JPH06272828A - Ignition gas burner - Google Patents

Abstract

PURPOSE:To prevent the occurrence of combustion instability to an ignition gas burner by a method wherein secondary air freed from mixture of boiler exhaust gas and air freed from mixture of boiler exhaust gas from a seal fan are fed to a combustion part formed externally of the tip part of a fuel gas nozzle pipe. CONSTITUTION:During the starting of a boiler, air discharged from a forced blower and a part of secondary air A, generated through mixture of air discharged from a forced blower and exhaust gas are introduced in a space 45 formed between outer and inner cylinders 23 and 24 through a duct 37. Air A3 for combustion from a seal fan 46 is introduced in the inner cylinder 24 through a duct 40. Fuel gas F is fed in a fuel gas nozzle pipe 27 and through energization to a high voltage cable 28 for ignition of an ignition device 31, sparks are sparked from an ignition plug 29. Thereby, since combustion gas F is burnt and a necessary amount of oxygen of given density can be ensured, combustion is carried out in a stable state.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ignition gas burner.

[0002]

2. Description of the Related Art An example of a general boiler will be described with reference to FIG. 3. Reference numeral 1 denotes a boiler body, which includes a furnace 2 and a rear heat transfer section 3, and a side wall 4 connecting the furnace 2 and the rear heat transfer section 3. ing.

Reference numeral 5 denotes a plurality of burner units arranged in front of the furnace 2 of the boiler body 1, each having a main burner 6 and an ignition gas burner 7 as shown in FIG.

Reference numeral 8 is a wind box for supplying the secondary air A ₂ to each burner unit 5, and 9 is a high pressure blower 10.
A duct for connecting the exhaust box G to the wind box 8; a duct 11 for feeding the exhaust gas G discharged from the rear heat transfer section 3 of the boiler body 1; a tube 12 arranged in the middle of the duct 11 for passing the exhaust gas G through the chimney 13. Induction fan that sends air into the atmosphere 1
Reference numeral 4 denotes an exhaust gas circulation duct, one end of which is connected to the middle portion of the duct 11 and the other end of which is connected to the outlet side of the high pressure blower 10 of the duct 9, and which is provided with an exhaust gas circulation fan 15 at the middle portion. In the figure, reference numeral 21 is a heat shield plate forming the outer wall of the wind box 8.

In the above-mentioned boiler, during normal operation, the air A ₁ is fed into the duct 9 by the high pressure blower 10 and the exhaust gas G fed through the exhaust gas circulation duct 14 by the exhaust gas circulation fan 15 is discharged. Part of duct 9
Is introduced into, slightly lower (approximately 15%) of the oxygen concentration by partially mixing air A ₁ and the exhaust gas G secondary air A ₂ is generated, the generated secondary air A ₂ is through the duct 9 Installed in the wind box 8
Is supplied to the inlet of the ignition gas burner 7 as shown by the arrow, and is injected into the furnace 2 through the ignition gas burner 7 together with the fuel, and at the same time, is ejected from the periphery of the main burner 6 and the ignition gas burner 7 into the furnace 2. Combustion gas is generated by burning the fuel, and the combustion gas heats the water in the boiler body 1 while passing through the secondary side wall 4 and the rear heat transfer section 3 from the furnace 2 to generate steam, and the rear heat transfer section 3 From the exhaust gas G to the exhaust gas duct 11 and a part of the exhaust gas G is introduced into the exhaust gas circulation duct 14 as described above, but the remaining exhaust gas G is sent from the duct 11 to the chimney 13 by the transparent draft fan 12. Is discharged into the atmosphere.

By mixing a part of the exhaust gas G into the air A ₁ , the oxygen concentration of the secondary air A ₂ becomes low, so that the combustion gas in the furnace 2 does not reach a high temperature and NO _x is generated. The amount can be suppressed.

On the other hand, when the boiler is started from the stopped state, after the ignition gas burner 7 of the burner unit 5 is ignited, the main burner 6 is ignited by the ignition gas burner 7, but the fuel gas injected from the ignition gas burner 7 is ignited. A predetermined concentration of oxygen is required to maintain the combustion state of.

[0008]

However, when the secondary air A ₂ having a low oxygen concentration is used for combustion of the fuel gas from the ignition gas burner 7, the amount of oxygen becomes insufficient and the ignition gas burner 7 disappears. It may be difficult to achieve stable combustion.

