JPS6248129B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a gas burner for ignition of a sintering machine, etc.
Specifically, the present invention relates to a gas burner that can uniformly ignite and burn a continuously fed layer of raw material such as ore in the width direction, and that can be easily controlled.

Generally, in a sintering machine, a layer of raw material such as ore is ignited in an ignition furnace and then sintered during movement. In this case, since the raw material layer has a wide width in the width direction perpendicular to its moving direction, uniform ignition of the raw material layer in the ignition furnace is important for quality and production.
A gas burner used in an ignition furnace is one in which a large number (approximately 10 to 20) of cylindrical gas burners are arranged in one or several rows in the furnace width direction on the ceiling of the ignition furnace, as shown in Figures 1a, b, and c. is used. However, the temperature of the raw material layer varies between directly below each burner and between them, and the surface of the raw material becomes overmelted directly below the burner, and since combustion gas does not directly hit between the burners, the raw material surface becomes unignited or insufficiently ignited, resulting in a uniform Sintering cannot be carried out, which hinders the improvement of the quality and productivity of sintered ore.

That is, FIGS. 1a and 1b are a cross-sectional view and a plan view of a sintering machine ignition furnace in which a conventional cylindrical burner is installed, and FIGS. 1c and d are explanatory diagrams of the combustion situation in the furnace. It is a graph of an example of the temperature distribution on the surface of the raw material layer based on this. As shown in FIGS. 1a and 1b, the bullet 1 of the sintering machine is continuously moved in the direction of arrow A via rollers 1a, and during the initial passage through the ignition furnace 2, the surface of the raw material layer 3 is ignited. Ru. This ignition furnace 2 has cylindrical burners 4 arranged in one row or several rows in the furnace width direction on the ceiling.
are installed, and the raw material layer is ignited from each cylindrical burner 4. In this ignition furnace 2, the positions of the burners 4 are arranged at regular intervals.
From burner 4 to frame 4 at intervals as shown in
a is injected, and the temperature distribution (gas distribution) in the furnace width direction
is not uniform, and variations occur in the temperature on the surface of the raw material layer (see Figure 1d).

More specifically, the temperature is high immediately below each burner, and the temperature is low between each burner. This causes uneven burning of the sintered layer, which causes quality and production problems.

From this point of view, even in conventional ignition furnaces, the interval between burners may be shortened, or
As disclosed in the above publication, an ignition system has been proposed in which a mixing combustion chamber is provided separately and the high-temperature exhaust gas is jetted out uniformly in the width direction of the ignition furnace, but all of these require a large amount of equipment cost. Furthermore, since the latter uses exhaust gas after combustion, it is necessary to preheat the mixing combustion chamber before starting operation, making it unsuitable as an ignition system for sintering furnaces that operate intermittently, and moreover, It has drawbacks such as difficulty in following changes in conditions and large energy loss.

The present invention eliminates these drawbacks and proposes a new gas burner that achieves a uniform combustion condition in the furnace width direction and is easy to control.

The present invention will be explained in detail below.

First, FIGS. 2a, b, and c are perspective views, plan views, and sectional views of a gas burner according to one embodiment of the present invention, and as shown in these figures, the fuel gas passage 5 and the combustion air passage 6 are Each of the passages 5 and 6 is constructed as a flow passage having an elongated slit-like cross section, and furthermore, each of these passages 5 and 6 is adjacent to each other, with a fuel gas passage 5 in the center and combustion air passages 6 on both sides thereof. That is, the fuel gas and combustion air passages are usually arranged such that combustion air passages 6 are arranged on both sides of the central fuel gas passage 5, as shown in FIGS. 2a, b, and c. Burns with air on both sides.

Next, the end portions of each of the passages 5 and 6 having the above structure are constricted to form constricted portions 5a and 6a, and these constricted portions 5a and 6a are connected to the mixing chamber 7. To ensure good mixing of the combustion air on both sides with the fuel gas, the length should be set at 50~
100 mm, and the mixture is injected from the tip of this mixing chamber 7 toward the raw material layer.

However, in the above configuration, if the fuel gas and combustion air passages are simply configured in parallel, mixing will occur only by diffusion mixing at the adjacent interface between the two, which will deteriorate the mixing and reduce the combustion rate. This long flame phenomenon is a serious disadvantage in sintering furnaces where the height inside the furnace is limited. In this case, the fuel gas and combustion air may be mixed in advance in a mixing chamber and the mixture may be sent to be combusted, but there is a risk of explosion or the like in this mixing in the mixing chamber.

In contrast to this point, in the present invention, each passage is not only configured in parallel, but also the fuel gas passage 5.
Combustion air passages 6 are provided on both sides of the combustion air passage 6, and constricted portions 5a, 6a are formed at the ends of each passage, and each constricted portion is oriented toward the mixing chamber 7, so that the fuel gas and the combustion Collision and mixing of air is promoted.

That is, in the throttle parts 5a and 6a, fuel gas and combustion air are throttled to increase the flow velocity, and in this high-speed state, they collide and mix in the mixing chamber 7 at a certain angle from the throttle part, promoting mixing. . Since the length of this mixing chamber 7 is 50 mm or more, sufficient mixing can be achieved and a stable frame can be obtained.
Since the length is about 100 mm, there is no practical problem.Furthermore, if the mixing chamber is longer than 100 mm when high-speed gas and air mix while diffusing each other, there is a risk that the air-fuel mixture formed will explode inside the mixing chamber. I don't like it when there are too many. Note that when mixing at the tip in this way, both walls 7a of the mixing chamber 7 are heated by heat radiation from inside the furnace, impairing their durability, and furthermore, the mixture inside the mixing chamber is heated. Risk of explosion. For this reason, it is preferable to protect this part with a refractory material or to cool it by providing a water-cooled or air-cooled pipe.

