DIRECTLY CHARGING DEVICE FOR DIRECTLY CHARGING REDUCED FINE IRON ORE INTO MELTER-GASIFIER

Abstract: A device for directly charging the raw material into a melter-gasifier (40) in a molten iron manufacturing facility using directly coal and fine iron ore is disclosed. The elutriation of fine dusts is maximally inhibited while directly charging coal and reduced fines into the melter-gasifier (40). The direct charging device is applied to a fluidized bed type final reducing furnace (30), and has a plurality of discharging outlets (31) for discharging said fines. Said melter-gasifier (40) receives lump coal to form a coal packed bed (41) within it and receives the reduced fine iron ore from the final reducing furnace (30). The direct charging device includes a plurality of charging inlets (51) formed on the side wall of the melter-gasifier (40) connected to conduits (52) to the discharging outlets (31) of the final reducing furnace (30) whereby reduced fine iron ore is continuously charged from the final reducing furnace (30) to the coal packed bed (41) of the melter-gasifier (40).

Description: DIRECTLY CHARGING DEVICE FOR DIRECTLY CHARGING REDUCED FINE IRON ORE INTO MELTER-GASIFIER FIELD OF THE INVENTION The present invention relates to a device in which a high temperature reduced fine iron ore can be directly charged into a melter-gasifier in a molten iron manufacturing process using the general coal and a fine iron ore. More specifically, the present invention relates to a device which is capable of directly charging a high temperature reduced fine iron ore into a coal packed bed type melter-gasifier while inhibiting elutriation loss, in a molten iron manufacturing process using the general coal and a fine iron ore, with a high temperature gas stream being formed within the melter- gasifier. BACKGROUND OF THE INVENTION Generally, in the blast furnace method which forms the main trend of the molten iron manufacturing process, the raw material has to have a ceratin strength, and has to have a particle size to ensure the gas permeability. Further, as the carbon source for providing a fuel and a reducing agent, coke is resorted, while as the raw iron ore, sintered agglomerates are used. Accordingly, the currently used blast furnace has a coke manufacturing facility and a iron ore sintering facility as the auxiliary facilities . The auxiliary facilities require an enormous expenditure, and brings environmental problems. The environmental problems require an investment in the anti-pollution facilities, with the result that the investments in the facilities are more increased. Therefore, the competitiveness of the blast furnace is being speedily faded. In efforts for coping with this situation, researches and developments are being carried out to replace the coke with the general coal, and to replace the iron ore agglomerates with the direct fine iron ore which occupies more than 80% of the total world production. The molten iron manufacturing facility which directly uses the general coal and the fine iron ore is disclosed in Austrian Patent Application No. AT2096/92. This facility includes 3-stage fluidized bed type furnaces including pre-heating furnace, pre-reducing furnaces and a final reducing furnace, and a melter- gasifier having a coal packed bed within it. In the manufacturing method using this molten iron manufacturing facility, a normal temperature fine iron ore is continuously charged into an uppermost reaction chamber (a pre-heater) to pass through the 3-stage fluidized bed type furnaces so as to be contacted with a high temperature reducing gas supplied from the melter-gasifier. During this process, the temperature of the fine iron ore is raised and its reduction is realized by more than 90%. The reduced fine iron ore is continuously charged into the melter-gasifier in which the coal packed bed is formed, so as to be melted within the coal packed bed. Thus a molten iron is manufactured, and discharged to the outside. Meanwhile, a general lump coal is continuously charged into the top of the melter-gasifier to form a coal packed bed of a certain height. Further, oxygen is injected through a plurality of tuyeres holes which are formed on a lower portion of the outer wall of the melter- gasifier. Thus the coal of the coal packed bed is burned, and the combustion gas rises to form a stream of a high temperature reducing gas so as to be supplied to the three pre-reducing furnaces . Meanwhile, within the melter-gasifier, the high temperature gas stream has a high velocity, and therefore, a large amount of fine dusts of the fine iron ore is inclined to be elutriated out of the furnaces . In order to prevent this phenomenon, a large space is provided above the