JPH11315314A - Operation of smelting reduction equipment and smelting reduction equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably supply electric power even at the time of periodically interrupting the operation for repairing a furnace body refractory and to efficiently execute the reoperation after interrupting the furnace operation, in a smelting reduction furnace for directly producing molten iron by adding iron raw material, carbonaceous material and flux and blowing pure oxygen and/or oxygen-enriched gas. SOLUTION: In this operating method of the smelting reduction equipment provided with one set of the waste heat boiler 12 for recovering by vaporization the tensile heat and latent heat of combustion gas generated from plural furnace bodies 1a, 1b, an electric power generating equipment 18 and an exhaust gas treating equipment 32, the combustible gas generated from the furnace body during operating in plural furnace bodies 1a, 1b, is recovered by vaporizing the sensible heat and the latent heat through the waste heat boiler 12 and the electric power generating equipment 18 and converted into the electric power. In the furnace body during preparing the operation in plural furnace bodies bodies, 1a, 1b, fuel and air or oxygen air separately introduced and burnt to execute the preheat of refractory and also, the low calorific exhaust gas after preheating is not passed through the waste heat boiler 12 and the electric power generating equipment 18, but exhausted after directly executing the exhaust gas treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smelting reduction method in which iron raw material, carbonaceous material, and a solvent are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas is blown into the molten iron or directly to produce molten iron. Equipment related.

[0002]

2. Description of the Related Art In the smelting reduction, an iron raw material, a carbonaceous material, and a medium are added to a furnace body, and pure oxygen and / or an oxygen-enhancing gas is blown into the furnace to reduce iron oxide in the iron raw material in a slag. , Hot metal or a method for directly manufacturing hot metal. In this method, a high-temperature combustible gas of about 1600 to 1800 ° C. is generated from the smelting reduction furnace.

Generally, in this type of smelting reduction method, a preliminarily reduced iron raw material, a carbonaceous material, and a solvent are added to a furnace main body, and CO gas and H ₂ gas in a combustible gas generated from the furnace main body are used to remove iron ore. The two-stage method of pre-reducing stone, and the addition of unreduced iron material, carbonaceous material, and a solvent in the furnace body to reduce the iron oxide in the iron material in the slag, resulting in the combustibility generated from the furnace body CO gas and H ₂ gas in the gas are completely heated in the waste heat boiler,
One-stage method of vaporizing and recovering the sensible heat and latent heat of the combustible gas and generating power (for example, JP-A-1-502276, JP-A-63-65011, JP-A-63-65007)
No., etc.).

[0004] The two-stage method has the advantage of higher energy efficiency than the one-stage method, but requires a pre-reduction furnace of a packed-bed type, a fluidized-bed type, or the like, so that the equipment is complicated and the capital investment is high. There are drawbacks such as the limitation of the shape of the iron raw material due to the uniformity of the reaction in the reduction furnace (for example, only a bulk iron raw material can be used in the filling method, and only a powdery iron raw material can be used in the fluidized bed method). For this reason, a simple one-stage method has recently attracted attention.

In this one-stage method, the rate of burning CO gas and H ₂ gas generated in the slag in a furnace space above the slag (hereinafter referred to as a secondary combustion zone) (hereinafter referred to as furnace 2).
The secondary combustion rate in the furnace = (CO ₂ % + H ₂ O)
_{%) / (CO 2% +} CO% + H 2 O% + H 2%) and defined) is raised and the combustion heat that convey useful slag, improve energy efficiency. That is, it is possible to reduce the carbon unit consumption, and at that time, the calorific value of the combustible gas generated from the furnace body, that is, the sum of sensible heat and latent heat, is reduced by the amount of the carbon unit consumption reduced. Is widely known. In this one-stage method, sensible heat and latent heat of a large amount of combustible gas generated from the furnace main body are vaporized, recovered, generated, and sold to the outside. Alternatively, it is important to compensate for the inefficiency of the two-stage method by reducing the amount of power purchased by using it in another facility in the factory.

