JPS5858206A - Controlling method for temperature of reducing gas in production of pig iron - Google Patents

Abstract

PURPOSE:To operate furnaces stably with high performance by providing a controller for temp. of reducing gases between a melting and gasifying furnace and a reducing furnace, and controlling the temp. of the reducing gases formed in the melting and gasifying furnace constant and supplying said gases to the reducing furnace. CONSTITUTION:A controller 10 for temp. of reducing gases is provided between a melting and gasifying furnace and a reducing furnace, and the reducing gases 4 formed in the melting and gasifying furnace are blown through a blow port 10-6 for reducing gases. At the samt time, steam 15 is blown through a steam blow port 10-7. Both are mixed in a mixing part (b) and are admitted into the coke packed layer (a) on a grid 10-5 to induce gasifying reaction of coke. The steam is converted to reducing gases of H2 and Co, and the temp. of a gaseous mixture 4' is changed. The gaseous mixture flows out through a gas drawing port 12-2 and is fed to the reducing furnace. Thus the temp. of the reducing gases formed in the melting and gasifying furnace is controlled freely by regulating the rate of the steam to be blown through the port 10-7.

Description

[Detailed Description of the Invention] This exploding occurs in a melting and gasifying furnace that turns coal into a lump and melts and reduces reduced iron, and a reducing furnace that reduces iron ore using the gas generated in this gasifier. The present invention relates to a method for controlling the temperature of reducing gas blown into a reducing furnace in a method for producing pig iron by combining the following methods.

The above-mentioned pig iron production method was first proposed by the present inventors (Japanese Patent Application No. H56468910), and it achieves high productivity and high thermal efficiency comparable to the blast furnace method, and uses low-grade raw materials. This is the latest ironmaking method that makes it possible to This ironmaking method blows high-temperature reducing gas produced in a melting and gasifying furnace that gasifies coal, etc. and melts and reduces reduced iron into a reducing furnace that produces reduced iron, which is the charging raw material for the melting and gasifying furnace. In this method, solid reduced iron produced in this reduction furnace is melted and reduced in the melting and gasification furnace to produce molten iron.

Figure 1 shows the ironmaking process. (1) shows the molten gas and sulfurizing furnace, (2) shows the reduction furnace, and the melting gasification furnace (1) shows the reduction furnace.
)K coal (3), etc. are input, and a reducing gaff (9 temperature control) is generated.
4) is injected into the reducing furnace (2), and the granular iron oxide (3) introduced from the upper part of the furnace is reduced to produce granular reduced iron. After death, the gas (5) is collected from the gas outlet and returned to the furnace. In this method, granular reduced iron (7) taken out from a lower reduced iron cutting port (6) is melted in a melting and gasifying furnace (1) to produce molten iron (8).

In such a process, it is important for operation to maintain the temperature of the reducing gas blown into the reduction furnace (2) for reducing particulate iron oxide at an appropriate value. This is due to the reasons shown below.

The reducing gas temperature required for reducing granular iron oxides, etc. is approximately 900°C.
℃ is the appropriate value, but if the reducing gas temperature fluctuates within a range of ±50℃ with respect to this appropriate temperature, the reduction rate of solid reduced iron produced in the reduction furnace will be +511. -10
-Change. When attempting to melt in this way, the load is light when solid reduced iron with a high reduction rate is charged (the temperature of the solid reduced iron charged is high, and the FeO
As a result, the temperature of the reducing gas produced (that is, the temperature of the reducing gas blown into the reduction furnace becomes higher and higher), the solid reduced iron grains eventually sinter in the reduction furnace, forming Kutsustar and becoming stable. On the other hand, when solid reduced iron with a low reduction rate is charged, the load is heavy, so the temperature of the reducing gas produced becomes lower and lower, and the solid reduced iron produced in the reduction furnace is As a result, the reduction rate of the melting and gasifying furnace becomes lower and lower, and the melting capacity of the melting and gasifying furnace decreases, resulting in a tofu pull.

