CN105543437A - Two-stage type entrained flow bed iron ore powder reduction process - Google Patents

Two-stage type entrained flow bed iron ore powder reduction process Download PDF

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Publication number
CN105543437A
CN105543437A CN201210424752.1A CN201210424752A CN105543437A CN 105543437 A CN105543437 A CN 105543437A CN 201210424752 A CN201210424752 A CN 201210424752A CN 105543437 A CN105543437 A CN 105543437A
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reduction
gas
breeze
coal gas
thick
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周久乐
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Dongfang Iron & Steel Co Ltd Shenyang City
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Dongfang Iron & Steel Co Ltd Shenyang City
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]

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Abstract

The invention relates to a two-stage type entrained flow bed iron ore powder reduction process. According to the process, direction reduction of iron ore powder is divided into two stages such as fine reduction and coarse reduction; at the coarse reduction stage, crushed and dried iron ore powder is conveyed into a coarse reduction furnace in an entrained flow bed manner by using fine reduction tail gas, and Fe2O3 and Fe3O4 in the iron ore powder in the coarse reduction furnace are reduced into topsoil body FeO; and in a fine reduction furnace, the ore powder uniformly descends and is mixed with high-temperature coal gas from an entrained flow bed coal gas generation furnace or high-temperature coal gas obtained through natural gas reforming, and at a temperature of 900-1100 DEG C, the topsoil body FeO in the ore powder react with hydrogen and carbon monoxide in the coal gas so as to obtain the elemental iron. According to the present invention, with the process, energy saving and emission reducing can be substantially achieved, most of the discharged carbon dioxide can be recycled, the consumed water can be controlled at the level of less than or equal to 0.5 T/T, and the sulphur is more than or equal to 95% and can be recycled; the emission of sulfur dioxide and nitrogen oxides does not exist, and the waste residue and the dust are completely recycled.

