JPH0610291B2 - Nozzle for fuel injection lance - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a nozzle for a fuel injection lance, and more specifically, a tip portion is inserted into a raw material in a furnace such as an electric furnace for smelting to support a liquid fuel. The present invention relates to a nozzle for a fuel injection lance into a raw material layer of an industrial furnace, which jets a combustible gas and inputs the combustion energy.

[Conventional technology]

Conventionally, electric furnaces for smelting steel or non-ferrous metals,
In particular, in an electric furnace for the reduction of ferroalloys, a liquid fuel such as heavy oil and a combustion-supporting gas such as oxygen gas or oxygen-enriched air are blown into a high-temperature raw material in the furnace for the purpose of partially removing power. In addition, the raw material (ore) is heated by the combustion energy of liquid fuel, and power is saved by increasing sensible heat. As a nozzle for a lance for blowing such a liquid fuel and a combustion-supporting gas, for example, a nozzle described in JP-A-1-167508 is known.

That is, as shown in FIGS. 5 and 6, the conventional nozzle 1
Is provided with a plurality of liquid fuel ejection holes 3 and 3 at an angle of 10 to 45 degrees outward from the nozzle center and the nozzle center axis of the nozzle 1 attached to the tip of the lance 2, and the combustion-supporting gas ejection hole 4 is , The inner circumference holes 4a, 4a at an angle of -20 to 20 degrees to the outside with respect to the nozzle center axis, and further on the concentric circle on the outer circumference side of this circumference, The outer peripheral holes 4b and 4b were respectively provided at an angle of 10 to 45 degrees with respect to the central axis.

[Problems to be Solved by the Invention]

In such a conventional nozzle shape, the fuel and the combustion-supporting gas are mixed at a high speed, and as a result, the combustion speed is increased and the fuel is burned in the vicinity of the nozzle 1 to form a flame F symmetrical about the central axis of the nozzle and the flame F. Will be concentrated. For this reason, the raw material in the furnace is often heated and melted locally, the raw material is locally melted without being dispersed, and a flue reaching the surface of the raw material is formed, and the combustion gas is blown out from this flue. However, the combustion energy could not be efficiently input to the raw material. In addition, the combustion gas that has blown through may raise the temperature of the furnace ceiling, possibly damaging the furnace ceiling bricks and other components of the furnace. Further, since the flame F is formed on the central axis of the nozzle, the flame is reflected on the nozzle 1, and the nozzle 1 is frequently melted and damaged.

Therefore, the present invention enables the combustion energy to be efficiently transferred to the raw material so that the flame is not appropriately dispersed to locally heat and melt the raw material in the furnace, and the flue to the surface of the raw material is not formed. Moreover, it is an object of the present invention to provide a nozzle for a lance that has almost no melting loss of the nozzle.

[Means for Solving the Problems]

In order to achieve the above object, the nozzle for a fuel injection lance of the present invention has a range in which a fuel injection hole for ejecting a liquid fuel corresponds to a lower side of 240 degrees or less on at least one circumference around the center axis of the nozzle. A plurality of holes are provided at an angle of 30 to 60 degrees downward with respect to the nozzle center axis, and the combustion-supporting gas ejection holes for ejecting the combustion-supporting gas are centered on the nozzle center axis inside the fuel ejection hole. On at least one circumference, a plurality of holes are formed downward at an angle of -20 to 20 degrees with respect to the central axis of the nozzle, and at least two outside the fuel injection holes are provided.
A plurality of holes at an angle of 30 to 60 degrees below the center axis of the nozzle on the inner circumference of one circumference, and on the outer circumference,
It is characterized in that a plurality of holes are provided below the central axis of the nozzle at an angle of 70 to 110 degrees.

[Action]

By forming the nozzle as described above, when the liquid fuel and the combustion-supporting gas ejected from the nozzle are burned in the high temperature raw material layer, the combustion is moderately delayed and the flame is appropriately dispersed. There is little local concentration, no flue is formed on the surface of the raw material, and thermal efficiency is improved.

