【DESCRIPTION】
【Invention Title】
INTEGRATED STEEL MANUFACTURING SYSTEM AND METHOD FOR INTEGRATED STEEL MANUFACTURING
【Technical Field】
The present invention relates to an integrated system and method for manufacturing steel, and more particularly, to an eco-friendly integrated system and method for manufacturing steel consuming low amounts of energy and markedly reducing environmental pollutants in a raw material processing process and an iron making process.
【Background Art】 Generally, molten iron is produced in a blast furnace, and steel through refining process converter by using the as main material. A making having energy efficiency productivity higher than that of furnace has not yet been developed. However, such requires coke obtained from particular kind coal carbon source functioning fuel reducing agent, usually sintered ore series agglomeration processes an source. That is, current require equipment for preliminarily processing raw materials
3 as coke making equipment and sintering equipment, thus enormous expenses may be required to construct such accessory well blast furnace apparatuses. Furthermore, preliminary raw-material processing generates considerable amounts of environmental pollutants SOx, NOx, dust, additional collect treat pollutants. Particularly, since regulations have been increasingly tightened in many countries, furnaces for producing molten iron are losing competitiveness due the incurred equipping thereof with pollutant equipment. A great deal research has conducted into developing processes aimed at solving above-described problems related furnaces. Among under development, a coal-based smelting reduction process is noteworthy because non-coking coal can used fuel reducing agent fine ore, accounting 80% worldwide ore production, an source. However, amount able produced through by unit not yet
4 sufficient, as compared to the amount of molten iron able be produced by a large blast furnace, such furnace capable producing three four million tons per year. Therefore, many pieces smelting reduction equipment have constructed in order produce same single which may take up area steel mill. In addition, if scrap is used make for insufficient iron, hot metal ratio (HMR) or lowered, and heat become insufficient. there an increasing need integrated system method manufacturing through processes simplified reducing ore making process.
【Disclosure】
【Technical Problem】 An aspect present invention provides eco-friendly from pig while consuming low amounts energy, wherein provided process performed via multiple routes.
5 Another aspect of the present invention provides an integrated system and method for manufacturing a steel sheet from molten produced as described above, by casting rolling in single process. at production capability three or more million tons per year to four year. large amount using scrap well iron through smelting reduction process equipment while solving problem insufficient heating that may worsen use increases. generating fewer pollutants reducing fine ore without preliminary directly performing on reduced electric furnace. The is not limited above-mentioned aspects, those having skill art which pertains will be able easily
6 understand other aspects of the present invention from descriptions provided below.
【Technical Solution】 According to an aspect invention, there is integrated system for manufacturing steel, including: iron making apparatus; and a steel apparatus configured produce molten agglomerated reduced received apparatus, wherein includes: fine ore reducing device including first second fluidized reduction furnace apparatuses respectively at least one ore; agglomerating devices agglomerate apparatuses, respectively; smelting by melting device. A final may be connected through gas supply pipe allowing flow therethrough,
7 may be connected to a final fluidized reduction furnace of the second apparatus through reducing gas connection pipe for allowing flow therethrough. The steel making include converter or an electric furnace, and agglomerating device agglomerated reduced iron transfer allow transferred According to another aspect of the present invention, there is provided an integrated system manufacturing steel, including: apparatus; configured produce molten from received scrap wherein includes: fine ore including that includes at least one ore; devices agglomerate smelting by melting device.
8 The steel making apparatus may include a converter or an electric furnace. A nozzle be provided in lower portion of the to supply fuel and oxygen (O2) converter, lance upper oxygen-containing gas converter. According to another aspect of the present invention, there is provided an integrated system for manufacturing steel, including: agglomerated reduced iron apparatus; furnace, wherein includes: fine ore reducing device including fluidized reduction furnace that includes at least one ore; agglomerating configured agglomerate received from apparatus. further slab casting which continuous machine cast molten produced by connected rolling mill series. produce having thickness 30 mm 150
9 rate of 4 mpm to 15 mpm, and the rolling mill may include a finishing mill, wherein integrated system further steel sheet heater coil box that be disposed between continuous casting machine store after coiling thereof. The roughing mill. According another aspect present invention, there is provided an method for manufacturing steel, including: performing molten iron making process; process produce from agglomerated reduced are produced in process, includes: producing fine ore by reducing first second fluidized reduction furnace apparatuses; agglomerating devices using ore, supplied apparatuses devices, respectively; smelting melting
10 received from the first agglomerating device. Exhaust gas discharged fluidized reduction furnace apparatus may be supplied to second used as a reducing gas. According another aspect of present invention, there is provided an integrated method for manufacturing steel, including: performing molten iron making process; and steel process produce by using produced in process, wherein includes: producing reduced fine ore fluidizing ore; agglomerated receiving melting device, scrap together with at hot melt ratio (HMR) 70 weight% or less.
11 agglomerating the reduced fine iron ore; and producing molten steel by melting agglomerated in an electric furnace. The integrated method may further include performing a slab casting process which continuous rolling are performed series, wherein be to cast produced of steel. at rate 4 mpm 15 produce having thickness 30 mm 150 mm, finish process, sheet heating coiling storing between finishing coiled stored process.
rough 【Advantageous Effects】 According system for manufacturing embodiments invention,
12 raw-material supply conditions or environments can be coped with in a flexible manner, and pollution markedly reduced. In addition, according to the integrated system method for manufacturing steel of invention, productivity comparable that an using blast furnace obtained. large amount produced scrap as well molten iron through smelting reduction process equipment while solving problem insufficient heating may worsen use increases. manufactured generating fewer pollutants by reducing fine ore without preliminary directly performing on reduced electric furnace.
