pulsations can lead to the destruction of the equipment in which they occur, resulting in much effort to avoid such flame and pressure pulsations. For example, special cushions and interiors may change the geometry of the combustion chamber. However, it only shifts the generated vibration frequency, and is not a general solution to the above problem. In other cases, special measures have been taken based on experience when flame and pressure pulsations occur.

[0003]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and apparatus for preventing such flame and pressure pulsations that have unacceptable pressure amplitudes.

[0004]

The features of the present invention for attaining the above object are to introduce a fluid into a combustion chamber and direct the fluid toward a flame in an outer peripheral region where an annular vortex is formed. Fluids are introduced in such a way that the fluids are mixed in the vortex while they are being formed. Therefore, the present invention
Based on the knowledge that flames, or annular vortices formed in the peripheral region of a combustion stream containing fuel and air, essentially enhance and supply the energy to maintain these pulsations. Is. These annular vortices are formed as the peripheral region of the combustion stream containing the fuel rolls up and, when the annular vortex is formed, integrates with the hot flue gas,
This causes the fuel / air mixture contained in the annular vortex to heat up rapidly. This causes a shocking type of exhaust reaction of the fuel, which causes pressure pulsations. This is an important point of view, because the temperature rise due to the hot exhaust gas in the vortex significantly increases the ignition capability range of the fuel-containing mixture found in the vortex. An effective way to avoid this adverse effect is to use the method according to the invention, which lowers the temperature of the mixture contained in the annular vortex, so that the reduced temperature level no longer causes ignition. And creates a mixture with no reaction capacity in the vortex.

In one embodiment of the invention, the fluid is a gas and as the vortex is formed, the gas is introduced into an area that will be incorporated into the vortex. When the vortex is formed, that is, when the peripheral region of the combustion flow containing fuel / air is rolled up. This lowers the temperature of the air-fuel mixture contained in the annular vortex. This is because, during the formation of the vortex, the relatively cold medium is confined together instead of the hot flue gas. This cooling effect causes the mixture containing fuel trapped in the annular vortex to be outside the ignition limits normally present in association with the hot flue gas, i.e. No more reaction or ignition capability.

In another embodiment, the fluid is a vaporizable liquid and is injected into the combustion chamber. As a result, liquid and / or gaseous vapors enter from outside the annular vortex formed in the outer region of the flame. At that time, for example, the liquid is ejected so that the liquid directly reaches the vortex. The liquid then vaporizes there, with the heat of vaporization necessary for this being taken away from the mixture present in the vortex. Thereby, the fuel-containing mixture trapped in the annular vortex is cooled correspondingly. The air-fuel mixture is at a reduced temperature level, where it lies in an annular vortex outside the predominant ignition limit. That is, there is no reaction or ignition capability anymore.

The preferred fluid used is
It is water or an aqueous solution. Within the framework of this application, these shall be included in the general concept of "water". When the liquid vaporizes in the annular vortex as described above, not only does the mixture in the vortex cool, but at the same time, the water vapor generated dilutes the mixture accordingly. Therefore, during cooling, the fuel concentration in the annular vortex shifts to the "excessively thin" region outside the ignition limits. However, basically, as the introduced liquid, liquid fuel (for example, kerosene, gasoline,
Etc.) can be used to lower the temperature of the air-fuel mixture. In that case, the temperature drop in the annular vortex causes the fuel concentration to move to a region that is "supersaturated" for ignition.

Besides spraying the vaporizable liquid directly into the vortex, it is also possible to spray the liquid in the intake (constricted) area of the annular vortex. By vaporizing the liquid in the peripheral region of the flame and / or in the hot flue gas, vapor cloud formation is allowed, which vapor cloud replaces the hot flue gas in an annular vortex. Trapped inside. This allows
The temperature of the air-fuel mixture contained in the annular vortex decreases. This is because, instead of hot flue gas, a relatively cool medium (eg, steam) is sucked together as the vortex is formed. Due to this temperature reduction and dilution, the air-fuel mixture present in the vortex is outside the temperature-independent ignition limit and no longer reacts or has the ignition capacity. In that case, the introduction of the fluid is preferably continuous. As a result, at any time, a sufficient amount of gas or liquid and / or vapor will be available in the combustion chamber to feed into the annular vortex formed. Basically, it is possible to reduce the temperature of the mixture by introducing a medium which is sufficiently fuel-containing or a cold gas such as pure combustion gas (for example methane or natural gas) as the fluid. In this case, the temperature drop in the annular vortex causes the fuel concentration to move into the "supersaturated" region for ignition.

