JP4155638B2 - Method for burning gaseous, liquid and medium or low calorie fuel in a burner and a burner for a heat generator for carrying out the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for burning gaseous, liquid and medium or low calorie fuel in a burner equipped with a swirl generator. The invention further relates to a heat generator burner for carrying out the method.
[0002]
[Prior art]
The burner for a heat generator, known from DE 19554713, is provided with a swirl flow generator 100 according to FIG. 1 of the publication, and the swirl flow Liquid fuel is injected axially into the generator through the fuel nozzle 103 in the form of a conical liquid fuel jet. A combustion air flow is introduced into the swirl flow generator between the swirl shell plates of the swirl flow generator, tangentially and at an angle to the liquid fuel jet, In particular, it is mixed with gaseous fuel via the outlet nozzle orifice 117. The outlet nozzle orifice 117 is mainly used for injecting fuel having a high heating value, typically 46 MJ / kg, mainly for injecting natural gas. For all other structural details of known burners, also called double burners, operated with two types of fuel, reference is made to the above-mentioned German published patent application.
[0003]
Burner systems for heat generators, which can be easily deduced, for example, on the basis of the above-mentioned publications, are designed especially for gas turbine operation. In the field of gas turbine applications, in addition to natural gas and fuel oils used as fuel for double burners, in the future, fuels that burn less toxic substances than conventional fuels, especially medium or low calorie fuels ( There is a demand to use (Mbtu fuel or LBtu fuel). For example, the Mbtu fuel or LBtu fuel, which is generated as a gas from the gasification of petroleum or heavy oil, has a large amount of hydrogen component and carbon monoxide component, and the calorific value of the Mbtu fuel is approximately 1 / of the calorific value of natural gas. Only 3 (about 15 MJ / kg).
[0004]
In principle, it is possible to mix gaseous medium calorie fuel with the combustion air flow through a tangential injection orifice like natural gas, but this will result in a relatively increased volume flow. On the basis of this, a very high local pressure loss occurs in the swirl flow generator, which has a persistent adverse effect on the flow stability of the resulting air jet. In addition, the high hydrogen content of the mixed medium calorie fuel with high reactivity is a great potential for causing a dangerous flashback into the burner. This kind of stimulation within the flow stream, elicit abnormal combustion of the supplied fuel, the emission values of which the combustion process, will significantly deteriorated for example by a significant increase of the NO _x components in the exhaust gas. Furthermore, the burner is overheated by flashback into the burner, so that the individual burner components are exposed to a strong heat load and almost reach the heat load limit.
[0005]
When MBtu fuel is injected in the vicinity of the burner outlet, the stability of the air swirl flow is not substantially affected and it is possible to avoid backfire into the burner, but based on a very short mixing zone. Te, mixing between the MBtu fuel and combustion air may be incomplete, with the result that the excessively high NO _x diffusion-like combustion accompanied emission is induced. Although NO _x emissions are reduced by adding a substantial amount of nitrogen or water vapor to the medium calorie fuel, such dilution of the fuel causes a reduction in the efficiency of the gas turbine plant. Equivalents are much true when using LBtu fuel.
[0006]
[Problems to be solved by the invention]
The object of the present invention is to provide a gas in a burner equipped with a swirl flow generator which atomizes liquid fuel in the form of a conical liquid fuel column surrounded by a swirling combustion air stream flowing in a tangential direction. A method for burning liquid and medium- or low-calorie fuels and a heat generator burner for carrying out the method, said fuel according to the following aspects a) to e) using a single burner To be able to burn the seeds. Ie:
a) a significant decrease in emission values that pollute the environment, in particular a significant decrease in NO _x emission values and CO emission values;
b) Stabilization of the flow relationship generated in the vortex generator, in particular the reduction or elimination of flashback into the burner;
c) guarantee of flame stability;
d) Energy gain due to complete combustion of fuel; and e) Increase efficiency of gas turbine plant by injecting medium calorie fuel into the burner without dilution.
[0007]
[Means for Solving the Problems]
The method of the present invention for solving the above-mentioned problems is characterized in that, in addition to the swirling combustion air flow flowing tangentially into the swirl flow generator, the gas and / or Alternatively, liquid fuel is injected and at least one injection means disposed inside the swirling flow generator causes medium or low calorie fuel to be axially and / or coaxially along the burner axis. Only injected and mixed with liquid and gaseous fuels and combustion air flow in the swirling flow generator, upstream of the area of the injection nozzle for liquid fuel, the injected medium or low calorie fuel to, so that others give rise to premixed combustion, also an advantageous embodiment means of the process described in claims 2 to 4.
[0008]
In order to solve the same problem, the burner construction means of the present invention operating according to the method described above, in a swirling flow generator , along the burner axis towards the liquid fuel column as claimed in claim 5 At least one third injection device for injecting medium or low calorie fuel into the swirling flow generator only in the axial and / or coaxial direction, and advantageous configurations means of the burner are described in claims 6-9.