However, in a smelting reduction furnace, it is necessary to interrupt the operation periodically, for example, about once every three to twelve months, for repairing the refractory of the furnace body, and power cannot be generated at that time. There was a problem in the stable supply of power.
That is, when selling electric power to the outside, the selling price becomes low. Or if you want to use it on other equipment in the factory,
There was a problem that hindered the operation of other facilities in the factory. Therefore, in order to solve these problems, a plurality of furnace bodies and a waste heat boiler and a power generation facility for vaporizing and recovering sensible heat and latent heat of the combustible gas generated from the furnace bodies are respectively provided. Japanese Patent Application Laid-Open No. 9-202909 proposes a structure in which the doors are connected by a duct that can be freely opened and closed.

A conventional technique proposed in Japanese Patent Application Laid-Open No. 9-202909 will be described below with reference to FIGS. FIG. 5 shows the furnace state and gas flow during operation in both the furnace A and the furnace B. The smelting reduction furnace has two furnaces, furnace A and furnace B. Furnace bodies 1-a and 1-b are lined with refractories 2-a and 2-b and water-cooled panels 3-a and 3-b. In the upper part of the furnace main bodies 1-a and 1-b, there are raw material input ports 4-a and 4-b for adding iron raw material, carbonaceous material and a solvent, and gas for discharging combustible gas generated from the furnace main body. Discharge ports 5-a and 5-b are provided. Furnace bodies 1-a and 1-b have lower tuyeres 9-a and 9-b and upper tuyeres 1-b.
0-a and 10-b are provided. Hot metal 7-a, 7-b accumulates at the bottom of the furnace bodies 1-a, 1-b, and hot metal 7-a, 7-b
Molten slags 8-a and 8-b having a lower specific gravity than 7-b are stored. Hot metal 7-a and 7-b are tap holes 20-a and 20-b of hot metal pools 25-a and 25-b. However, the molten slags 8-a and 8-b are continuously or intermittently discharged from the slag ports 21-a and 21-b of the slag reservoirs 26-a and 26-b, respectively.

[0008] The high-temperature combustible gas generated in the furnaces A and B is supplied to the exhaust ducts 6-a, 5-b connected to the gas discharge ports 5-a, 5-b at the top of the furnace bodies 1-a, 1-b. 6-b and exhaust merging duct 3
1, the waste gas is led to a waste heat boiler 12, where the sensible heat and latent heat of the combustible gas are vaporized and collected, and then discharged out of the system through exhaust gas treatment facilities such as a dust collector 13, a blower 14, and a chimney 15. On the other hand, the steam that has been turned into high pressure by the sensible heat and latent heat of the combustible gas in the waste heat boiler 12 is guided to a turbine 17 and a generator 18 through a steam pipe 16 and is converted into electric power. The exhaust ducts 6-a and 6-b are provided with exhaust gas dampers 19-a and 19-b, respectively.

FIG. 6 shows the furnace state and gas flow when the furnace A is in operation and the furnace B is out of operation. The high-temperature combustible gas generated in the furnace A is in the upper part of the furnace body 2-a. Through the gas exhaust port 5-a, the exhaust duct 6-a, and the open exhaust gas damper 19-a, which are led to the waste heat boiler 12, where the sensible heat and latent heat of the combustible gas are vaporized and collected. After that, exhaust gas treatment equipment 3 such as dust collector 13, blower 14, chimney 15, etc.
It is discharged out of the system through 2. On the other hand, the waste heat boiler 12
The high-pressure steam generated by the sensible heat and latent heat of the combustible gas passes through a steam pipe 16 and passes through a turbine 17 and a power generator 1.
8 and is converted into electric power. At this time, since the exhaust gas damper 19-b is in the closed state, even if the furnace B is in the operation stopped state, the operation of the furnace A and the sensible heat of
There is no hindrance to recovery of latent heat by vaporization.

In this structure, usually, both the furnace A and the furnace B are operated, and when the operation for the repair of the furnace A is stopped, only the furnace B is operated, and when the operation for the repair of the furnace B is stopped, only the furnace A is operated. Operate in

In addition, when both the furnaces A and B are operated, the secondary combustion rate in the furnace is increased and the calorific value of the combustible gas per furnace is reduced. In addition, when only one of the furnaces A and B is operated by one furnace, the secondary combustion rate in the furnace is reduced, and the heat of the combustible gas per furnace is doubled, so that the calorific value of the combustible gas in the two furnaces is always increased. By making it constant, a constant electric power can always be supplied regardless of the state of the furnace.