〔Example〕

Hereinafter, the present invention will be described in more detail based on an embodiment shown in FIGS. 1 to 4.

First, in FIGS. 1 and 2, FIG. 1 is a front view of a nozzle, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1, showing the arrangement of fuel ejection holes and combustion-supporting gas ejection holes. ing.

The nozzle 11 provided at the tip of the liquid fuel injection lance 10 widens the distance between the ejection holes and disperses and arranges the ejection holes, so that the tip portion is formed in a spherical shape. Inside the nozzle 11, a liquid fuel flow path 13 and a combustion-supporting gas flow path 14 are defined by a partition wall 12,
Each is connected to each flow path in the lance body. A plurality of fuel ejection holes 20 for ejecting the liquid fuel supplied from the lance body and a plurality of combustion-supporting gas ejection holes 30, 31, for ejecting combustion-supporting gas are provided at the tip of the liquid fuel flow path 13.
32 and 32 are arranged.

The fuel injection hole 20 is provided on the lower side 24 when the nozzle 11 is attached, on the circumference of the circumference around the central axis CL of the nozzle 11.
The range of 0 degrees or less, that is, the angle α in FIG. 1 is 2
It is provided at a portion of 40 degrees or less. In addition, the fuel injection hole 20
The fuel injection direction is in the range of 30 to 60 degrees downward with respect to the nozzle center axis CL, that is, the angle β in FIG. 2 is 30.
It is formed so as to fall within a range of -60 degrees.

One of the combustion-supporting gas ejection holes 30, 31, 32 is provided with at least one circumference centered on the nozzle central axis CL inside the circumference where the fuel ejection hole 20 is provided and with the fuel ejection hole. A plurality of nozzles are provided on at least two circles centered on the central axis of the nozzle outside the circle.

The jet direction of the combustion-supporting gas from these combustion-supporting gas ejection holes 30, 31, 32 is set to the following ranges, respectively.
First, the combustion-supporting gas ejection holes 30 provided on the innermost circumference are provided with −20 to 20 below the nozzle center axis CL.
The degree, that is, the angle γ in FIG. 2 is formed in the range of −20 to 20 degrees. The combustion-supporting gas ejection holes 31 provided on the middle circumference are 30 to 60 degrees downward with respect to the nozzle center axis CL, that is, the angle δ in FIG.
It is formed so as to be in the range of 0 degree. Further, the combustion-supporting gas ejection holes 32 provided on the outermost circumference are in the range of 70 to 110 degrees downward with respect to the nozzle center axis CL, that is, the angle ε in FIG. 2 is in the range of 70 to 110 degrees. Is formed as.

By arranging the liquid fuel ejection holes 20 and the combustion-supporting gas ejection holes 30, 31, 32 of the nozzle 11 in this way,
The liquid fuel and the combustion-supporting gas can be diffused into the raw material in the furnace, and the liquid fuel and the combustion-supporting gas can be gradually burned after being diffused to some extent, without being burned in the vicinity of the nozzle 11.

That is, as shown in FIGS. 3 and 4, the nozzle 1 of the present invention
In No. 1, a plurality of flames F can be formed, and combustion is delayed because the fuel and the combustion-supporting gas are mixed slowly, and a soft flame can be formed, so that the combustion energy can be dispersed. Become. Further, since the flame F is not formed on the central axis CL of the nozzle and does not burn in the vicinity of the nozzle 11, the reflection phenomenon of the flame F on the nozzle 11 is almost eliminated, and the melting damage of the nozzle 11 can be prevented. .

Next, the results of an experiment conducted by inserting two fuel injection lances into a high temperature granular raw material in a ferronickel reduction electric furnace (25000 KVA) using the nozzle of the present invention and a conventional nozzle will be described.

