CN85104824A - Process for producing sponge iron - Google Patents
Process for producing sponge iron Download PDFInfo
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- CN85104824A CN85104824A CN85104824.2A CN85104824A CN85104824A CN 85104824 A CN85104824 A CN 85104824A CN 85104824 A CN85104824 A CN 85104824A CN 85104824 A CN85104824 A CN 85104824A
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- fluidized
- bed reactor
- rotary kiln
- infeed
- bed
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Abstract
Material production sponge iron by direct reduction of iron oxide-containing in converter; The furnace charge that rotary kiln draws off is divided into sponge iron and contains the material that remains carbon, burning carbonaceous material in fluidized-bed reactor, and the heat that is produced by burning is used for generating except that scattering and disappearing.For guaranteeing to utilize the dump energy in the rotary kiln production process, and sulfurous gas, * nitrogen oxide and sulfurated lime composition reduce to minimum, the exhaust of rotary kiln dust-laden is infeeded fluidized-bed reactor carry out secondary combustion, enter most of oxygen-containing gas of fluidized-bed reactor, under the oxygen amount condition that metachemistry calculates, finish the burning of inflammable component, fluidized-bed reactor is discharged the solids recirculation of the folded band of gas and go into fluidized-bed reactor.
Description
The present invention relates in rotary kiln, use the technology of the material production sponge iron of the direct reduction of iron oxide-containing of solid carbon element reductive agent, in this technology, the furnace charge that draws off from rotary kiln is divided into sponge iron and contains the material that remains carbon, carbonaceous material burns in the fluidized-bed reactor of circulating fluidized bed is arranged, and the heat that burning produces is used for generating except that scattering and disappearing.
In rotary kiln, produce in the process of sponge iron, only have only that fixed carbon part (FC) can be used in reducing iron oxides in the reductive agent with the direct reducing iron oxides of solid carbon element reductive agent.In most of the cases, in the reductive agent inflammable volatile component only some is used for the furnace charge of preheating heating zone.Consequently, still contain inflammable gaseous state composition in the exhaust, and carrying the stove dirt of forming by the inflammable reductive agent of part secretly.The content of inflammable volatile component is than higher in the exhaust, if use the coal that contains high volatile component, for example brown coal are then all the more so.For this reason,, also to reclaim inflammable heat, just must make exhaust carry out secondary combustion if except sensible heat.For fear of the sponge iron reoxidation, must the control production process, make the furnace charge that draws off from rotary kiln, contain more or less residue carbon according to reactivity as the coal of reductive agent.Except residue carbon, the furnace charge that draws off also contains the lime-ash that has formed and is combined into the sulphur of sulfurated lime (Ca s) form, and sulphur is separated from sponge iron.
As everyone knows, according to disclosed 3300867 German application, in the exhaust of aftercombustion indoor secondary burning rotary kiln, heat of exhaust is used to produce steam, and steam is used for generating.For fear of overheated and incrustation, must and water under the situation of water cooling controlled temperature with multistage form, secondary combustion is carried out in exhaust.The latent heat of vaporization can't be used to produce steam.Under this process condition, fine particle solid contained in the exhaust does not have perfect combustion.The nonmagnetic substance of separating in the sponge iron from the rotary kiln discharging burns in circulating fluidized bed.The heat that burning produces is used for generating by vapour generator.Inflammable constituent in the exhaust has only been utilized a part, is included in the exhaust and the sulfurous gas that constitutes pollutent does not discharge.The objective of the invention is to make whole excess energies that can't be used for reducing iron oxides in the rotary kiln to obtain optimum utilization, make by sulfurous gas (so
2), * nitrogen oxide (NO
X) and the pollution that causes of sulfurated lime (Ca s) reduce to minimum.
Realize above-mentioned purpose according to the present invention, dust-laden exhaust with rotary kiln in the present invention infeeds fluidized-bed reactor and carries out secondary combustion there, infeed the oxygen-containing gas of fluidized-bed reactor to major general's major part, infeed the bottom of fluidized-bed reactor as fluidizing gas, under the oxygen amount condition that metachemistry calculates, finish the burning of inflammable component, the solids recirculation that the fluidized-bed reactor exhaust is carried secretly is gone into fluidized-bed reactor.And per hour the weight of this solid circle is five times in fluidized-bed reactor at least and contains solid weight.