Conventionally, as a countermeasure against this problem, when the temperature of the reducing gas generated in the melting gasification furnace decreases, the cutting speed of solid reduced iron in the reduction furnace is slowed down to suppress the decrease in reduction rate, and when the temperature of the reducing gas generated in the melting gasification furnace decreases, In addition to reducing the amount of reduced iron charged into the furnace, if the temperature of the reducing gas rises, increase the cutting speed of solid reduced iron to suppress the increase in reduction rate, and charge it into the melting and gasification furnace. A method is being used to increase the amount of reduced iron. However, in this method, the reducing gas temperature is 5
When the temperature drops to 0°C, the solid reduced iron cutting rate is reduced to about 1
On the other hand, when the reducing gas temperature decreases by 50°C, it is necessary to reduce the solid reduced iron cutting rate by about 5 degrees. , it is possible to improve the reducing gas utilization rate by only about 2-2, and as a result, fluctuations in the temperature of the reducing gas generated in the melting and gasifying furnace cause deterioration of the reducing gas utilization rate and decrease in productivity. There was a problem with stable operation, where a mistake in cutting out reduced iron could result in a toppling that would lead to an interruption in operation.

This invention was made in order to eliminate the deterioration of the reducing gas utilization rate and the decrease in productivity caused by temperature fluctuations of the reducing gas generated in such a melting gasifier, and to ensure stable operation. The outline of the invention is that a reducing gas temperature adjustment device is installed between a melting gasification furnace and a reduction furnace, and the temperature of the reducing gas generated in the melting gasification furnace is stabilized by the adjustment device and then supplied to the reduction furnace. It was designed to do so.

That is, the gist of this invention is to combine a melting gasifier that gasifies coal, etc. and melting and reducing reduced iron with a reducing furnace that reduces iron ore, and to transfer the gas produced in the melting gasifier to the reducing furnace. In a pig iron production method in which molten iron is obtained by melting the solid reduced iron produced in the reduction furnace in a melting and gasification furnace, a coke charging inlet and a gas outlet are installed at the top.
It has a lattice in the middle, a reducing gas inlet and a steam inlet below the lattice, a water supply inlet and an outlet in the lower part, and a coke-filled bed on the lattice and a water reservoir in the lower part. A reducing gas temperature adjustment device made of After death, the gasification reaction of the coke on the lattice is caused by the water vapor and carbon dioxide in the mixed gas, and the absorption of heat accompanying the reaction is utilized to adjust the amount of water vapor. The reducing gas temperature is characterized in that the temperature of the gas is controlled to a predetermined temperature and recovered as reducing gas from the gas vent port, and the ash produced by coke combustion is collected through a grate into a water reservoir below and discharged. This is a control method.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure 2 shows the pig iron making process of this invention.
In this method, a reducing gas temperature adjustment device 00 is installed in the conventional process shown in Figure 1, and the temperature of the reducing gas is controlled to a constant value by this device. This reducing gas temperature adjustment device 1ft (10
As shown in Fig. 3, the coke charging port (10-1> and gas outlet (1G-2) are located at the top, and the water supply port (10-3> and discharge port (10-4) is located at the bottom). ), and a reducing gaff inlet (10-6) and a steam inlet (10-s) below the grid (10-s) provided approximately in the middle.
-7), a coke packed bed -)- on the grate (10-5), and a reducing gas and steam mixing section below the grate).
It is a device with a closed structure, which has a main body and a water reservoir lc) formed at the bottom. Q is a temperature measuring device installed at the gas outlet, and (6) is an opening control circuit for nine pulp α4 installed in the steam supply pipe (to).

That is, 9 reducing gases (4
) of the temperature #a adjustment device αQ (10-
6) At the same time, blow in steam (to) through the steam inlet (10-7). The reducing gas and water vapor blown into the device are mixed in the mixing section (b) and then passed through the grid (10-5).
The coke flows into the upper coke packed bed (-) and causes the coke gasification reaction shown below.

H,o +C-1-H,+Co (a) This reaction is an endothermic reaction, and a water vapor inlet (10
-7) The water vapor blown in is transferred to reducing gases such as H8 and CO. Then, the reaction (a) occurs depending on the amount of water vapor, the temperature of the mixed gas (4) changes, and the mixed gas (4) flows out from the gas outlet (10-2) and is sent to the reduction furnace (2).

Therefore, in this invention, the temperature of the reducing gas produced in the melting and gasifying furnace can be freely adjusted by adjusting the amount of steam blown in from the steam inlet (10-7). This temperature adjustment is performed by measuring the outlet temperature with a temperature measuring device (b) installed at the gas outlet (10-2), and opening the pulp to a temperature (approximately 900°C) suitable for use in the reduction furnace (2). This can be done by adjusting the amount of water vapor using the temperature control circuit (2). Incidentally, since the temperature of the gas produced in the melting and gasifying furnace (1) is usually 1000 to 1200°C, the temperature of the high-temperature gas is lowered by steam in 6.1 Temperature Adjustment αQ.