Therefore, in order to supply a sufficient amount of oxygen to the ignition gas burner 7, as shown by the chain double-dashed line in FIG. 3, the duct 9 is located downstream of the connection part of the high pressure blower 10 and the connection part of the exhaust gas circulation duct 14. The branch duct 16 is connected to the upstream side of the branch duct 16 so that the air A ₁ containing no exhaust gas G extracted from the branch duct 16 is used as combustion air for the ignition gas burner 7.
However, it is difficult to lay the branch duct 16 up to the ignition gas burner 7, and the branch duct 16 needs to be bent many times in the middle, resulting in a high pressure loss, and thus the high-pressure blower 10 It is necessary to increase the power of, and there is a risk that waste will increase.

For this reason, conventionally, the high-pressure ventilator 10 is left as it is and a dedicated fan is provided. However, since an extra device is required, the equipment cost and the operation and maintenance cost are high.

In view of the above situation, the present invention sends a required amount of air having a sufficient oxygen concentration to an ignition gas burner with a simple device,
The purpose is to prevent combustion instability from occurring in the ignition gas burner.

[0012]

SUMMARY OF THE INVENTION The present invention is directed to a fuel gas nozzle tube for injecting fuel gas from the tip, an ignition device for igniting the fuel gas injected from the fuel gas nozzle tube, and the tip of the fuel gas nozzle tube. Secondary air feeding means for feeding secondary air mixed with boiler exhaust gas to the combustion section formed outside, and air without mixing the boiler exhaust gas from the seal fan to the combustion section as combustion air. It is provided with a combustion air feeding means for feeding.

[0013]

When the fuel gas is combusted, the air not mixed with the boiler exhaust gas sent from the seal fan is supplied to the combustion section as combustion air in addition to the secondary air mixed with the boiler exhaust gas. The amount and concentration of oxygen required for stable combustion are secured.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The ignition gas burner 7 of FIG. 1 is an embodiment of the present invention.

The heat shield plate 2 forming the wind box 8
1, an outer cylinder 23 having an opening 23a at the front end of the furnace is horizontally arranged, and an inner cylinder 24 having an opening 24a at the front end is fitted concentrically in the outer cylinder 23. A gland packing 25, which is fitted over the inner cylinder 24, is fitted inside the end portion, and the inner cylinder 24 is attached to the outer cylinder 23 at a required interval in the circumferential direction between the outer cylinder 23 and the inner cylinder 24. A plurality of support members 26 to be supported are inserted.

A fuel gas nozzle pipe 27 is inserted into the inner cylinder 24 in parallel with the inner cylinder 24, and the high voltage ignition cable 2 is used.
8 and the guide tube 30 in which the spark plug 29 is stored is inserted,
High-voltage cable 28 for ignition, spark plug 29, and guide tube 30
The ignition device 31 is formed by, and the tip end side (furnace side) of the fuel gas nozzle pipe 27 and the guide pipe 30 is fitted into the inner cylinder 24,
The diffuser plate 33, which is fixed and has the combustion air injection hole 32 formed therein, penetrates and is fixed to the tip end portion and the outer peripheral portion of the fuel gas nozzle pipe 27, which project forward from the diffuser plate 33. The fuel gas injection holes 34 and 35 are provided, and an opening 36 is provided at the tip of the guide tube 30 on the diffuser plate 33 side so that sparks can spark toward the fuel gas.

Secondary air A _{2 having} a low oxygen concentration from the duct 9 shown in FIG. 3 is placed at a required position in the wind box 8 of the outer cylinder 23.
Is connected to the duct 37 so that the end thereof opens into the wind box 8, and a damper 39 whose opening can be adjusted by a handle 38 installed outside is housed in the duct 37. .

A duct 40 adapted to allow a part of the combustion air A ₃ from the seal fan 46 to be introduced is connected to a portion of the inner cylinder 24 projecting rearward of the outer cylinder 23.
A damper 42 whose inside can be adjusted by a handle 41 installed outside is housed therein. Seal fan 46
Is a fan that is conventionally equipped to supply the seal air to the boiler instrumentation equipment through the duct 47, and it is necessary to supply the combustion air A ₃ of the ignition gas burner 7 as well. Needs to be slightly larger.

Further, a main burner 6 is installed in the vicinity of the ignition gas burner 7 shown in FIG. 1 as shown in FIG. 4 so that the main burner 6 can be ignited by the ignition gas burner 7 after ignition of the ignition gas burner 7.

In the figure, 43 is a packing pressing lid, 44
Is a lid attached to the rear end of the inner cylinder 24, 45 is a space formed between the outer cylinder 23 and the inner cylinder 24, and F is a fuel gas such as LPG.

In the ignition gas burner 7, the opening degree of the dampers 39, 42 is adjusted via the handles 38, 41 during the trial run so that the combustion air amount and oxygen concentration in the combustion section X on the tip side of the ignition gas burner 7 are ignited. The gas burner 7 is adjusted in advance so that the flame does not go out.