The fluidized-bed that the present invention uses is different from " traditional " fluidized-bed, and in fluidized-bed of the present invention, because unexpected variable density, the distribution that does not have clear and definite limiting bed is separated and formed to close phase and top layer gas zone.Between close phase and top layer gas zone, do not have unexpected variable density, but solid concentration reduces continuously to the top from the bottom in the reactor.
Operational condition definition expense rood (Froude) and Archimedes (Archimede) characteristic number represent that its result is as follows:
0.1≤3/4×F
2 r× (ρ
g)/(ρ
X-ρ
g) ≤10
And 0.01≤A
r≤ 100
(dk * g (the ρ of Ar=in the formula
k-ρ
g))/(ρ
g* V
2)
And Fr
2=(u
2)/(g * d
k)
And the relevant gas velocity of u=(meter per second)
A
r=Archimedes (Archimedes) number
F
r=Fu Lude (Froude) number
ρ
g=gas density (kilogram/rice
3)
ρ
k=density of solid particles (kilogram/rice
3)
d
k=spherical particle diameters (rice)
V=kinetic viscosity (rice
2/ second)
G=universal gravitational constant (meter per second
2)
In circulating fluidized bed, the combustion processes of solid carbon material is basically at United States Patent (USP) 4,165, narration in 717 and 4,111,158.The cross section of fluidized-bed reactor can be garden annular or rectangle.Lower section Ke Yi Change becomes taper; If it is lower to contain the speed of oxygen flow attitude oxidizing gases, will wish it is above-mentioned form especially.The dust-laden exhaust preferably above fluidizing gas inlet, 30% place of total reactor height introduces, and can infeed multistage position.Above the secondary air inlet, the gas velocity in the reactor is in 4 to 10 meter per second scopes.The average particulate diameter of fluid bed material is in 50 to 500 micrometer ranges in the reactor.Temperature in the reactor is adjusted in 800 to 1000 ℃ of scopes.The general air that adopts is as containing oxygen flow attitude oxidizing gases.Infeed fluidizing gas from 10% of the above total reactor height of reactor bottom or bottom.Iff being to come the controlling reactor temperature with the excessive air of control, the net quantity of heat that is produced by burning will be utilized by deflated Re Jiao Change in a waste heat boiler so.If be lower than in excess air under about 80% the situation and realize burning, just can obtain more effective thermal utilization and lower device and running cost, and the part heat that burning produces scatters and disappears by the cooling surface that fluidized-bed reactor has, and (perhaps) efflux of solids of reactor discharge cycles through in reactor and cools off in fluidized bed cooler, and the air that fluidized bed cooler is discharged infeeds fluidized-bed reactor.If cycling stream is cooled, the air of then discharging from fluidized bed cooler will not only infeed reactor lower part, also infeed in about 10% to 30% the zone of height for reactor, measure the above-mentioned air that is discharged from from the bottom, have at least the oxygen-containing gas of total amount of accounting for 60% to be infeeded lower region.Rotary kiln can be operated under the contact between solid charge and the gas atmosphere is the mode of convection current or following current.
In preferred example, under the condition of 20 to 80% excess airs, realize the burning that metachemistry calculates, in fluidized bed cooler, cooling is from the efflux of solids of fluidized-bed reactor discharge indirectly, and it is recirculated into fluidized-bed reactor, and, infeeded fluidized-bed reactor as secondary air from the warmed-up fluidizing gas of fluidized bed cooler, and (perhaps) the cooling surface dissipated heat that has by fluidized-bed reactor is used for generating with warmed-up cooling fluid.If the scope of excess air is 20 in 80%, especially at 30 to 60% o'clock, sulfurated lime (Ca S) can be oxidized to calcium sulfate (CaSO well
4), and sulfurous gas (SO
2) and calcium oxide (Ca O) can fully react and form calcium sulfate (CaSO
4), but same all perfect combustion of incendivity component, and the heat that is produced by burning also can obtain economical utilization.If use problematic solid, the danger of the cooling surface of making dirty that causes thus is the bottom at fluidized bed cooler, and especially will take the solid circle type of cooling to come dissipated heat this moment.
