JP7078787B2 - Fuel gas nozzle and gas burner equipped with it - Google Patents

Description

The present invention relates to a fuel gas nozzle capable of uniformly diluting a fuel gas with diluted air and preventing the generation of soot, and a gas burner provided with the fuel gas nozzle.

Various gas burners have been conventionally developed. For example, the "burner tileless gas burner" of Patent Document 1 is a combustion air supply pipe having a circular inner surface provided at the rear with a combustion air supply port for supplying combustion air in a tangential direction, and the combustion air supply pipe. A fuel gas supply pipe arranged in the center and having a plurality of straight gas ejection holes at the tip and a plurality of radial gas ejection holes on the outer peripheral surface near the tip, and a first flange portion attached at right angles to the fuel gas supply pipe. The first and second flanges are composed of a cylinder portion that protrudes forward from the outer peripheral portion of the flange portion with the fuel gas supply pipe at a predetermined interval and a second flange portion provided at right angles to the tip of the cylinder portion. A stabilizer having a plurality of through holes parallel to the combustion air supply pipe and attached so that the second flange portion is located at substantially the same level as the radial gas ejection hole, and a stabilizer protruding in front of the stabilizer are provided. It is composed of an ignition plug and a combustor having an inner diameter larger than the diameter of the stabilizer, which is replaceably attached to the tip of the combustion air supply pipe.

In Patent Document 2, "heat storage type burner and its low NOx combustion method", a primary fuel nozzle is provided so as to be able to inject from around the flow of combustion air in the nozzle of combustion air, and the secondary fuel nozzle is provided. A flame-retaining mechanism including a flow path capable of supplying flame-retaining air from around the injected secondary fuel is provided at the spout at the tip of the pipe so as to be substantially parallel to the combustion air nozzle from a place different from the combustion air. It can be blown directly into the furnace.

Patent Document 2 states that the generation of soot can be prevented by mixing air of about 0.5 to 5% of the total air flow rate with the fuel.

The "Blast Burner Ventury Mixer Mixing Ratio Adjusting Device" of Patent Document 3 sucks low-pressure fuel gas into the venturi by the energy of the jet by ejecting pressurized air from the nozzle toward the venturi. In the venturi mixer of the blast burner that creates the air-fuel mixture, the fuel gas inlet that receives the suction force due to the ejection of pressurized air from the nozzle is composed of double inner and outer valve members, and both inner and outer valves. A gas control valve is provided in which the members are relatively movable in the axial direction, and a slit is formed in either the inner valve member or the outer valve member of the gas control valve along the relative movement directions of the two. Therefore, the suction gas amount can be adjusted by changing the gas passage area by the relative movement of the inner and outer valve members in the axial direction.

In Patent Document 4, "a premix burner for reducing the amount of nitrogen oxides generated", fuel gas supplied at low pressure by ejecting combustion air toward a venture mixer is sucked and mixed in the venture mixer for combustion. In the premix burner configured for this purpose, a valve for controlling the primary air for combustion to be ejected toward the venture mixer so that the air ratio at the outlet of the diffuser is 1.0 or less is provided in the combustion air supply system. , The secondary air supply system is branched from the air supply system part downstream of this control valve, and the insufficient combustion air is used as the secondary air, and it is configured to be ejected into the combustion chamber at a position downstream of the premixed mixed gas. ing.

The "burner combustion atmosphere control device" of Patent Document 5 is a burner combustion atmosphere control device that supplies combustion gas to a venturi mixer passing through air via a zero governor to obtain a mixed gas, and is an outlet side of the venturi mixer. The tip end side of the secondary pressure adjusting gas introduction pipe is connected to the mixing chamber of the above, and the secondary pressure adjusting valve is connected to the secondary pressure adjusting gas introduction pipe.

Japanese Patent No. 2944579 Japanese Unexamined Patent Publication No. 2006-308249 Jitsukaisho 51-3433 Gazette Jikkai Sho 54-98631 Jitsufuku No. 2-16139 Gazette

Patent Document 1 discloses a combustion air supply pipe provided with a combustion air supply port at the rear, and a gas burner in which a fuel gas supply pipe is arranged in the center of the combustion air supply pipe, and Patent Document 2 discloses fuel. Disclosed a fuel nozzle (fuel gas nozzle) that can be directly blown into the furnace from a place different from the combustion air by providing a flame holding mechanism including a flow path that can supply flame holding air from around the fuel ejected from the ejection port. However, although the configuration is such that the air introduction pipe is connected, the fuel gas and the air are not sufficiently mixed, the fuel gas cannot be diluted appropriately, and the generation of soot cannot be sufficiently prevented.

