JPS63111112A - Direct reduction apparatus for iron ore - Google Patents

Abstract

PURPOSE:To improve the using efficiency of soot and to facilitate the production of sponge iron briquette by removing and recovering the soot sticking to the surface of sponge iron for preventing the development of cluster in a shaft furnace by inert gas recycling having a dust remover at the time of producing the sponge iron by reducing iron ore in the shaft furnace. CONSTITUTION:The granular iron ore 1 is charged in the shaft furnace 2 and by blowing the high temp. reducing gas generating from a reducing gas generator 7 from a tuyere 14 to produce the sponge iron 1a by solid reduction of the iron ore. In this case, the soot generated by incompletely burning the natural gas in a soot generator 20, is blown in the furnace from the tuyere 14, to prevent the development of cluster by sticking to the surface of iron ore. The sponge iron with soot stuck to the surface is flowed down from the upper inlet of lower discharging hopper 15b and then, by blowing N2 gas of N2 gas recycling piping 23 having the dust remover 25 from a nozzle 21a, the soot on the sponge iron surface is removed and recovered by the dust remover 25, to be reutilized in the shaft furnace. The sponge iron after removing the soot is easily made into briquette by a briquette machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for removing soot from reduced iron in a shaft furnace type reduction device among direct reduction devices for iron ore.

[Conventional technology]

An overview of the shaft furnace type direct reduction apparatus to which the present invention is applied will be explained with reference to a schematic overall configuration explanatory diagram shown in FIG.

This device includes a raw material conveyor 3 and a raw material charging device 4 that supply iron ore 1 in the form of granules or pellets to a shaft furnace (hereinafter referred to as the furnace) 2, and a discharge device that discharges reduced iron 1a to the outside of the furnace 2. 5, a container 6 for transporting the discharged reduced iron 1a to a pre-kerating plant or a storage yard (none of which are shown), a reducing gas generating furnace 7 such as hydrogen (H2), and a gas compressor. 9, a decarboxylation facility 10, a heating furnace 8, and other main components of a recycled reducing gas system 11.

The raw material charging device 4 includes an upper hopper 12a and a lower hopper 12b attached to the top of the furnace 2, and two upper and lower seal valves 13a, 13.
1) Karanashi, upper, lower hora/”12a.

121) between the seal valve 13a and the lower hot spring 12b
and the furnace 2 are separated gas-tightly by a seal valve 131), and the raw material 1 supplied from the container 3 according to a predetermined time schedule is transferred to the furnace 2 while maintaining airtightness from the atmosphere. Can be supplied within Inside the furnace 2,
Iron ore 1 is always retained at a predetermined level through a cutting device 15, which will be described later, and high-temperature reducing gas (H2, etc.) is supplied into the furnace from a large number of tuyeres 14 provided on the outer periphery of the lower part of the furnace body. By discharging the exhaust gas from a pipe line 11a at the top of the furnace, the iron ore 1 can be reduced to reduced iron 1a, that is, a sponge method. The exhaust gas at the top of the furnace is sucked through the pipe 11a by the gas compressor 9, pressurized, and sent to the decarboxylation equipment 10, where it is purified to the required purity and further regenerated into high-temperature reducing gas in the heating furnace 8. It is circulated and supplied to the tuyere 14 from the rear pipe line 11b1, the regulating valve 11C, and the pipe line 11d via the annular pipe 11θ. In this case, the amount of reducing gas consumed in the decarboxylation equipment 10 and the like is replenished with fresh gas from the reducing gas generating furnace 7. On the other hand, the reduced iron discharge device g15 includes a cutting device 15 such as a table feeder attached to the bottom of the furnace 2, upper and lower discharge hoppers 16a and 16b, and upper and lower double seal valves 17a.
, 17b, the upper discharge hopper 16a has an integral structure with the furnace 2, and the inside of the discharge hopper 16a, that is, the inside of the furnace 2 is connected to the lower discharge hopper via the upper double seal valve 17a. It is airtightly partitioned. The lower discharge hopper 161) is gas-tightly separated from the atmosphere by a lower seal valve 171). Also, the upper and lower hollers are '16a.

16t) respectively form an inverted conical cylinder or a square pyramidal cylinder with an appropriate inclination angle in order to smoothly discharge the reduced iron 1b by gravity. Here, the inside of the furnace 2 and the inside of the upper discharge hopper 16a are normally maintained at a predetermined pressure equal to or higher than atmospheric pressure. The soot generating furnace 20 completely burns natural gas (NG) in compressed air or I2 cable-enriched air to generate a medium-containing reducing gas. In the figure, 18 is an exhaust pressure valve, 19 is a medium-containing reducing gas supply pipe, and 30 is a preheating furnace.

