KR20200090512A - Pilot burner for large size burner - Google Patents

Abstract

The object of the present invention is to provide a pilot burner for a large burner, which stably implements ignition of a mixed gas and formation and maintenance of a flame under various operating conditions that can occur in the large burner. The pilot burner for a large burner according to an embodiment of the present invention includes: a supply nozzle that is installed on one side of a duct burner and supplies fuel; and a plasma ignition device that is installed in the chamber of the burner adjacent to the supply nozzle, and continuously supplies an arc jet formed by plasma discharge to a mixture of fuel injected to the front of the supply nozzle and supplied combustion air to ignite the mixture to form and maintain a flame.

Description

Pilot burner for large burners {PILOT BURNER FOR LARGE SIZE BURNER}

The present invention relates to a pilot burner for a large burner, and more particularly, to a pilot burner for a large burner that stably implements ignition of flame and maintenance of flame under various operating conditions that may occur in a large burner.

It is known that a coal-fired boiler performs ignition by a duct burner while supplying fuel (coal), and uses a pilot burner that uses gaseous or liquid fuel to ignite the duct burner. The pilot burner ignites a mixture of fuel and air supplied. After ignition, continuous combustion proceeds by the supplied fuel and air.

When operating a large burner, in some cases, a supply amount of fuel or a composition of fuel may be changed, or a relative amount of air may be changed. In this case, the large burner has a risk of fire due to unstable flame.

For example, a conventional pilot burner is ignited by supplying fuel and air (oxygen) to an ignition source such as a spark. And the ignition of the pilot burner ignites the mixed gas of fuel and air supplied through the supply nozzle.

The pilot burner applies a spark ignition method, and generates sparks in the range of several Hz depending on the spark ignition method. And the mixed gas of the supplied fuel and air may not be constantly supplied in a uniform state.

In this case, the discontinuous spark in the range of several Hz causes ignition instability depending on the supply conditions of the mixed gas mixed with fuel and air supplied non-uniformly. In addition, since the spark length is within a range of several mm, the probability of ignition of the mixed gas is low, and the time required from ignition to ignition is lengthened.

For example, a pilot burner of a thermal power plant must generate a flame maneuver within a few seconds (eg, 10 seconds) to generate a temperature rise, which may not satisfy these maneuvering conditions and cause ignition failure.

An object of the present invention is to provide a pilot burner for a large burner that stably implements ignition of a mixture (mixed gas), formation and maintenance of a flame under various operating conditions that may occur in a large burner.

An object of the present invention is to provide a pilot burner for a large burner which forms a continuous high temperature mixture (mixed gas) ignition condition in long (several cm) by continuous discharge of an arc jet by plasma discharge.

A pilot burner for a large burner according to an embodiment of the present invention is installed on one side of a duct burner to supply fuel and is installed in a chamber of the burner adjacent to the supply nozzle and injected in front of the supply nozzle And a plasma ignition device that continuously supplies an arc jet formed by plasma discharge to a mixture of fuel and supplied combustion air to ignite the mixture to form and maintain a flame.

The temperature of the arc jet can be maintained in the range of 400 ~ 1500 ℃.

The length of the arc jet may be maintained in the range of 1 to 9 cm.

The plasma ignition device supplies a discharge gas and pushes the generated high voltage discharge to a supplied discharge gas to generate a plasma, and is connected to the plasma generation unit to eject the plasma pushed out of the plasma generation unit. It may include an arc jet generator forming an arc jet.

The supply nozzle may include a one-fluid nozzle installed in the chamber to supply fuel, and a combustion air passage for supplying combustion air supplied to the blower to the outer periphery of the one-fluid nozzle.

The supply nozzle is installed in the chamber to supply fuel to an internal fuel pipe and to supply air for fuel injection to an air pipe provided outside of the fuel pipe, and a reason for supplying air for fuel injection, and combustion air supplied to a blower. It may include a combustion air passage to the outer periphery of the sieve nozzle.

The plasma ignition device may be installed in the chamber to spray the arc jet in front of the supply nozzle.

The injection direction of the arc jet may intersect at an angle θ set in the injection direction of the mixture.

The arc jet may be injected at a position spaced apart by a predetermined distance L from the tip of the supply nozzle.

The plasma ignition device is electrically grounded, and a discharge gas is introduced, a housing installed in the chamber, and an electrode installed inside the housing to form a discharge gap between the inner circumferential surface of the housing and an electrode to which a driving voltage is applied. It can contain.

