KR19990018895A - Hybrid Fluidized Bed Reduction Device for Iron Ore - Google Patents

Abstract

The present invention relates to a composite fluidized bed reduction apparatus of iron ore for producing reduced iron ore to reduce the iron in the solid state in the fluidized bed reduction furnace for reducing the iron ore to melt the molten gas in the molten gasifier to form pig iron as a final product. The present invention relates to a fluidized bed reducing apparatus for a powdered iron ore having a plurality of fluidized bed furnaces and cyclones to separate and reduce powdered iron ore into opposition and neutral / particulate, wherein the first fluidized bed furnace 100 is a second fluidized bed furnace 200. It is installed on the iron ore fluidized bed, which is an internal azeotropic zone, and the second outlet 105 for the ore and gas discharge of the first fluidized bed (100) is provided through the first conduit (106) of the second fluidized bed (200). It is connected to the inner lower, the lower end of the cyclone 300 is connected to the inner lower portion of the second fluidized bed 200 through the sixth conduit 302 penetrating the upper portion of the second fluidized bed (200) , In the case of reducing iron ore having a large particle size, iron ore having a large particle size distribution is utilized by efficiently utilizing energy such as reactivity of solid iron ore particles, gas utilization rate, and gas consumption in consideration of particle size distribution of raw iron ore, differentiation and reducing properties at high temperature. To optimize the reduction.

Description

Hybrid Fluidized Bed Reduction Device for Iron Ore

The present invention is to reduce the iron ore in the solid state in a fluidized bed reduction furnace to reduce the iron ore of a wide particle size, to produce a solid iron reduced in iron ore reduced by 85% or more to melt the molten gas in the molten gas furnace to form the final product pig iron The fluidized bed reduction apparatus, more specifically, in consideration of the particle size distribution of the raw iron ore, differentiation and reducing properties at a high temperature, the high temperature of 800-900 ℃ and CO + H ₂ reducing gas composition range of 60-100% By using high-temperature reducing gas, it is possible to use the energy such as reactivity of solid iron ore particles, gas utilization rate, gas consumption amount as efficiently as possible to achieve optimum operation in economical aspect using fluidized bed ore with wide particle size distribution The present invention relates to a complex fluidized bed reduction device of iron ore.

In general, the blast furnace method is capable of reducing iron ore by the fixed bed method due to the large size of solid particles. However, in the case of reduction of fine ore, when the flow rate is low like sticking bed, there is a possibility of operation interruption due to sticking. In order to secure air permeability, a fluidized bed method is adopted to smoothly move solid particles with sufficient flow velocity.

One example of reducing the iron-iron ore using the fluidized bed is the fluidized bed reduction furnace of JP-A-58-217615. This fluidized bed-type iron ore reduction furnace is largely divided into a cylindrical reduction furnace and a cyclone, and the cylindrical reduction furnace has an inlet for introducing raw iron ore and a high temperature reducing gas and an outlet for reducing iron ore by reducing gas. It is composed of a discharge port, the gas distribution plate is built in the inner lower portion of the reduction furnace. Sending the iron ore through the charging inlet while supplying the reducing gas at a desired flow rate through the lower gas distribution plate of the cylindrical reduction furnace, mixed with a high temperature reducing gas, stirred and reacted, and after a predetermined time the reduced iron ore is discharged Is discharged through. In this case, the formed fluidized bed is a bubble fluidized bed in which bubbles are grown while reducing gas supplied from a cylindrical reduction furnace becomes bubbles and passes through a particle layer in the upper part of the reduction furnace.

In the conventional fluidized-bed reduction furnace in consideration of economical aspects such as productivity, the reduction of the amount of fine iron ore scattered to the outside of the reduction furnace in a smooth flow state, to reduce the reducing gas consumption, to maximize the gas utilization rate Since the particle size of the loaded iron ore is strictly limited, there is a problem in that the iron ore having a wide particle size distribution cannot be processed. That is, the particle size distribution of iron ore charged in the conventional fluidized bed reduction furnace is generally limited to 0-0.5 mm, 0-1 mm, 1-2 mm and the like without having a wide range of particle sizes. However, the particle size of the actual iron ore is almost 8mm or less, and in order to use the iron ore having such a particle size, the iron ore loaded is sieved to a prescribed particle size in advance, or it is used to pulverize it below the specified particle size to reduce production speed. However, there is a problem that the loss in terms of economics due to the process and additional equipment burden.