On the other hand, the carbon in the coke is consumed by the reaction (a),
Ash remains, but the ash falls through the grate (10-5), enters the water m#) (c) below, mixes with the water υ→, and exits the device from the outlet (10-4). At the same time, the consumed amount of coke on the grate (10-5) is replenished from the coke charging port (10-1).

Alpha power indicates a mixture of water and ash, and (to) indicates coke.

With this invention method, approximately 50% of reducing gas is blown into the reducing furnace
ox77a, , average temperature 1050℃, temperature fluctuation i5
0℃, component power CO75%, H,22%, C0.2$
17) In order to process the crude reducing gas and obtain a reducing gas constant at 900°C, if the temperature of the crude reducing gas generated in the melting and gasifying furnace is, for example, 1000°C, approximately 1000 vHr of water vapor is added to the temperature adjustment device αQ. The amount of reducing gas obtained at this time is approximately
1°H, 22, 6chi, CO! There will be one fight. Further, the amount of coke consumed is approximately 1250 KV/Hr.

On the other hand, when the crude reducing gas temperature is 1050°C, approximately 16
30 If/Hr of steam should be injected, and in this case, a reducing gas of about 4.6KNWP/Hr is obtained, the components are C074-1H823 and C081, and the coke consumption is about 1650Y4/Hr. .

As a result of being able to keep the temperature of the obtained reducing gas within ±10°C, compared to the fluctuation of the crude reducing gas temperature of ±50°C, the fluctuation of the solid reduction rate produced in the reduction furnace (2) can be reduced to within ±10°C. ±2- or less, there is no need to adjust the cut-out speed in the reduction furnace, and compared to the conventional method, an improvement in reducing gas utilization rate of about 2 qk and an improvement in productivity of about 4- can be achieved.

As explained above, according to the present invention, the deterioration of the reducing gas utilization rate and the decrease in productivity caused by the temperature fluctuation of the reducing gas generated in the melting and gasifying furnace that gasifies coal, etc. and melts and reduces reduced iron can be prevented. resolved and stabilized. ′! 6 efficient operation can be achieved.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of a conventional iron making process using a melting gasification furnace and a smelting furnace, Fig. 2 is a system diagram showing an embodiment of the present invention, and Fig. 3 is a system diagram showing an example of the iron making process using a conventional melting gasification furnace and a smelting furnace. FIG. 2 is a schematic diagram showing an example of reducing gas temperature aiiiuia. 1... - Melting gasification furnace, 2... Reduction furnace, 3... Stone return, 4... Reducing gas, 5... Gas, 6... Reduced iron cutting port, 7... Granular reduced iron, 8... Molten iron, 10
...Reducing gas one-time adjustment device, 10-1...Coke charging inlet, 10-2...Gas outlet, 10-3-...Water supply port, 10-4...Discharge port, 10- 5... Lattice,
10-6...1 source gas inlet, 10-7-...steam inlet, 11...temperature measuring device, 12...pulp opening control circuit, 1...coke filled bed, b -... 4 joints,
c”・Water reservoir. Figure 2

Claims (1)

[Claims] A melting gasification furnace that gasifies coal, etc. and melts and reduces reduced iron, and combines a melting gasifier and a reduction furnace that reduces iron ore, and uses the gas produced in the melting gasifier as the reducing gas in the reduction furnace. In the pig iron noodle manufacturing method in which molten iron is obtained by melting the nine solid reduced iron produced in the reduction furnace in the melting and gasification furnace, a coke charging inlet and a gas outlet are installed at the top. ! “With a lattice in the middle,
A reduction-X temperature control system having a reducing gas inlet and a steam inlet below the grid, a water supply port and a water outlet at the bottom, a coke-filled bed on the grid, and a water reservoir at the bottom. A device is installed between the melting gasification furnace and the reduction furnace,
The gas generated in the melting gasifier is injected from the reducing gas inlet of the device, mixed with steam below the grate in the device, and then the coke on the grate is gasified by the water vapor and carbon dioxide in the mixed gas. The ash produced by the mixed gas is collected through the grid into the water reservoir below by causing a reaction and adjusting the amount of water vapor by utilizing the heat absorption accompanying the reaction.
A method for controlling reduction bus temperature in a pig iron manufacturing method characterized by discharge.