The housing supplies a discharge gas between the electrodes and pushes the generated high voltage discharge to the discharge gas to generate plasma, and gradually decreases in space from the position corresponding to the end of the electrode toward the supply direction, and the It may include a jet forming passage to form the arc jet by ejecting the plasma being pushed connected to the space.

The space is formed by a first distance (L1) for generating the plasma by pushing with the discharge gas, and the jet forming passage is formed at a second distance (L2) with a minimum diameter of the space at the tip of the space, and The second length L2 may be set to 0.5 to 10 (L2=(0.5 to 10.0)*L1) of the first length L1.

The jet forming passage may be formed of a cylinder of the same diameter throughout the second length range.

The jet forming passage may be formed with a diameter that is formed to be the largest diameter on the space side to have a variable diameter throughout the second length range and gradually decreases as the discharge gas is moved in a pushing direction.

The supply nozzle and the plasma ignition device may be used to ignite a boiler combustion chamber for coal-fired power generation or a boiler combustion chamber for gas turbine power generation.

The space and the jet forming passage may have a spiral groove on an inner surface.

According to an embodiment of the present invention, a plasma ignition device is installed on one side of a supply nozzle to continuously supply an arc jet formed by plasma discharge, so that a flame can be stably formed quickly and stably in a pilot burner, which can be generated in a combustion chamber of a large burner. It is possible to stably implement the ignition of the fuel/air mixture (mixed gas), the formation of a flame, and the maintenance of the flame under operating conditions (eg, fuel/air mixing conditions and heat supply conditions).

According to an embodiment of the present invention, a plasma ignition device continuously discharges an arc jet by plasma discharge to form a long (1 to 9 cm) ignition condition of a continuous high temperature (400 to 1500° C.), so that it may occur in a large burner. It is possible to stably implement flame formation and flame retention by igniting the flame on the pilot burner stably under various operating conditions.

1 is a partial cross-sectional view of a pilot burner for a large burner according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the plasma ignition device applied to the ignition device of FIG. 1.
3 is a cross-sectional view of a plasma ignition device applied to a pilot burner for a large burner according to a second embodiment of the present invention.
4 is a partial cross-sectional view of a pilot burner for a large burner according to a third embodiment of the present invention.
5 is a cross-sectional view of a plasma ignition device applied to a pilot burner for a large burner according to a fourth embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and the same reference numerals are attached to the same or similar elements throughout the specification.

1 is a partial cross-sectional view of a pilot burner for a large burner according to a first embodiment of the present invention. Referring to FIG. 1, the pilot burner 1 for a large burner of the first embodiment includes a supply nozzle 10 and a plasma ignition device 20. For example, the supply nozzle 10 and the plasma ignition device 20 are used for ignition of a combustion chamber of a coal-fired power generation boiler or a gas turbine power generation boiler.

The supply nozzle 10 is installed in one chamber 30 of the ignition duct burner connected to the combustion chamber of a large-scale power generation boiler of several tens of MW or more and is configured to supply a mixture of fuel and air (including mixed gas).

The plasma ignition device 20 is installed in the chamber 30 of the burner adjacent to the supply nozzle 10, and is formed by plasma discharge in a mixture of fuel and air (including mixed gas) injected in front of the supply nozzle 10 It is formed to continuously and continuously supply the arc jet.

In the combustion chamber of a coal-fired boiler, the mixture is made of coal and air because the fuel is coal, and in the combustion chamber of a gas turbine-fired boiler, the mixed gas is a mixture of fuel and air because the fuel is liquid or gas. Is done. The mixture and the gas mixture are described in parallel.

Therefore, the arc jet AJ supplied from the plasma ignition device 20 ignites the mixture (mixed gas) to form and maintain the flame F in the chamber of the duct burner. For example, the temperature of the arc jet AJ is maintained in the range of 400 to 1500°C, and the length of the arc jet AJ is maintained in the range of 1 to 9 cm.

When the temperature of the arc jet AJ is less than 400° C., the ignition of the mixture (mixed gas) may fail depending on the operating conditions in the chamber 30 and the conditions of the mixture (mixed gas). The ignition device 20 and the chamber 30 may be thermally damaged.

If the length of the arc jet (AJ) is less than 1 cm, the arc jet (AJ) may not reach the mixture (mixed gas) and ignition may fail. If it is more than 9 cm, the operating cost for the plasma ignition device 20 increases. And structural damage due to excessive power.

