JPH04116116A - Prereducing furnace for iron ore smelting reduction equipment - Google Patents

Abstract

PURPOSE:To effectively prevent the deposition and growth of dust in a nozzle hole by forming the nozzle hole in the diffuser plate of the fluidized-bed prereducing furnace with the suspended cylinders with the gas inlet directed toward the part except a gas introducing port. CONSTITUTION:A waste gas from a smelting and reducing furnace (not shown in the figure) is introduced from the gas introducing port 11 of a prereducing furnace main body A and injected into a prereducing chamber 8 from a gas blowing chamber 10 through the nozzle hole 6 of a diffuser plate 5 to form a fluidized bed. The iron ore is prereduced in the bed, then supplied to the smelting reduction furnace and further smelting-reduced. In this prereducing furnace, the hole 6 is formed with cylinders 7 with the upper part embedded in the diffuser plate main body 8 and the lower end closed. A gas inlet 72 directed toward the part except the position of the gas introducing port 11 is formed in the side part of the cylinder 7 below the plate 5. Consequently, the inflow of dust in the waste gas to the hole 6 is prevented, and the deposition of dust on the inner surface is effectively obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to an improvement of a preliminary reduction furnace in an iron ore smelting reduction facility.

[Conventional technology]

In iron ore smelting reduction, there is a method in which the equipment is depleted from a smelting reduction furnace and a fluidized bed pre-reduction furnace, and the exhaust gas generated in the smelting reduction furnace is used to fluidize the pre-reduction furnace fluidized bed and as reducing gas. Economically favorable. And as this fluidized bed,
A bubbling fluidized bed is particularly advantageous because it has a high degree of technical perfection and can suppress powdering caused by preheating and reduction of ore.

This pre-reduction furnace is equipped with a dispersion plate having a large number of nozzle holes (gas holes) for ejecting gas therein, and iron ore is charged into a pre-reduction chamber formed above the dispersion plate. 1. Exhaust gas (reducing gas) from the melting reduction furnace is introduced into the gas blowing chamber (wind box) below the dispersion plate. This exhaust gas is blown out into the preliminary reduction chamber above through the nozzle hole of the dispersion plate.
A fluidized bed is formed by the melting, and the iron ore is pre-reduced and preheated.

[Problem to be solved by the invention]

In such a preliminary reduction furnace, adhesion of dust contained in the exhaust gas to the dispersion plate poses a major problem.

In other words, the exhaust gas generated from the smelting reduction furnace contains a large amount of dust, and in many cases, fine dust of 10 μm or less cannot be removed by a dust removal device such as a cyclone. is directly introduced into the preliminary reduction furnace.

Since the above-mentioned dust contains a large amount of alkali compounds such as S, Na, and K, it becomes sticky in the exhaust gas at a temperature exceeding 900°C. Therefore, the dust introduced into the pre-reduction furnace will stick to the bottom surface of the dispersion plate and the like. It will adhere to the inner surface of the nozzle hole. In particular, the exhaust gas introduced into the gas blowing chamber is contracted when passing through the nozzle hole, and the gas flow rate inside the nozzle hole is extremely high (flow speed: several tens of m/see or more), so dust is generated on the inner surface of the nozzle hole. Particularly easy to adhere firmly. Such dust deposits gradually grow and eventually impede the smooth flow of exhaust gas, making it impossible to form a proper fluidized bed. Third
The figure shows such a situation, where 1 is a fluidized bed, 2 is a dispersion plate, 3 is a gas blowing chamber below the dispersion plate, and 4 is dust that has adhered and grown.

The present invention was made in view of such conventional problems, and an object of the present invention is to provide a pre-reduction furnace that can effectively prevent dust from adhering to and growing on the nozzle holes of the dispersion plate.

[Means to solve the problem]

For this reason, the present invention has a dispersion plate with a large number of nozzle holes penetrated inside the furnace, the upper part of the dispersion plate constitutes a preliminary reduction chamber, and the lower part of the dispersion plate constitutes a gas blowing chamber, In a fluidized bed pre-reduction furnace in which a gas inlet is formed on the side of the gas blowing chamber, the nozzle hole of the dispersion plate is formed into a cylinder whose upper end is open and whose lower end is closed, and whose upper part is made of a fireproof material. A gas inlet is embedded in a dispersion plate body made of a material, a lower part thereof hangs below the dispersion plate, and a gas inlet is formed in a side portion below the dispersion plate, facing in a direction other than the gas inlet position in the furnace circumferential direction. Its feature is that it is constructed from a cylindrical body.

