CN115652010A - Efficient heat exchange smelting reduction iron-making method and device - Google Patents

Abstract

The invention discloses a method and a device for smelting reduction iron making by high-efficiency heat exchange, relating to the technical field of metallurgy, wherein the method comprises the following steps: adjusting the proportion of the pulverized coal and the oxygen-enriched hot air; spraying the pulverized coal and the oxygen-enriched hot air which are adjusted in proportion into a molten pool together, and reacting to generate a first substance; and injecting the materials into the molten pool, and reacting the materials and the first substance to generate molten iron and top gas. According to the invention, a part of oxygen-enriched hot air and coal powder are directly sprayed into the molten pool through the same spray gun, the coal powder is combusted at the front end of the spray gun, the temperature of generated high-temperature CO can reach 2400-2700 ℃, and the high-temperature CO exchanges heat with iron slag in the molten pool, so that the temperature of the molten pool is increased, and the spray gun is simple and easy to operate and has strong practicability. The reaction temperature of the molten pool is greatly improved, sufficient heat is provided for the molten pool, the heat exchange is more sufficient, the unit consumption of ton iron fuel is effectively reduced, and when the temperature of the molten pool has a sufficient temperature heat source, namely the temperature reaches more than 1400 ℃, the oxygen-enriched hot air blowing amount at the top of the molten pool is gradually reduced to 0.

Description

A high-efficiency heat exchange smelting reduction ironmaking method and device

technical field

The invention relates to the technical field of metallurgy, in particular to a high-efficiency heat exchange smelting reduction ironmaking method and device.

Background technique

The HIsmelt smelting reduction ironmaking process is a cutting-edge technology in the field of metallurgy today. It uses non-coking coal powder and iron ore powder to produce liquid molten iron, and directly sprays pulverized coal powder ore into the molten pool for reduction reaction. Floating on the surface, the top of the reactor is blown into hot air, which burns with the floating reducing gas to generate heat, heats the floating slag and iron, and supplies heat for the molten pool.

The disadvantages of this technique are:

First, the molten iron slag that floats up is not in sufficient contact with the high-temperature flue gas generated by the combustion of gas at the top, and the heat transfer effect is not good. The temperature of the molten iron in the molten pool is only 1400-1450°C, and the flue gas volume is as high as 2700Nm3/t iron, The flue gas temperature reaches 1600°C, and a large amount of physical heat is lost outside the furnace along with the flue gas.

Second, the temperature of the molten pool is low, the reaction time is short, and the reaction is insufficient. There is a large amount of FeO (3-15%) in the slag. High, high fuel consumption per ton of iron.

Third, part of the molten iron is oxidized again by the oxygen sprayed from the top during the floating process to form FeO (Fe+O ₂ →FeO).

Contents of the invention

The object of the present invention is to provide a high-efficiency heat exchange smelting reduction ironmaking method and device, which greatly increases the reaction temperature of the molten pool, provides sufficient heat for the molten pool, and through sufficient heat exchange, the top gas temperature drops below 1000°C, effectively To reduce fuel consumption per ton of iron, when the temperature of the molten pool has a sufficient temperature heat source, that is, when the temperature reaches above 1400°C, gradually reduce the amount of oxygen-enriched hot air blown to the top of the molten pool to 0. To achieve the above object, the present invention provides the following technical solutions:

In one aspect, the present invention provides a high-efficiency heat exchange smelting reduction ironmaking method, the method comprising the following steps:

Adjust the ratio of pulverized coal and oxygen-enriched hot air;

Spray the adjusted proportion of pulverized coal and oxygen-enriched hot air into the molten pool, and react to form the first substance;

The materials are sprayed into the molten pool, and the materials react with each other and with the first material to generate molten iron and top gas.

Further, the method also includes the following steps:

When the temperature of the molten pool has a sufficient temperature heat source, gradually reduce the amount of oxygen-enriched hot air blown into the top of the molten pool to 0.

Further, the adjustment of the ratio of pulverized coal and oxygen-enriched hot air is specifically:

Adjust the mass ratio of C in pulverized coal to O ₂ in oxygen-enriched hot air: C:O ₂ ≥ 2:1.

Further, the materials include: iron ore powder, coal powder, dolomite and lime.

Further, the first substance is high-temperature CO; or high-temperature CO and coal powder.

Further, the composition and volume percentage of the top gas are:

The _N2 content is 35.1%-41.4%, the _CO2 content is 23.0%-24.2%, the CO content is 30.8%-37.6%, and the _H2 content is 3.6%-4.3%.

Based on the above method, on the other hand, the present invention also provides a high-efficiency heat exchange smelting reduction ironmaking device, which includes: an oxygen-coal spray gun, a material spray gun and a melting pool;

The oxygen-coal spray gun is used for spraying the adjusted proportion of coal powder and oxygen-enriched hot air into the molten pool together;

The material spray gun is used to spray the material into the molten pool;

The melting pool is used to provide a reaction site for the adjusted ratio of coal powder and oxygen-enriched hot air, and react to form the first substance;

And it is used to provide a reaction place between materials and materials and the first substance, and react to generate molten iron and top gas.

Further, an air inlet and an air outlet are provided at the top of the melting pool.

Further, m oxygen-coal spray guns and n material spray guns are arranged on the circumferential surface of the molten pool.

Further, a slag port and an iron port are provided at the bottom of the melting pool.

Technical effect and advantage of the present invention:

First, the present invention directly sprays a part of oxygen-enriched hot air and coal powder into the molten pool through the same spray gun, and the coal powder burns at the front end of the gun, and the temperature of the high-temperature CO produced can reach 2400-2700 °C, and the slag and iron in the molten pool Carry out heat exchange, increase the temperature of the molten pool, simple and easy to operate, and strong practicability.