[0012]

However, this structure still has the following problems. As described above, in the smelting reduction furnace, it is necessary to interrupt the operation periodically, for example, about once every 3 to 12 months, for repair of refractories. As shown in FIG. 7, furnace A is in operation and B
When the furnace is shut down for repairs, etc., in preparation for re-operation of the B furnace, the B furnace is used to preheat the refractory 2-b of the B furnace body 1-b.
It is necessary to supply a combustible gas, oxygen, or the like, which is a fuel, to the furnace body 1-b from, for example, the lower tuyere 9-b, which burns near the refractory 2-5 of the B furnace body 1-5, and Since the heat is removed by the preheating of the object 2-b and the cooling water of the water cooling panel 3-b, B
Exhaust gas having a low calorific value is generated from the furnace body 1-b. Therefore, the exhaust gas damper 19-b of the exhaust gas duct 6-b must be partially opened to discharge the exhaust gas.

In other words, in the furnace state where the furnace A is being operated and the furnace B is being prepared for operation, the above-mentioned low calorie exhaust gas generated from the B furnace main body 1-b which is preparing for operation is placed above the furnace main body 2-b. From the provided gas discharge port 5-b, through the exhaust gas damper 19-b in a partially open state of the exhaust gas duct 6-b, it is led to the waste heat boiler 12, and merges with the high calorific combustion gas of the furnace A. After the gas has a lower calorific value than normal, the sensible heat and the latent heat are vaporized and collected, and the gas passes through the steam pipe 16 to be supplied to the turbine 17 and the generator 1.
8 and is converted into electric power. Accordingly, the generated power at this time is constant with the generated power during the normal operation of two furnaces of the furnace A and the furnace B and the operation of only one furnace of the furnace A or the furnace B alone, because the calorific value of the combined exhaust gas is lower than usual. Instead, it will be lower.

[0014] For this reason, it was not possible to secure a stable power generation amount at this time, and there was a problem in terms of stable power supply. That is, when selling electric power to the outside, the selling price becomes low. Alternatively, when used in another facility in the factory, there is a problem that the operation of other facilities in the factory is hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems.
The purpose of the smelting reduction furnace is to enable the stable supply of electric power even during the preparation for re-operation after the periodic shutdown of the furnace operation for repairing the refractory of the furnace body, etc. The operation is to be carried out efficiently.

[0016]

The gist of the present invention is as follows. The method for operating a smelting reduction facility according to claim 1 includes, for a plurality of furnace bodies, a waste heat boiler, a power generation facility, and an exhaust gas treatment facility for vaporizing and recovering sensible heat and latent heat of a combustible gas generated from the furnace body. In the method for operating a smelting reduction facility having one, the combustible gas generated from the operating furnace body among the plurality of furnace bodies is vaporized and recovered from sensible heat and latent heat through the waste heat boiler and the power generation equipment. On the other hand, the furnace body which is ready for operation among the plurality of furnace bodies is separately heated and preheated by introducing and burning fuel and air or oxygen. The exhaust gas having a calorific value is characterized in that the exhaust gas is directly exhausted and then exhausted without passing through the waste heat boiler and the power generation equipment.

Further, the smelting reduction equipment according to claim 2 is:
For a plurality of furnace bodies, a waste heat boiler, a power generation facility, and an exhaust gas treatment facility for evaporating and recovering sensible heat and latent heat of combustible gas generated from the furnace body are provided, and the waste heat boiler, the power generation facility, In a smelting reduction facility in which an exhaust gas treatment facility is connected to the plurality of furnace bodies through a duct, the upper part of the hot metal pool and the upper part of the slag chamber of the plurality of furnace bodies are all connected by a connecting duct, and the connecting duct is connected to the exhaust gas. It is characterized in that it is formed so as to communicate with an exhaust gas duct leading to a processing facility.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
A description will be given based on FIG. In the present embodiment, the low calorific value exhaust gas generated from the operation preparation furnace B main body during the preheating of the refractory in the furnace,
The smelting reduction furnace, which has two smelting reduction furnaces, one waste heat boiler, and one power generation facility, which discharges the exhaust gas to the exhaust gas tact upstream of the dust collector, which is an exhaust gas treatment facility, from the upper part through the hot metal pool and the slag reservoir via a connection duct The equipment will be described, but it goes without saying that the present invention is also applied to a smelting reduction equipment having three or more furnace bodies.