However, the gas need not contain fuel. This means that the fuel contained in the annular vortex is diluted and that the fuel concentration moves to the "overly lean" out-of-ignition region. Moreover, there is no temperature rise that appears when the flue gas is trapped in the vortex. Preferably, the gas containing no fuel is air. Generally, a sufficient amount of air is available. In particular, air has an ambient temperature, in which case it is essentially sufficient to be regarded as "cold" in comparison with the hot flue gas. It is also conceivable to use an inert gas instead of air. However, there are certain cost drawbacks.

In order to ensure a cooling effect in the entire donut-shaped annular vortex, the gas is introduced evenly distributed around the flame, especially in a flow which extends mainly tangentially to the vortex. To do. This ensures the introduction of gas into the vortex. The liquid used as a fluid is
Similarly, it is injected into the combustion chamber while being evenly distributed around the flame. At that time, it is useful to atomize the liquid in the process of the injection. As a result, the liquid has as large a surface area as possible. This allows rapid and complete vaporization to be achieved. From the above it will be seen that it is most convenient to introduce the liquid directly into the annular vortex, i.e. to inject the liquid in the direction of the annular vortex in the combustion chamber.

To carry out the method according to the invention, a well-known combustion installation comprising a burner and a combustion chamber is further provided, first of all (1) in order to carry out the method described thus far, It is to have a gas outlet for introduction. That is, the gas supply device is arranged so that the gas supplied within the area where the annular vortex is formed (over its entire circumference) is confined through the rolling up of the outer region of the combustion flow. Alternatively,
(2) The combustion facility comprises at least one outlet opening for a vaporizable liquid. as a result,
In the area where the vortex is formed, the outer region of the combustion flow is rolled up, so that the liquid that has already vaporized or is about to vaporize in the vortex is sufficiently confined in the entire area of the vortex. Is guaranteed. The exact location of these vortex rolls is highly dependent on the shape and layout of each combustion chamber. The frequency and amplitude of the pressure pulsations produced by this type of vortex are essentially combustion chamber specific. Therefore, even with reference to the method according to the invention, the structural design of each combustion installation must be adapted individually.

[0012] Preferably, the combustion facility is constructed with a slit for the gas to be supplied, or a gas outlet opening in the form of a slit nozzle. This outlet surrounds the actual combustion flow. Through the outlet, corresponding cold gas is drawn from the gas jacket into the vortex where the annular vortex is formed. However, as long as the extra gas ensures that the gas is reliably introduced into the vortex, it is not only parallel to the burner and / or flame axis, but also to that axis. It becomes clear that there is also the possibility of outflow at an angle of. In particular, the magnitude of the velocity of gas flowing out of the gas outlet and the direction of the velocity vector are arbitrary within a wide range. Instead of the individual slits mentioned above, it is possible to provide a large number of individual small gas outlets, which outlets have a combustion flow and / or
Or, it is laid out in a ring shape around the flame. Choose a smaller distance between the individual gas outlets,
At the point where the vortex rolls up, the cold, diluted gas is supplied sufficiently continuously over the circumference of the flame.

In the case of combustion installations in which vaporizable liquid is injected into the combustion chamber, the outlet for the injection is configured as a jet nozzle or a spray nozzle, which are closely spaced on the outer circumference. As a result, the resulting jet of liquid, the cloud of water drops, or the cloud of vapor that occurs after vaporization of the liquid surrounds the combustion stream and / or flame as completely as possible at the swirl point. Further, the vaporizable liquid can be jetted in parallel with the burner or flame axis, or at an arbitrary angle. In particular, the liquid can be fed through a radial hole in the wall of the combustion chamber, at an angle of approximately 90 ° with respect to the burner or flame axis.
However, basically, the direction of the velocity vector of the ejected liquid and the magnitude of its ejection velocity can also be changed in a wide range. Of course, it is only necessary to ensure that the injection is selected so that the liquid and / or its vapor can be reliably confined in the annular vortex formed.

The above description of the means for solving problems, as well as the preferred embodiments of the present invention described below, will be better understood in connection with the drawings. To illustrate the invention, preferred embodiments are shown in the drawings. However, it will be appreciated that the invention is not limited to the structures and arrangements shown.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-section of the combustion equipment in which the burner 1 generates a flame 2 and the flame 2 faces the combustion chamber 3. The burner 1 is supplied with a combustion gas / air mixture 5 via a pipe 4, which mixture 5 is ignited downstream by a burner with a tilt box (not shown) and a flame 2 extending along a central axis 6 To form. At a certain axial distance from the burner 1, the outer region of the flame 2 develops into a donut-shaped annular vortex 7 at regular intervals, with a convergence between the annular vortex 7 and the flame 2. Slits 8 (having a convergent shape) are formed through which the gas around them is sucked into the annular vortex 7. Usually, the gas drawn in is hot flue gas from the combustion chamber 3. This gas is hot and heats the annular vortex 7 to a temperature at which the fuel / air mixture 5 contained in the annular vortex 7 is ignited. As a result, pressure pulsations are excited and / or periodically formed and burned through the cyclic formation of an annular vortex 7 containing the fuel / air mixture 5 and the exhaust reaction synchronized with the combustion pulsation. Pulsation is maintained and strengthened. At that time, the frequency of the pressure pulsation and the formation frequency of the toroidal annular vortex are the same. It does not depend on whether the discharge from the burner is laminar or vortex.

