CN101892340A - Method for preparing metallic iron by direction reduction in shaft furnace - Google Patents
Method for preparing metallic iron by direction reduction in shaft furnace Download PDFInfo
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- CN101892340A CN101892340A CN2010102363529A CN201010236352A CN101892340A CN 101892340 A CN101892340 A CN 101892340A CN 2010102363529 A CN2010102363529 A CN 2010102363529A CN 201010236352 A CN201010236352 A CN 201010236352A CN 101892340 A CN101892340 A CN 101892340A
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- shaft furnace
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Abstract
The invention discloses a method for preparing metallic iron by direct reduction in a shaft furnace. On the basis of the conventional shaft furnace, the shaft furnace has an air supply opening through which oxidizing gas such as air, oxygen-enriched air and oxygen can be supplied ; the distance from the central line of the air supply opening to a designed charge level is 1/3 to 4/5 of the distance from a hydrogen-enriched coal gas inlet to the charge level; and one to three layers of air supply openings can be formed on the different horizontal sections of the shaft furnace, and the air supply openings of each layer are symmetrically formed on the same horizontal section along the circumference. When the method of the invention is used, a small amount of mixed coal gas which contains CO and H2 can be combusted at a proper position of the upper part of the shaft furnace to make the temperature of the upper part of the shaft furnace higher, so that the generation condition of the reduction reaction are met or the generation rate of the reduction reaction is improved; and the reduction potential chemical energy is used in an ironmaking reactor as efficient as possible, so as to improve an energy flow utilization factor and efficiency and save energy substantially.
Description
Technical field
The invention belongs to metallurgical technology field, particularly a kind of shaft furnace that utilizes directly reduces the method for producing metallic iron.
Background technology
Shaft furnace is a principal reaction device of producing direct-reduced iron, also is dual-step type or three-wave-length smelting reduction process prereduction stage reactor commonly used.The technology core of shaft furnace reactor is the interaction rule between the distribution of coal gas stream reduction potential, heat flux distribution and coal gas stream and the iron content solid material.Production process is for to join shaft furnace by the dynamic distributor of ore with iron-bearing material from reactor top, form filling bed type iron content stock column, reducing gas enters shaft furnace from the bottom or the oblique equally distributed branch gas tube down of middle and lower part circumferential direction of packed bed, the descending furnace charge and the air-flow of rising are in reverse and capable process, finish heat transfer, mass transfer and chemical reduction reaction, the sponge iron that reduction generates is discharged through relative unit in the bottom of shaft furnace.
At present, Classical Shaft Furnace ironmaking reactor outlet coal gas contains a large amount of carbon monoxide CO and hydrogen H
2, as still containing the reducing gas of 60%-70% in the tail gas of MIDREX shaft furnace, illustrate that gas reduction gesture chemical energy is not efficiently utilized in the shaft furnace, cause energy consumption very high.Analyze its concrete reason and be mainly derived from following two aspects:
(1) indirect reduction needs the coal gas amount in the shaft furnace.For satisfying the reduction reaction thermodynamic condition of ferriferous oxide, determine the coal gas amount of demand from the reduction potential angle.Big quantity research has confirmed that the oxide compound of iron in the shaft furnace needs gradual deoxidizing, and wherein the reduction potential demand from FeO to Fe is the limiting element of whole furnace reduction institute air demand.For example, the utilization ratio of CO is the highest when under 800 ℃ FeO being reduced into metal Fe has only 30%, if merely as reductive agent, then ton iron needs pure CO coal gas 1333Nm
3Contain CO gas 933.33Nm in the coal gas that ton iron is discharged after the reduction reaction
3, far away more than with Fe
2O
3(ton iron needs 200Nm to required CO coal gas amount when being reduced into FeO
3).Therefore, consider that from satisfying thermodynamics reduction potential angle this production process iron per ton consumes reducing gas 1333Nm
3, the main component of the stock gas of generation is CO and CO
2, volume is respectively iron 733Nm per ton
3And 600Nm
3Outlet gas reduction gesture is 1.22.It is very high finally to cause exporting coal gas CO content.
