JPH0510238Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fluidized bed pre-reduction furnace for iron ore used in a smelting reduction method.

(Prior Art) In order to reduce iron ore to produce hot metal, methods such as using a blast furnace and melting iron ore reduced in a shaft furnace in an electric furnace have been adopted.

In the method using a blast furnace, a large amount of coke is used as a heat source and reducing agent, and iron ore, which is an iron source, is usually sintered to improve air permeability and reducing properties in the furnace. It is loaded into.

Therefore, the blast furnace method requires a large amount of energy and labor, as well as large equipment costs.

On the other hand, in the iron ore reduction method using a shaft furnace,
It requires pre-treatment to pelletize the iron ore, and it also has the disadvantage of consuming a large amount of natural gas, which is effective as a reducing agent and heat source.

As an alternative to such conventional hot metal production techniques, the smelting reduction method is attracting attention. The smelting reduction furnace used in this method was developed for the purpose of producing molten iron-based alloys using smaller-scale equipment without being restricted by the raw materials used.

The inventors of the present invention previously proposed one of such melt reduction methods in Japanese Patent Application Laid-open No. 64807/1983.

In addition, the inventors of the present invention have filed Japanese Patent Application No. 61-286599.
63-140019), proposed a preliminary reduction device as shown in FIG.

That is, an external particle circulation device is attached to the fluidized bed reduction furnace, and the configuration of this external particle circulation device is such that a cyclone 31 is connected to an outlet provided at the upper part of the fluidized bed reduction furnace 6, and the reducing gas 11 is entrained. It captures fine particles that are scattered.

A hopper 32 for temporarily storing captured particles is connected to the lower part of the cyclone 31. The hopper 32 temporarily stores the captured particles, and a predetermined amount is returned to the fluidized bed reduction furnace 6 by a circulating cutting device 33.

On the other hand, a plurality of gas outlets 34 and 35 are formed inside the fluidized bed reduction furnace 6. A bubbling fluidized bed 36 is located between the gas outlets 34 and 35.
A circulation outlet of the external particle circulation device is provided in this bubbling fluidized bed 36.

Further, a packed bed 37 is formed at the bottom of the fluidized bed reduction furnace 6, and a bottom blowing nozzle 38 is formed in the packed bed 37.
is provided.

In the figure, 39 is a cut-off valve for charging the raw material 25 such as fine ore, limestone, etc. into the fluidized bed reduction furnace 6, 40, 41,
42 is a flow rate adjustment valve for adjusting the amount of reducing gas blown out; 43 is a valve for cutting out fine-grained reduced ore; 4
4 is a valve for cutting out coarse-grained reduced ore.

(Problems to be Solved by the Invention) The present invention provides a fluidized bed reduction device that recovers non-circulating particles in a circulating fluidized bed pre-reduction furnace to stabilize the operation.

(Means for solving the problem) The present invention is a facility for producing reduced ore, in which an external particle circulation device is attached to a fluidized bed reduction furnace, and a discharge hopper is provided through a valve at the bottom of the fluidized bed reduction furnace, and a gas This is a circulating fluidized bed pre-reduction device in which a circulating gas nozzle and/or a fluidizing gas nozzle with a flow valve are provided in the furnace height direction.

The present invention will be explained below with reference to the drawings.

FIG. 1 is an overall explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of the main parts of the present invention.

In the figure, 6 is a fluidized bed reduction furnace, 10 is a settling tower of an external particle circulation device, 4 is a discharge hopper 5 is a valve, and a cyclone 31 system is installed at the top of the furnace.
5 is a product recovery system.

In the present invention, in the lower part of the fluidized bed reduction furnace 6, circulating gas nozzles 20 and/or fluidizing gas nozzles 22 are connected to the gas source in multiple stages in the direction of the furnace height through flow regulating valves 46 and 47, respectively.

The circulating gas nozzle is preferably located at the upper part of the connection between the reduction furnace 6 and the settling tower 10, and is oriented in the direction of the furnace circumference.
It is installed at an angle of 30°-60° with the horizontal plane to form a swirling flow in the fluidized bed.

Further, a fluidizing gas nozzle is provided at the bottom of the furnace to blow gas into the reduction furnace to form a fluidized bed.

The desired raw material is fluidized in the fluidized bed reduction furnace 6, circulated and reduced in the settling tower 10, but according to experiments, non-circulated coarse particles 30 remain at the bottom of the reduction furnace, and these become agglomerated or hang on shelves. forming a phenomenon.

Therefore, in the present invention, non-circulating coarse particles can be easily captured by reducing the amount of circulating gas and/or fluidizing gas at an arbitrary timing.
Can be collected in a discharge hopper.

That is, first, by opening the valve 5a and closing the valve 5b, the reduction furnace 6 becomes at the same pressure as the recovery hopper 4,
Then, by reducing the amount of blown gas through valves 46 and 47, the non-circulating coarse particles 30 fall to the discharge hopper under their own weight and are collected. Moreover, no disturbance occurs in the internal pressure of the reduction furnace 6.

(Effects of the invention) According to the invention, by reducing the amount of circulating gas and/or the amount of flowing assimilated gas at any timing, it is possible to easily recover the non-circulating coarse particles that remain at the bottom of the reduction furnace. This has the effect of preventing particle agglomeration and shelf hanging.

[Brief explanation of the drawing]

FIG. 1 is an overall explanatory diagram of the present invention, FIG. 2 is an explanatory diagram of the main part of FIG. 1, and FIG. 3 is an explanatory diagram of a conventional example. 6...Fluidized bed reduction furnace, 4...Discharge hopper, 1
0...Settlement tower, 20...Circulating gas nozzle, 22...
...Fluidization gas nozzle.

Claims (1)

[Scope of utility model registration request] In equipment for producing reduced ore, a fluidized bed reduction furnace is equipped with an external particle circulation device, a discharge hopper is provided at the bottom of the fluidized bed reduction furnace via a valve, and a circulating gas nozzle with a gas flow valve and/or fluidization is provided. A circulating fluidized bed pre-reduction device with gas nozzles installed in the height direction of the fluidized bed reduction furnace.