Metallurgical apparatus – Geographic or structural installation
Reexamination Certificate
1999-08-19
2001-08-21
King, Roy (Department: 1742)
Metallurgical apparatus
Geographic or structural installation
C266S156000, C266S172000, C266S217000
Reexamination Certificate
active
06277324
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for manufacturing molten pig iron and directly reduced iron by using a fine iron ore, and a method for manufacturing the molten pig iron by using the apparatus.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,978,387 discloses a typical method for manufacturing molten pig iron using raw iron ore and coal without carrying out pre-treatments.
According to this U.S. patent, a raw iron ore and coal are directly used, so that pre-treating steps such as sintering and coking can be skipped unlike in the other blast furnaces, thereby simplifying the process steps and the manufacturing facilities.
As illustrated in
FIG. 1
, the apparatus
400
of U.S. Pat. No. 4,978,387 includes: a melter-gasifier
410
for gasifying the coal and for melting a reduced iron; a packed bed type Dre-reducing furnace
432
for indirectly reducing the iron ore by using a reducing gas produced by the melter-gasifier
410
; and other auxiliary facilities.
The auxiliary facilities include: a cyclone
411
, a recycling device
412
, a melter-calciner
413
, and venturi scrubbers
433
and
434
.
Within the melter-gasifier
410
, the coal is gasified to produce a reducing gas for indirectly reducing the iron ore. Further, it utilizes the generated heat to melt the reduced iron which has been indirectly reduced by the pre-reducing furnace
432
. Meanwhile, the pre-reducing furnace
432
uses the reducing-gas of the melter-gasifier
410
to indirectly reduce the raw iron ore and the additives. The reduced iron thus produced is continuously discharged to be charged into the melter-gasifier
410
.
In this method, however, the raw material can be used in the form of agglomerates (8-35 mm), and therefore, a limit is encountered in the raw material. That is, over 80% of the production of iron ore in the world is fine iron ore, but the above facility can use only lump iron ore and the expensive pellets, this being a serious disadvantage.
Meanwhile, U.S. Pat. No. 5,192,486 discloses a direct iron ore reducing apparatus which uses fine iron ore.
As shown in
FIG. 2
, this apparatus
500
includes: a fluidized bed type pre-heating furnace
544
for pre-heating the iron ore by means of a hot air which has been heated by a combustion chamber
547
; 3-stage reducing furnaces
541
,
542
and
543
; a gas reformer
545
for producing a reducing gas; a heat exchanger
546
for heating the gas reformer
545
; gas cleaning scrubbers
549
and
550
; and a briquetting device
516
.
The gas reformer reforms a natural gas to produce a reducing gas for reducing the iron ore. Then the reformed gas is heated by the heat exchanger
546
to be supplied to a final reducing furnace
541
. The reducing gas sequentially passes through a second pre-reducing furnace
542
and a first pre-reducing furnace
543
to be cleaned by the gas cleaning scrubber
549
so as to be circulated by going through the heat exchanger
546
. The fine iron ore is fed into the pre-heating furnace to be pre-heated, and then, sequentially passes through the first pre-reducing furnace
543
, the second pre-reducing furnace
542
and the final reducing furnace
541
to be finally reduced. The reduced iron is agglomerated by the briquetting device
516
into briquettes.
The above described facility uses natural gas, and requires 4-stage fluidized bed type furnaces. Thus the facility is extremely complicated, and therefore, the initial facility cost is high, while the operation is also very complex.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the prior art.
Accordingly the present invention provides an apparatus and a method for manufacturing molten iron by using a fine iron ore, in which coal is used to produce a reducing gas, and a fine iron ore is used to produce molten iron and reduced iron in a simple and efficient manner.
In achieving the above objective in part or in whole, the apparatus for manufacturing a molten iron by directly using coal as the fuel according to the present invention is characterized in that: a high temperature reducing gas is sent from a melter-gasifier to a fluidized bed lime stone calcining furnace to calcine lime stone; the reducing gas is supplied to a second fluidized bed reducing furnace so as to manufacture a reduced iron directly; an off-gas from the second fluidized bed reducing furnace is supplied to a first fluidized bed furnace (disposed above the second fluidized bed reducing furnace) to pre-heat and pre-reduce the fine iron ore; and the calcined lime stone and the Finally reduced iron are supplied to a melter-gasifier to manufacture a molten iron.
In another aspect of the present invention, the apparatus for manufacturing a molten iron by directly using coal as the fuel according to the present invention is characterized in that: a high temperature reducing gas is sent from a melter-gasifier to a fluidized bed lime stone calcining furnace to calcine lime stone; the reducing gas is supplied to a second fluidized bed reducing furnace so as to manufacture a reduced iron directly; and an off-gas from the second fluidized bed reducing furnace is supplied to a first fluidized bed furnace (disposed above the second fluidized bed reducing furnace) to pre-heat and pre-reduce the fine iron ore, thereby manufacturing a reduced iron.
In still another aspect of the present invention, the apparatus for manufacturing a molten iron by directly using coal as the fuel according to the present invention is characterized in that: a high temperature reducing gas of a melter-gasifier is sent to a third fluidized bed reducing furnace to finally reduce and calcine a fine iron ore and a fine additive; this reducing gas is supplied to a second fluidized bed reducing furnace to pre-reduce and calcine the fine iron ore and the fine additive for the second time; its off-gas is supplied to a first fluidized bed reducing furnace (disposed above the second fluidized bed reducing furnace) for pre-reducing and calcining the fine iron ore and the fine additive for the first time; and the calcined additive and the finally reduced iron are supplied to the melter-gasifier, thereby manufacturing a molten iron.
In still another aspect of the present invention, a method for manufacturing a molten iron by using the above apparatus is provided.
REFERENCES:
patent: 4978387 (1990-12-01), Kepplinger
patent: 5192486 (1993-03-01), Whipp
patent: 5501721 (1996-03-01), Edlinger
patent: 5785733 (1998-07-01), Lee et al.
patent: 1167368 (1964-04-01), None
patent: WO9101799 (1991-02-01), None
patent: WO9417214 (1994-08-01), None
patent: 9801585 (1998-01-01), None
English translation of DE 1,167,368 to Walde, Apr. 4, 1964.
Cho Min Young
Joo Sang Hoon
Kang Heung Won
Kim Hang Goo
Lee Jun Hyuk
Banks Tima McGuthry
King Roy
Pohang Iron & Steel Co. LTD
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
LandOfFree
Apparatus for manufacturing molten pig iron and reduced iron... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for manufacturing molten pig iron and reduced iron..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for manufacturing molten pig iron and reduced iron... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534451