FIG. 1 shows a smelting reduction facility A according to the present invention.
Furnace conditions and gas flow during operation in both furnace B, FIG.
Furnace condition and gas flow when operating only one furnace in A furnace, Fig. 3
Shows the furnace state and gas flow of the operation furnace A and the operation preparation furnace B during refractory preheating. FIG. 4 shows the transition of the calorific value of the combustible gas of each furnace and the calorific value of the combustible gas of the two furnaces in accordance with the change of each operation state of the furnace A and the furnace B.

First, the operating state and gas flow of the furnace A and the furnace B in the smelting reduction facility according to the present invention will be described with reference to FIGS. 1, 2 and 3.
It has a furnace, and the furnace bodies 1-a and 1-b are lined with refractories 2-a and 2-b and water-cooled panels 3-a and 3-b.
In the upper part of -b, a raw material input port 4-a, 4-b for adding an iron raw material, a carbon material, and a medium solvent, and a gas discharge port 5-a, 5-, for discharging a combustible gas generated from the furnace body. b, exhaust gas duct 6-a,
6-b is provided. In addition, the hot metal pool 25-
a, the upper part of the slag reservoir 26-a, the upper part of the hot metal reservoir 25-b of the B furnace, and the upper part of the slag reservoir 26-b are all connected by the connecting duct 24. And this connection duct 24,
Dust collector 1 leading to dust collector 13 which is exhaust gas treatment equipment 32
3 The exhaust gas duct 29 on the upstream side is communicated by a duct 30.

Further, in the connecting duct 24, an A furnace,
Openable and closable gas dampers 27-a and 27-b are provided in portions near the upper portions of the hot metal pools 25-a and 25-b and the upper portions of the slag pools 26-a and 26-b of the B furnace. An opening / closing damper 28 is provided in the vicinity of the connection between the exhaust gas duct 29 and the duct 30 on the upstream side of the dust collector 13.

At the bottom of the furnace bodies 1-a and 1-b, hot metal 7-a and 7-
-b is accumulated, and molten slags 8-a, 8-b having a lower specific gravity than the hot metal 7-a, 7-b are stored above the hot metal 7-a, 7-b.
From the tap holes 20-a, 20-b of the molten iron pools 25-a, 25-b, and the molten slags 8-a, 8-5 from the slag pools 26-a, 2-5.
6-b are discharged continuously or intermittently from the slag outlets 21-a and 21-b, respectively.

The iron oxide (FeO and Fe ₂ O ₃ ) in the iron raw material supplied from the raw material input ports 4-a and 4-5 is converted into the carbon material supplied from the raw material input ports 4-a and 4-b. The following formulas (1) and (2) in the molten slags 8-a and 8-b depending on the medium carbon content
Is reduced by the reaction shown in FeO + C → Fe + CO (endothermic reaction) (1) Fe ₂ O ₃ + 3C → 2Fe + 3CO (endothermic reaction) (2)

A part of the carbon content in the carbonaceous material supplied from the raw material input ports 4-a, 4-b penetrates the furnace bodies 1-a, 1-b, and the molten slags 8-a, 8-b. Lower tuyere 9-
The oxygen is blown into the molten slags 8-a and 8-b through a and 9-b and oxidized by a reaction represented by the following formula (3). C + 1 / 2O ₂ → CO (exothermic reaction) (3) The energy efficiency of this smelting reduction furnace, that is, the basic unit of carbon material, is determined by the total amount of carbon necessary for the reactions of the formulas (1), (2) and (3). It is determined.

[0025]

In addition, the CO gas and the hydrogen content in the carbonaceous material generated in the molten slags 8-a and 8-b according to the above equations (1), (2) and (3) are converted to the furnace body 1-a and The upper tuyere 10-a, 1 which penetrates 1-b and is disposed toward the secondary combustion zones 11-a, 11-b.
Oxygen is oxidized by the reaction shown in the following formulas (4) and (5) with oxygen blown into the secondary combustion zone 11 through O-b. CO + 1 / 2O ₂ → CO ₂ (exothermic reaction) (4) H ₂ + 1 / 2O ₂ → H ₂ O (exothermic reaction) (5)

The reactions of the equations (4) and (5) are referred to as in-furnace secondary combustion, and the degree of the degree of the secondary combustion is represented by the in-furnace secondary combustion rate defined by the following equation (6). It is widely known that the secondary combustion rate is increased by increasing the flow rate of oxygen blown into the secondary combustion zones 11-a and 11-b through the upper tuyeres 10-a and 10-b. ing.