【Description of Drawings】
FIG. 1 is schematic view illustrating embodiment
13 of the invention. FIG. 2 is a schematic view illustrating an integrated system for manufacturing steel according to another embodiment 3 4 5 6 7 formed by adding slab casting apparatus 1. 8 2. 9
14 system for manufacturing steel of FIG. 3. 10 is a schematic view illustrating formed by adding slab casting apparatus to the integrated 4. 11 5. 12 6.
【Best Mode】 The present invention will now be described in detail.
In the present invention, the term "integrated system and method for manufacturing steel" denotes a steel making system and method including a process of producing molten iron from iron ore and a process of producing molten steel from the molten iron. An integrated steel manufacturing system of the invention can be described in two steps: an iron making process for producing molten iron, and a steel making process for producing molten steel.
In an iron making process, molten iron is produced by reducing fine iron ore using smelting reduction equipment (smelting furnace). In detail, fine iron ore is reduced by fluidization and is agglomerated, and molten
15
iron is produced by further reducing the agglomerated reduced fine iron ore in the smelting furnace. However, as described above, the amount of molten iron able to be produced in the smelting furnace is insufficient as compared to the amount of molten iron able to be produced in a blast furnace, and thus it may be required to construct a plurality of smelting furnaces to obtain a sufficient amount of molten iron. This lowers productivity and may make it difficult to find a site for building a steel mill.
According to an embodiment of the invention, a process of reducing fine iron ore by fluidization and agglomerating the reduced fine iron ore is additionally performed one or more times. This does not mean that agglomerated reduced fine iron ore prepared through an additional repetition of the process is melted and further reduced in a smelting furnace to produce molten iron, but means that agglomerated reduced fine iron ore prepared through an additional repetition of the process is reduced in the following steel making process to produce molten steel.
That is, the embodiment of the invention relates to an integrated system and method for manufacturing steel, in which: fine iron ore is reduced and agglomerated; a portion
16
of the agglomerated reduced fine iron ore is melted to produce molten iron; and molten steel is produced using the molten iron and the remainder of the agglomerated reduced fine iron ore as main materials.
FIG. 1 is a schematic view illustrating an integrated system for manufacturing steel according to the embodiment of invention. As shown in 1, includes iron making apparatus 10 and 20 (converter as example 20, will be described hereinafter case which converter). The includes: fine ore reducing device 11 ore; agglomerating devices 13 14 reduced by 11; smelting furnace 12 producing molten melting agglomerated 14. first fluidized reduction 111 second 112. Each
17 first fluidized reduction furnace apparatus 111 and the second 112 includes at least one furnace. In apparatuses 112, fine iron ore is reduced while being blown with gas. Fine step by in a series of furnaces 112. That is, furnaces, reducing The number unlimited. For example, two or more may be provided for sufficient to occur. another three provided. As described above, agglomerated supplied smelting (equipment) 12 through agglomerating device 13, further 12. this, include four 1111, 1112, 1113, 1114. Agglomerated made
18 fluidized reduction furnace apparatus 112 and the second agglomerating device 14 is directly supplied to converter 20 without additional smelting in 12. Thus, may include four furnaces 1121, 1122, 1123, 1124 for sufficient reduction. However, number of first apparatuses 111 not limited. In embodiment shown FIG. 1, includes 1111, 1112, 1113, 1114, 1124. Like general furnaces, gas distributing plates (shown). The devices 13 include: configured receive reduced fine iron ore from agglomerate ore;
19 and the second agglomerating device 14 configured to receive reduced fine iron ore from fluidized reduction furnace apparatus 112 agglomerate ore. The first 13 includes a hopper 131 for storing supplying 13, is connected final 1111 of 111 through supply pipe 132 141 14, 1121 142 smelting 12 produces molten by melting agglomerated received 13.
20 reduction furnace apparatus 111 of the fine iron ore reducing device 10 through a gas supply pipe 121 so that can flow therebetween, and fluidized furnaces 1111, 1112, 1113, 1114 first are connected to each other pipes (not shown) therebetween. Reducing is supplied 114 sequentially from final 1111 1114. On hand, 1114, 1111. The reduced by while being carried in Fine may be 1121, 1122, 1123, 1124 second 112 same manner as 111.
