KR101191969B1 - Control device and control method for reduction gas of pig iron manufacturing equipment - Google Patents

Abstract

PURPOSE: A reduction gas control device and method of a molten iron manufacturing system are provided to induce an additional reduction of hot compacted iron by increasing the temperature of reduction gas drawn into a reduction shaft, thereby saving fuel costs. CONSTITUTION: A reduction gas control device(40) of a molten iron manufacturing system(100) comprises a cooling gas source(41) storing cooling gas and first and second cooling gas supply lines(42,43) which are connected to the cooling gas source. The first cooling gas supply line leads a first cooling gas to the path of reduction gas discharged from a melting furnace(20) to a hot cyclone(21). The second cooling gas supply line leads a second cooling gas to the path of reduction gas discharged from the hot cyclone to a multi-stage flow path(11).

Description

CONTROL DEVICE AND CONTROL METHOD FOR REDUCTION GAS OF PIG IRON MANUFACTURING EQUIPMENT}

The present invention relates to a molten iron manufacturing equipment, and more particularly, to a reducing gas control device and a reducing gas control method for controlling the temperature of the reducing gas generated in the melting furnace is introduced into the multi-stage flow furnace and reduction shaft (reduction shaft). will be.

The recently developed FINEX process is used as raw material and fuel for steelmaking in the state of mining iron ore and fine coal in powder for the first time. This Finex process has the advantages of low fuel cost and less environmental pollution than the conventional blast furnace method.

Finex molten iron manufacturing equipment is composed of a multi-stage flow furnace and shaft furnace for reducing iron ore, and a melting furnace for receiving a molten iron ore provided with a coal packed layer therein and reduced iron ore. In the furnace, a large amount of carbon monoxide is generated by the combustion of coal, and the carbon monoxide is introduced into the multistage flow furnace and shaft furnace as reducing gas.

The reducing gas generated in the smelting furnace contains a large amount of potassium (K) component of the coal, which reacts with chlorine (Cl) contained in the coal to form potassium chloride (KCl). Potassium chloride is a low melting compound and has a melting point of approximately 750 ° C.

In the multi-stage flow path, a distribution plate is provided for evenly contacting the reducing gas while flowing iron ore. Hundreds of passage holes are formed in the dispersion plate. When the potassium chloride component in the reducing gas supplied from the melting furnace adheres in liquid form, the dispersion plate blocks the normal gas flow.

In order to prevent this, conventionally, a large amount of cooling gas is blown into the high temperature reducing gas generated in the melting furnace to lower the temperature of the reducing gas introduced into the multistage flow furnace to below the melting point of potassium chloride. That is, potassium chloride is made into a solid state so that liquid potassium chloride does not adhere to a dispersion plate. However, a significant heat loss occurs by artificially cooling the high temperature reducing gas generated in the melting furnace. This heat loss leads to higher fuel costs and higher charter costs.

The present invention is to provide a reducing gas control apparatus and reducing gas control method of the molten iron manufacturing equipment that can efficiently control the high temperature reducing gas generated in the melting furnace to minimize heat loss, and as a result reduce the fuel cost and the cost of the molten iron. do.

An embodiment of the present invention is a multi-stage flow furnace and shaft, a melting furnace for melting the reduction spectroscopy discharged from the shaft furnace, and a molten iron manufacturing equipment comprising a hot cyclone, a cooling gas source for storing the cooling gas, and cooling A first cooling gas supply line connected to a gas source and injecting primary cooling gas on a reducing gas path discharged from a melting furnace to a hot cyclone, and a reduction connected to a cooling gas source and discharged from a hot cyclone into a multistage flow path It provides a reducing gas control device including a second cooling gas supply line for introducing a secondary cooling gas on the gas path.

A gas discharge pipe is installed between the melting furnace and the hot cyclone, and the first cooling gas supply line may be connected to one point of the gas discharge pipe.

The shaft path side gas pipe is installed between the hot cyclone and the shaft path, and the flow path side gas pipe connected to the multi-stage flow path is branched from the shaft path side gas pipe, and the second cooling gas supply line is connected to the flow path side gas pipe. May be connected to one point.