On the other hand, Korean Patent No. 074056 has been presented as an example of a twin-type fluidized bed reduction furnace for solving the problems of the conventional fluidized bed reduction furnace.

As shown in FIG. 1, the twin-type fluidized bed iron ore reduction furnace presented above has a first fluidized bed furnace 10 for greatly reducing allele iron ore and a second fluidized bed furnace 20 for reducing medium / fine iron ore, as shown in FIG. 1. It consists of a cyclone 30 for collecting the fine iron ore.

The first fluidized bed passage 10 has a reducing gas supply port 11 formed at a lower end thereof, and a gas distribution plate 12 is mounted therein, and a first outlet 13 is formed at one lower side of the reactor. A second outlet 15 is formed in the second outlet 15 is connected to the lower side of the second fluidized bed passage 20 through the first conduit 16. In addition, an ore supply port 14 is formed at the lower side of the other side of the first fluidized bed 10.

The second fluidized bed furnace 20 has a reducing gas supply port 21 formed at a lower end thereof, a gas distribution plate 22 is mounted at an inner lower side thereof, and a third outlet 23 is formed at one lower side of the reactor. , The upper end is connected to one side of the cyclone (30). The lower end of the cyclone 30 is connected to the sixth conduit 35 and connected to one lower side of the second fluidized bed passage 20. A gas outlet 33 is formed at the upper end of the cyclone 30 to discharge the exhaust gas reacted with the iron ore into the atmosphere.

The process of reducing using the twin-type fluidized bed iron ore reduction furnace configured as described above is as follows.

That is, the iron ore is supplied to the ore supply port 14 of the first fluidized bed furnace 10, and at this time, by adjusting the flow rate of the reducing gas supplied through the first reduced gas supply port 11, the opposing iron ore is the first fluidized bed. Remaining in the furnace 10 to reduce and form a bubble or turbulent fluidized bed, the medium / fine iron ore is transported to the lower portion of the second fluidized bed furnace 20 via the first conduit 16 to the second fluidized bed furnace 20 Reducing while forming a bubble or turbulent fluidized bed by the low flow rate of the reducing gas supplied through the second gas supply port 21 in the inside, the reduced iron ore is respectively the first outlet 13 and the third outlet (23) Discharge via diesel.

The twin fluidized bed reduction furnace presented in Korean Patent No. 074056 effectively classifies and reduces alleles and medium / fine iron ores at a proper flow rate, thereby stabilizing the flow of iron ores having a wide particle size distribution and maintaining a uniform iron ore concentration. This good reduced iron can be obtained, there is an advantage that can reduce the scattering and reduce the gas source unit.

However, since the conventional twin fluidized bed uses two reactors, the first fluidized bed furnace 10 and the second fluidized bed furnace 20, the heat loss is larger and a lot more space than the conventional single type. need. In addition, since the reducing gas, which is also a heat source, must be divided into two and be supplied to each reactor, the heat loss in the supply pipe is large, so that it is difficult to supply a sufficient amount of heat to each reactor.

The present invention is to solve such a conventional problem, in the case of reducing iron ore having a large particle size in consideration of the particle size distribution of the raw iron ore, differentiation and reducing properties at high temperatures, the reactivity of the solid iron ore particles, gas utilization, gas consumption, etc. It is an object of the present invention to provide a complex fluidized bed reduction apparatus of iron ore that can efficiently reduce iron ore having a wide particle size distribution by using energy as efficiently as possible.

1 is a configuration diagram showing a twin type fluidized bed reduction furnace of a conventional iron ore

Figure 2 is a block diagram showing a hybrid fluidized bed reduction furnace of the iron ore according to the present invention.