coal packed bed. In this manner, the elutriation of the fine dusts is maximally inhibited. However, the average flow velocity within the mentioned space is about 0.5 m/sec. Therefore, it is inevitable that the high temperature fine iron ore having a size of 100 μm or less and the coal dusts of 400 μm or less are elutriated to the outside of the furnace. Particularly, considering the particle size distribution of the high temperature fine iron ore, the particles of 100 μm or less occupy 30 - 35 wt%. Thus a large amount of the reduced fine iron ore is elutriated out of the furnace. Accordingly, a high iron loss is caused, and therefore, the yield and productivity of the molten iron manufacturing process are greatly lowered. 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 a device for directly charging the raw material into a melter-gasifier in a molten iron manufacturing facility using directly the general coal and a fine iron ore, in which elutriation of the fine dusts is maximally inhibited while directly charging the general coal and a fine iron ore into the melter-gasifier. In achieving the above object, the direct charging device is applied to the molten iron manufacturing apparatus according to the present invention including: a fluidized bed type final reducing furnace for finally reducing a fine iron ore, and having a plurality of reduced fine iron ore discharging outlets for discharging a reduced fine iron ore to an outside of the furnace; and a melter-gasifier for receiving a general lump coal to form a coal packed bed within it, and to manufacture a molten iron by receiving the reduced fine iron ore from the fluidized bed type final reducing furnace, the direct charging device includes: a plurality of reduced fine iron ore charging inlets formed on a side wall of the melter-gasifier having the coal packed bed within it; and a plurality of fine reduced iron ore charging conduits for connecting reduced fine iron ore discharging outlets of the fluidized bed type final reducing furnace to the reduced fine iron ore charging inlets to carry a reduced fine iron ore, whereby the reduced fine iron ore is continuously charged from the fluidized bed type final reducing furnace into the coal packed bed of the melter-gasifier. BRIEF DESCRIPTION OF THE DRAWINGS The above object and other advantages of the present invention will become more apparent by describing in detail the preferred embodiment of the present invention with reference to the attached drawings in which: FIG. 1 schematically illustrates the device for directly charging the reduced fine iron ore into the melter-gasifier according to the present invention; FIG. 2 is an enlarged illustration of a portion of the device for directly charging the reduced fine iron ore into the melter-gasifier according to the present invention; and FIG. 3 illustrates an example of the layout of the device for directly charging the reduced fine iron ore into the melter-gasifier according to the present invention . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, a direct charging device 50 for directly charging a reduced fine iron ore into a melter- gasifier 40 according to the present invention is applied to a molten iron manufacturing apparatus . The apparatus includes: a fluidized bed type final reducing furnace 30 for finally reducing a fine iron ore, and having a plurality of reduced fine iron ore discharging outlets 31 for discharging a reduced fine iron ore to the outside of the furnace; and a melter-gasifier 40 for receiving a general lump coal to form a coal packed bed 41 within it, and to manufacture a molten iron by receiving the reduced fine iron ore from the fluidized bed type final reducing furnace 30. FIG. 1 illustrates a molten iron manufacturing apparatus which includes: a fluidized bed type pre- heating furnace 10 for drying and pre-heating the fine iron ore; a fluidized bed type pre-reducing furnace 20 for pre-reducing the dried and pre-heated fine iron ore; a fluidized bed type final reducing furnace 30 for finally reducing the pre-reduced fine iron ore; and a melter- gasifier 40 for manufacturing the finally reduced fine iron ore into a molten iron. However, the application of the direct charging device 50 for directly charging the reduced fine iron ore into the melter-gasifier 40 is not limited to the molten iron manufacturing apparatus of FIG. 1. For example, it can be applied to a molten iron manufacturing apparatus having 2-stage fluidized bed type furnaces . As shown in FIGs. 1 and 2, the directly charging device 50 includes: a plurality of reduced fine iron ore charging inlets 51 formed on the side wall of the melter- gasifier 40 having the coal packed bed 41 within it; and a plurality