A control valve may be installed in the first cooling gas supply line and the second cooling gas supply line to control the flow rates of the primary cooling gas and the secondary cooling gas, respectively.

The first cooling gas supply line may inject the primary cooling gas such that the reducing gas introduced into the hot cyclone and the shaft furnace has a temperature in the range of 800 ° C to 850 ° C.

The second cooling gas supply line may inject the secondary cooling gas so that the reducing gas introduced into the multi-stage flow path has a temperature in the range of 700 ° C to 750 ° C.

Another embodiment of the present invention is a multi-stage flow furnace and shaft, a melting furnace for melting the reduced spectroscopy discharged from the shaft furnace, and a molten iron manufacturing equipment comprising a hot cyclone, reducing gas discharged from the melting furnace to the hot cyclone Firstly reducing the temperature of the reducing gas introduced into the hot cyclone and the shaft furnace by injecting the primary cooling gas into the path, and then cooling the secondary cooling gas on the reducing gas path into the multistage flow path from the hot cyclone. It provides a reducing gas control method comprising the step of lowering the temperature of the reducing gas introduced into the multi-stage flow path to the secondary.

The primary falling temperature of the reducing gas may be in the range of 800 ° C to 850 ° C, and the secondary falling temperature of the reducing gas may be in the range of 700 ° C to 750 ° C.

The reducing gas control apparatus of the molten iron manufacturing equipment according to the present embodiment can individually control the temperature of the reducing gas introduced into the shaft furnace and the temperature of the reducing gas introduced into the multistage flow furnace according to the characteristics of the shaft furnace and the multistage flow furnace. have. In particular, the reducing gas control device can increase the temperature of the reducing gas introduced into the shaft furnace to induce further reduction of the compacted material (HCI), thereby effectively reducing fuel costs and lowering the manufacturing cost of the molten iron.

1 is a schematic diagram of a Finex molten iron manufacturing equipment having a reducing gas control apparatus according to an embodiment of the present invention.
2 is a graph showing the relationship between the temperature and the reduction rate of the reducing gas introduced into the shaft furnace.
3 is a graph showing melting points of particle sizes of hot compacted iron (HCI).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a schematic diagram of a Finex molten iron manufacturing equipment having a reducing gas control apparatus according to an embodiment of the present invention.

Referring to Figure 1, Finex molten iron manufacturing equipment 100 is largely equipped with a flow reduction furnace 10 including a multi-stage flow path 11 and a reduction shaft 12, and the coal filling layer therein It consists of a melting furnace 20.

Iron ore at room temperature is heated and reduced in contact with the high temperature reducing gas supplied from the melting furnace 20 while passing through the multistage flow furnace 11 and the shaft furnace 12 in sequence. Therefore, the iron ore is converted to high temperature reduction spectroscopy, the reduction spectroscopy is continuously charged into the melting furnace 20 and melted in the coal packed bed to be converted to molten iron. The converted molten iron is discharged out of the melting furnace 20.

In addition, the coal 20 is continuously supplied to the melting furnace 20, and oxygen is blown through a tuyere (not shown) formed on the outer wall of the melting furnace 20 to burn coal. As the combustion gas of coal rises in the melting furnace 20, it is converted into a high-temperature reducing gas stream and discharged from the melting furnace 20 to be supplied to the multistage flow furnace 11 and the shaft furnace 12.

The melting furnace 20 is connected to the hot cyclone 21 through the gas discharge pipe 31 so that the reducing gas generated in the melting furnace 20 is introduced into the hot cyclone 21 through the gas discharge pipe 31. The hot cyclone 21 collects dust contained in the reducing gas, and injects the collected dust back into the melting furnace 20 through the dust recovery pipe 32. The reducing gas from which dust is removed by the hot cyclone 21 is supplied to the multistage flow path 11 and the shaft furnace 12.

To this end, the hot cyclone 21 is connected to the shaft furnace 12 through the shaft furnace side gas pipe 33 to supply the reducing gas to the shaft furnace 12. In addition, the flow path side gas pipe 34 is branched from the shaft furnace side gas pipe 33 so that the reducing gas is supplied to the multi-stage flow path 11.

