JPH08226621A - Method and equipment for supplying fuel to burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of feeding fuel and an apparatus thereof, which has wide range of use and low in NOx emission by stabilizing combustion at a burner. SOLUTION: A burner is structured by arranging a pilot gas conduit pipe 15 only at the zone of a burner head 13 and as a parallel hole 15 with at least one axis inside the inner wall 4 of a main gas pipe 2. As a result of this, a pilot gas 16 is fed into an inside burner chamber 10, separately from fuel 11 and a blower air 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner suitable for both liquid and gaseous fuels, in particular a double cone burner, also a method and an apparatus for supplying fuel to a burner used for the purpose of producing hot gas. It is about.

[0002]

Burners are generally used near the lean extinction limit in order to reduce NOx emissions as much as possible. Therefore, it goes without saying that the burner adjustment range is significantly limited. In order to eliminate this drawback, it is possible, for example, to stop some burners and keep the remaining burners operating within a stable range during partial load of the gas turbine. However, this makes the temperature distribution over the entire circumference inconvenient.

Another possibility of improving the burner adjustment range is to enrich the fuel gas with additional fuel near the axis. This is also called internal piloting.
In this case, the stable range of the burner is correspondingly extended by the supply of pilot gas, so that reliable operation is ensured under all load conditions. In particular, the internal piloting method has become widely used since the present annular fuel chamber.

German Patent Publication No. 430695
No. 6, it is known to supply fuel to a double cone burner which operates with both liquid and gaseous fuel. In the case of this burner, the atomization of the fuel oil is carried out by means of a so-called air blast nozzle arranged in the burner head, in other words by the blower air compressed by the coaxial feed. Therefore, the burner, in addition to the main gas passage and the pilot gas passage,
A liquid fuel flow path and a blower air flow path are provided. The liquid fuel flow passage, the blower air flow passage, and the pilot gas flow passage are all provided in a fuel lance that can be inserted into the main gas flow passage. The fuel lance is connected to the air blast nozzle and mounted in the burner head.

A disadvantage of this air blast nozzle is that the blower air is injected with the gaseous fuel even when using pilot gas. This is because atomization is unnecessary when using pilot gas. The addition of air makes the pilot gas flame unstable and lowers the lean extinction limit of the flame. For this reason, methods and devices have been developed that can control the blower air inflow into the burner interior. As a result, when operating with gaseous fuel, the inflow of blower air into the burner chamber is throttled, for example, by introducing pilot gas into the blower air. However, it has been found that this results in the pilot gas being pre-diluted, resulting in uneven mixing with the blower air. As a result, the combustion of the pilot gas is hindered, and the stability of the burner under partial load is reduced.

In the case of fuel supply to a double-cone burner via a fuel lance, for example in the method described in DE-A-4306956, the maximum diameter of the fuel lance is the dimension of the burner head. Stipulated by Therefore, in the case of a small double cone burner, a small fuel lance, that is, a fuel lance having a small diameter is required. However, if the known fuel lance becomes smaller in proportion to the burner, as a result, the flow rate of the blower air or the fuel air also decreases. When the air amount decreases, the NOx emission amount increases during combustion with light oil.

Known fuel lances have a number of functions and are therefore relatively expensive to manufacture and assemble. in addition,
The pilot gas flow path must be sealed to the main gas flow path. On the one hand, this measure is costly, and on the other hand, the main gas enters the pilot gas flow path and risks the burner becoming unstable.

[0008]

The present invention is intended to eliminate all of the above-mentioned drawbacks. An object of the present invention is to provide a burner suitable for both liquid and gaseous fuels, and a method and a device for supplying the fuel so that the use range is expanded and the NOx emission value is reduced. In addition, the device is easy to manufacture, easy to assemble and more reliable to operate.

[0009]

According to the invention, this object is achieved in the case of a device according to the preamble of claim 1.
This has been solved by accommodating only the blower air flow passage and the liquid fuel flow passage in the fuel lance, including the liquid fuel nozzle. Pilot gas conduits should only be placed in the area of the burner head. This conduit is constructed as at least one hole in the main wall of the main gas pipe which is axially parallel.