of reduced fine iron ore charging conduits for connecting reduced fine iron ore discharging outlets 31 of the fluidized bed type final reducing furnace 30 to the reduced fine iron ore charging inlets 51 to carry the reduced fine iron ore. The number of the reduced fine iron ore charging inlets 51 should be preferably 4 or more, more preferably 6 - 8, so that a reduced fine iron ore 1 can be uniformly dispersed within the coal packed bed 41. If the diameter of the melter-gasifier 40 where the coal packed bed 41 is formed is about 7.3 , the reduced fine iron ore charging inlets 51 should be provided preferably in the number of 6 - 8. As shown in FIG. 3, the reduced fine iron ore charging inlets 51 are preferably formed around the circumference of the melter-gasifier 40 at certain angular intervals. Of course, the number of the reduced fine iron ore discharging outlets 31 of the fluidized bed type final reducing furnace 30 should be equal to or more than the number of the reduced fine iron ore charging inlets 51. The reduced fine iron ore charging inlets 51 should be formed on the side wall of the melter-gasifier 40 where the coal packed bed 41 is formed. Preferably, they should be formed on the side wall of the melter-gasifier 40 at a height equal to 10 - 20% of the height (thickness) of the coal packed bed 41 below an upper surface of the coal packed bed 41. More preferably, they should be disposed at a height equal to 15% below an upper surface of the coal packed bed 41. In selecting the positions of the reduced fine iron ore charging inlets 51, the elutriation of the reduced fine iron ore 1 to the outside of the furnace and the dispersion of the reduced fine iron ore within the coal packed bed have to be taken into account. If the positions of the reduced fine iron ore charging inlets 51 are too high, then the reduced fine iron ore is likely to be elutriated of the furnace, while if they are to low, the dispersion of the reduced fine iron ore into the coal packed bed becomes too slow. The reduced fine iron ore charging inlets 51 should preferably protrude into the melter-gasifier 40 by a certain length. The protruding length should be preferably 3- 50% of the radius of the coal packed bed. If the internal temperature and the atmosphere of the melter-gasifier 40 are taken into account, the protruding length should be preferably 3 - 7% of the radius of the coal packed bed, and more preferably, it should be 5%. If the protruding length of the reduced fine iron ore charging inlets 51 is too long, the dispersion capability of the reduced fine iron ore into the coal packed bed is lowered. Further, the reduced fine iron ore charging inlets 51 should be inclined downward, and the inclining angle should be preferably 20 - 45°. If the inclining angle is too small, the downward flow of the reduced fine iron ore is not smooth, while if the inclining angle is too large, the dispersion capability of the reduced fine iron ore within the coal packed bed is lowered. The reduced fine iron ore charging conduit 52 connects the reduced fine iron ore discharging outlet 31 of the fluidized bed type final reducing furnace 30 to the reduced fine iron ore charging inlet 51 to carry the reduced fine iron ore. The reduced fine iron ore charging conduit 52 is connected to the reduced fine iron ore charging inlet 51 in such a manner that the leading end of the conduit 52 and the rear end of the reduced iron charging inlet 51 are provided with a flange respectively, and that a contractible/extendable tube 53 is installed between the two flanges, thereby connecting the conduit 52 and the inlet 51 together. The reduced fine iron ore charging conduit 52 is preferably provided with a nitrogen injecting pipe 52a, so that the reduced fine iron ore can be smoothly carried down. Now the action of the device of the present invention will be described. The reduced fine iron ore 1 is discharged continuously from the plurality of the reduced fine iron ore discharging outlets 31 of the fluidized bed type final reducing furnace 30. Then the reduced fine iron ore 1 is carried down through the reduced fine iron ore charging conduits 52 by the help of gravity. Then the reduced fine iron ore 1 is continuously carried through the plurality of the reduced fine iron ore charging inlets 51 into the coal packed bed 41 to be dispersed through spaces formed between the coal particles. The coal particles within the coal packed bed 41 continuously move downward, while the reduced fine iron ore among the coal particles also moves downward together with the coal particles of the coal packed bed. Therefore, around the leading end of the reduced fine iron ore charging inlet 51, there is continuously formed new spaces