Furthermore, since the passages 5 and 6 are formed in layers, it is important to maintain uniformity in temperature in the width direction of the furnace, and the flow of fuel gas and combustion air to these passages 5 and 6 is important. It is necessary that the supply be uniform. From this point, each passage 5, 6 is connected via a header 8, 9 with a number of branch pipes 10, 11 in between.
It is preferable to carry out this with the intervention of. With this configuration, fuel gas and combustion air can be supplied without drifting.

Note that branch pipes are usually provided at two or more locations, preferably at least three locations, and particularly preferably at least four locations per meter of furnace width. In addition, the width of each passage 5, 6 at the burner base is made larger than that at the burner tip,
The flow velocity in this portion can be kept low, and with this configuration, the uniformity in the longitudinal direction, that is, in the oven width direction, is further improved.

Next, examples will be described.

First, the gas burner shown in Fig. 3a is used, and the dimensions of this burner are the length l = 1000 shown in Fig. 2b.
mm, l ₁ = 70 mm, l ₂ = 84 mm, l ₃ = 14 as shown in Figure 3a.
mm, l ₄ = 23 mm, l ₅ = 66 mm, l ₆ = 200 mm, and l ₇ = 100 mm.

In this burner, each branch pipe that supplies fuel gas and combustion air is arranged at equal intervals of 4 per 1000 mm.
There are places set up.

Next, a mixed gas of blast furnace gas and coke gas (calories 2300 to 2600 Kcal/Nm ³ , theoretical air amount 2.2
〜2.4Nm ³ /Nm ³ ) 200 to 400Nm ³ /hour was supplied, and combustion air was combusted at an air ratio of 1.0 to 1.3, showing good combustion conditions, as shown in Figures 3b and c. It was as shown in.

In other words, Fig. 3b is the same as arrow A in Fig. 2b.
- Shows the temperature distribution in each cross-sectional view of A, B-B and CC, where A is the temperature of the A-A cross section in the arrow direction, B is the temperature in the B-B cross section in the arrow direction, and C is the temperature in the C-C cross section in the arrow direction. From FIG. 3b, it can be seen that the temperature distributions in the A-A, B-B, and C-C sections are equal.

Furthermore, Fig. 3c is a graph showing the temperature distribution in the vertical direction measured every 200mm from the burner tip in the cross section taken along arrow C-C in Fig. 2b, where symbol a is 800mm and b is 600mm from the burner tip. , C is 400mm, d
indicates each case of 200mm. In Figure 3c, as the distance from the burner increases, the temperature level increases, but the change is small.

In other words, it shows that the burner according to the invention has good combustibility and its flame is short. Furthermore, Figures 3b and 3c show a mountain-shaped temperature distribution with sharp peaks, but it is desirable to minimize the energy required for ignition by performing concentrated ignition like in a sintering ignition furnace. It can be seen that the optimum temperature distribution is obtained when In addition, when actually applying it to an ignition furnace, the length of the burner should be equal to the width of the ignition furnace, or the width of the ignition furnace should be divided into several parts.
Burners may be installed in series corresponding to each, and in this case, they are installed and burned as shown in FIGS. 4a and 4b.

[Brief explanation of the drawing]

Figures 1a, b, and c are longitudinal sectional views, plan views, and cross-sectional views of the ignition furnace of a sintering machine equipped with a conventional gas burner, and Figure 1d is the width of the ignition furnace of the raw material layer at that time. FIGS. 2a, b and c are perspective views, plan views and cross-sectional views of a gas burner according to one embodiment of the present invention, and FIG. 3a is shown in FIG. 2c. An explanatory diagram of an example of dimensions when implementing a gas burner, Figures 3b and 3c are graphs showing the combustion situation when burning with the gas burner according to the present invention, and Figures 4a and b are according to the present invention. FIG. 1 is a longitudinal cross-sectional view and a plan view showing an ignition furnace of a sintering machine equipped with a gas burner. Code, 5... Fuel gas passage, 6... Combustion air passage, 5a, 6a... Throttle part, 7... Mixing chamber,
8, 9...Hetsuda.

Claims (1)

[Claims] 1. The fuel gas passage and the combustion air passage are arranged in layers with elongated slit-like cross sections, and the fuel gas passage is arranged in the center, and the combustion air passage is arranged parallel to both sides of the central fuel gas passage. a constricted portion is formed at the tip of the fuel gas passage, and the tips of the combustion air passages on both sides are also constricted to form a constricted portion, and these constricted portions are directed toward the constricted portion of the fuel gas passage, and In an ignition gas burner such as a sintering machine, in which a mixing chamber is connected to the tip of each throttle part of the fuel gas passage and the combustion air passage, the tips of the fuel gas passage and the combustion air passage are connected to a mixing chamber. It is configured as an open section with a slit-shaped cross section that is open as it is, and furthermore, the length of the mixing chamber connected to the tip of each constriction section is 50 to 50 mm.
A gas burner for ignition of sintering machines, etc., characterized by having a diameter of 100 mm.