(2) thermal equilibrium needs the coal gas amount in the shaft furnace.From the heat supply angle, because the restriction (850 ℃) of inlet gas temperature makes and has to feed a large amount of coal gas for satisfying thermal equilibrium.For the direct reduction iron making shaft furnace, its coal gas source mainly contains three types: gas renormalizing cracking, coke-oven gas and Fu Qing gas maked coal.Adopting the sort of mode coal gas all is by CO+H
2Mix to constitute, if be 92%Fe by raw material
2O
3Constitute CO:H in the reducing gas with 8% gangue
2Be equal proportion, the shaft furnace thermosteresis is 15%, and temperature of exit gas is 300 ℃ of calculating, takes all factors into consideration the required coal gas amount of ton iron 1870Nm from thermal equilibrium angle and reduction potential as can be known
3, its coal gas demand is much larger than the 1333Nm of reduction potential demand
3, then calculate and obtain CO according to the oxygen balance principle
2Volume is 600Nm
3/ tFe, then CO content 〉=733Nm
3/ tFe.Make and exist the CO gas content higher in the reactor outlet coal gas.Because H
2Reduction is heat absorption, promptly uses H
21 mole the iron of reducing need absorb the 50035J heat, and the CO reduction is heat release, promptly with the iron heat release 11705J of 1 mole of CO reduction, so along with H in the coal gas
2This problem will be more outstanding during the increasing of content.
How making efficient utilization of reduction potential chemical energy of coal gas in the shaft furnace is the subject matter that the present invention will solve.By analysis, the key that the coal gas chemical energy is not fully utilized in the stove be the to rise thermodynamics and kinetics condition of coal gas distribution does not seriously match, thereby causes in the shaft furnace gas utilization rate low, and the direct-reduced iron degree of metalization is low, gas consumption amount height, the Carbon emission height.In order to overcome the drawback that chemical energy is not fully utilized, common way is now, and a part of tail gas is flowed to Combustion of Hot Air Furnace, and remaining will be exported as coal gas.Another kind method is the thinking of stock gas recycle, this is that Chinese scholars was recognized after the importance of stock gas chemical energy utilization in succession by researching and proposing in recent years, and in gas base directly reducing iron process MIDREX, adopted the coal gas that to have discharged after dedusting, to mix with Sweet natural gas, reformation by reforming furnace obtains high reducing gas and direct heat is delivered in the shaft furnace again, produces solid-state metal sponge iron.
For the coal gas recycle, no matter be to be applied to direct reduction iron making technologies such as fusion reducing furnaces such as blast furnace, COREX or MIDREX, its starting point all is that the residue reduction potential of coal gas is returned to reactor again after heating up and reforming, these modes not only increase extras, but also have transformation efficiency and thermo-efficiency, especially need problems such as the extra reformation equipment that heats up.Therefore, the present invention is conceived to the optimum matching of thermodynamic condition in the shaft furnace, dynamic conditions and transmission course, physical energy and the chemical energy while maximum using acquisition system in, thus reach the target of energy-saving and emission-reduction, this significance also of the present invention just place.
Summary of the invention
At above technical problem, the present invention designs a kind of utilization and sets up the novel method that the shaft furnace of apparatus of oxygen supply (hereinafter to be referred as the oxygen supply shaft furnace) is smelted iron, and present method can fundamentally solve in the shaft furnace physical energy and chemical energy and not match and cause the low problem of gas utilization rate.
Design of the present invention is exactly to be conceived to directly utilize unreacted carbon monoxide CO and hydrogen H to greatest extent in the shaft furnace that plays the effect of ironmaking reactor
2Chemical energy, the method for employing improves its dynamic conditions, in appropriate location, shaft furnace top, the burning small part contain CO and hydrogen H
2Mixed gas, improve the temperature on shaft furnace top with this, thereby, efficiently utilize the reduction potential chemical energy at the ironmaking inside reactor as far as possible for satisfying the reduction reaction occurrence condition or improving the reduction reaction generation rate, can fluently use coefficient from improving it in essence.
The advantage of this method that the present invention proposes is apparent, reactor top coal gas chemical energy will make upper space indirect reduction be able to abundant development when being fully used, raising is gone into the prereduction degree of stove iron-bearing material and is alleviated the direct reductive demand of reactor lower part, and from reduction and the consumption of two aspects minimizings of heat demand carbon element, thereby can realize reducing coke ratio and reduce carbonic acid gas CO
2The set objective of quantity discharged.