Description

A kind of two-part air flow bed reduction of iron ore fines technique
Technical field
The present invention relates to a kind of non-blast furnace ironmaking technology, especially a kind of two-part air flow bed reduction of iron ore fines technique.
Background technology
Blast furnace technology has thousands of years history, has been the technological process of production of comparative maturity advanced person at present, and due to a large amount of expensive coking coal of blast furnace ironmaking consumption, higher energy consumption, in recent years, whole world metallargist is in discuss and study non-blast furnace ironmaking technique.
At present, the coal-based direct melting and reducing iron process of China's Baosteel Introduced From Abroad, fuel ratio 800kgce/T, wherein 20% is coke; The coal of Korea S " FINEX " is than about 700kgce/T; China's coal-based direct reduction iron energy consumption great majority are at more than 800kgce/T, indivedual enterprise is at about 1000kgce/T, non-blast furnace ironmaking energy consumption high major cause produces a large amount of high heating value gas not obtain scientific utilization, majority is by coal gas converting electrical energy, and the efficiency of energy utilization of gas shift electric energy only has 32%-45%.Therefore, relevant department has advised that non-blast furnace ironmaking project should not go up again in China.
Summary of the invention
The object of the invention is for solving above-mentioned prior art Problems existing, and a kind of two-part air flow bed reduction of iron ore fines technique is provided, this technique is combined at gas maked coal (or the coal gas after reforming with Sweet natural gas, coke-oven gas) and two-part air flow bed breeze reducing process, by coal gas and powdered iron ore direct production reduction straight iron powder, smelt ultra-clean steel raw material for electric arc furnace, line frequency induction furnace; Also steel scrap can be replaced for converter.
The technical scheme adopted is:
A kind of two-part air flow bed reduction of iron ore fines technique, is characterized in that powdered iron ore direct-reduction being divided into essence reduction carries out with thick reduction two sections; Its technological process is as follows:
First, dry pulverized coal is made coal gas (or with gas renormalizing) through air flow bed producer gas generator, gas temperature requires that being greater than 1200 DEG C is less than 1450 DEG C, pressure>=0.3MPa, coal gas hydrogen content V h2> 30%, (V in coal gas h2O+ V cO2) ≯ 0.5%, coal gas can directly enter breeze fine reduction furnace through dedusting (also can not dedusting).Meanwhile, by powdered iron ore to be restored, broken dry, its moisture ≯ 0.1%, and being preheating to > 100 DEG C, breeze is crushed to below 100 orders, and reduction tail gas (through thick dedusting) combines with breeze and forms air flow bed and directly send into thick reduction furnace.
From air flow bed producer gas generator coal gas (or with coal gas after gas renormalizing), first enter fine reduction furnace, after essence reduction, smart reducing gas exhaust temperature is greater than 900 DEG C, is less than 1100 DEG C, after thick dedusting, enters thick reduction furnace.
Be the reduction of breeze first paragraph in thick reduction furnace, this section is by Fe in breeze 2o 3and Fe 3o 4be reduced to floating scholar's body (FeO) and remove wherein sulfur impurity, and breeze is preheating to 750 DEG C-850 DEG C, through prereduction breeze by every wheel feeder, directly entering fine reduction furnace.After thick reduction, exhaust temperature is greater than 750 DEG C and is less than between 900 DEG C, tail gas is cooled to 250 DEG C-300 DEG C through waste heat boiler, again through the dedusting of net bag type dust remover essence, dedusting get off dust be exactly breeze reduction product, return thick reduction furnace, dedusting tail gas, through spray column aqueous sodium hydroxide solution spray process, removes H in coal gas 2s, temperature is reduced to less than 30 DEG C further, and the coal gas after spray through dehydration, then removes carbonic acid gas in coal gas through pressure swing adsorption technique, and carbonic acid gas recoverable, after decarburization, coal gas enters among storage tank.
Through prereduction and desulfurization breeze temperature between 750 DEG C-900 DEG C, through entering fine reduction furnace every wheel, controlled every wheel, adjustable speed, guarantee that charging is even, it is the reduction of breeze second segment in fine reduction furnace, surface dust body (FeO) is reduced to metal straight iron powder, after reduction, pure iron temperature is between 900 DEG C-1100 DEG C, because iron powder proportion is greater than gangue powder proportion more than two times, control gas flow rate in reduction furnace and be greater than the elutriation speed of gangue dust, gangue is effectively separated with iron powder, gangue powder (containing oxide compound) enters the thick dedusting of essence reduction tail gas by fine reduction furnace top (containing coal ash) and removes, this dedusting product contains a small amount of iron powder, after magnetic separation, brickmaking or be used as him.
Above-mentioned coke-oven gas or Sweet natural gas or other coal gas containing methane, before participation breeze direct-reduced iron, will be reformed to methane, allocate suitable quantity of water steam into and input heat accumulating horizontal hotblast stove together, make CH by methane 4+ H 2o=CO+3H 2reaction is carried out thoroughly, and is preheating to more than 1200 DEG C temperature simultaneously.
In above-mentioned two sections of reduction processes, if three place's waste heat boilers, reclaim reaction process waste heat, the thick reducing gas using waste heat from tail gas of first paragraph and the rear straight iron powder waste heat recovery of essence reduction, and the waste heat recovery of essence reduction tail gas thick dedusting dust, waste heat can be made to convert energy conversion efficiency about 32% to.
Adopt above-mentioned two-phase method technique to reduce straight iron powder consumed energy per ton to can be controlled between (286kgce/T iron powder is to 340kgce/T iron powder).