With the above configuration, while the iron ore 1 descends in the furnace 2, it comes into contact with the reducing gas blown in from the tuyere 14 and is reduced to high-purity sponge 1&, which is sequentially passed through the cutting device 15. It is discharged to the upper discharge hopper 16FL. The hopper 16
In the sponge method 1a in a, when a certain amount is reached, the upper double seal valve 17a is opened and closed, and the lower discharge hopper 161 is discharged by gravity.
). In this case, the exhaust pressure valve 18 is closed. Next, when discharging the sponge 1a in the lower hopper (t161) to the container 6, the upper double seal valve 17a is closed and the exhaust pressure valve 18 is opened to the atmosphere. After bringing the pressure (equivalent to . . . ) to atmospheric pressure, it can be easily discharged by gravity by opening the lower double seal valve 17b. Here, the sponge material 1a in the container 6 is granular and has a high temperature (
(e.g., approximately 800°C) to facilitate transportation to the next processing step, such as a steel factory or storage yard, and to prevent re-oxidation of the surface caused by the atmosphere during transportation and storage. Usually, it is transported to a briquetting plant adjacent to the furnace 2, where it is compression-molded into briquettes of the desired shape, cooled, and stored in a storage yard.
Alternatively, it is transported to a steel factory.

[Problem that the invention seeks to solve]

In the conventional direct reduction equipment described above, it is necessary to control extremely precise operating conditions such as the properties of the reducing gas suitable for the brand of iron ore being processed and the gas temperature in the furnace. Due to the dispersion of iron ores, iron ores often combine with each other in the furnace 2, forming so-called clusters (C1us
ter), and these clusters gradually expand in size, resulting in ore clogging in the furnace, a so-called shelf-hanging phenomenon, which ultimately leads to a serious accident in which the furnace is unable to operate. .

Therefore, in the conventional apparatus described above, soot is supplied from the pipe line 19 to the annular pipe 118, and is blown into the furnace 2 through the tuyere 14 together with the reducing gas (H2, etc.), and the iron ore 1 and reduced iron in the furnace are By attaching soot to the surface of 1a, the occurrence of siffusion is prevented.

However, when soot is blown into the furnace 2 in this way, the container 6
The soot adheres to the surface of the sponge 1a that is discharged to the container, and if compression molding is performed in this state, for example, in a roll-type briquette machine, the adhering soot will inhibit the compression bonding of the sponge 1a. A major problem arises in that briquettes cannot be formed into a predetermined shape.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention (a) blows an inert gas such as nitrogen (N2) into the upper part of the lower discharge hopper around the flow path of the reduced iron that falls and flows into the hopper; An annular blow hood is provided.

(b) A blower and a conduit are provided to supply inert gas (N2) to the blow hood. (c) Inert gas (N2) blown into the hot spring from the upper part of the lower discharge hopper,
Pipe line leading to the suction side of the blower (inert gas pipe line)
is provided, and a blood remover is interposed in the conduit.

[Effect]

The inert gas blown into the reduced iron flowing in the lower discharge hopper separates and removes soot. The soot-containing inert gas extracted from the exhaust gas pipe at the top of the lower discharge hopper is blown into the lower discharge hopper around the inflowing reduced iron after the soot is removed by a dethromer, and the inert gas is inert. Configure gas recycling.

〔Example〕

A detailed explanation will be given below with reference to the drawings. FIG. 1 is a schematic overall configuration explanatory diagram of the iron ore direct reduction apparatus of the present invention.
Components that are the same or similar to those of the conventional device shown in FIG. 2 are designated by the same reference numerals, and redundant explanation of the configuration will be omitted.

In the apparatus of the present invention, as shown in the figure, within the lower discharge hopper 161) of the reduced iron discharge device 5, the reduced iron flows approximately equally in the circumferential direction along the periphery of the inflow passage 1b, which is charged by gravity from the upper discharge hopper 16a. A substantially annular blowing hood 21 having a plurality of gas nozzles 21a arranged at pitches and in the vertical direction is attached, and an inert gas such as nitrogen (N2) is supplied to these nozzles 21a by a blower 22 through a conduit. 2
Reduced iron 1a is supplied through 31L1 valve 231) and is falling.
The structure is such that soot can be sprayed from around the reduced iron 1a to separate and scatter soot that has adhered to or mixed in the reduced iron 1a. On the other hand, an exhaust gas pipe 23Q is installed at an appropriate position on the top of the discharge hopper 161), and a mixed gas of inert gas (N2) and soot blown from the gas nozzle 21a is transferred to the valve 23d1, the pipe 23e1, the gas cooler 24, the pipe The recycled gas pipe 23 is configured to suction the gas by the blower 22 through the dust remover 25 and the pipe 23g, and supply it again to the blowing hood 21. If necessary, a gas heater (not shown) may be installed on the exit side of the dust remover 25 to prevent cooling of the reduced iron. The inner dimensions of the blowing hood 21 are such that the inner surface of the hood 21 is close to the falling reduced iron 1a without coming into contact with it, and the height is such that the top of the reduced iron 1a staying in the hopper 16b and the hopper An appropriate space is provided between the tops of the nozzle 211L.
It is set so that the soot that has adhered to and accumulated on the reduced iron 1a can be efficiently separated and scattered by the gas (N2) blown in from the exhaust gas pipe 23C, and can be easily sucked and discharged together with the gas (N2) into the exhaust gas pipe 23C. Ru.