At the time of starting the boiler, the high pressure ventilator 10 discharges air.
Air A released₁Generated by mixing the exhaust gas G with the secondary
Air A₂Part of the outer cylinder 23 and the inner cylinder 2 through the duct 37.
4. Introduce into space 45 formed between 4 and seal
Combustion air A from the fan 46₃Through duct 40
It is introduced into the inner cylinder 24, and the fuel gas is supplied to the fuel gas nozzle pipe 27.
F to feed the ignition high voltage cable 28 of the ignition device 31.
Electricity is applied to spark from the spark plug 29. this
Therefore, the secondary air A₂From the space 45 to the fuel gas nozzle tube 2
To the combustion section X outside the tip of 7 and the combustion air A₃Is
From the inner cylinder 24 through the combustion air injection hole 32 to the combustion section
Further, in X, the fuel gas F has the fuel gas injection holes 34 and 35.
And the fuel gas F
And air A ₂, A₃Sparks from the spark plug 29 are released into the mixed gas of
The fuel gas F is ignited and ignites, and the fuel gas F burns.
Air A₂, A₃Oxygen concentration of combustion air formed by mixing
The degree is about 17%.

Fuel gas nozzle tube 27 of ignition gas burner 7
In the portion of the fuel gas F injected from the secondary air A _{2 having} a low oxygen concentration mixed with the exhaust gas G shown in FIG. 3, normal air not mixed with the exhaust gas from the seal fan 46 is used for combustion. Since it is sent as the air A ₃ , a required amount of oxygen of a predetermined concentration can be secured, and therefore the combustion of the fuel gas F is performed stably and does not disappear during operation.

After the ignition gas burner 7 is ignited, fuel is injected from the main burner 6 shown in FIG. 4, and the fuel injected from the main burner 6 is ignited.

The ignition gas burner 7 of FIG. 2 is another embodiment of the present invention. In this embodiment, the outer cylinder 23 of FIG. 1 is eliminated and the duct 37 is replaced by the fuel gas nozzle pipe 27 and the ignition device 31.
This is an example in which it is directly connected to the tube 24b in which

In the case of such a construction, both the combustion air A ₃ from the seal fan and the secondary air A ₂ mixed with a part of the exhaust gas of the boiler pass through the inside of the cylinder 24b and the combustion air injection hole 32. The fuel gas F is ejected from the fuel cell to the combustion section X and the fuel gas F is combusted. Thus, also in this case, in addition to the secondary air A ₂ in which a part of the exhaust gas G of the boiler shown in FIG. 3 is mixed, the air from the seal fan is also jetted to the combustion section X as the combustion air A _3. Therefore, a required amount of oxygen having a predetermined concentration can be secured, and stable combustion can be performed. In this case it is necessary the secondary air A ₂ is slightly higher than the pressure of the pressure of secondary air A ₂ of the combustion air A ₃ so as not to flow back into the sealed fan 46.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0029]

According to the ignition gas burner of the present invention, it is possible to supply, as the combustion air, not the secondary air containing the exhaust gas but also the air not containing the exhaust gas without providing a dedicated fan. Therefore, there is no risk of running out of oxygen during operation, the flame does not disappear, and therefore a stable combustion state can be secured, and the equipment cost is low, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of an ignition gas burner of the present invention.

FIG. 2 is a vertical sectional view of another embodiment of the ignition gas burner of the present invention.

FIG. 3 is a general air system diagram of a boiler.

FIG. 4 is a plan view of a burner unit including an ignition gas burner and a main burner.

[Explanation of symbols]

23 Outer Cylinder (Secondary Air Supplying Means) 24 Inner Cylinder (Combustion Air Supplying Means) 24b Cylinder (Combustion Air Supplying Means, Secondary Air Supplying Means) 27 Fuel Gas Nozzle Pipe 31 Ignition Device 32 Combustion Air Injection hole (combustion air feeding means) 37 Duct (secondary air feeding means) 39 Damper (secondary air feeding means) 40 Duct (combustion air feeding means) 42 Damper (combustion air feeding means) 45 Space (Secondary Air Supplying Means) 47 Secondary Air Inlet 48 Burner Throat F Fuel Gas A ₂ Secondary Air A ₃ Combustion Air G Exhaust Gas (Boiler Exhaust Gas) X Combustion Part

Claims (1)

[Claims] 1. A fuel gas nozzle tube for injecting fuel gas from a tip portion, an ignition device for igniting fuel gas injected from the fuel gas nozzle tube, and a combustion section formed outside the tip portion of the fuel gas nozzle tube. Secondary air feeding means for feeding the secondary air mixed with the boiler exhaust gas, and the combustion air feeding for feeding the air not mixed with the boiler exhaust gas from the seal fan to the combustion section as combustion air An ignition gas burner, characterized in that it comprises means.