The shaft furnace that utilizes according to the present invention directly reduces the method for producing metallic iron, described shaft furnace is for feeding the air feed port of oxidizing gas such as air, oxygen-rich air, oxygen to the increase from charge level 1/3-4/5 of design charge level distance from rich hydrogen reduction gas entry in existing shaft furnace, the medullary ray of described air feed port is rich hydrogen reduction gas entry to 1/3～4/5 of the distance of charge level to the distance of design charge level, air feed port can be provided with 1～3 layer in shaft furnace different levels cross section, every layer of air feed port in same horizontal section along the circumference symmetric arrangement.
Description of drawings
Shown in Figure 1 is the employed device synoptic diagram of this invention.
Embodiment
The present invention will be described below in conjunction with accompanying drawing.1 is the shaft furnace body among the figure, and 2 is the iron-bearing material feeding bin, and 3 is the direct-reduced iron discharge gate, and 4 is rich hydrogen reduction gas entry, and 5 are the stock gas outlet, and 6 is the oxidizing gas air feed port.
By accompanying drawing 1 as seen: this invention and the employed shaft furnace of general direct reduction are basic identical, promptly above shaft furnace 1, be provided with iron-bearing material feeding bin 2, this storehouse inlet is connected with feeding device, the bottom links to each other with shaft furnace top charging bole, be provided with direct-reduced iron discharge gate 3 in the bottom of shaft furnace and the reduced iron collector arrangement communicates, the bottom of shaft furnace body 1 is provided with rich hydrogen reduction gas entry 4, the top of shaft furnace body 1 also is provided with stock gas outlet 5, and this outlet and gas line communicate; With in the past directly the employed shaft furnace of reduction different be the air feed port 6 of also having set up many places oxidizing gas such as air, oxygen-rich air or oxygen on the top of shaft furnace body 1, this air feed port is located at from rich hydrogen reduction gas entry 4 to the design charge level, specifically highly be: the medullary ray of air feed port 6 is a rich hydrogen reduction gas entry 4 to 1/3～4/5 of the distance of charge level to the distance of design charge level, air feed port 6 can be provided with 1～3 layer in shaft furnace different levels cross section in this interval, every layer of air feed port in same horizontal section along the circumference symmetric arrangement.Give further instruction below in conjunction with embodiment.
The oxygen supply shaft furnace device of setting up that adopts in the embodiment of the invention comprises shaft furnace body 1, iron-bearing material feeding bin 2, direct-reduced iron discharge gate 3, rich hydrogen reduction gas entry 4, stock gas outlet 5 and oxidizing gas air feed port 6.Raw material is by iron-bearing material feeding bin 2, the raw material that will be made of pelletizing and flux etc. is by pack into the top of reduction shaft furnace of predetermined charge, raw material is in decline process gradually, with interact with the upstream reducing gas of raw material descending direction, finish material preheating and reduction process, by the time raw material is when reducing to the shaft furnace bottom, iron ore in the raw material has been reduced into sponge iron, discharge by direct-reduced iron discharge gate 3, enter among other equipment, further process.Reducing gas carbon monoxide CO and hydrogen H
2Enter in the stove from rich hydrogen reduction gas entry 4, participate in discharging by stock gas outlet 5 after the reduction reaction.
1/3 place in the distance to the design charge level that is shaft furnace from its rich hydrogen reduction gas entry 4 medullary rays of the distance from charge level blasts air, oxygen-rich air or oxygen by air feed port 6, and its air demand is to blast gas to add up to the flow of pure oxygen be 5Nm
3～30Nm
3/ ton iron.The oxygen that blasts is with carbon monoxide CO and hydrogen H
2Reaction to improve the temperature on shaft furnace top, is satisfied the reduction reaction occurrence condition or is improved the reduction reaction generation rate, thereby directly efficiently utilize reduction potential chemical energy as much as possible in shaft furnace inside, from improving its utilization coefficient in essence.
The furnace charge that adds is compared no change with Classical Shaft Furnace, feeds reducing gas in the shaft furnace bottom as reductive agent, and general reducing gas oxidisability is 5%-15%, and temperature is 750-950 ℃.
After implementing this invention, shaft furnace efficient and degree of metalization all are greatly improved, and the shaft furnace exhaust temperature is 100-450 ℃, and tail gas residue reduction potential is for leveling off to zero, and gas utilization rate is near 100%.