[0009]
【The invention's effect】
The idea that forms the basis of the present invention comprises, for example, a gaseous fuel such as natural gas, a liquid fuel such as petroleum, and a medium or low calorie fuel, also called Mbtu fuel or LBtu fuel, with a swirl flow generator. To burn together in a single burner, in which case the medium or low calorie fuel is injected axially and / or coaxially into the burner or into the swirl generator Is to do. The injection of the fuel into the swirling flow generator is performed in the vicinity of an injection nozzle for liquid fuel, and the liquid fuel is injected into the swirling flow generator or burner in the injected state. It takes the form of a conical liquid fuel column. Thus, in addition to the finely sprayed liquid fuel, it is ensured that the medium or low calorie fuel injected into the inside of the swirl generator is perfectly mixed with the liquid fuel.
[0010]
By injecting medium or low calorie fuel axially or coaxially within the vortex generator, a significant change in the burner flow field occurs. In other words, the axial flow component of the burner flow field is expanded by the additional injection of medium calorie fuel, and the rotational flow component of the burner flow field is reduced approximately equally. However, the reduction of the rotational flow component, as is known per se, for example, as is apparent from the description of the German Patent Application Publication No. 19547913 mentioned above, particularly column 4, lines 55-66. This causes destabilization of so-called “backflow bubbles” formed for the stabilization of the flame in the backflow zone.
[0011]
Unlike the previously described double burner principle, the risk of flashback is thus significantly increased because the flow regularly blows off the backflow bubbles formed in the backflow zone based on the increased axial flow component. Reduced.
[0012]
As already mentioned at the beginning, medium calorie fuel or low calorie fuel has a high hydrogen content and therefore has high reactivity. Nevertheless, the fuel ensures the flame stability required for combustion. This is because a stable flame is generated without actively forming a backflow zone.
[0013]
Also, good mixing of the injected fuel and the combustion air flow injected into the vortex generator by supplying medium or low calorie fuel upstream of the injection nozzle area for liquid fuel Occurs. Thus was based on a long blending area, the premixed combustion having a relatively good NO _x emission value occurs, the NO _x emission values are obtained during natural gas premixed combustion.
[0014]
There is also no need to add nitrogen or water vapor to reduce the emission value accordingly. This has the advantage in particular that a reduction in the efficiency of the entire gas turbine plant associated with dilution by the addition of nitrogen or steam is avoided.
[0015]
The burner of the present invention configured to carry out the method of the present invention can also be regarded as an extension of the double burner described in the published German Patent Application No. 19547913 mentioned above, and According to the invention, in addition to the fuel supply system for natural gas and liquid fuel, it has a third fuel supply system for injecting medium calorie fuel or low calorie fuel into the swirling flow generator. Yes. Particularly preferably, the injection nozzle is open through the swirl flow shell plate of the swirl flow generator in the vicinity of the region of the central spray nozzle for injecting liquid fuel into the swirl flow generator. The medium-calorie fuel or the low-calorie fuel is injected into the inside of the rotational flow generator by the injection nozzle. The injection of medium or low calorie fuel is effected axially and / or coaxially with respect to the liquid fuel inlet or with respect to the axis of symmetry of the rotational flow generator.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
The burner shown in FIG. 1 comprises a swirl flow generator 1 and a mixing section 2 connected to the swirl flow generator 1 in the flow direction. The whirling flow generator 1 is a conical structure that is loaded several times in the tangential direction by a combustion air stream 3 (see FIG. 2) flowing in the tangential direction. Details of the flow shaping and configuration of the swirl flow generator 1 and the flow movements that can be generated by the shape of the swirl flow generator 1 are shown in FIGS. Since the description is based on 5, the description is omitted here. Further, the configuration of the mixing section 2 bordering on the vortex generator 1 is not an object of the present invention, but the mixing section 2 includes a transition piece 21 having a plurality of transition passages 22 and a transition piece 21. The mixing tube 23 is in direct contact. These burner components are only mentioned to clarify the burner unit that supplies the fuel necessary for the combustion process.
[0018]
An injection nozzle 4 for injecting liquid fuel into the inside of the rotational flow generator 1 is provided at the axial center of the upper region of the rotational flow generator 1 formed in a conical shape. A plurality of supply conduits 5 (see arrows) are provided on the same axis around the injection nozzle 4 for supplying medium calorie fuel, and the supply conduits pass through the rotational flow generating shell shell plates 6 and 7. Yes. In addition to the air flow (not shown) formed inside the swirl flow generator 1, medium-calorie fuel finely distributed through a plurality of suitable injection nozzles 8 is swung in the axial or coaxial direction. It reaches into the dynamic flow generator 1 and mixes with the air flow.
[0019]
Similarly, a plurality of supply passages 9 for gaseous fuel are provided, and the gaseous fuel is supplied from the outside in the tangential direction together with the combustion air flow into the rotational flow generator 1 (see FIG. 2). .