In preferred example, above the fluidizing gas inlet, locate, will contain the material and the exhaust of rotary kiln dust-laden that remain carbon and infeed fluidized-bed reactor.This layout will cause lower gas pressure to descend, and however, still will guarantee enough residence time so that above-mentioned residue carbon species and dust-laden exhaust perfect combustion.
In preferred example, also replenish and infeed new carbon materials to fluidized-bed reactor.This measure makes might extra generating and with the simple method compensated waving.
In preferred example, place, rotary kiln exhaust entrance top, the suspended substance mean density is adjusted in 5 to 50 kilograms/meter in the fluidized-bed reactor
3In the scope.If refrigeration cycle solid in fluidized-bed, then aerosol density is preferably 5 to 20 kilograms/meter
3; If finish cooling by the cooling surface that reactor has, then aerosol density is preferably 15 to 30 kilograms/meter
3, and infeed with higher speed under the situation of new coal, if belong to first kind of situation, then aerosol density is preferably 15 to 30 kilograms/meter
3; If belong to second kind of situation, then aerosol density is preferably 20 to 50 kilograms/meter
3These numerical value can make under each situation, scatter and disappear by corresponding heat, make and obtain good temperature control in the fluidized-bed reactor.
In preferred example, the stove dirt that will can obtain in the power station infeeds fluidized-bed reactor.Stove dirt can obtain in the power station, just as the result of collection dust in the cracked and room of coal in the transfer point in transit.This stove dirt is removed with aforesaid way easily, and their contained combustiblecomponentss can obtain utilizing in this case.
In preferred example, sulfide is infeeded fluidized-bed reactor.If from the solid that rotary kiln draws off, the mol ratio of calcium and sulphur is lower than 1.2 to 1.5 scope, then this sulfide is infeeded reactor.This measure guarantees that the content of sulfurous gas in the fluidized-bed reactor exhaust will be lower than 200 milligrams/standard rice
3
The present invention will be described in more detail by an example and with reference to accompanying drawing.
To infeed rotary kiln at the loading end of rotary kiln (1) by the furnace charge (2) that iron ore, coal and solubility promoter are formed.The furnace charge that draws off (3) is divided into sponge iron (5) and nonmagnetic substance (6) at segregation section (4).Nonmagnetic substance (6) comprises residue carbon, lime-ash and sweetening agent.Exhaust (7) is infeeded dust settling chamber (8).Fluidizing gas (10) is infeeded the bottom of fluidized-bed reactor (9).Nonmagnetic substance (6) is infeeded the lower region of fluidized-bed reactor (9) by pipeline (11).The exhaust of dust settling chamber (8) is infeeded fluidized-bed reactor (9) at the place, inlet top of connecting tube (11) by pipeline (12).Gas-suspended solid forms in fluidized-bed reactor (9), and is full of whole fluidized-bed reactor.By pipeline (13) suspended substance is infeeded circulation cyclonic separator (14) from reactor head, in cyclonic separator (14), separate gas and solid.By pipeline (15) isolating solids recirculation is gone into fluidized-bed reactor.By pipeline (16) Purge gas is infeeded vapour generator (17), and use cooling fluid (18) to carry out indirect Re Jiao Change cooling and purifying gas there, thereby cooling fluid (18) is transformed into superheated vapour, by pipeline (19) superheated vapour infeeded power station (20) and is used for generating.Transmit electric power to the user by electric wire (21).The gas that will leave vapour generator (17) by pipeline (22) infeeds cyclonic separator (23), and enters static gas purifier (25) from separator (23) by pipeline (24), enters atmosphere from cleaner (25) by pipeline (26).By pipeline (30) stove dirt (27), (28), (29) collected in vapour generator (17), cyclonic separator (23) and static gas purifier (25) are recirculated into fluidized-bed reactor.By pipeline (31) a part of solid is infeeded fluidized bed cooler (32) from the lower region of fluidized-bed reactor (9), and after cooling indirectly, be recirculated into fluidized-bed reactor (9) by pipeline (33).By pipeline (34) this solid part is entered pit.Fluidized bed cooler (32) is formed by two sections, and infeeds fluidizing air (35) from the bottom.Discharge the off-air that has heated from the water cooler top, it is infeeded fluidized-bed reactor (9) as secondary air by pipeline (33).In fluidized bed cooler (32), carry out indirectly heat with water of condensation (37) and hand over the Change cooling solid, infeed water of condensation (37) from the steam collector of vapour generator (17).Discharge the saturation steam that produces owing to Re Jiao Change by pipeline (38), and it is infeeded vapour generator (17).By pipeline (39), the stove dirt that will collect in dust settling chamber (8) infeeds fluidized-bed reactor (9).By pipeline (40), infeed stove dirt to fluidized-bed reactor (9), collected dust can obtain in the cracked and room of this stove dirt interior coal because rotation is stood.The stove dirt that can obtain in further production period of sponge iron or contiguous power station also can be infeeded fluidized-bed reactor.Can infeed new coal to fluidized-bed reactor (9) by pipeline (41).Reactor (9) comprises the cooling surface (42) that is connected with vapour generator (17).