Example
800 ℃ of shaft furnace inlet gas temperatures, raw material is Fe by weight percentage
2O
3Content 92%+ gangue content 8%, rich hydrogen reduction coal gas is 50%CO and 50%H
2Temperature of exit gas is 300 ℃ of calculating, the distance that air feed port is arranged on from charge level is 1/3 place of shaft furnace distance to the design charge level from its rich hydrogen reduction gas entry 4 medullary rays, and along 4 oxygen blast mouths of circumference symmetric arrangement, blowing oxygen quantity is 15.68Nm in the same horizontal section of shaft furnace
3/ tFe, reducing gas consumption are 1400Nm
3If/tFe is with Classical Shaft Furnace 1870Nm
3Be standard, the present invention will reduce row's carbon amount 28.72%.
Corresponding Classical Shaft Furnace and the thermal equilibrium analysis table of setting up the oxygen blast shaft furnace of the present invention are as follows
Classical Shaft Furnace
The oxygen blast shaft furnace
From table, can know the heat of finding out oxygen blast shaft furnace when finishing same throughput and coal gas demand than Classical Shaft Furnace respectively from 2069679.48kJ/mol and 1870Nm
3Drop to 1873185.75kJ/mol and 1400Nm
3, illustrating that gas utilization rate significantly improves, its inner chemical energy utilization has compensated bringing the demand of sensible heat into.Calculation result shows that effects of energy saving and emission reduction of the present invention is obvious.
Claims (2)
1. one kind is utilized shaft furnace directly to reduce the method for producing metallic iron, it is characterized in that described shaft furnace is for increasing the air feed port that can feed oxidizing gas such as air, oxygen-rich air, oxygen in existing shaft furnace, the medullary ray of described air feed port is rich hydrogen reduction gas entry to 1/3～4/5 of the distance of charge level to the distance of design charge level, air feed port can be provided with 1～3 layer in shaft furnace different levels cross section, every layer of air feed port in same horizontal section along the circumference symmetric arrangement.
2. a kind of shaft furnace that utilizes according to claim 1 directly reduces the method for producing metallic iron, and to add up to the pure oxygen flow be 5Nm to the air demand that it is characterized in that blasting air, oxygen-rich air or oxygen by air feed port in order to blast gas
3～30Nm
3/ ton iron.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102363529A CN101892340A (en) | 2010-07-26 | 2010-07-26 | Method for preparing metallic iron by direction reduction in shaft furnace |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102363529A CN101892340A (en) | 2010-07-26 | 2010-07-26 | Method for preparing metallic iron by direction reduction in shaft furnace |
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| CN101892340A true CN101892340A (en) | 2010-11-24 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103088185A (en) * | 2013-02-22 | 2013-05-08 | 陈谦 | Coal-based direct reduced iron shaft furnace |
| CN103966383A (en) * | 2014-04-15 | 2014-08-06 | 山西太钢不锈钢股份有限公司 | Melting method of oxygen-enriched shaft furnace |
| CN104988332A (en) * | 2015-07-06 | 2015-10-21 | 中南大学 | One-step copper smelting process and device |
| CN106918686A (en) * | 2017-03-14 | 2017-07-04 | 东北大学 | It is a kind of for studying the experimental provision that fine ore reacts during exercise |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1327072A (en) * | 2000-06-02 | 2001-12-19 | 株式会社神户制钢所 | Method and device for making metal iron |
-
2010
- 2010-07-26 CN CN2010102363529A patent/CN101892340A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1327072A (en) * | 2000-06-02 | 2001-12-19 | 株式会社神户制钢所 | Method and device for making metal iron |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103088185A (en) * | 2013-02-22 | 2013-05-08 | 陈谦 | Coal-based direct reduced iron shaft furnace |
| CN103088185B (en) * | 2013-02-22 | 2014-12-24 | 陈谦 | Coal-based direct reduced iron shaft furnace |
| CN103966383A (en) * | 2014-04-15 | 2014-08-06 | 山西太钢不锈钢股份有限公司 | Melting method of oxygen-enriched shaft furnace |
| CN104988332A (en) * | 2015-07-06 | 2015-10-21 | 中南大学 | One-step copper smelting process and device |
| CN104988332B (en) * | 2015-07-06 | 2017-04-12 | 中南大学 | One-step copper smelting process and device |
| CN106918686A (en) * | 2017-03-14 | 2017-07-04 | 东北大学 | It is a kind of for studying the experimental provision that fine ore reacts during exercise |
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Application publication date: 20101124 |