21 That is, the fluidized reduction furnaces 1121, 1122, 1123, and 1124 of second furnace apparatus 112 are connected to each other through gas supply pipes (not shown) so that can flow therebetween. Reducing is supplied from final 1121 first 1124. On hand, fine iron ore 1124, reduced by reducing while being sequentially carried in 1121. may be smelting or an additional line. In embodiments invention, 1114 111 a connection pipe 1116 for efficient use gas. emitted
22 from the first fluidized reduction furnace apparatus 111 can be supplied to second 112. The reducing gas connection pipe 1116 connects 1114 of final 1111 112 so that emitted For using more efficiently as described later, or 1124 at least one equipment and apparatuses may connected 1121 through a circulation 1115 1125, other equipment. If includes 1125
23 fluidized reduction furnace 1114 of the first apparatus 111 can be connected to final 1121 second 112 allow gas flow therebetween. However, even in case that circulation pipe 1115 or 1125 is provided, reducing connection 1116 may not but directly between and 112. In some cases, one pipes 1125. embodiment invention, 1111 through 1115. A carbon dioxide removing device 118 provided on 1115, an exhaust discharge 1181 118. addition, a heater (shown)
24 a portion of the first circulation pipe 1115 between carbon dioxide removing device 118 and final fluidized reduction furnace 1111 so as to heat circulating gas. The provided on removes from gas emitted 111, then is supplied or second apparatus 112. In this way, reducing can be recycled. addition, heater may used control temperature 1121 1114 1124 112 connected through 1125. A 116 1125, an exhaust discharge 1161 116. 117 1125
25 The carbon dioxide removing device 116 provided on the second circulation pipe 1125 removes from gas emitted fluidized reduction furnace apparatus, and then is supplied to final furnace. In this way, reducing can be recycled. addition, heater 117 may used control temperature of circulating gas. another embodiment invention, a dust collector (not shown) such as wet-type disposed an exhaust line connection connecting first apparatuses 111 112 so remove dust, sulfur, other impurities After iron making process, steel process performed using apparatus including refining equipment converter or electric converter, oxygen oxygen-containing convert molten almost saturated with into by burning off gas, heated heat generated combustion burnable substances. There are many kinds converters, any kind
26 converter can be used in the present invention. That is, there are many kinds of converters such as top-blown converters, bottom-top and multi-other especially designed by different steel companies, any kind In invention, since agglomerated reduced iron well high-temperature molten is supplied a main material from making process, having high heat efficiency may used. embodiment explained below materials for producing 20 apparatus 10 second agglomerating device 14, includes lance 21 nozzle 22 on upper lower sides thereof, respectively. Oxygen through provided side to refine steel. At this time, fuel source together with oxygen. For example, coal or combustible gas fuel. However, Fuel
27 oxygen or may be supplied and blown together with a carrier gas such as nitrogen through an additional nozzle. In addition to fuel, powder quicklime that can control the basicity of slag function seeds decarbonizing reaction lower side converter 20 gas. The lance 21 used blow oxygen-containing air into 20. Oxygen-secondarily burns carbon monoxide (post-combustion) produced result decarbonization molten steel, thus steel further heated. At this time, heater additionally disposed on supply passage increase combustion efficiency any kind heater. For example, heat exchanging type pebble using waste discharged from is denoted by reference numeral 211. second agglomerating device 14 connected each other agglomerated reduced iron transfer pipe 23. case, owing 23 between
28 device 14, agglomerated reduced iron can be prevented from being oxidized while transferred therebetween. The inside of the transfer pipe 23 may filled with nitrogen gas. As described above, oxygen blown through nozzle 22 provided in lower portion converter 20. Instead that, into 20 lance 21 or another (not shown) to refine molten steel. FIGS. 2 and 3 illustrate integrated systems for manufacturing steel according other embodiments invention. system FIG. has substantially same structure as 1 except that first fluidized reduction furnace apparatus 111 includes three furnaces 1111, 1112, 1113. an electric 20-is used instead In addition, number smelting changed 2. 4 a schematic view illustrating
29 system for manufacturing steel according to another embodiment of the invention. As shown in FIG. 4, integrated 1' other includes an iron making apparatus 10' and a 20' (converter is as example 20', will be described hereinafter case which converter). According includes: fine ore reducing device 11' ore; agglomerating 13' reduced by 11'; smelting furnace 12' producing molten melting agglomerated 13'. The fluidized reduction 111', 111' at least one furnace. reduces while fluidizing using gas. Fine step series furnaces 111'.