In-furnace secondary combustion rate = (CO ₂ % + H ₂ O%) / (CO ₂ % + CO% + H ₂ O% + H ₂ %) (6) where: _{CO 2%, CO%, H2} O%, H2
% Indicates the volume fraction of each component of the combustible gas at the gas outlets 5-a and 5-b.

When the secondary combustion rate in the furnace is increased, a part of the reaction heat of the equations (4) and (5) in the secondary combustion zones 11-a and 11-b is converted into the molten slags 8-a and 8-b. To reduce the amount of carbon necessary for the exothermic reaction of the formula (3) in the slag, thereby reducing the carbon unit consumption and the calorific value of the combustible gas.

FIG. 1 shows the furnace conditions and gas flows during operation in both the furnace A and the furnace B. The high-temperature combustible gas generated in the furnaces A and B is stored in the hot metal pool of the furnace A and the furnace B. 25-a, 2
5-b, the accumulation gas dampers 27-a and 27-b of the connection duct 24 communicating with the upper portions of the slag accumulation chambers 26-a and 26-b are closed, and the exhaust gas duct 29 on the upstream side of the dust collector 13 Since the opening / closing damper 28 of the connection duct 24 in the vicinity is in a closed state, the gas discharge ports 5-a and 5-b disposed above the furnace bodies 1-a and 1-5 and the exhaust gas duct 6-a , 6-
b, after being guided to the waste heat boiler 12 through the exhaust gas dampers 19-a, 19-b and the exhaust gas merging duct 31 which are both open, the sensible heat and latent heat of the combustible gas are vaporized and recovered, 32 dust collector 13 and blower 1
4. It is discharged outside the system through the chimney 15 and the like. On the other hand, the steam that has been turned into high-pressure steam by the sensible heat and latent heat of the combustible gas in the waste heat boiler 12 passes through the steam pipe 16 through the turbine 17.
And it is guided to the power generator 18 and converted into electric power.

FIG. 2 shows the furnace condition and gas flow when the furnace A is in operation and the furnace B is in operation. The molten metal pools 25-a and 25-b and the slag pool 26- in the furnace A and the furnace B are shown in FIG. a, 26
gas damper 2 of the connecting duct 24 communicating with the upper part of -b
7-a and 27-b are closed, and the open / close damper 28 of the connection duct 24 near the exhaust gas duct 29 on the upstream side of the dust collector 13 is closed. The reactive gas is guided to the waste heat boiler 12 through a gas discharge port 5-a, an exhaust gas duct 6-a, an open exhaust gas damper 19-a, and an exhaust merging duct 31 provided at the upper part of the furnace body 1-a. After the sensible heat and latent heat of the combustible gas are vaporized and collected, the dust collector 13, which is the exhaust gas treatment facility 32,
It is discharged out of the system through a blower 14, a chimney 15, and the like.

On the other hand, the steam which has been turned into high-pressure steam by the sensible heat and latent heat of the combustible gas in the waste heat boiler 12
6 and is led to a turbine 17 and a generator 18 to be converted into electric power. At this time, since the exhaust gas damper 19-b is in a closed state, even if the furnace B is in an operation stopped state, the furnace A is operated and the above-mentioned flammable gas of flammable gas is recovered by vaporization of the latent heat. Does not cause a problem.

FIG. 3 shows the furnace state and gas flow of the operation furnace A and the operation preparation furnace B during preheating of the refractory in the furnace. Since the gas damper 27-a of the connecting duct 24 communicating with the upper part of the hot metal pool 25-a and the slag chamber 26-a of the furnace A is in a closed state, the high-temperature combustible gas generated in the furnace A is not The gas is guided to the waste heat boiler 12 through the gas exhaust port 5-a, the exhaust gas duct 6-a, the exhaust gas damper 19-a in the open state, and the exhaust merging duct 31 provided at the upper portion of the main body 1-a, and the combustible gas is emitted. After the sensible heat and latent heat of the gas are vaporized and collected, the dust collector 13, the blower 14, and the chimney 1,
It is discharged out of the system through 5 and the like. On the other hand, waste heat boiler 1
The steam that has been converted into high pressure by the sensible heat and latent heat of the combustible gas in 2 is led to a turbine 17 and a generator 18 through a steam pipe 16 and is converted into electric power.

