JPH05196214A - Composite gas burner structure - Google Patents

Abstract

PURPOSE:To provide a composite gas burner structure capable of stable combustion, of preventing production of any dust, and of reduction of fuel cost, and further of improvements of combustion efficiency and environmental condition. CONSTITUTION:A high calorie gas burner 18 is disposed on the outer periphery of a low heat value gas burner 8, and a gas collision plate 21 is provided in the vicinity of the high heat value gas burner 18, whereby a mixture ratio is improved and a flame holding region is widened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite gas burner structure provided in a combustion device, and in particular, a low-calorie gas produced as a by-product from a blast furnace and a high-calorie gas such as natural gas are burned coaxially. The present invention relates to a composite gas burner structure suitable for.

[0002]

2. Description of the Related Art Blast furnace gas, converter gas, and coke that have been conventionally generated in steelworks due to concerns about future depletion of oil reserves, instability of political conditions in production areas, and environmental regulations. By-product gas such as furnace gas is the main fuel,
I was operating a boiler for private power generation in a steel mill. In addition, liquefied natural gas (LNG) is increasingly used as a backup fuel when there is no shortage of by-product gas, a burner for stabilization, or when there is no by-product gas, instead of heavy oil that has been conventionally used.

5 to 7 show a conventional burner structure when the above-described by-product gas is used as boiler fuel. As a by-product gas, for example, blast furnace gas (BFG) has components of N ₂ of 52 to 56%, H _{2 of 2.5} to 4%, CO of 21 to 23%, and CO ₂ of 17 to 20%. The calorific value is 600 to 1100 KCal / m ³ N, which is 1/10 or less of the calorific value of heavy oil or natural gas. For this reason,
It is difficult to self-combust without a stabilizing burner, and a design concept is adopted in which it is jetted from the burner at low flow rate to diffuse combustion. Moreover, since the calorific value is small, it is necessary to supply an extremely large amount of fuel. Therefore, as shown in FIGS. 5 to 7, the blast furnace gas burner (low-calorie gas burner) 8 has a large cylindrical shape with the burner center as an axis, and the BFG from the supply port 7 has a low flow velocity of 15 to 25 m / s. Supplied within. Further, the BFG is supplied to the furnace 1 from the tip of the blast furnace gas burner 8 while being slightly swirled, and flame holding is maintained.

In FIG. 5, a heavy oil burner (high calorie gas burner) 9 is mounted on the central axis of a blast furnace gas burner 8, and a burner impeller 13 is provided at the tip of the heavy oil burner 9. Further, the heavy oil burner 9 can be attached to and detached from the blast furnace gas burner 8 via the slip-off device 16, and the heavy oil 10 is supplied from the base end of the heavy oil burner 9. Further, the tip of the blast furnace gas burner 8 is inserted into the casing 6 of the wind box 3, and the combustion air 5 is supplied toward the burner throat 2 via the air register 4.

FIG. 6 shows a coke oven gas burner 12 concentrically provided on the outer periphery of a heavy oil burner 9. A coke oven gas (COG) 11 is supplied from the base end of the coke oven gas burner 12 and a COG jet nozzle at the tip. Eject from 19. COG11 has a calorific value of about 4500 KCal / m ³ N, and when the BFG7 is extinguished or when the BFG7 is extinguished.
Burn at the same time. When COG11 is used, since it has a high calorie, combustion can be continued, and the gas ejection speed can be increased. By arranging the COG ejection nozzles 19 in a radial manner, C is provided on the downstream side of the COG ejection nozzles 19.
The OG rewinding flow 20 is generated so that flame holding can be performed.

FIG. 7 is a coke oven gas burner 1 shown in FIG.
A converter gas burner 15 is coaxially provided between the No. 2 and the heavy oil burner 9.

FIG. 8 shows an example of the structure of a burner for co-firing LNG and heavy oil. Calorific value 10,000 to 11000KC
The LNG having al / m ³ N is fed from the gas ring 17 to the LNG burner 18 via the gas supply pipe 22 to 150
It is jetted at a speed of ~ 300 m / s. 15-40% of a part of the jetted LNG is guided to the burner impeller 13 for flame holding, and 60-85% of LNG is well mixed with the combustion air 5 to prevent the generation of soot and oxygen monoxide. There is.

[0008]

However, if the low calorie fuel such as BFG or COG derived from the blast furnace or the coke oven as described above is stopped by closing the inlet valve of each burner and igniting the LNG burner. As there is a fuel nozzle near the center of the burner, most of it does not reach even when the combustion air is supplied. For this reason, there is a problem that LNG is thermally decomposed at a high temperature and soot is generated by the released carbon.

Further, it is difficult to install a flame holding plate inside the blast furnace gas burner in order to hold the flame of the LNG flame without impairing the combustibility of the low-calorie gas. For this reason, there is also a problem that the LNG flame is blown off and the risk of misfire is high.

The present invention provides a composite gas burner structure capable of stable combustion, preventing generation of dust, etc., reducing fuel cost, improving combustion efficiency and improving environment. With the goal.

[0011]

In order to achieve the above-mentioned object, a composite gas burner structure according to the present invention is a composite gas burner structure in which a low-calorie gas burner and a high-calorie gas burner are coaxially arranged. A plurality of high-calorie gas burners are arranged on the outer circumference, and a gas collision plate having an L-shaped cross-section is provided near each of the high-calorie gas burners.

The gas impingement plate may be provided at a position where 15 to 50% of the gas ejected from the high-calorie gas burner is impinged to form a flame holding gas.