30 That is, in the fluidized reduction furnaces, fine iron ore is reduced step by a reducing gas. The number of furnaces not limited. For example, two or more may be provided. In another three four As described above, integrated steel manufacturing system shown FIG. 4, furnace apparatus 111' includes 1111', 1112', 1113', and 1114'. Like general 1114' include gas distributing plates (shown). agglomerating device 13' receives from agglomerates ore. hopper 131' for storing supplying to first 13', connected final 1111' through supply pipe 132' receive
31 fine iron ore. The smelting furnace 12' produces molten by melting agglomerated reduced received from the first agglomerating device 13'. is connected to final fluidized reduction 1111' of apparatus 111' ore reducing 10' through a gas supply pipe 121' so that can flow therebetween, and furnaces 1111', 1112', 1113', 1114' are each other pipes (not shown) therebetween. Reducing sequentially supplied 1114'. On hand, 1114', 1111'. while being carried in
32 1112', and 1111'. The final fluidized reduction furnace 1111' the first 1114' of apparatus 111' may be connected to each other through a circulation pipe 1115' so that gas can flow therebetween. A carbon dioxide removing device 118' provided on 1115', an exhaust discharge 1181' 118'. In addition, heater (not shown) portion between as heat circulating gas. 118 1115 removes from emitted 1114', then is supplied this way, reducing recycled. used control temperature another embodiment invention, dust collector such wet-type disposed line
33 pipe 1115'. After the iron making process, a steel process may be performed using apparatus including refining equipment. At this time, sufficient amount of molten not obtained if produced by smelting furnace is only used. Therefore, in current embodiment, large scrap added range 30 weight% to 70 hot metal ratio (HMR). If HMR reduced less than weight%, heat become insufficient. supplied apparatus, apparatus. To end, feeder provided front The chute. within above-mentioned range, it difficult maintain general especially, an for converting into steel. In case, through sufficiently continuous casting machine. address problem, example, pure oxygen blown converter burn or oxidize elements such as C, Mn, and Fe increase temperature
34 steel using the combustion or reaction heat. If temperature of molten is not sufficiently high, an excessive amount oxygen may be blown thereinto to generate more oxidation heat, known as "over-blowing." In this case, Fe excessively oxidized cause problems such loss steel, generation slag, and slag. Therefore, if a general converter used in manner, it difficult maintain HMR within above-mentioned low range proposed embodiment invention. Thus, according present invention, electric furnace having structure described below making apparatus. That is, since main materials supplied process include scrap fed on separate path well hot iron, required use thermally efficient method. To end, apparatus following converter. for producing 20' are iron from 10' through path,
35 converter 20' includes a lance 21' and nozzle 22' on upper lower sides thereof. Oxygen is blown through the provided in portion of to refine molten steel. At this time, fuel may be as heat source, together with oxygen. For example, coal or combustible gas fuel. However, any other kind used. In addition, oxygen supplied carrier such nitrogen an additional nozzle. addition fuel, powder quicklime that can control basicity slag function seeds decarbonizing reaction side gas. The used blow oxygen-containing air into 20'. Oxygen-secondarily burns carbon monoxide (post-combustion) produced result decarbonization steel, thus steel further heated. heater additionally disposed supply passage increase combustion efficiency heater. exchanging
36 type heater or a pebble using heat of waste gas discharged from the converter 20'. The is denoted by reference numeral 211'. According to research carried out inventors, temperature (T), flow rate Q), and blowing time t) oxygen-containing may satisfy following Formula 1. [1] 0.1 ≤ aTQt 6 where denotes proportional constant, 1.25x10-7(1/(°C·m3)), units T, Q, t are °C, m3/time, time. 1 shows relationship among conditions for generating sufficient post-combustion case in which HMR low as present embodiment invention. It preferable that be equal greater than 0.1. However, since process re-combusting carbon monoxide rising molten steel, amount limited, thus if 6, efficiency decreases. Therefore, upper limit set 6. Oxygen blown into through nozzle 22' disposed lower portion so refine steel. oxygen instead
37 be blown through the lance 21' or an additional (not shown). FIG. 5 illustrates integrated system for manufacturing steel according to another embodiment of invention. The 2' is substantially same as 1' 4 except that electric furnace 20-used instead converter 20' a making apparatus. includes electrode generating heat by arc. In case in which HMR low invention, molten can sufficiently heated using 1'. 6 Referring 6, 1" agglomerated reduced iron apparatus 10" and 20". According other shown includes: fine ore reducing device 11" ore; agglomerating 13"
38 reducing device 11". The fine iron ore 11" includes fluidized reduction furnace apparatus 111", and the 111" at least one furnace. reduces while fluidizing using gas. Fine is reduced step by in a series of furnaces 111". That is, furnaces, number not limited. For example, two or more may be provided. In another four As described above, integrated steel manufacturing system shown FIG. 4, 1111", 1112", 1113", 1114". Like general 1114" include gas distributing plates (shown).
39 The agglomerating device 13" receives reduced fine iron ore from the fluidized reduction furnace apparatus 111" and agglomerates ore. includes a hopper 131" for storing supplying to first 13", is connected final 1111" of through supply pipe 132" receive furnaces 1111", 1112", 1113", 1114" are each other gas (not shown) so that can be supplied therethrough. Reducing 121" sequentially 1114". reducing may LNG or syngas. Alternatively, purpose recycling resources, by-product emitted steel mill such as coke out COG) Finex FOG) Herein, refers equipment including smelting iron,
40 agglomerated by an apparatus such as the reduced iron making 10). Fine ore is supplied to fluidized reduction furnaces 1114", 1113", 1112", and 1111" from first furnace 1114" final 1111". The fine reducing gas while being sequentially carried in of 111" may be connected each other through a circulation pipe 1115" so that can flow therebetween. A carbon dioxide removing device 118" provided on 1115", exhaust discharge 1181" 118". In addition, heater (not shown) portion between heat circulating gas. 118 1115 removes emitted
