JPH06180186A - Gas injection device for circulating fluidization reduction device - Google Patents

Abstract

(57) [Summary] [Objective] To provide a gas injection device for uniformly dispersing a reducing gas in a fluidized bed reduction furnace. [Structure] A solid-gas separator and a downcomer are installed in parallel in a fluidized bed reduction furnace having a windbox, and the fluidized bed reduction furnace and the windbox are connected by a plurality of introduction pipes, and an orifice is provided in each introduction pipe. A gas injection device of a circulating fluidization reduction device characterized by being provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas injection device for a circulating fluidization reduction device.

[0002]

2. Description of the Related Art A reducing gas is introduced as a main fluidizing gas into a fluidized-bed reduction furnace charged with iron ore for fluidized reduction.
A circulating fluidized reduction method is known in which the reduced ore and the gas that have been discharged are separated by a solid-gas separator, and the reduced ore is circulated and supplied below the furnace. The inventor of the present invention has previously mentioned that the Japanese Patent Application Laid-Open No. 1-244277.
No. 6, the main fluidizing gas as a high-circulation-amount high-speed flow device is opened above the circulating particle supply confluence part, and the auxiliary gas is blown from the inclined pipe near the confluence part and the lower part of the confluence part to obtain a high circulation amount Proposed.

Further, in the gas blowing apparatus of the circulating fluidized bed reducing apparatus of Japanese Patent Laid-Open No. 3-294410, a circulating fluidized bed reducing apparatus was proposed in which a gas swirling fin was provided at the tip of the main fluidizing gas introduction pipe.

On the other hand, with the aim of improving productivity and reducing equipment costs,
The size of the fluidized bed reduction furnace has been increased, but it is difficult to uniformly disperse the reducing gas in the fluidized bed reduction furnace with one main fluidized gas introduction pipe, and multiple main fluidized gas introduction pipes must be provided. Has been aimed at. However, depending on the flow condition in the furnace, the gas passes through only the pipe with the multiple main flow gas introduction pipes, and the other pipes have a small amount of gas passage, and the ore in the furnace travels along the pipe to the windbox. There is a situation in which a stable operation cannot be continued as well as a drop in efficiency.

[0005]

SUMMARY OF THE INVENTION The present invention provides a gas injection device for uniformly dispersing a reducing gas in a fluidized bed reduction furnace.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a fluidized bed reduction furnace having a windbox with a solid-gas separator and a downcomer in parallel, and to provide a fluidized bed reduction furnace and a windbox with a plurality of gas introduction pipes. And an orifice provided in each of the introduction pipes. Further, the present invention is a gas injection device of a circulating fluidization reduction device in which an orifice having a pressure loss in the introduction pipe region / a pressure loss in the fluidized bed region ≧ 20% is provided in the introduction pipe.

[0007]

The present invention will be described in detail below with reference to the drawings. In FIG. 1, a reducing gas 2 is placed in a fluidized bed reduction furnace 1 charged with iron ore.
Through a plurality of gas introduction pipes 3 as a main flowing gas,
It is introduced into the furnace from the wind box 4. The reduced ore that has been fluidized and reduced is separated from the gas in the solid gas separator 5 above the furnace,
The reduced ore is circulated and supplied to the lower side of the furnace through the downcomer 6, and a part thereof is taken out from the product reduced ore discharge port 7. FIG. 2 is a main part of the present invention, in which the gas introduction pipe 3 has gas introduction nozzles 3-1, 3-2, 3-3, and the introduction of the main gas that connects the wind box 4 and the fluidized bed reduction furnace An orifice 11 is provided in the pipe 3 so that the cross-sectional area d _{2 in the} middle of the pipe is smaller than the cross-sectional area d ₁ of the gas outlet. Reference numeral 12 is a support plate.

In the present invention, an orifice is provided in each of the plurality of main flow gas introduction pipes to increase the ventilation resistance when the gas passes through the pipes, so that the reducing gas can be uniformly dispersed in the plurality of gas introduction pipes. Becomes Further, by setting the pressure drop in that portion to 20% or more of the total pressure loss in the fluidized bed portion, almost no falling ore is dropped into the windbox. That is, as shown in FIG. 3, by securing a pressure drop of 20% or more of the pressure loss Δp ₁ in the fluidized bed portion in the gas introduction pipe portion, the amount of falling ore is almost eliminated and the gas utilization rate is improved.

Therefore, in the present invention, an orifice is formed in the gas introducing pipe, but preferably the gas introducing pipe pressure loss Δp.
₂ / Fluidized bed pressure loss Δp ₁ ≧ 20%. The present invention eliminates the concentration of gas flow in a specific pipe by providing an orifice in the main flow gas introduction pipe, and enables stable and uniform gas supply from each pipe even if the flow state changes. Become. For this reason, the ore in each part of the fluidized bed stably contacts and flows with the reducing gas, so that the entire furnace can be effectively utilized for the reduction and the gas utilization rate is improved.

[0010]

INDUSTRIAL APPLICABILITY The present invention can evenly distribute gas throughout the furnace even in a large fluidized bed reduction furnace that requires a plurality of main fluidized gas introduction pipes, eliminates falling mine, and stabilizes the flow and reduction reactions. Progresses rapidly and has an extremely great effect in practical use.

[Brief description of drawings]

FIG. 1 is an overall explanatory view of the present invention.

FIG. 2 is an explanatory diagram of a main part of the present invention.

FIG. 3 is a chart showing the relationship between gas inlet pipe pressure loss / fluidized bed pressure loss and the amount of orefall and gas utilization rate.

Claims (2)

[Claims] 1. A solid-gas separator and a downcomer are installed side by side in a fluidized bed reduction furnace having a windbox, and the fluidized bed reduction furnace and the windbox are connected by a plurality of gas introduction pipes, and in each of the introduction pipes. A gas injection device for a circulating fluidization reduction device, which is characterized in that an orifice is provided in the. 2. The gas blowing device of the circulating fluidization reduction apparatus according to claim 1, wherein the introduction pipe is provided with an orifice having a pressure loss in the introduction pipe region / a pressure loss in the fluidized bed region ≧ 20%.