Therefore, as a configuration in which the fuel gas and the air are mixed, in Patent Document 3, a venturi that creates an air-fuel mixture by sucking the low-pressure fuel gas into the venturi by ejecting pressurized air from the nozzle toward the venturi. A mixer is provided. In Patent Document 4, the fuel gas supplied at low pressure is suction-mixed in the Ventury mixer for combustion. In Patent Document 5, the fuel gas is supplied to the Ventury mixer via zero governor to supply the mixed gas. I'm trying to get it.

Since air is ejected from the venturi provided in the center of the flow path in the fuel nozzle using the Venturi mixer of the background technology, the distribution (mixing ratio) of the mixture of fuel gas and combustion air is in and around the center of the flow path. There was a problem that the flame was not stable.

The present invention has been devised in view of the above-mentioned conventional problems, and provides a fuel gas nozzle capable of uniformly diluting a fuel gas with diluted air and preventing soot generation, and a gas burner provided with the fuel gas nozzle. The purpose is to do.

The fuel gas nozzle according to the present invention is a fuel gas nozzle that supplies fuel gas mixed with combustion air, and is in a direction intersecting the downstream pipe portion along the ejection direction of the fuel gas into the furnace and the ejection direction. The upstream pipe portion provided and connected to the downstream pipe portion, the bent portion formed by the connection between the upstream pipe portion and the downstream pipe portion, and the bent portion extended to the side opposite to the ejection direction. The fuel gas flow path is provided with an extension portion, and the fuel gas flows from the upstream pipe portion toward the downstream pipe portion, and the fuel gas flow path is inserted along the fuel gas ejection direction from the extension portion. A diluted air ejection pipe that ejects diluted air in the direction of fuel gas ejection is provided in the downstream pipe portion of the above , and the diluted air ejection pipe has a pore size smaller than the inner diameter of the diluted air ejection pipe. A plurality of ejection holes are provided, and the insertion tip of the diluted air ejection pipe is from the inner wall surface of the upstream pipe portion on the extension portion side to the pipe axis of the upstream pipe portion in the insertion direction of the diluted air ejection pipe. It is characterized by being located in the range of.

The diluted air ejection pipe has a flat surface-shaped ejection head portion, and the diluted air ejection hole is provided in the ejection head portion.

The flow velocity of the diluted air ejected from the diluted air ejection hole is characterized by being larger than the flow velocity of the fuel gas flowing in the fuel gas flow path.

The pressure in the diluted air ejection pipe is characterized by being higher than the pressure in the fuel gas flow path.

The gas burner provided with the fuel gas nozzle according to the present invention is characterized by comprising the above fuel gas nozzle and a combustion air nozzle for supplying combustion air.

In the fuel gas nozzle and the gas burner provided with the fuel gas nozzle according to the present invention, the fuel gas can be uniformly diluted with diluted air to prevent the generation of soot. Specifically, since the insertion tip of the diluted air ejection pipe is located in the insertion direction of the diluted air ejection pipe, it is located in a range from the inner wall surface of the upstream pipe portion on the extending portion side to the pipe axis of the upstream pipe portion. Mixing unevenness is unlikely to occur.

It is a side sectional view which shows a preferable embodiment of the fuel gas nozzle which concerns on this invention, and the gas burner provided with this. FIG. 1 is an enlarged view of part A in FIG. FIG. 2 is a cross-sectional view taken along the line B in FIG. It is a side sectional view explaining the application example to the general burner of the fuel gas nozzle which concerns on this invention.

Hereinafter, a preferred embodiment of the fuel gas nozzle and the gas burner provided with the fuel gas nozzle according to the present invention will be described in detail with reference to the accompanying drawings.

In the present embodiment, as shown in FIG. 1, a regenerator 2 having a heat storage unit 1 is shown as an example of a gas burner, and a case where the regenerate burner 2 is provided with a fuel gas nozzle 3 will be described.

The regenerator 2 is provided, for example, on each of the furnace walls 4b facing the work (not shown) arranged in the furnace 4a of the heating furnace 4. Note that FIG. 1 shows a regenerator 2 provided on one of the facing furnace walls 4b.

The regenerator 2 is arranged adjacent to an air supply / exhaust nozzle (combustion air nozzle) 5 that alternately repeats supply of combustion air to the furnace 4a and exhaust gas from the furnace 4a, and an air supply / exhaust nozzle 5. It is provided with a fuel gas nozzle 3 for supplying fuel gas mixed with combustion air toward the inside of the furnace 4a.

In the illustrated example, the air supply / exhaust nozzle 5 is arranged substantially horizontally, and the fuel gas nozzle 3 is diagonally arranged so that the fuel gas is mixed with the combustion air from the air supply / exhaust nozzle 5.