In reduction process, in coal and breeze, the detrimental impurity such as sulphur arsenic is all by hydrogen reduction in coal gas, after the process of buck spray, forms sulfide solution, reoxidizes to form elemental sulfur and be recovered; Spray buck can recycle.Produce straight iron powder per ton recyclable 0.8-1.35 ton carbonic acid gas, valuable utilization can be become; Produce reduced iron Carbon emission per ton to can be controlled between 264kg/T to 320kg/T.
In sum, this technique solves a numerous difficult problem in current non-blast furnace ironmaking technique.
This technique tool has the following advantages:
1, the applicable variety of reducing gas is extensive, both can utilize low grade coal gas reduction, reduction after Sweet natural gas, coke-oven gas also can be used to reform.
2, the kind that powdered iron ore is applicable is extensive, both can use high grade iron breeze, and also can use low-grade iron ore powder, particularly rhombohedral iron ore and limonite.
3, this technique does not have the consumption of coking coal.
4, can energy-saving and emission-reduction by a relatively large margin, and the carbonic acid gas of discharge can major part be recycled, and water loss, can control in below 0.5T/T level, sulphur more than 95%, recoverable; Do not have the discharge of sulfurous gas and oxynitride, waste residue and dust are all recycled.
5, all Fe3+ reduction technology of comprehensive cost have and significantly reduce.
6, this technique, coal gas can reclaim and recycle, and gas utilization rate is high.
Embodiment
This example be in gasifying coal as the technique of reducing gas, to produce the flow process that 1,500,000 tons of reduced irons are target per year.
First coal in 150t/h is made coal dust, 52500Nm 3the water vapor of/h pure oxygen and 30t/h is heated to 1350 DEG C-1400 DEG C through heat accumulating horizontal high temperature hot-blast furnace, dry pulverized coal and high temperature pure oxygen, water vapor make coal gas (or with gas renormalizing) through air flow bed producer gas generator, gas temperature 1300 DEG C-1350 DEG C, pressure 0.85MPa, coal gas hydrogen content V h2=40%, (V in coal gas h2O+ V cO2)=0.4%, coal gas directly enters breeze fine reduction furnace through dedusting (also can not dedusting).Meanwhile, by powdered iron ore 324t/h to be restored, broken dry, its moisture 0.07-0.09%, and be preheating to 110 DEG C-130 DEG C, breeze is crushed to 200 orders, and reduction tail gas (through thick dedusting) combines with breeze and forms air flow bed and directly send into thick reduction furnace.
From air flow bed producer gas generator coal gas (or the coal gas after reforming with Sweet natural gas, coke-oven gas), first enter fine reduction furnace, after essence reduction, smart reducing gas exhaust temperature 950 DEG C-1050 DEG C, after thick dedusting, enters thick reduction furnace.
Reduction in thick reduction furnace is first paragraph reduction, and this section is by Fe in breeze 2o 3and Fe 3o 4be reduced to floating scholar's body (FeO) and remove wherein sulphur, phosphorus impurities, and breeze is preheating to 770 DEG C-850 DEG C, through prereduction breeze by every wheel feeder, directly entering fine reduction furnace.After thick reduction, exhaust temperature 790 DEG C is less than between 700 DEG C, tail gas is cooled to 270 DEG C-280 DEG C through waste heat boiler, again through the dedusting of Stainless Steel Wire net bag type dust remover essence, the dedusting dust that gets off returns thick reduction furnace, dedusting tail gas, through spray column aqueous sodium hydroxide solution spray process, removes H in coal gas 2the oxide compound of S and phosphorus, temperature is reduced to less than 25 DEG C further, and coal gas through dehydration, then removes carbonic acid gas in coal gas through pressure swing adsorption technique, and carbonic acid gas recoverable, after decarburization, coal gas enters among storage tank.Coal gas in storage tank again through gas compressor by pipeline, is compressed to 1.2MPa (1.4 times of suitable gas yield), reforms, be heated to 1350 DEG C-1400 DEG C and send back among gas furnace through horizontal regenerative hot blast stove.
Through prereduction and desulfurization breeze temperature between 770 DEG C-850 DEG C, through entering fine reduction furnace every wheel, controlled every wheel, adjustable speed, guarantee that charging is even, (second segment breeze reduction surface dust body (FeO) in fine reduction furnace, be reduced to metal straight iron powder, after reduction, pure iron temperature is between 950 DEG C-1050 DEG C, because iron powder proportion is greater than gangue powder proportion more than two times, in suitable control reduction furnace, gas flow rate is greater than the elutriation speed of gangue dust, gangue is effectively separated with iron powder, gangue powder (containing oxide compound) is by fine reduction furnace top (containing coal ash), enter the thick dedusting of essence reduction tail gas to remove, this dedusting product contains a small amount of iron powder, after answering magnetic separation, brickmaking or be used as him.
In two sections of reduction processes, if three place's waste heat boilers, reclaim reaction process sensible heat, first paragraph thick reducing gas tail gas sensible heat and the rear straight iron powder Exposure degree of essence reduction, and essence reduction tail gas thick dedusting dust Exposure degree, waste heat can be made to convert energy conversion efficiency about 32% to.
The processing parameter implemented is as follows:
The main consumption indicators of device produces 1500000 tons/year per year
Coal amount: 150T/h in consumption per hour
Consumption pure oxygen per hour: 52500NM 3/ h
Consumption water vapor per hour: 30T/h
Consumption breeze per hour: 324T/h
Product pure iron amount per hour: 200T/h
Generated energy per hour: 85MWh (200)
Device is from current consumption: 29240KWh
Reduced iron comprehensive energy consumption per ton: 325kgce/T
Producing coal ash quantity per hour (containing ore gangue amount): 184T/h
Recovery sulphur per hour: 503.7kg/h
Sulfur recovery rate: 95%.

