JPH04110410A - Pre-reduction furnace in smelting reduction equipment for iron ore - Google Patents

Abstract

PURPOSE:To effectively prevent stickiness and growth of dust to a dispersion plate by constituting the dispersion plate in a fluidized bed type pre-reduction furnace with plural rotatable bar-like bodies parallelly arranged at the suitable interval. CONSTITUTION:The pre-reduction chamber 6 in upper part of the dispersion plate 8 for partitioning inner part of the pre-reduction furnace body 5 and a gas blowing chamber 7 in lower part, are constituted, respectively. The above dispersion plate 8 is constituted of plural rotatable bar-like bodies 9 parallelly arranged at the suitable interval 10. The exhaust gas from a smelting reduction furnace guided in the gas blowing chamber 7 is blown into the pre-reduction chamber 6 through gap 10 of each bar-like body 9 to form the fluidized bed. The above bar-like body 9 is periodically rotated and the lower face side sticking the dust is turned to the fluidized bed side. By this method, the stuck material is quickly detached and removed from the bar-like body 9 by contact with fluidized ore particles.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to an improvement of a pre-reduction furnace used in iron ore smelting and reduction equipment.

[Conventional technology]

In the smelting reduction of iron ore, the equipment consists of a smelting reduction furnace and a fluidized bed pre-reduction furnace.
A method in which the gas is used to fluidize the fluidized bed of the pre-reducing furnace and as a reducing gas is economically preferable. 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 the 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 ('a original gas) from the melting reduction furnace is introduced into the waste blowing chamber (wind box) below the dispersion plate. This waste is blown out through the nozzle holes of the dispersion plate into the pre-reduction chambers on three sides, thereby forming a fluidized bed and pre-reducing and preheating 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 1-, of which fine dust 1- of ]0 μn1 or less cannot be removed by dust removal equipment such as cyclones in many cases. The exhaust gas containing fine dust] is directly introduced into the preliminary reduction furnace.

Since the above-mentioned dust contains a large amount of alkaline earth metals such as S, Na, and K%, it becomes sticky in the exhaust gas at a temperature exceeding 900°C. It will adhere to the bottom surface of the plate and 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: about 100 m/see), so the inner surface of the nozzle hole has a small amount of water.・Especially tends to adhere firmly. Such deposits due to dust gradually grow and eventually impede the smooth flow of the reducing gas, making it impossible to form a proper therapeutic layer. Figure 8 shows this situation.]
- is a fluidized bed, 2 is a dispersion plate, 3 is a gas blowing chamber below the dispersion plate, and 4 is attached and grown dust.

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 a dispersion plate. [Means for Solving the Problems] Therefore, the present invention is characterized in that the dispersion plate is constituted by a plurality of rotatable rod-shaped bodies arranged in parallel with an appropriate gap.

[Effect]

Even on the dispersion plate of conventional pre-reduction furnaces, even if das l- adheres to the upper surface or the outlet of the nozzle hole, it easily peels off due to the violent movement of the fluidized ore particles, and therefore the inner surface of the nozzle hole Gesture 1 like the bottom surface of the dispersion plate
There is almost no risk of adhesion or growth. The present invention has focused on this fact, and consists of a dispersion plate made up of a plurality of rod-shaped bodies arranged in parallel, and by rotating each rod-shaped body periodically, the lower surface side of the rod-shaped bodies on which dust is attached is directed upward, That is, it is directed toward the flow tlJ side, and the deposited dust is peeled off by the fluidized ore particles.

The exhaust gas introduced into the gas blowing chamber is blown into the pre-reduction chamber through the gaps between the rod-like bodies constituting the distribution plate. Each rod-shaped body is periodically rotated through an appropriate rotation angle (for example, 180°).
only rotates. As a result, the lower surface of the rod to which the dust 1~ is attached is directed toward the fluidized bed, and the dust is quickly peeled off and removed from the rod by contact with the fluidized ore particles. Therefore, by periodically repeating the rotation of the rod-like body, dust may adhere to the dispersion plate.
Growth can be appropriately prevented.