As shown in FIGS. 1 and 2, the fuel gas nozzle 3 has a gas ejection hole 3a for supplying fuel gas to the inside 4a of the furnace, and has a supply main 6 and a supply main 6 forming a flow path for the fuel gas. It is composed of a diluted air ejection pipe 7 which is inserted into the inside and supplies diluted air (air for dilution; the same applies hereinafter).

The supply main 6 has a gas ejection hole 3a, is provided so as to penetrate the furnace wall 4b, and has a downstream pipe portion 6a along the direction of ejection of fuel gas from the gas ejection hole 3a into the furnace 4a and a furnace wall. It is provided with an upstream pipe portion 6b that is connected to the downstream pipe portion 6a that protrudes from 4b to the outside of the furnace and extends in a direction that intersects the injection direction.

The fuel gas flows from the upstream pipe portion 6b of the supply main pipe 6 toward the downstream pipe portion 6a in the curved flow path of the fuel gas of the supply main pipe 6.

The supply main 6 is provided with a regulating valve (not shown) for adjusting the supply amount of fuel gas on the upstream pipe portion 6b side.

The downstream pipe portion 6a is provided with an extension portion 6d extending to the side opposite to the gas ejection hole 3a side in a bending portion 6c formed by connecting the upstream pipe portions 6b having different directions, and the extension portion 6d is provided. A mounting flange 6e is provided at the tip of the.

The diluted air ejection pipe 7 is inserted from the extending portion 6d into the downstream pipe portion 6a of the supply main pipe 6 along the ejection direction of the fuel gas ejected from the gas ejection hole 3a.

As shown in FIGS. 2 and 3, the diluted air ejection pipe 7 is formed with an outer diameter D2 smaller than the inner diameter D1 of the downstream pipe portion 6a.

At the insertion tip of the diluted air ejection pipe 7, an ejection head portion 7a for ejecting and supplying diluted air in the flow direction of the fuel gas flowing through the downstream pipe portion 6a is provided.

The ejection head portion 7a has a flat surface shape, and is provided with a plurality of diluted air ejection holes 7b having a pore diameter D4 smaller than the inner diameter D3 of the diluted air ejection pipe 7.

Although not shown, the diluted air ejection pipe 7 is provided with a control valve for adjusting the supply amount of the diluted air, at least on the upstream side of the ejection head portion 7a.

The diluted air ejection pipe 7 is provided with a flange 7c on the side opposite to the ejection head portion 7a. The flange 7c comes into contact with the mounting flange 6e when the diluted air ejection pipe 7 is inserted into the supply main pipe 6 from the extension portion 6d, and is joined to the mounting flange 6e with bolts and nuts.

In the diluted air ejection pipe 7, when the flange 7c is joined to the mounting flange 6e, the ejection head portion 7a is located at or around the bent portion 6c of the supply main pipe 6.

In the present embodiment, an example in which the supply main pipe 6 and the diluted air ejection pipe 7 are joined by flange joining is shown, but it goes without saying that other connecting structures such as screw joining may be adopted.

The position of the ejection head portion 7a, which is the insertion tip of the diluted air ejection pipe 7, is from the inner wall surface of the upstream pipe portion 6b on the extension portion 6d side in the insertion direction of the diluted air ejection pipe 7. It is preferable that the portion 6b is located in the range R up to the center line (tube axis) C because uneven mixing is less likely to occur.

The pressure of the diluted air in the diluted air ejection pipe 7 is set higher than the pressure of the fuel gas in the supply main pipe 6.

Further, the diluted air ejected from the diluted air ejection pipe 7 is ejected from a plurality of diluted air ejection holes 7b having a pore diameter D4 smaller than the inner diameter D3 of the diluted air ejection pipe 7, and is a fuel gas flowing in the supply main pipe 6. It is set faster than the flow of.

As described above, the flow velocity of the diluted air ejected from the diluted air ejection hole 7b is larger than the flow velocity of the fuel gas flowing in the supply main pipe 6.

According to the fuel gas nozzle 3 of the present embodiment, since the diluted air ejection pipe 7 is provided in the supply main 6 through which the fuel gas flows, the diluted air is supplied into the supply main 6 and the supply main 6 is supplied. It is possible to dilute the fuel gas in the fuel gas with diluted air in a uniform distribution to prevent the generation of soot in combustion with the combustion air.

At this time, since the diluted air ejection pipe 7 supplies the diluted air in the flow direction of the fuel gas, it does not interfere with the flow of the fuel gas.

Further, since the diluted air ejection hole 7b provided in the ejection head portion 7a at the tip of the diluted air ejection pipe 7 has a hole diameter D4 smaller than the inner diameter D3 of the diluted air ejection pipe 7, the diluted air is quickly discharged from the diluted air ejection pipe 7. It can be ejected at a speed.

Further, since a plurality of diluted air ejection holes 7b are provided in the flat surface-shaped ejection head portion 7a, the diluted air can be dispersed and ejected so as not to be concentrated in one place, and the diluted air can be ejected. Can be mixed with fuel gas in a well-distributed manner.