to receive the reduced fine iron ore. Therefore, the reduced fine iron ore can continuously flow downward. Meanwhile, the gas permeability around the charging inlets can be aggravated due to the continuous charging, and therefore, four or more of the charging inlets 51, more preferably 6 - 8 charging inlets 51 should be uniformly dispersedly provided. Further, the leading end of the charging inlet 51 is disposed near to the surface of the coal packed bed 41, so that the gas permeability would be smooth. Further, the leading end of the charging inlet 51 is disposed at a height below the surface of the coal packed bed equal to 10 - 20% of the total thickness of the coal packed bed 41. Further, in order to prevent the aggravation of the gas permeability, the leading end of the charging inlet 51 is disposed below the surface of the coal packed bed at a height equal to 3 - 50% of the radius of the coal packed bed. Meanwhile, the reduced fine iron ore charging conduit 52 is preferably provided with a nitrogen purging pipe 52a, so that the reduced fine iron ore can be smoothly carried. A contractible/extendable tube 53 is installed between the two flanges, thereby connecting the conduit 52 and the inlet 51 together. Thus the contractible/extendable tube absorbs the thermal stress. Now the present invention will be described based on an actual example. <Example> In order to evaluated the elutriation rate of the fine iron ore, there was used a coal packed bed which had a superficial velocity of 0.4 m/sec and an average air space rate of 0.4. Into this coal packed bed, a fine iron ore having particles sizes of 8 mm or less were put from above. That is, the fine iron ore was put into the upper space and to the heights of 10%, 30% and 50% of the thickness of the coal packed bed respectively. In this manner, the maximum particle size among the elutriated particles was measured. In the case where the fine iron ore was put into the upper space, the maximum particle size was 100 μm. In the case where the fine iron ore was put to the height of 10%, the maximum particle size was 30 μm. In the case where the fine iron ore was put to the heights of 30% and 50%, the maximum particle size was 10 μm or less. Therefore it could be known that the deeper the fine iron ore was put, the smaller the maximum size became. If the fine iron ore is put to a lower height, the fine iron ore particles are surrounded by more coal particles. Therefore, it can be known that the elutriation of the fine iron ore particles by the rising gas streams is significantly reduced compared with the case of putting the fine iron ore into the upper space. According to the present invention as described above, the elutriation loss of the fine iron ore particles due to the rising gas streams is minimized, and a means for continuously feeding the pre-reduced fine iron ore into the melter-gasifier is provided. Therefore, in the manufacturing line, the loss of the iron can be greatly reduced.

Claims: WHAT IS CLAIMED IS: 1. A direct charging device for directly charging a reduced fine iron ore into a melter-gasifier applied to a molten iron manufacturing apparatus including: a fluidized bed type final reducing furnace 30 for finally reducing a fine iron ore, and having a plurality of reduced fine iron ore discharging outlets 31 for discharging a reduced fine iron ore to an outside of said furnace 30; and said melter-gasifier 40 receiving a general lump coal to form a coal packed bed 41 within it, and to manufacture a molten iron by receiving the reduced fine iron ore from said fluidized bed type final reducing furnace 30, the direct charging device comprising: a plurality of reduced fine iron ore charging inlets 51 formed on a side wall of said melter-gasifier 40 having said coal packed bed 41 within it; and a plurality of reduced fine iron ore charging conduits 52 for connecting said reduced fine iron ore discharging outlets 31 of said fluidized bed type final reducing furnace 30 to said reduced fine iron ore charging inlets 51, whereby a reduced fine iron ore is continuously charged from said fluidized bed type final reducing furnace 30 into said coal packed bed 41 of said melter-gasifier 40. 2. The direct charging device as claimed in claim 1, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore discharging outlet 31 are provided in a number of four respectively. 3. The direct charging device as claimed in claim 2, wherein said melter-gasifier 40 (where said coal packed bed 41 is formed) has a diameter of about 7.3 m; and said reduced fine iron ore charging inlet 51 and said reduced fine iron ore discharging outlet 31 are provided in a number of 6-8 respectively. 