When the temperature of the arc jet (AJ) is 400 to 1500°C, and the length of the arc jet (AJ) is 1 to 9 cm, ignition of the mixture (mixed gas) is stably performed, and the flame (F) in the chamber 31 is achieved. The formation and maintenance of the material is stably implemented, mechanical damage is prevented, and economic efficiency can be improved.

FIG. 2 is a cross-sectional view of the plasma ignition device applied to the ignition device of FIG. 1. 1 and 2, the plasma ignition device 20 includes a plasma generation unit 201 and an arc jet generation unit 202.

The plasma generation unit 201 generates a high voltage discharge by supplying a discharge gas, generates a plasma P while being pushed by the supplied discharge gas, and supplies the plasma P to the arc jet generation unit 202.

The arc jet generation unit 202 is connected to the plasma generation unit 201 and is an arc point anchored in the plasma generation unit 201 and the jet jet of the excitation state plasma P of high temperature conditions formed thereby. (AJ).

The ejected arc jet AJ is supplied to the fuel/air mixture (mixed gas) supplied from the supply nozzle 10 to ignite the mixture (mixed gas) to form a flame (F), and the formed flame (F) Is kept in the chamber 30. That is, the arc jet AJ forms a flame F and stably implements the maintenance of the formed flame F.

Specifically, in the pilot burner 1 for a large burner, the supply nozzle 10 includes an air pipe 11, a fuel pipe 12, and a mixing pipe 13. The air pipe 11 is installed in the chamber 30 and supplies air for fuel injection into the chamber 30.

In the case of a liquid fuel such as light oil, the fuel pipe 12 is installed inside the air pipe 11. The supply nozzle 10 is formed of an air spray nozzle that supplies air for fuel injection through the air pipe 11 and fuel through the fuel pipe 12 together, and fuel and air into the interior of the chamber 30 A mixture of (mixed gas) is supplied.

The pilot burner 1 for a large burner is provided with a combustion air passage 31 that supplies combustion air to the chamber 30. Therefore, air for combustion is supplied to the mixture (mixed gas) inside the chamber 30 through a blower (not shown).

Since the mixing tube 13 is formed to expand in front of the air tube 11, air and fuel injected by air supplied for injection are mixed in a wider area than the air tube 11, and the mixture (mixed gas) is mixed in the chamber 30 ).

The plasma ignition device 20 is installed in the chamber 30 to spray the arc jet AJ generated and ejected in the front of the mixing tube 13. The injection direction of the arc jet AJ is inclined to intersect at an angle θ set in the injection direction of the mixed gas. Therefore, the injected arc jet AJ can be effectively ignited while being in contact with the injected fuel and air mixture (mixed gas).

And the arc jet AJ is injected at a position spaced apart by a set distance L from the tip of the mixing tube 13. The arc jet AJ is injected into a mixture (mixed gas) in a state in which fuel and air are sufficiently mixed in front of the mixing tube 13 to realize ignition of the mixture (mixed gas).

The plasma ignition device 20 is electrically grounded, and a housing 21 for introducing a discharge gas, and an electrode to form a discharge gap G between the inner circumferential surface of the housing 21 and to which a driving voltage HV is applied ( 22).

The housing 21 includes a space 211 that gradually decreases from a position corresponding to the end of the electrode 22, and a jet formation passage 212. In addition, the housing 21 is elongated to form a passage 213 connected to the space 211 and is installed in the chamber 30, and the passage 213 is discharge gas in the discharge gap G and the space 211. It is possible to stably supply.

The electrode 22 is installed in the passage 213 inside the housing 21 through the insulating member 23, and the insulating member 23 is provided with a supply passage 231 for distribution of supplied air, and high temperature It can be formed of refractory materials that withstand the environment.

The space 211 of the housing 21 supplies the discharge gas to the discharge gap G between the electrodes 22, and pushes the high voltage discharge generated in the discharge gap G to the supplied discharge gas to push the plasma P ). The jet forming passage 212 is connected to the space 211 to allow the arc jet AJ to be formed due to the ejection of the plasma P being pushed.

The space 211 is gradually narrowed and is formed at a first distance L1 to push the discharge gas to generate plasma P. That is, in the discharge gap G, the discharge gas is discharged by a high voltage, and the plasma P is formed by the supplied discharge gas, pushed by the first distance L1, and the plasma P is supplied to the jet formation passage 212. do.

The jet forming passage 212 has a minimum diameter of the space 211 at the tip of the space 211 and is formed at a second distance L2. The second length L2 may be set to 0.5 to 10 (L2=(0.5 to 10.0)*L1) of the first length L1.