Therefore, it is possible to uniformly dilute the fuel gas with the diluted air ejected from the plurality of diluted air ejection holes 7b into the supply main 6 without uneven mixing, and prevent the generation of soot in combustion with the combustion air. can.

Further, since the flow velocity of the diluted air ejected from the diluted air ejection hole 7b is larger than the flow velocity of the fuel gas flowing in the supply main 6, the diluted air can be ejected more vigorously in the supply main 6. .. Therefore, the fuel gas can be efficiently diluted. Further, it is possible to prevent the fuel gas from flowing into the diluted air ejection pipe 7.

Further, since the pressure in the diluted air ejection pipe 7 is higher than the pressure in the supply main 6, the diluted air can be reliably ejected into the supply main 6. This also prevents the fuel gas from flowing into the diluted air ejection pipe 7.

According to the regenerate burner 2 of the present embodiment, since the fuel gas nozzle 3 capable of uniformly diluting the fuel gas and the air supply / exhaust nozzle 5 for supplying the combustion air can be formed, a stable flame can be formed and also. It is also possible to suppress the generation of soot.

In the above embodiment, an example in which the fuel gas nozzle 3 is provided in the regenerator burner 2 has been described, but it is needless to say that the fuel gas nozzle 3 can be applied to a gas burner other than the regenerate burner 2. FIG. 4 shows an example of application of the present invention to an ordinary general burner 8.

In a general burner 8, a fuel gas nozzle 3 is provided inside a combustion air nozzle 9 communicating with a furnace 4a. As described above, the fuel gas nozzle 3 includes a supply main pipe 6 and a diluted air ejection pipe 7. The diluted air ejection pipe 7 is inserted into the supply main pipe 6 from a portion corresponding to the above-mentioned extension portion 6d in the same manner as in the above embodiment. Of course, even with such a configuration, the same action and effect as those of the above-described embodiment can be obtained.

Further, the above-described embodiment is for facilitating the understanding of the present invention, and is not for limiting the interpretation of the present invention. It goes without saying that the present invention can be modified and improved without departing from the spirit thereof, and the present invention includes an equivalent thereof.

1 Heat storage part 2 Regeneration burner 3 Fuel gas nozzle 3a Gas ejection hole 4 Heating furnace 4a In-furnace 4b Furnace wall 5 Supply / exhaust nozzle 6 Supply main pipe 6a Downstream pipe part 6b Upstream pipe part 6c Bending part 6d Extension part 6e Mounting flange 7 Diluting Air ejection pipe 7a Ejecting head 7b Diluted air ejection hole 7c Flange 8 General burner 9 Combustion air nozzle D1 Inner diameter of downstream pipe D2 Outer diameter of diluted air ejection pipe D3 Inner diameter of diluted air ejection pipe D4 Diluted air ejection hole Hole diameter

Claims (5)

A fuel gas nozzle that supplies fuel gas mixed with combustion air.
A downstream pipe portion along the direction of fuel gas ejection into the furnace, an upstream pipe portion provided in a direction intersecting the ejection direction and connected to the downstream pipe portion, and these upstream pipe portions and downstream pipe portions. A fuel gas having a bent portion formed by the connection and an extended portion extending in the direction opposite to the ejection direction in the bent portion, and the fuel gas flows from the upstream pipe portion to the downstream pipe portion. Channel and
A diluted air ejection pipe that is inserted from the extending portion along the ejection direction of the fuel gas and ejects the diluted air in the ejection direction of the fuel gas is provided in the downstream pipe portion of the fuel gas flow path.
The diluted air ejection pipe is provided with a plurality of diluted air ejection holes having a pore diameter smaller than the inner diameter of the diluted air ejection pipe.
The insertion tip of the diluted air ejection pipe is located in the range from the inner wall surface of the upstream pipe portion on the extending portion side to the pipe axis of the upstream pipe portion in the insertion direction of the diluted air ejection pipe. Featuring a fuel gas nozzle. The fuel gas nozzle according to claim 1, wherein the diluted air ejection pipe has a flat surface-shaped ejection head portion, and the diluted air ejection hole is provided in the ejection head portion. The fuel gas nozzle according to claim 1 or 2, wherein the flow velocity of the diluted air ejected from the diluted air ejection hole is larger than the flow velocity of the fuel gas flowing in the fuel gas flow path. The fuel gas nozzle according to any one of claims 1 to 3, wherein the pressure in the diluted air ejection pipe is higher than the pressure in the fuel gas flow path. A gas burner provided with a fuel gas nozzle comprising the fuel gas nozzle according to any one of claims 1 to 4 and a combustion air nozzle for supplying combustion air.

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