At this time, in order to preheat the refractory 2-b of the furnace main body 1-b, the operation preparation furnace B supplies the B furnace main body 1-b with a combustible gas such as fuel, oxygen, etc. It is necessary to supply from the port 9-b, which burns near the refractory 2-b of the B furnace body 1-b and becomes a high-temperature gas, and is used for preheating the refractory 2-b below the reaction tank 22-b. Provided. At this time, since the exhaust gas damper 19-b for the operation preparation furnace B is in a closed state, the high-temperature gas for preheating generated in the operation preparation furnace B during the preheating of the refractory 2-b in the furnace is: After being supplied to the refractory 2-b below the reaction tank 22-b, the refractory 2-b is led into the hot metal pool 25-b and the slag pool 26-b, and is used for preheating the refractory 2-b in the pool.

Further, the hot metal pool 25-b of the operation preparation furnace B,
Connecting duct 2 communicating with the upper part of the slag reservoir 26-b
4 when the gas damper 27-b is in the open state, and the exhaust duct 2 on the upstream side of the dust collector 13 in the connecting duct 24.
9, the opening / closing damper 28 is in an open state.
The exhaust gas of low calorific value after being subjected to the preheating of the refractory 2-b in the furnace B passes through the connection duct 24 from the respective outlets of the hot metal pool 25-b and the upper part of the slag pool 26-b, The exhaust gas is discharged to the exhaust gas duct 29 on the upstream side of the dust collector 13 which is the processing equipment 32, and the dust collector 13, the blower 14,
It is discharged outside the system via the chimney 15. Therefore, it can be separated from the high-calorie combustible gas generated from the operation furnace A.

The high-temperature gas used for preheating the refractory 2-b of the operation preparation furnace B does not pass through the gas discharge port 5-b provided at the upper part of the furnace main body 1-b, and the hot metal pool is not heated. 25-b, which is discharged from the upper part of the slag reservoir 26-b, the heat removal by the cooling water of the water cooling panel 3-b can be reduced, and the molten iron reservoir 2
5-b, preheating of the slag pool 26-b is also possible. As described above, even when the furnace B is in the operation preparation state such as the furnace preheating, the operation of the furnace A and the recovery of the flammable gas from the sensible heat and the latent heat by vaporization are not hindered.

FIG. 4 shows the change in the calorific value of the combustible gas of each furnace and the calorific value of the combustible gas of the two furnaces in accordance with the change of each operation state of the furnaces A and B shown in FIGS. . Fig. 1
Is the calorific value of the combustible gas in both the furnace A and the furnace B shown in FIG. Here, the calorific value of the combustible gas per furnace is decreased by increasing the in-furnace secondary combustion rate of both furnaces, and the calorific value of the combustible gas of the two furnaces is kept constant.
The unit is operated in the furnace A shown in FIG. 2 and the calorific value of the combustible gas in the state where the furnace B is stopped, or is operated in the furnace A shown in FIG. 3 and the furnace B is ready for re-operation (preheating of the refractory in the furnace). ) The amount of heat of the combustible gas in the state. Here, since the calorific value of the combustion gas of the operation preparation furnace B becomes zero, the heat of the combustible gas of the operation furnace A is doubled by lowering the in-furnace secondary combustion rate of the operation furnace A, and the total of the two furnaces is reduced. The calorific value of the combustible gas is kept constant.

As described above, the total calorific value of the combustible gas in the two furnaces can be kept constant at all times as shown in the lowermost diagram in FIG. When the furnace B is operating and the furnace A is preparing for operation, the dampers are switched so that the gas flow in the furnace is opposite to the gas flow described above.