At this time, if the second distance (L2) is short and has a value less than the set length, the arc point is pushed out after the second distance (L2) space, and the arc point is generated outside the plasma ignition device (20) to stabilize the arc jet (AJ) Becomes a condition that cannot be formed.

In addition, when the second distance L2 is long and has a value exceeding the set length, the generated arc jet AJ is not discharged or is discharged to a length of 1 cm or less, which is difficult to ignite.

The jet forming passage 212 is formed as a cylinder of the same diameter throughout the second length (L2) range. At least the second length L2 is larger than the diameter φ of the jet forming passage 212. Therefore, the arc jet AJ is formed while the plasma P is discharged through the jet forming passage 212. That is, the arc jet AJ is discharged.

When the discharge gas is supplied, since the space 211 forms a contracted structure, the generated plasma P can be continuously formed without fluctuations in the inlet or space 211 of the jet forming passage 212. .

Since the plasma P is continuously formed, the arc jet AJ having a temperature of 400 to 1500°C can be continuously discharged according to the conditions of the driving voltage HV supplied by rapid heat transfer.

The arc jet AJ continuously discharged is injected into a mixture of fuel and air (mixed gas) supplied to the front of the mixing tube 13 to stably generate ignition of the mixture (mixed gas). The mixture (mixed gas) forms and maintains a flame (F).

Since the plasma ignition device 20 continuously supplies the arc jet AJ formed by plasma discharge, it is possible to stably implement flame formation and maintenance of the flame by ignition of the mixture (mixed gas) under various operating conditions in the chamber 30. Can.

For example, the operating conditions may include a mixture ratio of air and fuel for the operation of the pilot burner, and heat supply conditions to be supplied by a large burner.

3 is a cross-sectional view of a plasma ignition device applied to a pilot burner for a large burner according to a second embodiment of the present invention. Referring to FIG. 3, in the pilot burner for a large-sized burner in the second embodiment, the jet forming passage 312 of the plasma ignition device 220 is formed with a diameter that gradually decreases as it goes in the direction in which the discharge gas is pushed.

That is, the jet forming passage 312 has a variable diameter in the entire range of the second length L22, is formed as a first diameter φ1 at the space 211 side, and is formed as a second diameter φ2 at the end. That is, the second diameter φ2 is smaller than the first diameter φ1 of the jet forming passage 312. Therefore, as the plasma P is discharged through the jet forming passage 312, an arc jet AJ is formed.

The arc jet AJ forms a minimum diameter at the end of the jet forming passage 312 and is discharged. When the first diameter φ1 and the diameter φ are the same, the jet forming passage 212 of the first embodiment In comparison, the mixture (mixed gas) is sprayed deeper into the mixture (mixed gas) supplied to the front of the mixing tube 13 to ignite the mixture (mixed gas) more effectively.

Since the plasma ignition device 220 ignites even on the surface and deep portion of the mixture (mixed gas), it is possible to more stably implement the formation of the flame F and the maintenance of the flame.

4 is a partial cross-sectional view of a pilot burner for a large burner according to a third embodiment of the present invention. Referring to FIG. 4, in the pilot burner 4 for a large burner of the third embodiment, the supply nozzle 410 is formed of an airless spray nozzle that sprays and supplies fuel only, and supplies fuel to the interior of the chamber 30. To supply.

That is, the supply nozzle 410 includes a fuel pipe 412 and an expansion pipe 413. In the case of a liquid fuel such as light oil, the supply nozzle 410 supplies fuel through the fuel pipe 412, and diffuses fuel injected through the expansion pipe 413 in a wider area than the fuel pipe 412, so that the chamber ( 30) Supply inside.

The pilot burner 4 for the large-scale burner has a combustion air passage 31 that supplies combustion air to the chamber 30. Therefore, air for combustion is supplied to the mixture (mixed gas) inside the chamber 30 through a blower (not shown).

5 is a cross-sectional view of a plasma ignition device applied to a pilot burner for a large burner according to a fourth embodiment of the present invention. Referring to FIG. 5, in the pilot burner for the large-scale burner of the fourth embodiment, the space 511 and the jet forming passage 512 of the plasma ignition device 520 have a spiral groove on the inner surface.

The groove of the jet forming passage 512 rotates the flow of the ejected arc jet AJ, through which the arc point can be moved. That is, the groove of the jet forming passage 512 formed to be connected to the arc jet generation unit 502 and the plasma generation unit 501 is an arc jet generation unit 502 to the arc point anchored in the plasma generation unit 501 Moving to, thereby forming an arc jet (AJ) that rotates with the ejection of the excitation state plasma (P) of the high-temperature conditions to be formed.