* Explanation of symbols for main parts of the drawings

100: first fluidized bed 101: gas supply port

102: first gas distribution plate 103: first outlet

104: iron ore supply port 105: second outlet

200: second fluidized bed furnace 200a: reduced portion

200c: enlarged portion 201: gas supply port

202: second gas distribution plate 203: third outlet

300: cyclone

As a technical configuration for achieving the above object, the present invention has a first and second fluidized bed furnace having a gas distribution plate in the lower inner side and a reducing gas supply port at the lower end thereof, respectively, in the first fluidized bed furnace, Is divided into opposition and neutral / particulate, and the neutral / particulate iron ore is supplied to the second fluidized bed through the second outlet to reduce the iron ore while forming a fluidized bed and discharged through the ore outlet, respectively, from the second fluidized bed furnace In a fluidized bed reduction apparatus of a ferrous ore having a cyclone to separate the fine iron ore contained in the flue gas of the exhaust gas to be recycled to the fluidized bed furnace, the first fluidized bed is an iron ore fluidized bed which is an internal azeotropic region of the second fluidized bed furnace It is installed in the upper portion, the second outlet for the ore and gas discharge to the first fluidized bed is the inner lower portion of the second fluidized bed through the first conduit Is connected, the lower end of the cyclone is the first of the fine iron ores hybrid fluidized bed type reducing apparatus, characterized in that connected to the inner bottom of the second fluidized bed via a sixth conduit passing through an upper portion of a second fluid bed to maryeonham.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention is composed of a first fluidized bed furnace and a second fluidized bed furnace is divided into the opposing and neutral / fine granules of the combined fluidized bed to reduce and form a bubble fluidized bed, respectively, and the fine iron ore contained in the exhaust gas of the second fluidized bed It is composed of a cyclone separated from this gas to be recycled to the lower side of the second fluidized bed, and the first fluidized bed is located in the second fluidized bed furnace, so that the heat loss and installation space can be significantly reduced compared to the conventional twin type. Has a configuration.

That is, Figure 2 is a schematic view showing a composite fluidized bed reduction device of the iron ore according to the present invention, the position higher than the heavy / fine iron ore fluidized bed formed in the second fluidized bed 200, that is, the tower column ( installed in the freeboard zone, and the raw iron ore charged from the second conduit 107 is classified into opposing and medium / fine by the controlled gas flow rate, so that the opposing iron ore remains in the first fluidized bed 100 and the first gas. It is reduced by forming a bubble or turbulent fluidized bed by reducing gas of high gas flow rate supplied through the supply port 101, and the medium / fine iron ore is lowered to the second fluidized bed furnace 200 through the first conduit 106 A low flow rate at which the first fluidized bed furnace 100 configured to be conveyed, and the heavy / fine powdered iron ore conveyed by entraining the waste gas from the first fluidized bed furnace 100 are transported through the second gas supply port 201. Bubble by reducing gas of The second fluidized bed furnace 200 is reduced while forming a turbulent fluidized bed, and the cyclone ore contained in the exhaust gas of the second fluidized bed furnace 200 is separated from the gas cyclone configured to recycle to the lower portion of the second fluidized bed furnace 200 300, including.

The first fluidized bed 100 has a substantially cylindrical shape, a first gas supply port 101 for receiving a reducing gas is formed at a lower end thereof, and a first gas distribution plate 102 is mounted inside the lower part. In addition, a first discharge port 103 connected to the third conduit 108 for discharging the ore is formed at one lower side, and an iron ore supply port 104 connected to the second conduit 107 for supplying ferrous iron ore is provided at the lower side of the other side. Is formed, a second discharge port 105 for the discharge of ore and gas is formed at the top to be connected to the lower portion of the second fluidized bed 200 through the first conduit 106.

The second fluidized bed 200 is formed of a heavy-duty cylinder shape of a rough upper and lower strait that the inner diameter of the upper side is larger than the inner diameter of the lower side. The upper side enlarged portion 200c having a large inner diameter and the lower portion having a small inner diameter are formed. It is composed of a side reduction portion (200a), and the inclined portion (200b) of the inner diameter is gradually changed so as to connect the expansion portion (200c) and the reduction portion (200a), the lower side reduction portion (200a) of iron ore It is to suppress the scattering of the ultrafine iron ore by increasing the gas utilization rate by improving the flow rate of the bubble to improve the gas unit, and by reducing the flow rate of the upper part of the furnace by lowering the flow rate of the furnace.