[Effect]

The exhaust gas supplied from the gas inlet to the gas blowing chamber below the distribution plate enters the nozzle hole from the gas inlet at the bottom of the cylinder and is blown into the preliminary reduction chamber above the distribution plate. Here, the dust in the exhaust gas introduced from the gas inlet has an inertial force, and the gas inlet of the cylinder is formed so as to face in a direction other than the gas inlet position in the furnace circumferential direction. Because of this, it is difficult for dust to enter the gas inlet of the cylindrical body, and therefore the amount of dust flowing into the cylindrical body, that is, the nozzle hole, is suppressed, and the formation of deposits due to dust on the inner surface is effectively suppressed. It will be done. In addition, since the gas inlet is provided on the side of the cylinder below the distribution plate, the problem of deposits growing on the bottom surface of the distribution plate clogging the nozzle hole entrance as shown in FIG. 3 can be appropriately solved. It can be avoided.

〔Example〕

1 and 2 show an embodiment of the present invention,
A is a main body of the preliminary reduction furnace, and 5 is a dispersion plate that partitions the inside of the furnace, and this dispersion plate 5 has a large number of nozzle holes 6 provided in the vertical direction. The upper part of this dispersion plate 5 constitutes a preliminary reduction chamber 9, and the lower part constitutes a gas blowing chamber 10.

A gas inlet 11 is provided on the side of this gas blowing chamber 10, and a gas conduit 12 from a melting reduction furnace is connected to this.

Each nozzle hole 6 of the distribution plate 5 is constituted by a cylinder 7 (metal cylinder) whose upper part is embedded in a distribution plate main body 8 made of a refractory material. The lower part 71 of this cylindrical body 7 hangs below the dispersion plate, and the lower end is closed.

A gas inlet lower 2 is formed on the side of the lower portion of the cylinder 71 below the distribution plate and faces in the direction opposite to the position of the gas inlet 11 in the furnace circumferential direction.

According to the above configuration, the exhaust gas introduced into the gas blowing chamber 10 from the gas inlet 11 enters the cylinder 7 (nozzle hole 6) from the gas inflow lower 2 of the cylinder lower part 71, and enters the upper reserve. It is blown into the reduction chamber 9.

At this time, since the dust in the exhaust gas introduced from the gas inlet 11 has an inertial force, the gas inlet lower cylindrical body is formed facing in the direction opposite to the position of the gas inlet 11 in the furnace circumferential direction. Therefore, the amount of dust flowing into the nozzle hole is suppressed, and dust adhesion on the inner surface of the nozzle hole is effectively suppressed. Furthermore, since the gas inflow lower 2 is provided on the side of the cylinder below the dispersion plate, there is no influence from deposits that grow on the bottom surface of the dispersion plate 5, and the deposits that grow on the bottom surface of the dispersion plate do not pass through the nozzle holes. The problem of blocking the entrance can also be appropriately avoided.

The gas inlet lower 2 is most preferably provided so as to face approximately 180 degrees opposite the position of the gas inlet 11 in the circumferential direction of the furnace, as in this embodiment, but it may be provided in other directions other than the direction of the gas inlet. This does not preclude the installation in such a way that the

〔Effect of the invention〕

According to the present invention described above, the amount of dust flowing into the nozzle hole of the dispersion plate can be significantly reduced compared to the conventional method, so that dust adhesion and growth on the inner surface of the nozzle hole can be effectively prevented. In addition, there is almost no fear that deposits growing on the lower surface of the dispersion plate will clog the nozzle hole inlet, so that the exhaust gas can be stably blown into the fluidized bed.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention,
FIG. 1 is a longitudinal sectional view, and FIG. 2 is an enlarged sectional view of the nozzle hole in FIG. 1. FIG. 3 is an explanatory diagram showing the state of dust adhesion in a conventional preliminary reduction furnace. In the figure, 5 is a dispersion plate, 6 is a nozzle hole, 7 is a cylinder, and 8
1 is the dispersion plate main body, 9 is the preliminary reduction chamber, 10 is the gas blowing chamber, 1
1 is a gas inlet, 71 is a lower part of the cylinder, 72 is a gas inlet,
A is the main body of the preliminary reduction furnace. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] A dispersion plate with a large number of nozzle holes penetrated inside the furnace is provided, the upper part of the dispersion plate constitutes a preliminary reduction chamber, the lower part of the dispersion plate constitutes a gas blowing chamber, and the side of the gas blowing chamber In a fluidized bed pre-reduction furnace with a gas inlet in the
The nozzle hole of the dispersion plate is a cylindrical body whose upper end is open and whose lower end is closed, the upper part of which is embedded in the dispersion plate body made of refractory material, and the lower part of which hangs below the dispersion plate. 1. A pre-reduction furnace for iron ore smelting and reduction equipment, characterized in that it is constituted by a cylindrical body in which a gas inlet facing in a direction other than the gas inlet position in the circumferential direction of the furnace is formed on the side of the cylinder.