Claims (2)

1. a two-section type air flow bed reduction of iron ore fines technique, it is characterized in that this technique powdered iron ore direct-reduction is divided into essence reduction to carry out with thick reduction two sections, its technological process is as follows:
First, dry pulverized coal is made coal gas through air flow bed producer gas generator, gas temperature requires that being greater than 1200 DEG C is less than 1450 DEG C, pressure>=0.3MPa, coal gas hydrogen content V h2> 30%, carbonic acid gas and water (V in coal gas h2O+ V cO2) ≯ 0.5%, coal gas enters breeze fine reduction furnace through dedusting, simultaneously, by powdered iron ore to be restored, broken dry, its moisture ≯ 0.1%, and be preheating to > 100 DEG C, breeze is crushed to below 100 orders, and reduction tail gas to combine with breeze through thick dedusting and forms air flow bed and directly send into thick reduction furnace;
From air flow bed producer gas generator coal gas, first enter fine reduction furnace, after essence reduction, smart reducing gas exhaust temperature is greater than 900 DEG C, is less than 1100 DEG C, after thick dedusting, enters thick reduction furnace;
Be the reduction of breeze first paragraph in thick reduction furnace, this section is by Fe in breeze 2o 3and Fe 3o 4be reduced to floating scholar's body (FeO) and remove wherein sulfur impurity, and breeze is preheating to 750 DEG C-850 DEG C, pass through every wheel feeder through prereduction breeze, directly enter fine reduction furnace, after thick reduction, exhaust temperature is greater than 750 DEG C and is less than between 900 DEG C, tail gas is cooled to 250 DEG C-300 DEG C through waste heat boiler, again through the dedusting of net bag type dust remover essence, dedusting get off dust be exactly breeze reduction product, return thick reduction furnace, dedusting tail gas, through spray column aqueous sodium hydroxide solution spray process, removes H in coal gas 2s, temperature is reduced to less than 30 DEG C further, and the coal gas after spray through dehydration, then removes carbonic acid gas in coal gas through pressure swing adsorption technique, and after decarburization, coal gas enters among storage tank;
Through prereduction and desulfurization breeze temperature between 750 DEG C-900 DEG C, through entering fine reduction furnace every wheel, it is the reduction of breeze second segment in fine reduction furnace, surface dust body (FeO) is reduced to metal straight iron powder, after reduction, pure iron temperature is between 900 DEG C-1100 DEG C, control gas flow rate in reduction furnace and be greater than the elutriation speed of gangue dust, gangue is effectively separated with iron powder, iron powder after reduction is deposited in the lock hopper of fine reduction furnace bottom and discharges, gangue powder enters in tails dedusting tank with tail gas, and the tail gas through the thick dedusting of high temperature enters in thick reduction furnace.
2. a kind of two-section type air flow bed reduction of iron ore fines technique according to claim 1, it is characterized in that described coke-oven gas or Sweet natural gas or other coal gas containing methane is before participation breeze direct-reduced iron, to reform to methane, allocate suitable quantity of water steam into by methane and input heat accumulating horizontal hotblast stove together, make CH 4+ H 2o=CO+3H 2reaction is carried out thoroughly, and is preheating to more than 1200 DEG C temperature simultaneously.
CN201210424752.1A 2012-10-24 2012-10-24 Two-stage type entrained flow bed iron ore powder reduction process Pending CN105543437A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110578029A (en) * 2019-09-25 2019-12-17 山东大学 Two-section type descending entrained flow iron-making system and iron-making process
CN111961784A (en) * 2020-08-31 2020-11-20 山东大学 Method and system for reduction reaction of iron ore powder in bubbling bed
CN113403440A (en) * 2021-06-11 2021-09-17 张振逵 Production process and equipment for virus-free sponge iron hydrogen carbon steel industrial chain
CN115261542A (en) * 2022-07-11 2022-11-01 山东祥桓环境科技有限公司 Circulating fluidized bed direct reduction method and process for short-process smelting of coal powder and mineral powder

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110578029A (en) * 2019-09-25 2019-12-17 山东大学 Two-section type descending entrained flow iron-making system and iron-making process
CN110578029B (en) * 2019-09-25 2020-11-10 山东大学 Two-section type descending entrained flow iron-making system and iron-making process
CN111961784A (en) * 2020-08-31 2020-11-20 山东大学 Method and system for reduction reaction of iron ore powder in bubbling bed
CN113403440A (en) * 2021-06-11 2021-09-17 张振逵 Production process and equipment for virus-free sponge iron hydrogen carbon steel industrial chain
CN115261542A (en) * 2022-07-11 2022-11-01 山东祥桓环境科技有限公司 Circulating fluidized bed direct reduction method and process for short-process smelting of coal powder and mineral powder
CN115261542B (en) * 2022-07-11 2024-05-31 山东祥桓环境科技有限公司 Circulating fluidized bed direct reduction system and process for short-process smelting of coal dust and mineral powder

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