A second gas supply port 201 is formed at a lower end of the reduction part 200a to receive a reducing gas, and a second gas distribution plate 202 is mounted at a lower inner side thereof, and a lower side thereof is configured to discharge ore. A third outlet 203 is formed which is connected to the fifth conduit 205. In addition, a fourth discharge port 204 for discharging gas is formed at an upper end of the enlarged part 200c and is connected to one side of the cyclone 300 through the seventh conduit 305.

The cyclone 300 is a fine iron ore contained in the exhaust gas of the second fluidized bed 200 flowing into the inlet 301 through the seventh conduit 305 is separated from the gas inside the lower portion of the second fluidized bed 200 The sixth conduit 305 is connected to the lower end 302 to be recirculated deep into the furnace. In addition, a gas discharge port 303 is formed at the upper end of the cyclone 300 to discharge the exhaust gas reacted with the iron ore through the gas discharge pipe 304 to the atmosphere.

Hereinafter, a method of reducing the iron ore using the composite fluidized bed reduction device of the iron ore of the present invention configured as described above will be described.

By maintaining the reducing gas flow rate supplied to the first fluidized bed (100) above the end speed of the neutral ore to classify the raw iron ore supplied to the first fluidized bed (100) into opposition and medium / fine, the opposing iron ore Remaining in the fluidized bed furnace 100 to form a bubble or turbulent fluidized bed to reduce, and the medium / fine iron ore is sent to the lower portion of the second fluidized bed furnace 200 via the first conduit 106 to the second gas supply port ( The reducing gas supplied through 201 is used to reduce and form a bubble fluidized bed separately, and then discharged through the first outlet 103 and the third outlet 203, respectively. The ultrafine iron ore contained in the exhaust gas of the second fluidized bed 200 is supplied to the cyclone 300 through the seventh conduit 305, separated from the gas in the cyclone 300, and lowered from the second fluidized bed 200. Recirculate to the bottom of the neutral / fine fluidized bed formed at

In the case of reducing the iron ore using the hybrid fluidized bed reduction furnace as in the present invention, the gas flow rate in the first fluidized bed reactor (100), considering the smooth flow and scattering amount of the iron ore staying in the furnace It is preferable to set it in the range of 1.2-2.5 times the minimum fluidization rate, and it is preferable to set the gas flow rate in a 2nd fluidized bed furnace in the range of 1.2-1.8 times the minimum fluidization rate.

In addition, the height from the dispersion plate 102 of the first fluidized bed furnace 100 is preferably set to 10-15 times its inner diameter, and the reduced portion 200a and the inclined part 200b of the second fluidized bed furnace 200 are provided. The height from the dispersion plate 202 is preferably set to 5-10 times the inner diameter of the reduction portion 100a, and the height of the enlarged portion 200c of the second fluidized bed 200 is preferably 2-4 times the inner diameter thereof. The first fluidized bed 100 should be installed in the freeboard zone in the second fluidized bed 200, that is, the lower end portion of the first fluidized bed furnace 100 is preferably kept higher than the third ore outlet 203.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

The reduction was performed using the reduction apparatus of FIG. 3 having the same size as in Table 1 under the reduction conditions shown in Tables 2 to 4.

Fluidized bed reduction furnace height and inner diameter First fluidized bed Inner diameter: 0.2m Height (from the surface of the dispersion plate): 3.0m Second fluidized bed Reduced part inner diameter: 0.5m Enlarged part inner diameter: 0.75m Inclined part + reduced part height (from the surface of the dispersion plate): 4.0m Enlarged part height: 2.5m

Chemical Composition and Particle Size Distribution of Raw Iron Powders Chemical composition _{T.Fe: 62.17FeO: 0.51SiO 2: 5.5TiO} 2: 0.11Mn: 0.05S: 0.12P: 0.65 can be determined: 2.32 Particle size distribution 0-0.05mm: 4.6% 0.05-0.15mm: 5.4% 0.15-0.5mm: 16.8% 0.5-4.75mm: 59.4% 4.75-8mm: 13.8%

Reducing gas component, temperature and pressure Gas composition CO: 65% H ₂ : 25% CO ₂ : 5% N ₂ : 5% Temperature About 850 ℃ pressure 2.0kgf / ㎠