The pilot gas conduit is of this construction
Since it is no longer a component of the fuel lance, the blower air flow path is defined by the burner diameter, or burner head,
Furthermore, even if the diameter of the fuel lance does not change, it can be made larger in the radial direction. As a result, the blower air or the combustion air can be used in a larger amount for oil combustion, while the NOx emission amount is reduced.

For the same reason, the diameter of the blower air passage is
Even when using a small burner, and thus a burner with a correspondingly small fuel lance, a larger construction than before is possible. This also makes it possible to supply a larger amount of blower air or combustion air.

Due to the separation of the pilot gas conduits, the fuel lance, which consists solely of the liquid fuel flow path and the blower flow path, is now optimally configured according to its function and is also very simple to manufacture. In addition, the lance no longer needs to be sealed against the incoming main gas.

The main gas supply pipe and the main gas pipe, the pilot gas supply pipe and the axially parallel holes are all interconnected in a known manner inside a burner hood in a stoffschluessig manner. The pilot gas supply pipe is open upstream of the connecting portion between the main gas supply pipe and the main gas pipe.

Such a device can be realized relatively easily by the casting technique. For assembly, the pilot supply pipe is welded first, followed by the main gas supply pipe.

In the case of the double cone type burner, it is particularly advantageous when two holes parallel to the axis are provided in the inner wall of the main gas pipe. These holes take on the function of the pilot gas conduit in the area of the burner head. There is sufficient radial space in the inner wall to provide the holes so that the fuel head diameter remains constant compared to the solution with the pilot gas conduit extending into the fuel lance.

[0016]

When the burner is operating, the pilot gas is introduced into the burner inner chamber separately from the liquid fuel supplied by the fuel lance and the blower air. By spatially separating the introduction or blowing of the pilot gas and the blower air, an unequal mixture of both gases is prevented, and thus predilution of the pilot gas is also prevented. Therefore, more stable combustion becomes possible in the burner inner chamber, which naturally increases the stability of the burner at the time of partial load and expands the range of use thereof.

The supply of the pilot gas into the pilot gas passage and the supply of the main gas into the main gas pipe are performed in the burner hood, and the pilot gas is supplied upstream of the main gas.

[0018]

1 shows an embodiment of the invention in the form of fuel supply to a double-cone burner used in a gas turbine. In the drawings, only those elements necessary for understanding the present invention are shown. For example, the fuel supply to the fuel lance and the mounting in the gas turbine housing are not shown. The flow direction of the working medium is indicated by arrows.

The illustrated device comprises a burner 1 configured as a double-cone burner, the burner 1 and an annular main gas pipe 2 being joined in a material-connecting manner. The main gas pipe 2 is
It is formed by the outer wall 3 and the inner wall 4, and a main gas flow path 5 is provided between the both walls. A fuel lance 6 is detachably fixed to the inside of the main gas pipe 2, that is, inside the hollow chamber at the center thereof. The fuel lance 6 receives a liquid fuel flow passage 7 and a blower air flow passage 8 coaxial therewith. The fuel lance 6 opens into the burner inner chamber 9 via a liquid fuel nozzle 9 configured as an air blast nozzle. The fuel lance 6 is supplied with liquid fuel 11 and blower air 12 from an outer end (not shown).

In the double cone type burner 1, a burner head 13 is fixed to a burner hood 14. Main gas pipe 2
Two axially parallel holes are formed as pilot gas conduits 15 in the inner wall 4 of the. The hole 15 is the inner chamber 1 of the burner.
Serves to feed pilot gas 16 into the zero. In the case of another burner 1, this function can of course also be realized with a single hole 15 or with three or more axially parallel holes 15.

The main gas flow path 5 is joined to the main gas supply pipe 17 in a material-connecting manner, while the hole 15 has an annular chamber 18 therein.
Is also connected to a separate pilot gas supply pipe 19 in a material connection manner. These joinings are performed by welding corresponding components, for example. These joints are provided in the burner hood 14, and the pilot supply pipe 19 is opened upstream of the main gas supply pipe 17.