Example:
With diameter is that 8 to 16 millimeters burning pellet infeeds rotary kiln.This pellet has the chemical ingredients of following weight percent:
Iron (total amount) (Fe
Always) 6.7
Divalent iron ion (Fe
++) 0.8
Calcium oxide (CaO) 0.6
Magnesium oxide (MgO) 0.3
Silicon-dioxide (SiO
2) 2.0
Aluminium sesquioxide (Al
2O
3) 0.9
Other is 0.5 years old
Reductive agent is made up of the brown coal piece that contains 15% moisture content, and this coal cinder is a kind of size less than 40 millimeters particle.They have the composition of following dry basis weight percent.
Fixed carbon (FC) 44
Lime-ash 5
Sulphur (S) 0.5
Rotary kiln with 37,050 kilograms/time charging speed filling pellet, with 21,900 kilograms/time charging speed filling brown coal.All charging contain 4,240 kilograms/time water with 75,000 standard rices
3The speed of the supplying gas introducing air in/time.The furnace charge that draws off from rotary kiln by discharge rate be 26,350 kilograms/time sponge iron and discharge rate be 1120 kilograms/time nonmagnetic substance form.Nonmagnetic substance comprise discharge rate be 240 kilograms/time fixed carbon.With 101,300 standard rices
3The speed in/time is discharged gas, and exhaust contain discharge rate be 2,020 kilograms/time stove dirt.This stove dirt contain discharge rate be 750 kilograms/time fixed carbon.Exhaust has the composition of following volume percent:
Carbon monoxide (CO) 6.5
Carbonic acid gas (CO
2) 18.1
Hydrogen (H
2) 3.2
Water (H
2O) 14.8
Nitrogen (N
2) 57.4
The temperature of discharging gas is 850 ℃.
With 34,000 standard rices
3The speed of supplying gas in/time is blown into fluidizing air to fluidized-bed reactor.Solid with 216,000 kilograms/time speed enter fluidized bed cooler from fluidized-bed reactor.With 220 kilograms/time speed discharge solid from fluidized bed cooler, and under 400 ℃, residuum is recirculated into fluidized-bed reactor.With 14,000 standard rices
3The speed in/time infeeds fluidizing air to fluidized bed cooler, and under 500 ℃ it is infeeded fluidized-bed reactor as secondary air.Cooling liqs is made up of water of condensation, this water of condensation with 67,500 kilograms/time speed infeeded fluidized bed cooler from the steam collector of vapour generator, and be recirculated into superheater as saturation steam.To contain 150 gram/standard rices
3The gas of stove dirt is with 144,400 standard rices
3The speed in/time infeeds vapour generator from separate hydrocyclone under 850 ℃ of temperature.This gas is purified in separate hydrocyclone subsequently and contains 10 gram/standard rices
3Stove dirt, and in the static gas purifier, further be purified to and contain the 50 milligrams/standard rice of having an appointment
3Stove dirt.In vapour generator, cyclonic separator and static gas purifier, with 20,200 kilograms/time speed collect stove dirt, and it is recycled into fluidized-bed reactor.In vapour generator, with 84,200 kilograms/time speed produce the steam of 100 crust and 500 ℃.Thereby net electrical power amounts to 25 megawatts.Exhaust contains and is lower than 200 milligrams/standard rice
3Sulfurous gas (SO
2) and be lower than 200 milligrams/standard rice
3X nitrogen oxide (NO
X).Sulphur is in fact as calcium sulfate (CaSO
4) be eliminated fully in stove dirt.