[0039]

In the smelting reduction furnace of the present invention, the upper part of the molten iron pool and the upper part of the slag pool of the plurality of furnace bodies are all connected by a connecting duct, and the connecting duct is connected to an exhaust gas duct connected to an exhaust gas treatment facility. As a result, the exhaust gas having a low calorific value after the preheating of the refractory in the furnace in the furnace body which is preparing for the operation is exhausted after the exhaust gas treatment directly without passing through the waste heat boiler and the power generation equipment. Therefore, the low calorific value exhaust gas generated from the furnace ready for operation can be separated from the high heat combustible gas generated from the furnace during operation. As a result, even if there is a furnace ready for operation, power generation The following effects can be expected by keeping the total calorific value of the combustible gas supplied to the above constant at all times.

(1) One furnace operation which was a problem of the prior art
The power supply amount can be kept constant without reducing the waste heat power generation amount in the furnace state in preparation for one furnace operation. (2) Since the amount of generated power is constant, when selling power to the outside, the power selling price increases. (3) Since the amount of generated power is constant, when the power is used by other facilities in the factory, it does not hinder the operation of other facilities in the factory. (4) The amount of heat removed from the cooling water of the water cooling panel can be reduced, and the fuel for refractory preheating of the operation preparation furnace can be reduced. (5) A preheating burner for storing molten iron and slag is not required.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a furnace state and a gas flow during operation in both a furnace A and a furnace B.

FIG. 2 is an explanatory diagram showing a furnace state and a gas flow when only one furnace A is operated.

FIG. 3 is an explanatory view showing a furnace state and a gas flow of an operation furnace A and an operation preparation furnace 8 during refractory preheating.

FIG. 4 is a diagram showing changes in the calorific value of the combustible gas in each furnace and the calorific value of the combustible gas in the two furnaces in accordance with the change in each operation state of the furnace A and the furnace B.

FIG. 5 is an explanatory diagram showing a furnace state and a gas flow during operation in both the conventional furnace A and furnace B.

FIG. 6 is an explanatory diagram showing a furnace state and a gas flow when only one conventional furnace A is operated.

FIG. 7 is an explanatory view showing a furnace state and a gas flow of a conventional operation furnace A and a conventional operation furnace B.

[Explanation of symbols]

 1: Furnace body 2: Refractory 3: Water-cooled panel 4: Raw material input port 5: Gas discharge port 6: Exhaust gas duct 7: Hot metal 8: Molten slag 9: Lower tuyere 10: Upper tuyere 11: Secondary combustion zone 12 : Waste heat boiler 13: Dust collector 14: Blower 15: Chimney 16: Steam piping 17: Turbine 18: Generator 19: Exhaust gas damper 20: Tap hole 21: Slag port 22: Reaction tank 24: Connecting duct 25: Hot metal pool 26: Slag pool 27: Gas damper 28: Opening / closing damper 29: Exhaust gas duct 30: Duct 31: Exhaust junction duct 32: Exhaust gas treatment equipment Additional numbers -a indicate A furnace, and -b indicates B furnace.

Claims (2)

[Claims] 1. A smelting reduction facility having a waste heat boiler, a power generation facility, and an exhaust gas treatment facility for vaporizing and recovering sensible heat and latent heat of combustible gas generated from a furnace body for a plurality of furnace bodies. In the operating method, of the plurality of furnace bodies, the combustible gas generated from the operating furnace body is sensible heat through the waste heat boiler and the power generation equipment, and the latent heat is vaporized to recover and convert the electric power. Among the plurality of furnace bodies, the furnace body that is ready for operation is separately heated and air or oxygen is introduced and burned to perform refractory preheating. A method for operating a smelting reduction facility, wherein exhaust gas treatment is performed directly after exhaust gas treatment without passing through a heat boiler and a power generation facility. 2. A waste heat boiler for evaporating and recovering the sensible heat and latent heat of the combustible gas generated from the furnace main body, a power generation facility, and an exhaust gas treatment facility are provided for a plurality of furnace bodies.
In a smelting reduction facility in which the waste heat boiler, the power generation facility, and the exhaust gas treatment facility are connected to the plurality of furnace bodies via ducts, the upper part of the hot metal pool and the upper part of the slag chamber of the plurality of furnace bodies are all connected by a connection duct. A smelting reduction facility wherein the connection duct is formed so as to communicate with an exhaust gas duct leading to the exhaust gas treatment facility.