When the double cone type burner 1 is operated, the main gas 20 is directly introduced into the burner head 13, that is, the main gas passage 5 through the main gas supply pipe 17. From the flow path 5, the main gas 20 passes through a side opening of the burner 1 (not shown), flows into the burner inner chamber 10, and burns in the inner chamber 10 together with the pilot gas 16. For this purpose, pilot gas 16 is guided to the burner head 13 via a pilot gas supply pipe 19 and introduced into the two holes 15 in the burner hood 14. The injection of the pilot gas 16 into the burner chamber 10 takes place axially parallel to the liquid fuel 11 guided in the fuel lance 6, and in particular separately from the blower air 12. As a result, the pilot gas 16 reaches the inner chamber 10 without being diluted and can be stably burned there.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a double cone burner having a fuel lance.

[Explanation of symbols]

1 burner, 2 main gas pipe, 3 outer wall, 4 inner wall, 5 main gas flow passage, 6 fuel lance, 7 liquid fuel flow passage, 8 blower air flow passage, 9 air blast
Nozzle, 10 burner inner chamber, 11 liquid fuel, 1
2 blower air, 13 fuel, 14 burner hood, 15 pilot gas conduit, 16 pilot gas, 17 main gas supply pipe, 18 annular chamber, 19
Pilot gas supply pipe, 20 main gases

Claims (5)

[Claims] 1. A device for supplying fuel to a burner suitable for both liquid and gaseous fuels, in particular a double cone type burner, comprising: a) a main gas supply pipe (17) and a pilot gas supply pipe (19). ) Is provided, gaseous fuel from the outside is fed through these supply pipes, and is introduced into the burner inner chamber (10) through the burner head (13), and further, b) the burner (1) and materials. An annular main gas pipe (2) connected in a connection manner is provided, and the main gas pipe (2) includes an outer wall (3), an inner wall (4), and a main gas flow passage (5) located therebetween. And also in the area of the burner head (13) in order from outside to inside, the pilot gas conduit (1
5), blower air flow path (8) and liquid fuel flow path (7)
And c) a fuel lance (6) removably mounted inside the main gas pipe (2), the downstream end of which is a liquid fuel nozzle (9). Through the burner inner chamber (1
0) d) the fuel lance (6) consists only of a liquid fuel flow path (7) with a liquid fuel nozzle (9) and a blower air flow path (8), e ) The pyrodid gas conduit (15) is arranged only in the area of the burner head (13) and is configured as at least one axis-parallel hole in the inner wall (4) of the main gas pipe (2). A device that supplies fuel to the burner. 2. Main gas supply pipe (17) and main gas pipe (2)
And the pilot gas supply pipe (19) and the hole (15) parallel to the axis, both of which are known per se in the burner hood (1
4) are connected to each other in a material-connecting manner in the pilot gas supply pipe (19) and are connected to the main gas supply pipe (17).
Device according to claim 1, characterized in that it is open upstream of the. 3. An axially parallel hole (15) is formed in the inner wall (4) of the main gas pipe (2),
The device according to claim 2. 4. A method of supplying fuel to a burner (1) suitable for both liquid and gaseous fuels, in particular a double cone type burner, comprising: a) supplying fuel supplied from the outside to a fuel head (13).
To the inner chamber (10) of the burner via b) and b) in addition to the main gas (20), the pilot gas (1
6) is introduced into the burner (1), and c) the liquid fuel (11) is atomized by the blower air (12), d) the burner of the liquid fuel (11) and the blower air (12) The supply to the inner chamber (10) is effected by a fuel lance (6) in a manner known per se, while the pilot gas (16) is additionally introduced separately.
How to fuel a burner. 5. The supply of pilot gas (16) into the pilot gas supply pipe (19) and the supply of main gas into the main gas pipe (2) are carried out in a burner hood (14) known per se. Moreover, the pilot gas (16) is the main gas (20)
5. The method according to claim 4, characterized in that it is supplied upstream of the.