Gas Flow Rate in Fluidized Bed Reduction Furnace First fluidized bed Flow rate: 3.0m / s Second fluidized bed Upper flow rate of enlarged part: 0.14m / s Dispersion plate flow rate: 0.32m / s

After the reduction of the iron ore as described above, the average gas utilization rate and the gas unit was investigated, the gas utilization was about 30-35%, the gas source unit was 1200-1300 Nm 3 / ton-ore. In addition, the reduced iron discharged from the first outlet 103, the third outlet 203 was in the range of 88-95% reduction, it was found that the reduction rate of the fine iron ore was rather high. Ore discharge was possible within 60 minutes after the ore input from the ore hopper, which indicates that the production rate of reduced iron is excellent. In particular, it was possible to operate while maintaining the temperature in the reactor at 850 ℃ without heat supplement from the outside.

As described above, the present invention takes advantage of the conventional twin type which can improve the gas source unit by dividing and reducing the fine iron ore having a wide particle size distribution by particle size, and by installing the first fluidized bed furnace in the second fluidized bed furnace, By reducing the loss and ensuring a sufficient royal can improve the problem of the conventional twin type and has an excellent effect that the installation space is required much smaller than the twin type.

In addition, the present invention can obtain reduced iron having a relatively uniform reduction rate regardless of the particle size of the iron ore, and at the same time obtain reduced iron classified by particle diameter, so that it is possible to supply reduced iron at an appropriate size for each of the input equipment and the input position when the furnace is introduced into According to the supply flow rate of the reducing gas it is possible to control the amount and size of reduced iron discharged through each outlet, and to control the reduction rate by controlling the residence time in the iron ore furnace.

Claims (7)

The first and second fluidized bed furnaces, each having a gas distribution plate at the inner lower part and a reducing gas supply hole at the lower end thereof, are provided to separate the iron ore into opposition and neutral / fine particles in the first fluidized bed furnace. By supplying to the second fluidized bed through the second outlet to the second fluidized bed, reduced ore powdered iron by forming the fluidized bed by particle size, respectively, is discharged through the ore outlet, and the fine iron ore contained in the exhaust gas from the second fluidized bed to separate from the gas In the fluidized bed reduction apparatus of the iron ore with a cyclone to be recirculated to the fluidized bed furnace, the first fluidized bed (100) is installed on the iron ore fluidized bed which is an internal azeostat area of the second fluidized bed (200), The second outlet 105 for the ore and gas discharge of the first fluidized bed 100 is connected to the inner lower part of the second fluidized bed 200 through the first conduit 106, and the cycle The lower end portion of the 300 is connected to the inner bottom of the second fluidized bed 200 through the sixth conduit 302 penetrating the upper portion of the second fluidized bed 200, the fluidized bed ore complex fluidized bed reduction apparatus . According to claim 1, wherein the second fluidized bed 200 is a central inclined portion 200b, the inner diameter is gradually changed, the lower reduction portion 200a to maintain the inner diameter of the lower end of the inclined portion (200b) and , Composite fluidized bed reduction device of iron ore characterized in that the upper and lower narrow type consisting of the upper expansion portion (200c) to maintain the inner diameter of the upper end of the inclined portion (200b). The method of claim 1, wherein the flow rate of the gas in the first fluidized bed furnace (100) is in the range of 1.2-2.5 times the minimum fluidization rate of the iron ore staying in the furnace. The method of claim 1, wherein the flow rate of the gas in the second fluidized bed furnace (200) is in the range of 1.2-1.8 times the minimum fluidization rate of the iron ore staying in the furnace. The composite fluidized bed according to any one of claims 1 to 3, wherein the height from the dispersion plate 102 of the first fluidized bed furnace 100 is in the range of 10-15 times the inner diameter. Reduction device. The height of the reduction part 200a and the inclination part 200b of the second fluidized layer 200 is equal to 5 of the reduction part inner diameter. Set to -10 times, the height of the expanded portion (200c) is a complex fluidized bed reduction device of iron ore characterized in that the inner diameter is 2-4 times. The method of claim 1, wherein the first fluidized bed (100) is a complex type of iron ore characterized in that the lower end is maintained higher than the third outlet 203 for the ore discharge of the second fluidized bed (200). Fluidized bed reducing device.