41 and then the gas is supplied to final fluidized reduction furnace 1111". In this way, reducing can be recycled. addition, heater may used control temperature of circulating gas. another embodiment invention, a dust collector (not shown) such as wet-type disposed on an exhaust line circulation pipe 1115". for more stable reducing, additional equipment 14" rotary hearth RHF) after apparatus 111" so further reduce agglomerated reduced iron. For example, in front or behind agglomerating device 13". After iron making process, steel process performed using including refining equipment. molten but supplied, thus large amount heat required To end, according present electric 20" used. The generates by creating arc
42 electrode, and is thus suitable to heat agglomerated reduced iron having a relatively low calorific power. The electric furnace 20" can use any kind of power such as DC power, AC 2-phase 3-A reducing agent may be supplied the for facilitate iron. Examples include: carbon agents recarbonizing agents, coal, coal briquettes, coke, fine coal; waste plastics; ferroalloy ferrosilicon ferromanganese; metal aluminum, silicon, manganese. Since generate large amount heat, scrap steel together with producing more molten steel. In this case, whole charging materials (+ steel, hereinafter referred main materials) include 30 weight% or preferably, 90 converter agglomerating device 13" connected each other through an transfer pipe 23". owing
43 agglomerated reduced iron transfer pipe 23" connected between the converter 20" and agglomerating device 13", can be prevented from being oxidized while transferred therebetween. The inside of may filled with nitrogen gas. In present embodiment invention, a slab casting apparatus disposed downstream steel making so as to cast motel into slabs. For compact equipment structure, include continuous machine rolling mill, mill my arranged in series. Herein, expression "series" means that outlet is substantially same inlet mill. other words, are installed at space. FIGS. 7 12 illustrate systems constructed by adding apparatuses 30 integrated manufacturing 1, 2, 3, 1', 2', 1" 1 6. As shown drawings, 31 for continuously molten produced 20 or
44 electric furnace 20-1 into a slab. If the thickness of slab is too thick, it may be difficult to roll with rolling mill. That is, immediately after cast by continuous casting machine 31, have 30 mm 150 mm. Preferably, equal or less than 120 100 mm, and more preferably, 70 In some preferable embodiments, discharged from mold 313 31 40 200 ratio reduction at liquid core region 314 located just before an outlet 40% less, 30% 25% less. The not performed if desired obtained. A rolled mill 32. cutting device 315 disposed between 32 so that work can proceed continuously even in case processing rates are different. includes finishing 326 for
45 rolling into steel sheets. A heater 324 may be disposed between the continuous casting machine 31 and finishing mill 326. The an induction furnace or a tunnel furnace, preferred for compact equipment structure. slab discharge unit 323 at least one place before after (in drawings, is 324). perpendicular transverse) direction to feeding dealing with errors previous next process separating defective slab. have length corresponding of two slabs example, 5.5 m 11 m). If necessary, heated, rolled desired thickness through finish process. At this time, final products coiled not depending on thicknesses thereof consumer's requests. 326 include three eight roller rows. More specifically, four seven cooling device 328 coil box 325 For
46 between the heater 324 and finishing mill 326. The coil box 325 may store a slab or steel sheet roughly rolled according to an embodiment of invention. function as buffer for having time spare, making temperature uniform, handling different processing rates 326 continuous casting machine 31 roughing 322 (described later) provided another be thermally insulated. In case rolling process, not fed through 325. invention, disposed at any position For example, before in front 324. A scale removing device 321 least one remove from process protecting rollers. cutting 327 after
47 mill 326 to cut a steel sheet into desired lengths. The cutting machine 327 may be shearing machine. In the present invention, structures of fluidized reduction furnace, agglomerating device, and smelting furnace are not limited. For example, have conventional known in art which invention pertains. Herein, terms "first" second" used indicate order elements but distinguish one element from another element. addition, initial" final" based on feeding direction fine iron ore. ore is first supplied referred as finally final furnace. embodiments converter explained device for converting molten making process. However, an electric instead converter. after process, secondary refining process additionally performed.
48 process may be performed on molten steel discharged from a converter or an electric furnace to adjust the composition of according properties final products and temperature suitable for casting. The secondary refining include any using device known in art which present invention pertains, such as bubbling device, vacuum heating device. That is, is not limited particular equipment. In embodiment invention, making apparatus further downstream side converter. Furthermore, process, at least one desulfurizing dephosphorizing disposed between smelting (furnace) remove sulfur phosphorus iron produced by then supply furnace. addition, pretreatment "primary process" industry, before furnace,
49 included in the steel making process of invention. That is, apparatus invention may be understood as a system including: converter or electric furnace; and hot metal pretreatment device secondary refining disposed front behind furnace. However, such devices are not essential thus apparatus. An integrated method for manufacturing will now described with reference to FIG. 1 according an embodiment As shown 1, present invention, molten iron is produced using including 10 20. The includes: fine ore reducing 11; first agglomerating 13; second 14; smelting furnace 12. 11 includes fluidized reduction 111 112. In processed into reduced by