According to the invention, air 11, which preferably has an ambient temperature, is introduced into the combustion chamber 3 through the gas outlet 10. This gas outlet 10 has a shaft 6
Are arranged on the wall 9 of the combustion chamber 3 in a uniformly distributed manner around the. As a result, as shown by the arrow 12 in FIG.
The air 11 is sucked into the convergent slit 8 so that it is tangential to the annular vortex 7, so that the air 11 is replaced by the hot flue gas. At the same time, the circular vortex 7
And the fuel content is correspondingly reduced. As a result, no more ignition occurs in the annular vortex 7, and correspondingly no periodic combustion of the annular vortex 7, which causes pressure pulsations. Therefore, it is possible to prevent the above-mentioned pressure pulsation from occurring, and to prevent the effect of exerting a strong mechanical and thermal load on the combustion equipment. The gas outlets 10 distributed around the central axis 6 of the flame at sufficiently even intervals have the effect of adequately cooling the toroidal annular vortex 7 around the entire circumference of the flame 2,
Proper tilting of the gas outlet 10 with respect to the flame axis 6 ensures that the outlet of the gas outlet is oriented as close as possible to the area in which the annular vortex 7 is formed, so that In the best possible way, the gas is supplied to the annular vortex 7 formed therein.

FIG. 2 shows a combustion installation similar to the combustion installation shown in FIG. 1, with the same parts being provided with the same reference symbols. However, in the case of the combustion equipment shown in FIG. 2, in the combustion chamber 3, not gas as a fluid,
A vaporizable liquid is provided. The nozzle 13 is the combustion chamber 3
Mounted on the wall 9 of the combustion chamber 3 in an evenly distributed manner about the axis 6, a nozzle 13 supplies a vaporizable liquid 14, preferably water, through the wall 9 of the combustion chamber 3, It is injected into the vortex 7. Then, the water injected into the annular vortex 7 is vaporized, and the heat of vaporization necessary for that is taken out from the hot annular vortex 7 to cool the annular vortex 7. The steam generated at the same time reduces the fuel concentration in the annular vortex 7.

Due to the decrease in temperature in the annular vortex 7 and the concomitant decrease in fuel concentration in this way, the annular vortex 7 is no longer ignited and the pressure does not rise accordingly. Therefore, it is possible to prevent the above-mentioned pressure pulsation from occurring, and avoid the adverse effect of exerting a strong mechanical and thermal load on the combustion equipment. By arranging the injection nozzles 13 around the central axis 6 of the flame 2 with a sufficiently uniform spacing, it is possible to supply a vaporizable liquid to the toroidal annular vortex 7 around the entire circumference of the flame 2 and correspondingly. To be cooled. Proper tilting of the nozzle 13 with respect to the central axis 6 of the flame 2 then ensures that the injected liquid is injected as close as possible to the place where the annular vortex 7 occurs. When the liquid is injected into the region adjacent to the flame 2 or the peripheral region of the flame 2 before the flow of the flame 2 forms the donut-shaped annular vortex 7, the liquid is vaporized there, and the vapor generated thereby is generated. Replaced by hot flue gas. These cold vapors are then drawn into the annular vortex 7, instead of the flue gas, thereby producing a similar low temperature and diluting the fuel, which results in a cycle of the exhaust reaction of the annular vortex 7. Occurrence is prevented.

In summary, the present invention provides a laminar or annular vortex, independent of the method of combustion control, ie dispersive, partially premixed or fully premixed, depending on the donut shape, flow guidance. There is an advantage in that the pressure pulsation that is energetically maintained or enhanced by the periodic release reaction or the combustion can be prevented.

Those skilled in the art will appreciate that modifications can be made to the specific embodiments described above without departing from the basic broad concept of the invention.
Therefore, it is understood that the invention is not limited to the particular embodiments disclosed. However, the appended claims at least cover modifications within the spirit of the invention. It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

1 is a principle diagram of an apparatus for carrying out the method according to the invention with a donut-shaped annular vortex forming a flame and a gas as introduced fluid.