Note that it is sufficient to rotate the rod-shaped body at appropriate time intervals, but depending on the situation, it is also possible to rotate the rod-shaped body all the time.

〔Example〕

1 and 2 show an embodiment of the present invention,
Reference numeral 5 denotes a main body of the preliminary reduction furnace, and 8 denotes a distribution plate that partitions the inside of the furnace.The upper part of this distribution plate 8 constitutes a preliminary reduction chamber 6, and the lower part constitutes a gas blowing chamber 7. This gas blowing chamber 7 is provided with a gas blowing port (not shown), to which a gas conduit from the melting reduction furnace is connected.

The dispersion plate 8 is composed of a plurality of rotatable rod-shaped bodies 9 arranged in parallel with an appropriate gap of 1.0.

Both ends of these rod-shaped bodies 9 are rotatably supported outside the furnace, and can be rotationally driven by the moving device N11-.

The exhaust gas introduced into the gas blowing chamber 7 is blown into the preliminary reduction chamber 6 through the gaps 10 between the rod-like bodies 9 .

The exhaust gas has a temperature of 800°C or more in the gas blowing chamber,
In order to ensure strength under such high temperature conditions, it is preferable that the rod-shaped body 9 has a hollow structure and that a cooling medium is allowed to flow inside the rod-shaped body 9.

The cross-sectional shape of the rod-shaped body 9 is arbitrary, and in addition to the round cross-section as in this embodiment, it can be any suitable shape such as a triangular cross-section as shown in FIG. 3, or a polygonal cross-section.

Further, the gap 10 between the rod-shaped bodies 9 can be formed by providing small-diameter portions 12 or groove portions 13 at intervals in the longitudinal direction of the rod-shaped bodies 9, as shown in FIGS. 4 to 6, for example. They may be formed at intervals in the longitudinal direction. In addition, in the example shown in FIG.
This is an example in which 2 is provided.

In the pre-reducing furnace as described above, when high temperature exhaust gas containing a large amount of dust passes through the dispersion plate for a long time, deposits due to the dust 1 form on the lower surface of each rod-shaped body 9 constituting the dispersion plate. . In this state, the rod-shaped body 9 is rotated as shown in FIGS. 7(a) and 7(b), and the lower surface side of the rod-shaped body to which the dust 1- is attached is directed toward the fluidized bed side.

This causes the deposits to come into contact with the fluidized ore particles.1. It is quickly peeled off and removed from the rod-shaped body. In particular, since the deposits are in a softened state at high temperatures, such removal is easy. Therefore, by periodically repeating the rotation of such a rod-like body, it is possible to appropriately prevent dust from accumulating and growing on the dispersion plate.

〔Effect of the invention〕

According to the present invention described above, since adhesion and growth of dust on the dispersion plate is effectively prevented, 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 cross-sectional view, and FIG. 2 is a cross-sectional view taken along the line ■■■ in FIG. FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention. 4 to 6 are plan views showing structural examples of rod-shaped bodies constituting the dispersion plate, respectively. Figure 7 (a)
, (b) are explanatory diagrams showing how to use the preliminary reduction furnace of the present invention. FIG. 8 is an explanatory diagram showing the state of landing on dust 1 in a conventional preliminary reduction furnace. In the figure, 5 is a furnace main body, 6 is a preliminary reduction chamber, 7 is a gas blowing chamber, 8 is a dispersion plate, 9 is a rod-shaped body, and 10 is a gap. one

Claims (1)

[Claims] 1. A pre-reduction furnace for iron ore melting and reduction equipment, characterized in that the dispersion plate is constituted by a plurality of rotatable rod-shaped bodies arranged in parallel with appropriate gaps in the pre-reduction furnace of the fluidized bed type.