50 fluidized reduction furnace apparatus 112. In detail, fine iron ore and other materials are supplied to the furnaces, reduced while reducing gas is introduced through supply pipe form flow layers. The furnaces may have a sufficiently large specific area small grain size so as be easily blown by gas. present embodiment of invention, having 12 mm or less used. Preferably, 10 More preferably, 8 It preferable that degree 50% 80% first 111. described below, (known "FOG") containing relatively amount dust sulfur discharged from smelting used reduce ore, thus if high gas, sticking phenomenon occur. Therefore, due possibility additional in 12,
51 at the first fluidized reduction furnace apparatus 111 may be set to within above-mentioned range. It preferable that fine iron ore reduced a degree of 80% 95% by second 112. In another embodiment invention, gas exhausted from is used as reducing in Since dust and sulfur are removed exhaust gas, possibility described problem reduces, thus 112 Fine supplied agglomerating device 13 14, respectively, so produce agglomerated iron. The devices 14 according method known art which present invention pertains, such methods using apparatuses disclosed Korean Patent Application Laid-open Publication Nos.: 10-2005-0068319 2003-0085795. That is, various techniques related
52 agglomerated reduced iron using the first and second agglomerating devices 13 14. Thereafter, produced by device is supplied to smelting furnace 12 produce molten iron. It may be preferable that 14 at a high temperature of 500°C 800°when being or steel making apparatus. A reducing agent together with so as further reduce The carbon such coal agent. Examples agents include briquettes, lump coal, coke. Molten 12, are converter 20 steel. Before 20, processed through least one desulfurizing process, dephosphorizing any other pretreatment process. For efficient processing in it
53 be preferable that 40% to 80% of molten iron and 20% 60% agglomerated reduced supplied the converter 20. Referring FIG. 1, is produced from prepared through first fluidized reduction furnace apparatus 111. However, may second 112. In addition, all 111 not smelting 12. That is, a portion directly steel making apparatus. Similarly, 112 but some thereof If one apparatuses out order, or other integrated method for manufacturing steel,
54 exhaust gas discharged from the first fluidized reduction furnace apparatus 111 may be supplied as reducing to second 112 through connection pipe 1116. Exhaust at least one of and apparatuses circulated a gas. The undergo carbon dioxide removing process performed by device 116 or 118 temperature adjusting heater 117 (on is not shown), then other 112. When molten steel produced in converter 20, fuel oxygen O2) lower side 20 heat steel. In addition, granular material such quicklime powder that can control basicity slag function seeds decarbonizing reaction blown into together with oxygen. when oxygen-containing air upper
55 converter 20 so as to secondarily burn carbon monoxide (post-combustion) and thus increase thermal efficiency. The oxygen-containing gas may be blown into the after being heated, For this, heat exchange with waste discharged from 20. An integrated method for manufacturing steel will now described reference FIG. 4 according another embodiment of invention. As shown in 4, other invention, molten iron is produced using making apparatus including 10' 20'. includes: fine ore reducing device 11'; agglomerating 13'; smelting furnace 12'. 11' includes fluidized reduction 111'. In present processed reduced by detail, materials are supplied furnaces, while
56 is introduced through the gas supply pipe to form flow layers. The fine iron ore supplied into fluidized reduction furnaces may have a sufficiently large specific area and small grain size so as be easily blown reduced by reducing gas. In present embodiment of invention, having 12 mm or less used. Preferably, 10 More preferably, 8 It preferable that degree 50% greater furnace apparatus 111' for easy additional at smelting 12'. described below, (known "FOG") containing relatively amount dust sulfur discharged from 12' used reduce ore, thus if high gas, sticking phenomenon occur. Therefore, when in are considered, it 80% less. Fine
57 furnace apparatus 111' is supplied to the agglomerating device 13' produce agglomerated reduced iron. The may iron according a method known in art which present invention pertains, such as methods using apparatuses disclosed Korean Patent Application Laid-open Publication Nos.: 10-2005-0068319 and 2003-0085795. That is, various techniques related be used devices 13'. Thereafter, produced by smelting 12' molten It preferable that at high temperature of 500°C 800°when being 12'. A reducing agent together with so further reduce carbon coal agent. Examples agents include briquettes, lump coal, coke. At this time, Si included burned oxygen blown into steel making
58 heat the molten iron. Therefore, it may be preferable that iron include 0.1 weight% or more of Si. More preferably, 0.3 However, if concentration Si is too high, basicity slag excessively increased in a steel making process, and thus processes such as desulfurizing process dephosphorizing inefficiently performed. upper limit set to 1.0 weight%, 0.5 weight%. The produced by smelting furnace 12' supplied converter 20' together with scrap produce steel. Before 20', processed through at least one any other pretreatment process. At this time, sufficient amount steel, HMR 70% less. That is, required increase portion so heating difficult. 30% greater.
59 In the fluidized reduction furnace apparatus 111', exhaust gas discharged from first may be circulated as reducing gas. The undergo at least one of a carbon dioxide removing process performed by device 118' and temperature adjusting heater (not shown), then supplied to final 111'. When molten steel is produced in converter 20', fuel oxygen O2) through lower side 20' heat steel. addition, granular material such quicklime powder that can control basicity slag function seeds decarbonizing reaction blown into together with oxygen. when oxygen-containing air upper so secondarily burn monoxide post-combustion) thus increase thermal efficiency. after being heated, For this,
60 blown into the converter 20' after heat exchange with waste gas discharged from 20'. With reference to FIG. 6, an integrated method for manufacturing steel will now be described according another embodiment of invention. As shown in other invention, molten iron is produced using agglomerated reduced making apparatus 10" and electric furnace 20". The includes fine ore reducing device 11" agglomerating 13". fluidized reduction 111". In processed by 111" 10". detail, materials are supplied furnaces, while introduced through supply pipe form flow layers. furnaces have a sufficiently large specific area small grain size so as easily gas.