Next, the operation of the apparatus of the present invention having the above configuration will be described. In addition, FIG. 1 shows reduced iron 1a into the lower discharge hopper 16b.
is being discharged, and inert gas (N2) is being circulated and supplied.

First, before discharging the reduced iron 1a from the upper discharge hopper 16a to the lower hopper 16b, the blower 22 is started, the valves 23b and 23d are opened, and gas (N2) is blown into the hood 2.
1 and recycled, open the upper double seal valve 17a. Thus, while the reduced iron 1a falling by gravity into the lower hopper 16b passes through the blowing hood 21, the attached or mixed soot is separated and scattered by the gas, and the reduced iron 1a is sent together with the gas from the pipe 23C to the gas cooler 24. After the gas temperature is cooled to a required temperature, the dust containing soot is removed by the dust remover 25, and the purified gas (N2) is circulated and supplied to the blower hood 21 by the blower 22. . If necessary, a gas heater (not shown) is provided on the exit side of the dust remover 25 to prevent cooling of the reduced iron. Note that an inert gas generator (not shown) is installed and connected to the inert gas recycle line 23 to replenish the amount of gas consumed in the inert gas recycle line 23 and the lower discharge hopper 16).

After the discharge of the reduced iron 1a to the hopper 161) is completed, the double seal valve 17a is closed, and after the soot in the conch/hole 16b is completely removed, the valves 231) and 23 (L) are closed, and Then, the blower 22 is stopped to prepare for the next discharge operation.The reduced iron 1a is discharged into the container 6 according to the same procedure as in the conventional device (Fig. 2), transported to the briquetting plant, and formed into briquettes. .

Furthermore, in the apparatus illustrated above, the gas blowing nozzle of the lower discharge hopper 16b is made into a substantially annular blowing hood, but the shape of the nozzle is not limited to this, and in short, the gas is discharged from the discharge hopper 161). Of course, any structure is sufficient as long as it does not obstruct the flow of the reduced iron 1a and allows gas to pass through while the reduced iron is falling.

〔Effect of the invention〕

When discharging reduced iron from the upper discharge hopper to the lower discharge hopper, inert gas (M2
) to separate and scatter the soot that has adhered to and mixed in the reduced iron.The reduced iron discharged into the container is free of soot and dirt, unlike conventional equipment.
As a result, in the subsequent briquette machine, the reduced iron discharged from the reduction device can be used to form briquettes in a desired shape very easily and stably, thereby improving production efficiency. The inert gas that is blown into the bottom exhaust pipe flows through the recycling pipe and is recycled, making it economical.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the overall configuration of a shaft furnace type direct reduction apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the overall configuration of a conventional shaft furnace type direct reduction apparatus. 1...Iron ore raw material 1a...Reduced iron 1b...
・Reduced iron flow path 2...Shaft furnace 5...Reduced iron discharge device 16a, 16b...Discharge hopper 20
...Soot generating furnace 21...Blowing hood 21a.
...Gas nozzle 22...Blower 23...Inert gas recycling pipe 24...Gas cooler 25...Dust removal device sub-agent 2 patent attorneys and non-Kaimoto important literary figures

Claims (1)

[Claims] A direct reduction device for iron ore that supplies reducing gas added with fine carbon (suit) into a shaft furnace to reduce granular or pelleted iron ore to reduced iron, and discharges the reduced iron out of the furnace at a high temperature. In this method, a substantially annular blowing hood is provided at the upper part of the lower discharge hopper of the reduced iron discharge device for blowing an inert gas from the periphery against the flow of the reduced iron along the flow path of the reduced iron falling into the hopper. , an inert gas comprising a pipe line including a blower that supplies inert gas to the blowing hood, and a pipe line including a dust remover that sucks inert gas from the upper part of the lower discharge hopper and supplies it to the blower. A direct reduction device for iron ore, characterized in that a recycling pipe is provided and soot separated from reduced iron is removed by a dust remover in the inert gas recycling pipe.