Specialized metallurgical processes – compositions for use therei – Processes – Producing or treating free metal
Reexamination Certificate
1999-01-04
2001-05-01
King, Roy (Department: 1742)
Specialized metallurgical processes, compositions for use therei
Processes
Producing or treating free metal
C075S453000, C075S487000, C266S156000, C266S157000, C266S172000
Reexamination Certificate
active
06224650
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for manufacturing molten iron by using a calcination furnace, and a manufacturing method therefor. More specifically, the present invention relates to an apparatus for manufacturing molten iron by using a calcination furnace, and a manufacturing method therefor, in which a high temperature reducing gas (1000 to 1100° C.) from a melter gasifier is used as a calcination heat in a calcination furnace so as to cool the high temperature reducing gas to the optimum reduction temperature (800 to 850° C.), and so as to supply the cooled reducing gas to a shaft furnace, whereby the manufacture of the molten iron can be efficiently carried out, and a high thermal efficiency is realized even without a separate gas cooling device.
2. Description of the Prior Art
Generally, the molten iron manufacturing apparatus which utilizes the smelting reduction such as COREX, DIOS, HISMELT or the like which is under study for replacing the blast furnace is equipped with a melter gasifier and a shaft furnace. Thus by utilizing the high temperature reducing gas from the melter gasifier, the iron ore which is filled in the shaft furnace is made to undergo a reduction. Then the reduced iron ore which has undergone the reduction is transferred to a melter gasifier to make it undergo a final reduction.
As shown in
FIG. 1
, U.S. Pat. No. 4,978,387 discloses a molten iron manufacturing apparatus which uses the ordinary coal. In this conventional molten iron manufacturing apparatus, an iron ore
1
a
and additives (lime stone and dolomite)
1
b
are put into a shaft furnace
2
, and then the iron ore
1
a
is made to undergo a reduction by 90 to 95%. Then a melter gasifier
5
is filled with an ordinary coal
3
, the reduced iron ore and a calcined additive. Then the ordinary coal is burned within the melter gasifier so as to produce heat and a reducing gas. By utilizing the heat and the reducing gas, the iron ore which has been reduced in the shaft furnace
2
is smelted and finally reduced for the second time. Under this condition, the gas which is produced in the melter gasifier
5
has a temperature of 1000 to 1100° C.
Meanwhile, the reducing gas which is produced in the above described manner is transferred through a generator gas line
6
(which is connected to the melter gasifier
5
) to a cyclone
7
. The cyclone
7
captures the dusts within the reducing gas, and the high temperature reducing gas is supplied through a reducing gas line
9
to the shaft furnace
2
. Meanwhile, the dusts which have been captured by the cyclone
7
are made to return through a dust burner
8
to the melter gasifier
5
.
The reducing gas which is supplied to the shaft furnace
2
has to be maintained at a temperature of 800-850° C., and therefore, the hot reducing gas which has been discharged from the cyclone
7
and which has a temperature of 1000-1100° C. has to be necessarily cooled. In order to be cooled, a part of the hot reducing gas which has removed the dusts is transferred through a cooling gas line
10
(which is connected to the reducing gas line
9
) to a venturi scrubber
11
so as to be cooled.
The reducing gas which has been cooled by the venturi scrubber
11
is supplied by a compressor
12
to a mixed gas line
13
which is connected to the generator gas line
6
of the melter gasifier
5
. Thus the cooled reducing gas is mixed with the hot reducing gas which has been produced in the melter gasifier
5
, with the result that the hot reducing gas of 1000-1100° C. is adjusted to the optimum reducing temperature of 800-850° C. The reducing gas which has been temperature-adjusted is finally exactly adjusted to 800-850° C. in the reducing gas line
9
so as to be supplied to the shaft furnace
2
. Further, this reducing gas furnishes heat for the reduction of the iron ore
1
a
and the calcination of the additives (lime stone and dolomite)
1
b.
However, in the above described conventional molten iron manufacturing apparatus which uses the ordinary coal, the reducing gas which is produced in the melter gasifier has a temperature of above 1000° C. Therefore, its temperature is adjusted to an optimum reducing temperature of 800-850° C., and then, the reducing gas is supplied to the shaft furnace. For this purpose, a separate cooling device such as the venturi scrubber
11
is necessarily required. Further, if the cooled reducing gas is to be supplied to the mixed gas line
13
which is connected to the melter gasifier
5
, a separate pressing and sending device such as the compressor
12
is required, and the compressor is frequently disordered, thereby causing problems.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional techniques.
Therefore it is an object of the present invention to provide an apparatus for manufacturing molten iron by using a calcination furnace and a manufacturing method therefor, in which additives are heated and calcined by using a hot reducing gas, and thus, the hot additives are supplied to a shaft furnace and a melter gasifier, so that the heat loss due to the temperature-raising and calcination of the additives can be decreased.
It is another object of the present invention to provide an apparatus for manufacturing molten iron by using a calcination furnace and a manufacturing method therefor, in which a separate cooling device is excluded so as to simplify the facility, and the hot reducing gas is cooled to the optimum reducing temperature without using the cooling device so as to maximize the thermal efficiency.
In achieving the above objects, the apparatus for manufacturing molten iron including a shaft furnace for receiving an iron ore and additives, and a melter gasifier for receiving a reduced iron ore, calcined additives and an ordinary coal according to the present invention includes:
a calcination furnace for receiving a hot reducing gas through a reducing gas line from a cyclone (which is connected through a generator gas line to the melter gasifier), for receiving the additives, and for calcining the additives by means of the hot reducing gas to cool the hot reducing gas to an optimum reducing temperature suitable for the shaft furnace so as to send the reducing gas through a reducing gas line to the shaft furnace; and a plurality of additive feeding lines connected between the calcination furnace, the shaft furnace and the melter gasifier, for supplying the calcined additives to the shaft furnace and to the melter gasifier, after the additive has been calcined by the hot reducing gas in the calcination furnace.
In another aspect of the present invention, the method for manufacturing a molten iron by using a shaft furnace for receiving an iron ore and additives, and a melter gasifier for receiving a reduced iron ore, calcined additives and ordinary coal, so as to reduce the iron ore to a molten iron according to the present invention includes the steps of:
burning the ordinary coal within the melter gasifier, and smelt-reducing a reduced iron ore, so as to produce a hot reducing gas;
separating and capturing dusts contained within the hot reducing gas;
sending the hot reducing gas to a calcination furnace to calcine the additives contained therein, so as to cool the hot reducing gas to a temperature level suitable for the shaft furnace;
supplying the cooled reducing gas to the shaft furnace to reduce the iron ore and to calcine the additives; and
putting the reduced iron ore and the calcined additives of the shaft furnace into the melter gasifier, and making the reduced iron ore undergo a final reduction.
REFERENCES:
patent: 3936296 (1976-02-01), Campbell
patent: 4181502 (1980-01-01), Weber et al.
patent: 4195821 (1980-04-01), Beggs et al.
patent: 4448402 (1984-05-01), Weber et al.
patent: 4588439 (1986-05-01), Kepplinger et al.
patent: 4849015 (1989-07-01), Fassbinder
patent: 4978387 (1990-12-01), Kepplinger
patent: 5630862 (1997-05-01), Greenwalt
patent: 1167368 (1964-04-01), None
patent: WO 94
Jung Young Chae
Lee Sang Deok
Park Yoon Chul
King Roy
McGuthry-Banks Tima
Pohang Iron & Steel Co. Ltd.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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