The reducing gas control device 40 according to the present embodiment is configured to individually control the temperature of the reducing gas introduced into the shaft furnace 12 and the temperature of the reducing gas introduced into the multistage flow passage 11. In particular, the reducing gas control device 40 is configured to reduce the fuel cost by increasing the temperature of the reducing gas introduced into the shaft furnace 12 to induce further reduction in the shaft furnace 12.

Specifically, the reducing gas control device 40 according to the present embodiment is connected to the cooling gas supply source 41, the cooling gas supply source 41 and the gas discharge pipe 31 to supply the primary cooling gas to the gas discharge pipe (31). Second cooling for injecting the second cooling gas into the flow path side gas pipe 34 by connecting the first cooling gas supply line 42 to be injected, the cooling gas supply source 41 and the flow path side gas pipe 34. And a gas supply line 43.

The cooling gas stored in the cooling gas source 41 may have a temperature of approximately 20 ° C. to 50 ° C. Control valves 44 may be installed in the first cooling gas supply line 42 and the second cooling gas supply line 43 to control the flow rates of the primary cooling gas and the secondary cooling gas, respectively.

The first cooling gas supply line 42 is connected to one point (first point, P1) of the gas discharge pipe 31 to inject the primary cooling gas into the gas discharge pipe 31. The reducing gas discharged from the melting furnace 20 to the gas discharge pipe 31 represents a temperature of about 950 ° C to 1050 ° C. The reducing gas is mixed with the primary cooling gas while passing through the first point P1 of the gas discharge pipe 31, and the temperature is first lowered. The reducing gas whose temperature is lowered is introduced into the shaft furnace 12 via the hot cyclone 21 and the shaft furnace side gas pipe 33.

The second cooling gas supply line 43 is connected to one point (second point, P2) of the flow path side gas pipe 34 to inject the secondary cooling gas into the flow path side gas pipe 34. The reducing gas flowing through the flow path side gas pipe 34 before the second point P2 maintains the same temperature as the reducing gas introduced into the shaft furnace 12, but passes through the second point P2 and the secondary cooling gas. Mixed with and the temperature drops secondarily. The reducing gas whose temperature is lowered is sequentially supplied to the multistage flow path 11.

The reducing gas mixed with the primary cooling gas at the first point P1 and introduced into the hot cyclone 21 and the shaft furnace 12 may have a temperature in a range of 800 ° C to 850 ° C. In addition, the reducing gas mixed with the secondary cooling gas at the second point P2 and introduced into the multi-stage flow path 11 may have a temperature in the range of 700 ° C to 750 ° C.

In this embodiment, the temperature of the reducing gas introduced into the hot cyclone 21 and the shaft furnace 12 is higher than the temperature of the reducing gas provided in common with the conventional multistage flow furnace (approximately 700 ° C to 750 ° C).

As such, as the temperature of the reducing gas introduced into the shaft furnace 12 is increased, it is possible to induce an additional reduction in the compacted material (HCI), which is an agglomerated form of iron ore reduced in the multistage flow path 11. Therefore, it is possible to reduce the fuel cost by increasing the reduction efficiency of the flow reduction furnace 10, as a result it is possible to lower the manufacturing cost of the molten iron.

2 is a graph showing the relationship between the temperature and the reduction rate of the reducing gas introduced into the shaft furnace.

Referring to Figure 2, the higher the temperature of the reducing gas can be seen that the reduction rate to the shaft is higher. In particular, it is expected that the reduction rate of at least 10% or more of hot compacted iron (HCI) may be increased in the case of the reducing gas having a temperature of 850 ° C compared to the comparative example having a temperature of 750 ° C. This result leads to a reduction of coal consumption of 50 kg per ton of molten iron, thereby effectively reducing the manufacturing cost of the molten iron.

On the other hand, due to the rise in the temperature of the reducing gas introduced into the shaft furnace 12, there is a possibility that the compacted material (HCI) is melted in the shaft furnace 12 and attached to the shaft furnace 12 inside. 3 is a graph showing melting points of grain size (HCI) by particle size.

Referring to FIG. 3, the compacted material (HCI) has a melting point of 1300 ° C. or more in all particle sizes ranging from 5 mm to 30 mm. Therefore, even if the temperature of the reducing gas introduced into the shaft furnace to 800 ℃ to 850 ℃ level can be confirmed that the melting of the compacted material (HCI) in the shaft inside.