61 fine iron ore having a grain size of 12 mm or less may be used. Preferably, 10 More preferably, 8 It preferable that reduced to reduction degree 80% greater by the fluidized furnace apparatus 111" for easy additional at electric 20". is as much possible, upper limit not limited. Fine supplied agglomerating device 13" produce agglomerated iron. The according method known in art which present invention pertains, such methods using apparatuses disclosed Korean Patent Application Laid-open Publication Nos.: 10-2005-0068319 and 2003-0085795. That is, various techniques related used devices 13". Thereafter, produced
62 furnace 20" to produce molten steel. It may be preferable that agglomerated reduced iron produced by the agglomerating device 13" at a high temperature of 500°C 800°when being supplied electric 20". At this time, for stably obtaining desired reduction degree in other embodiment present invention, additional reducing equipment 14" such as rotary hearth (RHF) can direct DRI) disposed after fluidized apparatus 111" so further reduce iron. In addition, more stable reduction, For example, front or behind 13". case, not equal greater than 80%. That is, it sufficient 80% is into
63 In the fluidized reduction furnace apparatus 111", exhaust gas discharged from first may be circulated as reducing gas. The undergo at least one of a carbon dioxide removing process performed by device 118" and temperature adjusting heater (not shown), then supplied to final 111". above-described steel making process, secondary refining additionally after converter or electric in other embodiment). any known art which present invention pertains. That is, is limited particular process. an embodiment invention, include before converter. addition, hot metal pretreatment Furthermore, embodiment, explained example apparatus. However, shown FIG. 5,
64 furnace may be used instead of the converter. Since electric generate heat using an arc, a steel making process can fully performed in even case that HMR is relatively low. Furthermore, according to present invention, large amount molten iron as compared method related art which only scrap melted furnace, and thus various products having high quality manufactured. According another embodiment slab casting after process. The include continuous rolling for compact equipment structure. At this time, series. Embodiments invention will now described with reference FIGS. 7 12 showing systems further including apparatuses, shown drawings. A cast method. If thickness too thick, load acting on mill 32 increases. Therefore, so roll directly process, it preferable produced
65 casting process have a thickness of 30 mm to 150 mm. More preferably, the slab may 120 or less, 100 70 In some preferable embodiments, discharged from mold 313 continuous machine 31 be 40 200 mm, and ratio reduction at liquid core region 314 located just before outlet 40% 30% 25% less. The not performed if desired is obtained. addition, it that rate 4 mpm 15 mpm, more 8 mpm. A rolled in following rolling process. At this time, cut after then supplied so work can proceed continuously even case processing rates mill are different. include finish process, heating between heat temperature level for
66 rolling process. A heater such as an induction furnace or a tunnel may be used in the heating The preferred for compact equipment structure. If emergency situation occurs, slab discharged from position before after heater. is rolled to desired thickness final product through finish At this time, products coiled not coiled, depending on thicknesses thereof consumer's requests. cooling process performed Before process, storing which steel sheet roughly according embodiment of invention and stored coil box 325. 325 function buffer having time spare, making temperature uniform, handling different processing rates finishing mill 326 roughing 322 (described later) provided another invention. It preferable that have 20 mm less. In case continuous performed. invention, rough
67 rolling process may be performed before the finish process. A scale removing at least one of rough and to remove from a steel sheet for protecting or rollers. cutting after cut into desired lengths. The cooling As described above, according integrated manufacturing system embodiments present invention, since both molten iron agglomerated reduced can produced by single making apparatus, amount able unit equipment is comparable large blast furnace such as having an annual capacity three millions tons four tons. That is, 1.3 2.5 million annually using smelting furnace, agglomerating device supplied directly converter. Therefore, high productivity
68 comparable to that of a large blast furnace can be obtained by properly adjusting the amounts molten iron and agglomerated reduced iron. In addition, since steel making apparatus, is, converter have improved thermal efficiency, work done at low HMR, thus produced in flexible working environments. according present invention, equipment compactly constructed without furnace, various high-quality products manufactured as compared typical electric-method not using (conventional use only scrap steel). Furthermore, integrated system for manufacturing embodiments is supplied electric heated, very compact systems related art.
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【We Claim】
【Claim 1】
An integrated system for manufacturing steel, comprising:
an iron making apparatus; and
a steel making apparatus configured to produce molten steel from molten iron and agglomerated reduced iron received from the iron making apparatus,
wherein the iron making apparatus comprises:
a fine iron ore reducing device comprising first and second fluidized reduction furnace apparatuses each comprising at least one fluidized reduction furnace for reducing fine iron ore;
first and second agglomerating devices configured to agglomerate reduced fine iron ore received from the first and second fluidized reduction furnace apparatuses, respectively; and
a smelting furnace configured to produce molten iron by melting agglomerated reduced iron received from the first agglomerating device.
【Claim 2】
The integrated system as claimed in claim 1, wherein a final fluidized reduction furnace of the first fluidized reduction furnace apparatus is connected to the smelting
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furnace through a gas supply pipe for allowing gas to flow therethrough, and a first fluidized reduction furnace of the first fluidized reduction furnace apparatus is connected to a final fluidized reduction furnace of the second fluidized reduction furnace apparatus through a reducing gas connection pipe for allowing gas to flow therethrough.
【Claim 3】
The integrated system as claimed in claim 1 or 2, wherein the steel making apparatus comprises a converter or an electric furnace, and the converter or the electric furnace is connected to the second agglomerating device through an agglomerated reduced iron transfer pipe to allow agglomerated reduced iron to be transferred therethrough.
【Claim 4】
An integrated system for manufacturing steel, comprising:
an iron making apparatus; and
a steel making apparatus configured to produce molten steel from molten iron received from the iron making apparatus and scrap steel,
wherein the iron making apparatus comprises:
a fine iron ore reducing device comprising fluidized reduction furnace apparatus that comprises at least one
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fluidized reduction furnace for reducing fine iron ore;
an agglomerating devices configured to agglomerate reduced fine iron ore received from the fluidized reduction furnace apparatus; and
a smelting furnace configured to produce molten iron by melting agglomerated reduced iron received from the agglomerating device.