Further, the high-calorie gas burner uses 15 to 50% of the ejected gas as a flame holding gas, and the jet direction of the flame holding gas is the same direction and / or the opposite direction to the swirling flow of the combustion air. A combination may be used.

[0014]

According to the present invention, about 15 to 30% of the gas ejected from the tip of the high-calorie gas burner is made to collide with the bottom of the gas collision plate having an L-shaped cross section. Then, the flame-holding region is created by the mixture of the high-calorie gas that has collided with the vortex of the combustion air generated downstream of the gas collision plate. Further, the remaining high-calorie gas is ejected toward the furnace at an angle inclined with respect to the burner axis so that mixing with the combustion air can be achieved. In this way, a wide flame holding region is obtained, and moreover, the combustion air reaches the nozzle tip sufficiently, and stable combustion can be performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the composite gas burner structure of the present invention will be described with reference to the drawings.

1 to 4 show the configuration of an embodiment of the present invention. In these figures, parts corresponding to those of the conventional example shown in FIGS. 5 to 8 are designated by the same reference numerals, and the description thereof will be omitted as appropriate. In this embodiment, a composite gas burner that combines a BFG burner (blast furnace gas burner) 8 and an LNG burner 18 will be described. The feature of this embodiment is that a plurality of, for example, 6 LNG burners (high-calorie gas burners) 18 are coaxially arranged on the outer circumference of the BFG burner (low-calorie gas burner) 8 and the axial direction is provided at the tip of the BFG burner 8. The gas impingement plate 21 having an L-shaped cross-section consisting of a bottom plate parallel to the vertical plate and a vertical plate perpendicular thereto is attached by linking it to the number of LNG burners 18, and the structure of the other parts is shown in FIG. It is almost the same as the example.

Next, the operation of this embodiment will be described with reference to FIGS. At the time of LNG combustion, there is a small amount of combustion air in the BFG burner 8 and smoke may be emitted. Therefore, the ejection angle from the fuel ejection nozzle toward the throat 2 which is the combustion air flow passage is determined. That is, as shown in FIG.
About 70 to 85% of the LNG ejected from the burner 18 is used as the load gas 24, and the angles α _{1 to} α ₂ with respect to the axis of the LNG burner 18 are ejected toward the furnace 1 with an angle α _{1 to} α ₂ of 30 to 50 degrees. As a result, the mixing ratio of fuel and air can be improved, LNG can be prevented from becoming a bright flame at high temperatures, and soot can be prevented from being released due to thermal decomposition of carbon.

The remaining about 15 to 30% of the gas ejected from the nozzle of the LNG burner 18 is used as the flame holding gas 23 and is made to collide with the bottom plate portion of the gas collision plate 21. Flame holding gas 2 that collided
3 and the combustion air 5 are mixed in the downstream of the vertical plate of the gas collision plate 21 to form a vortex, forming an LNG flame holding region. At this time, in order to secure a wide flame holding region, the jet direction of the flame holding gas 23 is made to be the same direction as the jet direction of the combustion air, or a combination of both the same direction and the opposite direction.

In the above-mentioned embodiment, the composite gas burner in which the BFG burner 8 and the LNG burner 18 are combined is explained, but it is also applicable to the composite gas burner in which another high calorie gas burner and a low calorie gas burner are combined.

[0020]

According to the composite gas burner structure of the present invention,
A high-calorie gas burner was installed around the low-calorie gas burner, and a gas collision plate was installed near the gas outlet of the high-calorie gas burner, so the mixing ratio of fuel and air was improved, and carbon was released and soot was generated. Things can be prevented and the environment can be improved. Further, since a part of the gas ejected from the high-calorie gas burner is made to collide with the gas collision plate, it is possible to form a wide flame holding region and achieve stable combustion, thereby reducing combustion cost and combustion efficiency. Can be achieved.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of an embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is an enlarged view showing a main part of FIG.

FIG. 4 is a partially enlarged cross-sectional view illustrating the operation of the gas collision plate of FIG.

FIG. 5 is a vertical sectional view showing an example of a conventional combined gas burner of a heavy oil burner and a BFG burner.

FIG. 6 is a vertical cross-sectional view showing an example of a composite gas burner of a conventional heavy oil burner, BFG burner and COG burner.

FIG. 7 is a vertical cross-sectional view showing an example of a combined gas burner of a conventional heavy oil burner, BFG burner, LNG burner, and COG burner.

FIG. 8 is a vertical cross-sectional view showing an example of a composite gas burner of a conventional heavy oil burner and an LNG burner.

[Explanation of symbols]

 5 Combustion air 8 Blast furnace gas burner (low calorie gas burner) 18 LNG burner (high calorie gas burner) 21 Gas collision plate

Claims (3)

[Claims] 1. A composite gas burner structure in which a low-calorie gas burner and a high-calorie gas burner are coaxially arranged, and a plurality of the high-calorie gas burners are arranged on the outer periphery of the low-calorie gas burner, and each of the high-calorie gas burners is provided. A composite gas burner structure characterized in that gas collision plates each having an L-shaped cross section are provided in the vicinity thereof. 2. The gas impingement plate is provided at a position where 15% to 50% of the gas ejected from the high-calorie gas burner is impinged to form a flame holding gas. Combined gas burner structure. 3. The high-calorie gas burner uses 15 to 50% of the ejected gas as a flame holding gas, and the flame holding gas is jetted in the same direction and / or in the opposite direction to the swirling flow of combustion air. The composite gas burner structure according to claim 1, wherein the combination is a combination of directions.