Although preferred embodiments of the present invention have been described through the above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims and the description of the invention and the accompanying drawings. It is natural to fall within the scope.

1, 4: Pilot burners 10, 410: Supply nozzle
11: air pipe 12, 412: fuel pipe
13: mixing tube 20, 220, 520: plasma ignition device
21: housing 22: electrode
30: chamber 31: combustion air passage
201, 501: plasma generating unit 202, 502: arc jet generating unit
211, 511: Space 212, 312: Jet formation passage
213: passage 413: expansion tube
512: jet formation passage AJ: arc jet
F: Flame G: Discharge gap
HV: Driving voltage L: Distance
L1: First distance L2, L22: Second distance
P: Plasma θ: Angle
φ: diameter φ1, φ2: first, second diameter

Claims (16)

A supply nozzle installed on one side of the duct burner to supply fuel; And
It is installed in the chamber of the burner adjacent to the supply nozzle and continuously supplies an arc jet formed by plasma discharge to a mixture of fuel injected in front of the supply nozzle and supplied combustion air to ignite the flame by igniting the mixture. Plasma ignition device to form and maintain
Pilot burner for a large burner comprising a. According to claim 1,
The temperature of the arc jet
Pilot burner for large burners maintained in the range of 400~1500℃. According to claim 1,
The length of the arc jet is
Pilot burner for large burners maintained in the range of 1 to 9 cm. According to claim 1,
The plasma ignition device
A plasma generating unit that supplies a discharge gas and pushes the generated high voltage discharge to the supplied discharge gas to generate plasma; and
An arc jet generator connected to the plasma generator and ejecting the plasma pushed out of the plasma generator to form the arc jet
Pilot burner for a large burner comprising a. According to claim 1,
The supply nozzle
One fluid nozzle installed in the chamber to supply fuel, and
Combustion air passage for supplying the combustion air supplied to the blower to the outer periphery of the one-fluid nozzle
Pilot burner for a large burner comprising a. According to claim 1,
The supply nozzle
A reasoner nozzle installed in the chamber to supply fuel to an internal fuel pipe and to supply air for fuel injection to an air pipe provided outside the fuel pipe, and
Combustion air passage for supplying the combustion air supplied to the blower to the outer periphery of the dwarf body nozzle
Pilot burner for a large burner comprising a. The method of claim 5 or 6,
The plasma ignition device
A pilot burner for a large burner installed in the chamber to spray the arc jet in front of the supply nozzle. The method of claim 7,
The injection direction of the arc jet
Pilot burner for a large burner that crosses obliquely at an angle (θ) set in the injection direction of the mixture. The method of claim 7,
The arc jet
Pilot burner for a large burner that is injected at a position spaced apart by a distance (L) set at the tip of the supply nozzle. The method of claim 5 or 6,
The plasma ignition device
A housing which is electrically grounded, which discharges gas and is installed in the chamber, and
An electrode installed inside the housing to form a discharge gap between the inner circumferential surface of the housing and to which a driving voltage is applied
Pilot burner for a large burner comprising a. The method of claim 10,
The housing
A space that is gradually narrowed while supplying a discharge gas between the electrodes and pushing the generated high-voltage discharge to a discharge gas to be supplied to generate plasma and going from the position corresponding to the end of the electrode toward the supply direction, and
A jet forming passage connecting the space and ejecting the pushed plasma to form the arc jet
Pilot burner for a large burner comprising a. The method of claim 11,
The space
It is formed by a first distance (L1) for generating the plasma by pushing to the discharge gas,
The jet forming passage
It is formed at the tip of the space at a second distance (L2) with the minimum diameter of the space,
The second length (L2) is
A pilot burner for a large burner set to 0.5 to 10 (L2=(0.5 to 10.0)*L1) of the first length L1. The method of claim 12,
The jet forming passage
A pilot burner for a large burner formed of a cylinder of the same diameter throughout the second length range. The method of claim 12,
The jet forming passage
A pilot burner for a large burner that is formed to have a maximum diameter at the space side and has a diameter that gradually decreases as the discharge gas is pushed in a direction to have a variable diameter throughout the second length range. According to claim 1,
The supply nozzle and the plasma ignition device
Used for ignition of boiler combustion chamber for coal-fired power generation or boiler combustion chamber for gas turbine power generation
Pilot burner for large burners. The method of claim 11,
The space and the jet forming passage
Pilot burner for large burners with a spiral groove on the inner surface.

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