FIG. 2 is a principle diagram of an apparatus corresponding to FIG. 1, which uses a vaporizable liquid as the introduced fluid.

[Explanation of symbols]

 1 Burner 2 Flame 3 Combustion Chamber 4 Pipe 5 Combustion Gas / Air Mixture 6 Central Axis 7 Annular Vortex 8 Slit 9 Wall 10 Gas Outlet Opening 11 Air 13 Nozzle 14 Liquid

Front Page Continuation (71) Applicant 596106032 De Fau Gäve Weiter Ferrain Des Garth- und Wasserfages-Tehini-Wissen Schlossen Fair-Eniging-DVGW DEUTSCHER VERE IN DES GAS- UND WA SSERFACHES-TECHNIS CH- WISSENSHAFTLIC HE HE VEREI NIGUNG- Germany 53-53 ) Applicant 596106043 Horst Büchner France F-67500 Marianthal Du de Malgrave de Bade 3 3, RUE DU MARGRAVE DE BADE, F-67500 MARI ENTHAL, FRANCE (71) Applicant 596106054 Wolfgang Roykel WOLFGANG LEUCKEL Germany Dürhe Deerheim 67098 Bart・ U DEN HOOD 15 AUF DER JUDENHUT 15, D-67098 BAD DUERKHEI M, BUNDESREPUBLIK D EUTSCHLAND (72) Inventor Horst Büchner France Ef-67500 Marianthal Ryu de Malgrauveau de Badoud Inventor Roykel Germany Day-67098 Bad Durkheim Auf der Youdenhut 15

Claims (23)

[Claims] 1. Burner (1) for generating a flame (2)
And a method for suppressing flame and pressure pulsations in a combustion installation comprising a combustion chamber (3) to which the flame (2) is directed, the annular vortex (7) being formed in the outer region of the flame (2). Of the fluid (11, 1) into the combustion chamber (3) so as to enter from the outside.
4) Supplying method 2. Method according to claim 1, characterized in that the fluid (11, 14) is supplied continuously. 3. Method according to claim 1, characterized in that the fluid (11, 14) is supplied in a uniformly distributed manner around the flame (2). 4. Method according to claim 1, characterized in that the fluid is a gas (11). 5. The gas (11) separates the fuel component and the temperature so that the fuel / air / gas mixture forming the annular vortex (7) is outside the ignition limit depending on the temperature and the fuel component. The method of claim 4, comprising. 6. Process according to claim 4, characterized in that the gas (11) is fuel-free. 7. Method according to claim 4, characterized in that the gas (11) is composed of air. 8. Method according to claim 4, characterized in that the gas (11) is supplied mainly tangentially to the annular vortex (7). 9. The fluid is composed of a vaporizable liquid (14) injected into the combustion chamber (3), whereby the liquid (14) and / or its gaseous vapor are transferred to the annular vortex ( Method according to claim 1, characterized in that it is introduced in 7). 10. The liquid (14) is the annular vortex (7).
10. The method of claim 9, wherein the method is vaporized in the. 11. A method according to claim 9, characterized in that the liquid (14) is composed of water. 12. A method according to claim 9, characterized in that the liquid (14) comprises a liquid fuel. 13. The liquid (1) to the combustion chamber (3).
Method according to claim 9, characterized in that the jet of 4) is directed to the place of formation of the annular vortex (7). 14. A method according to claim 9, characterized in that the liquid (14) is atomized as it is injected into the combustion chamber (3). 15. A fuel / steam / gas / air mixture is formed in the annular vortex (7), the mixture being outside the ignition limit depending on temperature and fuel composition. Item 9. The method according to Item 9. 16. A burner (1), a combustion chamber (3), and a supply device (10, 13) for supplying a fluid by the method according to any one of claims 1 to 15. A device for suppressing flames and pressure pulsations in a characteristic combustion facility. 17. Device according to claim 16, characterized in that the supply devices (10, 13) are arranged uniformly around the central axis (6) of the flame (2). 18. Device according to claim 16, characterized in that the supply device (10, 13) is arranged on a side wall (9) of the combustion chamber (3). 19. Device according to claim 16, characterized in that the supply device (10, 13) is provided inclined relative to the axis (6) of the flame (2). 20. The supply device (10) is constituted by a gas outlet opening.
7. The apparatus according to 6. 21. Device according to claim 16, characterized in that the supply device (13) comprises a nozzle for introducing a vaporizable liquid. 22. Device according to claim 21, characterized in that the nozzle is configured as a jet nozzle whose jet direction is directed towards the annular vortex (7). 23. The device according to claim 21, wherein the nozzle is configured as an atomizing nozzle.