First, as the nozzle according to the present invention, the nozzle having the structure shown in FIGS. 1 and 2 was used. The fuel injection hole of this nozzle is the lower side 180 when the nozzle is attached to the tip of the lance.
On the same circumference in the range of degrees (α = 180 °), the injection direction is 45 ° (β = 45 °) below the nozzle center axis CL.
Four fuel-supporting gas injection holes are provided on the same circumference inside the fuel injection hole, and the injection direction is 0 degrees below the central axis of the nozzle (γ = 0 °; parallel to the central axis). , On the same circumference outside the fuel injection hole, the injection direction is 4 below the central axis of the nozzle.
Four nozzles with 5 degrees (δ = 45 °), and the injection direction is 90 degrees (ε
= 90 °), four in total, twelve in total.

Further, as a conventional nozzle, there is the one described in JP-A-1-16750.
A nozzle having the structure described in Japanese Patent No. 8 was used.

In addition, heavy fuel oil C is used as the liquid fuel, and its flow rate is 90 to 1
00 / h, oxygen was used as the combustion-supporting gas, and the flow rate was set to 150 to 200 Nm ³ / h.

As a result, in the nozzle of the present invention, a flue through which combustion gas blows through the surface could hardly be formed without locally heating and melting the high temperature granular raw material. That is, the conventional nozzle blowout frequency was 28 times in 225 hours of operation,
The nozzle of the present invention was used only once during the operation time of 439 hours, and a great improvement could be seen. Therefore, the nozzle of the present invention was able to inject the combustion energy into the raw material in a state where the thermal efficiency was very high. In addition, since the combustion gas hardly blows through the surface, the rise in the furnace ceiling temperature and the damage to the furnace roof brick due to the combustion gas are almost eliminated, and the slower combustion eliminates the melting damage of the nozzle.

〔The invention's effect〕

As described above, in the nozzle of the present invention, the ejection holes for the fuel and the combustion-supporting gas are provided within the range limited to 240 degrees or less at the time of attaching the lance and at a specific angle.
Multiple flames can be formed depending on the direction of jetting, and combustion can be moderately delayed, and the combustion energy can be dispersed and input into the raw material in the industrial furnace. Combustion energy can be input in a state in which thermal efficiency is high without the gas blowing through the surface.

Further, since the combustion gas hardly blows to the surface of the raw material, the rise of the furnace ceiling temperature due to the combustion gas is eliminated, and the risk of damage to the furnace ceiling bricks is eliminated. further,. Since the combustion is dispersed and slowed, the melt loss of the nozzle can be greatly reduced.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a front view of a nozzle, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 shows a combustion state. A side view, FIG. 4 is a front view of the same, FIGS. 5 and 6 show a combustion state of a conventional nozzle, FIG. 5 is a side view, and FIG. 6 is a front view. 10 ... Lance, 11 ... Nozzle, 20 ... Fuel ejection hole, 30, 31, 32 ... Combustion-supporting gas ejection hole

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Miyake 3054-3 Shimokurosawa, Takane-cho, Kitakoma-gun, Yamanashi Nihon Oxygen Co., Ltd. (56) References Japanese Patent Publication No. 51-35165 (JP, B2) Japanese Publication No. -40524 (JP, B2) JP-B 51-1204 (JP, B2) JP-B 60-6417 (JP, Y2)

Claims (1)

[Claims] 1. In a nozzle for a fuel injection lance for injecting and burning liquid fuel and combustion-supporting gas into a raw material layer in an industrial furnace, a fuel injection hole for injecting the liquid fuel is formed around a center axis of the nozzle. A plurality of holes are provided at an angle of 30 to 60 degrees downward with respect to the central axis of the nozzle in the range of 240 degrees or less on the lower side of at least one circumference, and the combustion-supporting gas is ejected to eject the combustion-supporting gas. The holes on at least one circumference centered on the central axis of the nozzle inside the fuel ejection hole, and -20 to 20 downward with respect to the central axis of the nozzle.
Multiple holes at an angle of 30 degrees, a plurality of holes at an angle of 30 to 60 degrees on the inner circumference of at least two circumferences outside the fuel injection hole, and a further outer circumference. In addition, a nozzle for a fuel injection lance is characterized in that a plurality of holes are provided below the central axis of the nozzle at an angle of 70 to 110 degrees.