JPH04191310A - Pre-reduction furnace in smelting reduction device for iron ore - Google Patents

Abstract

PURPOSE:To easily remove dust stucked to the inner face of a nozzle hole by providing gas flow inlets on the lower part of cylindrical body embedding an upper part in a dispersing plate body in a pre-reduction furnace to be nozzle holes and allowing the lower part of this cylindrical body to be opened/closed with a lid body. CONSTITUTION:The dispersing plate 5 penetrating plural nozzle holes 6 is disposed in the inside of the pre-reduction furnace body A and segmented into a pre-reduction chamber 13 forming a fluidized bed at the upper part and a gas injecting chamber 14 at the lower part. In the above-mentioned fluidized bed type pre-reduction furnace, the nozzle holes 6 in the above-mentioned dispersing plate 5 are constituted of metal cylindrical bodies 7 embedded in the refractory-made dispersing plate body 51 at the upper part and arranging the gas flow inlets 8 at the lower part. Upper part of this cylindrical body 7 is opened and the lower end hanging downward is penetrated to out of the furnace at furnace bottom part 9, and this lower end is closed with the lid body 10 capable of opening/closing. During operating the pre-reduction furnace, reducing gas from a gas introducing hole 15 is introduced into the pre-reduction chamber 13 from the gas flow inlet 8 through the cylindrical body 7 and the nozzle hole 6, and also by suitably opening the lid body 10, cleaning device 11 providing an injection pipe 12 is inserted and the stuck dust in the nozzle hole 6 is blasted and removed.

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]

For smelting reduction of iron ore, an economical method is to configure the equipment with a smelting reduction furnace and a fluidized bed pre-reduction furnace, and use the exhaust gas generated in the smelting reduction furnace to fluidize the fluidized bed of the pre-reduction furnace and as reducing gas. It is preferable. 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. The exhaust gas (reducing gas) from the melting reduction furnace is introduced into the gas blowing chamber (wind box) below the distribution plate. This exhaust gas is blown out into the preliminary reduction chamber above through the nozzle hole of the 5 dispersion plate.
This forms a fluidized bed to pre-reduce and pre-heat the iron ore.

[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 dust contains a large amount of alkaline 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 velocity inside the nozzle hole is extremely high (flow velocity: tens of meters or more), so dust is particularly strong on the inner surface of the nozzle hole. Easy to adhere to. Such dust deposits gradually grow and eventually impede the smooth flow of exhaust gas, making it impossible to form a proper fluidized bed. Second
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 preliminary reduction furnace that can easily clean and remove dust adhering to the inner surface of a nozzle hole.

[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, and 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 layered pre-reduction furnace, each nozzle hole of the dispersion plate is connected to a cylindrical body with an open upper end, the upper part of which is embedded in the dispersion plate body made of refractory material, and the lower part of the dispersion plate that hangs below the five dispersion plates. It is characterized in that it is composed of a cylindrical body in which an inlet is formed and whose lower end extends through the bottom of the furnace and is located outside the furnace, and the lower end of each cylindrical body is closed with a lid that can be opened and closed.

[Effect]

The exhaust gas supplied from the gas inlet to the gas blowing chamber below the distribution plate enters the cylinder (nozzle hole) from the gas inlet at the bottom of the cylinder and is blown into the preliminary reduction chamber above the distribution plate.

While the furnace is in operation, with a certain amount of dust attached to the inner surface of the nozzle hole, open the lid at the bottom of the cylinder located outside the furnace, insert the cleaning means from the open end, and remove the dust adhered to the inner surface of the cylinder. Clean and remove. As this cleaning means, means such as a blasting device (sandblasting, shot blasting, etc.) or a blasting device can be used.

By cleaning the cylinders one by one in this manner, the amount of gas supplied to the preliminary reduction chamber is hardly affected.

〔Example〕

FIG. 1 shows an embodiment of the present invention, where A is a pre-reducing furnace main body, 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. The upper part of this dispersion plate 5 constitutes a preliminary reduction chamber 13, and the lower part constitutes a gas blowing chamber 14. A gas inlet 15 is provided on the side of the gas blowing chamber 14, and a gas conduit 16 from the 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 51 made of a refractory material. The lower part 71 of this cylinder 7 hangs below the distribution plate, and the lower end penetrates the furnace bottom 9 and is located outside the furnace.

A gas inlet 8 is formed in the side of the lower part 71 of the cylinder, and the lower end of the cylinder located outside the furnace is closed with a lid 10 that can be opened and closed.

Note that 17 is a discharge port for discharging dust and blasting particles discharged from the gas inlet during cleaning of the cylindrical body to the outside of the furnace.

According to the above configuration, the exhaust gas introduced into the gas blowing chamber 14 from the gas inlet 15 flows into the cylinder 7 (nozzle hole 6) from the gas inlet 8 in the lower part 71 of the cylinder, and flows into the upper cylinder body 7 (nozzle hole 6). It is blown into the preliminary reduction chamber 13.

After operating for a certain period of time, dust adheres to the inner surface of the cylindrical body 7.

At this stage, the cylinders 7 are cleaned one by one.

This cleaning is performed while the furnace is running. After opening the lid 10 at the lower end of the cylinder located outside the furnace, the cleaning device 11 is inserted from the open end to clean and remove dust attached to the inner surface of the cylinder. do. In the embodiment shown in FIG. 1, a blasting device (sandblasting, shot blasting, etc.) is used as the cleaning device 11.
is used. This blasting device has an injection pipe 12 for performing sandblasting and the like, and this injection pipe 12 is inserted into the cylinder 7 to clean the inner surface of the cylinder. In addition, 12
0 is a seal body provided on the outer periphery of the injection pipe to seal gas.

Note that since the cylinders can be cleaned one by one as described above, the amount of gas supplied to the preliminary reduction chamber is hardly affected.

〔Effect of the invention〕

According to the present invention described above, the dust deposited on the inner surface of the nozzle hole can be easily cleaned and removed while the furnace is in operation, so that the exhaust gas can be stably blown into the fluidized bed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention and a cleaning state of a nozzle hole. FIG. 2 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
9 is a gas inlet, 9 is a furnace bottom, and 10 is a lid. 71 is the lower part of the cylinder.

Claims (1)

[Claims] A fluidized bed pre-reduction furnace that has a dispersion plate with a large number of nozzle holes penetrated inside the furnace, the upper part of the dispersion plate constitutes a pre-reduction chamber, and the lower part of the distribution plate constitutes a gas blowing chamber. Each nozzle hole of the distribution plate is formed by a cylinder whose upper end is open, the upper part of which is embedded in the distribution plate main body made of refractory material, and the gas inlet is formed in the lower part hanging down below the distribution plate, A preliminary reduction furnace for iron ore smelting and reduction equipment, characterized in that the lower end of each cylinder is formed by a cylinder whose lower end penetrates through the furnace bottom and is located outside the furnace, and the lower end of each cylinder is closed with a cover body that can be opened and closed. .