【Claim 5】
The integrated system as claimed in claim 4, wherein the steel making apparatus comprises a converter or an electric furnace.
【Claim 6】
The integrated system as claimed in claim 3 or 5, wherein a nozzle is provided in a lower portion of the converter to supply fuel and oxygen (O2) to the converter, and a lance is provided in an upper portion of the converter to supply oxygen-containing gas to the converter.
【Claim 7】
An integrated system for manufacturing steel, comprising:
an agglomerated reduced iron making apparatus; and
an electric furnace,
wherein the agglomerated reduced iron making apparatus comprises:
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a fine iron ore reducing device comprising a fluidized reduction furnace apparatus that comprises at least one fluidized reduction furnace for reducing fine iron ore; and
an agglomerating device configured to agglomerate reduced fine iron ore received from the fluidized reduction furnace apparatus.
【Claim 8】
The integrated system as claimed in any one of claims 1 to 7, further comprising a slab casting apparatus in which a continuous casting machine configured to cast molten steel produced by the steel making apparatus is connected to a rolling mill in series.
【Claim 9】
The integrated system as claimed in claim 8, wherein the continuous casting machine is configured to produce a slab having a thickness of 30 mm to 150 mm at a rate of 4 mpm to 15 mpm, and the rolling mill comprises a finishing mill,
wherein the integrated system further comprises a steel sheet heater and a coil box that are disposed between the continuous casting machine and the finishing mill, and the coil box stores a steel sheet after coiling thereof.
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【Claim 10】
The integrated system as claimed in claim 9, further comprising a roughing mill between the continuous casting machine and the finishing mill.
【Claim 11】
An integrated method for manufacturing steel, comprising:
performing a molten iron making process; and
performing a molten steel making process to produce molten steel from molten iron and agglomerated reduced iron that are produced in the molten iron making process,
wherein the molten iron making process comprises:
producing reduced fine iron ore by reducing fine iron ore in first and second fluidized reduction furnace apparatuses;
producing agglomerated reduced iron in first and second agglomerating devices by using reduced fine iron ore, supplied from the first and second fluidized reduction furnace apparatuses to the first and second agglomerating devices, respectively; and
producing molten iron in a smelting furnace by melting agglomerated reduced iron received from the first agglomerating device.
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【Claim 12】
The integrated method as claimed in claim 11, wherein exhaust gas discharged from the first fluidized reduction furnace apparatus is supplied to the second fluidized reduction furnace apparatus to be used as a reducing gas.
【Claim 13】
An integrated method for manufacturing steel, comprising:
performing a molten iron making process; and
performing a molten steel making process to produce molten steel by using molten iron produced in the molten iron making process,
wherein the molten iron making process comprises:
producing reduced fine iron ore by fluidizing and reducing fine iron ore;
producing agglomerated reduced iron by receiving and agglomerating the reduced fine iron ore; and
producing molten iron by melting agglomerated reduced iron produced by an agglomerating device,
wherein in the steel making process, scrap steel is used together with the molten iron at a hot melt ratio (HMR) of 70 weight% or less.
【Claim 14】
An integrated method for manufacturing steel,
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comprising:
producing reduced fine iron ore by fluidizing and reducing fine iron ore;
producing agglomerated reduced iron by receiving and agglomerating the reduced fine iron ore; and
producing molten steel by melting the agglomerated reduced iron in an electric furnace.
【Claim 15】
The integrated method as claimed in any one of claims 11 to 14, further comprising performing a slab casting process in which a continuous casting process and a rolling process are performed in series, wherein the continuous casting process is performed to cast molten iron produced in the producing of the molten steel.
【Claim 16】
The integrated method as claimed in claim 15, wherein the continuous casting process is performed at a rate of 4 mpm to 15 mpm to produce a slab having a thickness of 30 mm to 150 mm, and the rolling process comprises a finish rolling process,
wherein the integrated method further comprises a steel sheet heating process and a coiling and storing process between the continuous casting process and the finishing rolling process, and a steel sheet is coiled and
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stored in the coiling and storing process.
【Claim 17】
The integrated method as claimed in claim 16, further comprising a rough process between the casting process and the finishing rolling process. Date: 22 July 2013. [Dr. Ramesh Kr. Mehta] Patent Attorney for the Applicants Regn. No. - IN/PA-267] Of Mehta & Associates
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Original/Duplicate Abstract Title of the Invention:-
“Integrated Steel Manufacturing System and Method for Integrated Steel Manufacturing”
Provided is an integrated system for manufacturing steel including an iron making apparatus and a steel making apparatus. The steel making apparatus produces molten steel from molten iron and agglomerated reduced iron received from the iron making apparatus. The iron making apparatus includes a first iron ore reducing device, first and second agglomerating devices, and a smelting furnace. The fine iron ore reducing device includes first and second fluidized reduction furnace apparatuses respectively including at least one fluidized reduction furnace for reducing fine iron ore. The first and second agglomerating devices agglomerates reduced fine iron ore received from the first and second fluidized reduction furnace apparatuses, respectively. The smelting furnace produces molten iron by melting agglomerated reduced iron received from the first agglomerating device.