Referring again to FIG. 1, the temperature of the reducing gas mixed with the secondary cooling gas and introduced into the multistage flow path 11 is in the range of 700 ° C. to 750 ° C. FIG. This temperature is lower than the melting point of potassium chloride (KCl) contained in the reducing gas, and prevents the liquid potassium chloride from blocking the passage hole of the dispersion plate (not shown) provided in the multistage flow path 11. Therefore, the dispersion plate can smoothly perform the function of evenly contacting the reducing gas while flowing iron ore.

As such, the reducing gas control device 40 according to the present embodiment individually controls the temperature of the reducing gas introduced into the shaft furnace 12 and the temperature of the reducing gas introduced into the multistage flow passage 11, in particular, the shaft furnace. Increasing the temperature of the reducing gas introduced in (12) induces further reduction of the compacted material (HCI), which can effectively contribute to reducing fuel costs and lowering the manufacturing cost of the molten iron.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

100: molten iron manufacturing equipment 10: fluid reduction furnace
11: multistage flow path 12: with shaft
20: melting furnace 21: hot cyclone
31: gas discharge pipe 32: dust recovery pipe
33: gas passage on the shaft side 34: gas pipeline on the flow path side
40: reducing gas control device 41: cooling gas supply source
42: first cooling gas supply line 43: second cooling gas supply line
44: control valve

Claims (8)

In the multi-stage flow furnace and shaft, a melting furnace for melting the reduced spectroscopy discharged from the shaft furnace, and a molten iron manufacturing equipment comprising a hot cyclone,
A cooling gas source for storing cooling gas;
A first cooling gas supply line connected to the cooling gas supply source and configured to input a primary cooling gas on a reducing gas path discharged from the melting furnace to the hot cyclone; And
A second cooling gas supply line connected to the cooling gas supply source and supplying a secondary cooling gas on a reducing gas path discharged from the hot cyclone to the multistage flow path;
Reducing gas control device of the molten iron manufacturing equipment comprising a. The method of claim 1,
A gas discharge pipe is installed between the melting furnace and the hot cyclone,
The first cooling gas supply line is a reducing gas control device of the molten iron manufacturing equipment connected to one point of the gas discharge pipe. The method of claim 2,
A shaft road side gas pipe is installed between the hot cyclone and the shaft road,
A flow path side gas pipe connected to the multi-stage flow path is branched from the shaft road side gas pipe,
The second cooling gas supply line is a reducing gas control device of the molten iron manufacturing equipment is connected to a point of the flow pipe side gas pipe. The method of claim 3,
And a control valve for controlling flow rates of the primary cooling gas and the secondary cooling gas, respectively, in the first cooling gas supply line and the second cooling gas supply line. 5. The method according to any one of claims 1 to 4,
The first cooling gas supply line is the reduction gas control of the molten iron manufacturing equipment for introducing the primary cooling gas so that the reducing gas introduced into the hot cyclone and the shaft furnace has a temperature in the range of 800 ℃ to 850 ℃ Device. The method of claim 5,
The second cooling gas supply line is a reducing gas control device of the molten iron manufacturing equipment for introducing the secondary cooling gas so that the reducing gas introduced into the multi-stage flow path has a temperature in the range of 700 ℃ to 750 ℃. In the multi-stage flow furnace and shaft, a melting furnace for melting the reduced spectroscopy discharged from the shaft furnace, and a molten iron manufacturing equipment comprising a hot cyclone,
Injecting a primary cooling gas on a reducing gas path discharged from the melting furnace to the hot cyclone to lower the temperature of the reducing gas introduced into the hot cyclone and the shaft furnace to the primary; And
Injecting a secondary cooling gas on the reducing gas path introduced into the multistage flow path in the hot cyclone to lower the temperature of the reducing gas introduced into the multistage flow path to the secondary;
Reducing gas control method of the molten iron manufacturing equipment comprising a. The method of claim 7, wherein
The first falling temperature of the reducing gas is in the range of 800 ℃ to 850 ℃, the second falling temperature of the reducing gas is a reducing gas control method of the molten iron manufacturing equipment belonging to the range of 700 ℃ to 750 ℃.

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