4. The direct charging device as claimed in any one of claims 1 to 3, wherein said reduced fine iron ore charging inlets 51 are installed around a circumference of said melter-gasifier 40 at certain angular intervals. 5. The direct charging device as claimed in any one of claims 1 to 3, wherein said reduced fine iron ore charging inlets 51 are disposed on a side wall of said melter-gasifier 40 at a height equal to 10 - 20% of a thickness of said coal packed bed 41 below an upper surface of said coal packed bed 41. 6. The direct charging device as claimed in claim 5, wherein said reduced fine iron ore charging inlets 51 are disposed on a side wall of said melter-gasifier 40 at a height equal to 15% of a thickness of said coal packed bed 41 below an upper surface of said coal packed bed 41. 7. The direct charging device as claimed in any one of claims 1 to 3, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 50% of a radius of said coal packed bed 41. 8. The direct charging device as claimed in claim 7, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 7% of a radius of said coal packed bed 41. 9. The direct charging device as claimed in claim 5, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 50% of a radius of said coal packed bed 41. 10. The direct charging device as claimed in claim 9, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 7% of a radius of said coal packed bed 41. 11. The direct charging device as claimed in claim 6, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 50% of a radius of said coal packed bed 41. 12. The direct charging device as claimed in claim 11, wherein said reduced fine iron ore charging inlets 51 are protruded from a side wall of said melter-gasifier 40 into its interior as much as 3 - 7% of a radius of said coal packed bed 41. 13. The direct charging device as claimed in any one of claims 1 to 3, wherein said reduced fine iron ore charging inlets 51 are inclined downward at an angle of 20 - 45°. 14. The direct charging device as claimed in claim 5, wherein said reduced fine iron ore charging inlets 51 are inclined downward at an angle of 20 - 45°. 15. The direct charging device as claimed in claim 7, wherein said reduced fine iron ore charging inlets 51 are inclined downward at an angle of 20 - 45°. 16. The direct charging device as claimed in any one of claims 6, 8, 9, 10, 11 and 12, wherein said reduced fine iron ore charging inlets 51 are inclined downward at an angle of 20 - 45°. 17. The direct charging device as claimed in any one of claims 1 to 3, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible /extendable tube between said two flanges. 18. The direct charging device as claimed in claim 5, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible/extendable tube between said two flanges. 19. The direct charging device as claimed in claim 7, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible /extendable tube between said two flanges. 20. The direct charging device as claimed in any one of claims 6, 8, 9, 10, 11, 12, 14 and 15, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible /extendable tube between said two flanges. 21. The direct charging device as claimed in claim 13, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible /extendable tube between said two flanges. 22. The direct charging device as claimed in claim 16, wherein said reduced fine iron ore charging inlet 51 and said reduced fine iron ore charging conduit 52 are joined together by forming a flange on a leading end of said reduced fine iron ore charging conduit 52 and a rear end of said reduced fine iron ore charging inlet 51, and by inserting a contractible /extendable tube between said two flanges . 23. The direct charging device as claimed in claim 17, wherein said reduced fine iron ore charging conduit 52 is provided with a nitrogen purging pipe 52a to make a flow of the reduced fine iron ore smooth. 24. The direct charging device as claimed in claim 20, wherein said reduced fine iron ore charging conduit 52 is provided with a nitrogen purging pipe 52a to make a flow of the reduced fine iron ore smooth. 25. The direct charging device as claimed in any one of claims 18, 19, 21 and 22, wherein said reduced fine iron ore charging conduit 52 is provided with a nitrogen purging pipe 52a to make a flow of the reduced fine iron ore smooth.

Inventors: JOO SANG HOON, SHIN MYOUNG KYUN, JOO, SANG, HOON, SHIN, MYOUNG, KYUN
Applicants: JOO SANG HOON, PO HANG IRON & STEEL, RES INST IND SCIENCE & TECH, SHIN MYOUNG KYUN, VOEST ALPINE IND ANLAGEN, JOO, SANG, HOON, POHANG IRON & STEEL CO., LTD., RESEARCH INSTITUTE OF INDUSTRIAL SCIENCE & TECHNOLOGY, SHIN, MYOUNG, KYUN, VOEST-ALPINE INDUSTRIEANLAGENBAU GMBH
Application year: 1998
Main classification: C21B13
IPC codes: C21B13