[0020]
In contrast to the prior art, the additional coaxial supply of medium calorie fuel enhances the axial component of the flow and the flow passes in particular through the transition piece 21 formed with the transition passage 22 and the mixing tube 23. After that, based on the strengthened axial component, in the case of a known double burner, a so-called “rotating flow collapsed body” (backflow) formed in the region of the combustion chamber 10 in the immediate vicinity of the mixing tube 23. Bubble) will be blown out regularly.
[0021]
The most effective supply of medium calorie fuel is particularly advantageously formed coaxially in the swirl flow generating shell shells 6, 6 ', 7, 7' as shown in FIG. This is done by the fuel nozzle orifice 8. The medium calorie fuel is injected through one or a plurality of nozzles per rotational flow generating shell shell plate.
[0022]
An injection nozzle 4 for liquid fuel is provided at the axial center of the rotatory flow generator 1 constructed in accordance with the present invention shown in a cross-sectional view in FIG. 2, and a plurality of rotations are performed by distributing the angle around the injection nozzle. Flow generating shell shell plates 6, 6 ', 7, 7' are arranged. A combustion air flow 3 is introduced tangentially into the inside of the swirl flow generator 1 between the adjacent swirl flow generating shell shell plates, the combustion air flow having a supply passage having a plurality of suitable inlet nozzles. 9 is mixed with natural gas. In the illustrated example, the vortex generating shell shell plates 6, 6 ', 7, 7' are pierced by one nozzle orifice 8 for medium calorie fuel injection. Depending on the application, it is possible to provide a plurality of nozzle orifices 8 for each shell shell plate of the swirling flow generator, so that the coaxial supply amount of medium calorie fuel toward the burner can be varied over a wide range. is there.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of a burner constructed according to the present invention.
FIG. 2 is a schematic cross-sectional view of a whirling flow generator having an MBtu fuel injection section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating flow generator, 2 Mixing zone, 3 Combustion air flow, 4 Injection nozzle for liquid fuel, 4 'Conical liquid fuel column, 5 Supply conduit for medium calorie fuel, 6, 6', 7, 7 ′ Rotating flow generating shell shell plate, 8 Nozzle or nozzle orifice for medium calorie fuel injection, 9 Supply passage for gaseous and / or liquid fuel, 10 Combustion chamber, 21 Transition piece, 22 Transition passage, 23 Mixing tube

Claims (9)

Gas in a burner with a swirl flow generator (1) which atomizes liquid fuel in the form of a conical liquid fuel column (4 ') surrounded by a swirling combustion air stream flowing in tangentially In a method of burning fuel in the form, liquid as well as medium or low calories,
In addition to injecting gaseous and / or liquid fuel into the swirling combustion air stream (3) flowing in the tangential direction into the swirling flow generator (1), the swirling flow generator (1) A medium flow or low calorie fuel is injected only axially and / or coaxially along the burner axis by means of at least one injection means (8) arranged inside the rotary flow generator (1) The premixed combustion is performed by mixing the injected medium calorie fuel or low calorie fuel with the liquid and gaseous fuel and the combustion air stream (3) upstream of the region of the injection nozzle for liquid fuel. A method for burning gaseous, liquid as well as medium or low calorie fuel in a burner, characterized in that it is produced.   The process according to claim 1, wherein the medium or low calorie fuel is injected without dilution, i.e. without adding additives such as nitrogen and / or water vapor. The flow field consisting of fuel and combustion air flow (3) extending axially in the burner has a large axial flow component so as to reduce or avoid the risk of flashback. Or the method of 2 . The method according to any one of claims 1 to 3 , wherein the medium calorie fuel or the low calorie fuel is collected as a gas by gasification of petroleum or heavy oil. A swirl flow generator (1) for combustion air flow (3) and means for injecting fuel and a shaft into the swirl flow generator (1) in the form of a conical liquid fuel column (4 ') Tangentially injected into the swirl flow generator (1) together with at least one first injection device (4) for liquid fuel sprayed in the direction and the combustion air flow (3) A heat generator for carrying out the method according to any one of claims 1 to 4 , comprising at least one second injection device (9) for gaseous and / or liquid fuels. In the burner, the medium calorie fuel or the low calorie fuel is swirled in the swirling flow generator (1) only in the axial direction and / or the coaxial direction along the burner axis toward the liquid fuel column (4 '). It is characterized in that at least one third injection device (8) for injecting into the dynamic flow generator (1) is provided. That, the burner of the heat generation dexterity. The burner according to claim 5 , wherein the third injection device (8) is provided in the swirl flow generator (1) immediately downstream of the first injection device (4). Gyratory flow generator (1) is made of individual gyrating flow generation shell shell plate for the medium-calorie fuel or low calorie fuel is bubbler (6,6 ', 7,7'), according to claim 5 or 6. Burner according to 6 . The burner according to claim 7 , wherein one or a plurality of third injection devices (8) are provided for each swirl flow generating shell shell plate. 9. Burner according to any one of claims 5 to 8 , wherein the third injection device (8) has at least one nozzle outlet for finely distributing fuel.

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