Advantage provided by the invention mainly is, whole used heat that in rotary furnace, can obtain owing to direct-reduction, economized form with the unit group of high-efficiency operation is used for generating, be that also all solids can obtain with a kind of form that they can be discharged, and also is in the waste gas such as sulfur dioxide (SO2) and X nitrogen oxide (NOX) contaminant capacity be reduced to minimum. The electric power of producing can be fit to various needs well, if namely need to reduce then can the storing solid carbon material, if need to increase then can consume the material of storing or feed additional new coal. Even also can satisfy other needs in the rotary furnace phase of closing down.
Claims (8)
1, in rotary kiln, contain the technical process of the material production sponge iron of ferric oxide with the direct reduction of solid carbon element reductive agent, wherein the furnace charge that draws off from rotary kiln is divided into sponge iron and contains the material that remains carbon, burning carbonaceous material in the fluidized-bed reactor of circulating fluidized bed is arranged, the heat that is produced by burning is used for generating except that scattering and disappearing, it is characterized in that, to infeed fluidized-bed reactor from the dust-laden exhaust of rotary kiln, and carry out secondary combustion there, infeeded most of oxygen-containing gas of fluidized-bed reactor to the major general, infeed the bottom of fluidized-bed reactor as fluidizing gas, under the oxygen amount condition that metachemistry calculates, finish the burning of inflammable component, fluidized-bed reactor is discharged the solids recirculation of the folded band of gas and go into fluidized-bed reactor.And per hour the weight of this solid circle is five times in the contained solid weight of fluidized-bed reactor at least.
2, according to the technology of claim 1, it is characterized in that, under the condition of 20 to 80% excess airs, finish the burning that metachemistry calculates, discharge efflux of solids from fluidized-bed reactor, it is cooled off in the fluidized bed cooler indirect, and being recirculated into fluidized-bed reactor, the fluidizing gas that has heated of self-fluidized type bed water cooler infeeds fluidized-bed reactor as secondary air in the future, and (perhaps) the cooling surface dissipated heat that has by fluidized-bed reactor is used for generating with the cooling liqs that has heated.
3, according to claim 1 technology, it is characterized in that, above the fluidizing gas inlet, locate, infeed the dust-laden exhaust that contains residue carbon species and rotary kiln to fluidized-bed reactor.
4, according to the technology of claim 1, it is characterized in that, replenish to fluidized-bed reactor and infeed new carbon material.
5, according to the technology of claim 1, it is characterized in that, place, rotary kiln exhaust entrance top, the mean density of suspended substance is adjusted to 5 to 50 kilograms/meter in the fluidized-bed reactor
3
6, according to the technology of claim 1, it is characterized in that, infeed the stove dirt that can obtain to fluidized-bed reactor.
7, according to the technology of claim 1, it is characterized in that, by dust settling chamber, infeed the exhaust of rotary kiln, and the stove dirt that will collect separately infeeds fluidized-bed reactor in dust settling chamber to fluidized-bed reactor.
8, according to the technology of claim 1, it is characterized in that, infeed sulfide to fluidized-bed reactor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85104824.2A CN1004880B (en) | 1984-08-04 | 1985-06-22 | Process for producing sponge iron |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19843428782 DE3428782A1 (en) | 1984-08-04 | 1984-08-04 | METHOD FOR PRODUCING IRON SPONGE |
| CN85104824.2A CN1004880B (en) | 1984-08-04 | 1985-06-22 | Process for producing sponge iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85104824A true CN85104824A (en) | 1986-12-17 |
| CN1004880B CN1004880B (en) | 1989-07-26 |
Family
ID=25741803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85104824.2A Expired CN1004880B (en) | 1984-08-04 | 1985-06-22 | Process for producing sponge iron |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1004880B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105683399A (en) * | 2013-12-24 | 2016-06-15 | 株式会社Posco | Molten iron manufacturing apparatus and manufacturing method thereof |
-
1985
- 1985-06-22 CN CN85104824.2A patent/CN1004880B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105683399A (en) * | 2013-12-24 | 2016-06-15 | 株式会社Posco | Molten iron manufacturing apparatus and manufacturing method thereof |
| CN105683399B (en) * | 2013-12-24 | 2018-01-23 | 株式会社Posco | Molten iron preparation facilities and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1004880B (en) | 1989-07-26 |
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