Second, the high-efficiency heat exchange smelting reduction ironmaking method of the present invention can be extended to other smelting reduction ironmaking processes, and has great application value.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure pointed out in the written description, claims hereof as well as the appended drawings.

Description of drawings

Fig. 1 is a flow chart of the high-efficiency heat exchange smelting reduction ironmaking method of the present invention;

Fig. 2 is a schematic diagram of a traditional HIsmelt smelting reduction reaction furnace;

Fig. 3 is a schematic diagram of the high-efficiency heat exchange smelting reduction ironmaking reactor of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to solve the deficiencies of the prior art, on the one hand, the present invention discloses a high-efficiency heat exchange smelting reduction ironmaking method. Figure 1 is a flow chart of the high-efficiency heat exchange smelting reduction ironmaking method of the present invention, as shown in Figure 1, the Said method comprises the steps:

Adjust the ratio of pulverized coal and oxygen-enriched hot air;

Spray the adjusted proportion of pulverized coal and oxygen-enriched hot air into the molten pool, and react to form the first substance;

The materials are sprayed into the molten pool, and the materials react with each other and with the first material to generate molten iron and top gas.

Preferably, the method also includes the steps of:

When the temperature of the molten pool has a sufficient temperature heat source, gradually reduce the amount of oxygen-enriched hot air blown into the top of the molten pool to 0.

Preferably, the ratio of said adjustment of pulverized coal and oxygen-enriched hot air is specifically:

Adjust the mass ratio of C in pulverized coal to O ₂ in oxygen-enriched hot air: C:O ₂ ≥ 2:1.

Preferably, the materials include: iron ore powder, coal powder, dolomite and lime.

Preferably, the first substance is high-temperature CO; or high-temperature CO and coal powder.

Preferably, the composition and volume percentage of the top gas are:

The _N2 content is 35.1%-41.4%, the _CO2 content is 23.0%-24.2%, the CO content is 30.8%-37.6%, and the _H2 content is 3.6%-4.3%.

Based on the above method, on the other hand, the present invention also discloses a high-efficiency heat exchange smelting reduction ironmaking device, which includes: an oxygen-coal spray gun, a material spray gun and a melting pool;

The oxygen-coal spray gun is used for spraying the adjusted proportion of coal powder and oxygen-enriched hot air into the molten pool together;

The material spray gun is used to spray the material into the molten pool;

The melting pool is used to provide a reaction site for the adjusted ratio of coal powder and oxygen-enriched hot air, and react to form the first substance;

And it is used to provide a reaction place between materials and materials and the first substance, and react to generate molten iron and top gas.

Preferably, an air inlet and an air outlet are provided at the top of the melting pool.

Preferably, m oxygen-coal spray guns and n material spray guns are arranged on the circumferential surface of the melting pool.

Preferably, a slag port and an iron port are provided at the bottom of the melting pool.

Take the industrial test carried out by a certain iron and steel plant as an example below to further describe the present invention. Fig. 2 is a schematic diagram of a traditional HIsmelt smelting reduction reaction furnace. :

Comparative example:

2000 tons of iron ore powder, 1104 tons of coal powder and 322 tons of flux were sprayed into the molten pool through the material spray gun, and 3×10 ⁶ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) was blown from the top of the reactor in the molten pool. After full reaction, 1,183 tons of molten iron and 507 tons of slag were produced. The temperature of the molten iron was 1,380°C. The components and volume percentages of the generated top gas were: N ₂ content 44.56%, CO ₂ content 19.78%, CO 2 The content of Fe is 21.40%, the content of _H2 is 3.35%, the content of Fe in slag is 12%, and the total fuel ratio is 551.8kg/t.

Based on the novel smelting reduction ironmaking method and device of the present invention, the present invention has carried out four phase tests, and Fig. 3 is a schematic diagram of the high-efficiency heat exchange smelting reduction ironmaking reaction furnace of the present invention, as shown in Fig. 3 , the oxygen coal gun pulverized coal and Oxygen-enriched hot air ratio reaches C:O ₂ ≥ 2:1, gradually increase the amount of pulverized coal and hot air injected by the oxygen coal lance, reduce the amount of pulverized coal injected by the mixing lance and the hot air amount on the furnace top, increase the temperature of molten iron, and carry iron in the slag And the total fuel ratio decreases, the calorific value of gas increases. The specific experimental process is as follows:

Example 1:

Spray 200 tons of pulverized coal and 4.23×10 ⁵ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) into the melting pool through a coal-oxygen spray gun, and inject 2,000 tons of iron ore powder and 868 tons of pulverized coal into the molten pool through a material spray gun , 322 tons of flux, 2.37×10 ⁶ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) is blasted from the top of the molten pool reactor. After full reaction, 1,198 tons of molten iron and 498 tons of slag are produced, and the temperature of the molten iron is At 1400°C, the composition and volume percentage of the generated furnace top gas are: N ₂ content 41.4%, CO ₂ content 24.2%, CO content 30.8%, H ₂ content 3.6%, Fe content in slag 10.4% , the total fuel ratio is 534.2kg/t.

Example 2:

Spray 400 tons of pulverized coal and 8.46×10 ⁵ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) into the melting pool through a coal-oxygen spray gun, and inject 2,000 tons of iron ore powder and 641 tons of pulverized coal into the molten pool through a material spray gun , 322 tons of flux, 1.73×10 ⁶ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) is blasted from the top of the molten pool reactor. After full reaction, 1,217 tons of molten iron and 487 tons of slag are produced, of which the temperature of molten iron is 1,420 ℃, the composition and mass percentage of the generated furnace top gas are: N ₂ content is 38.3%, CO ₂ content is 23.1%, CO content is 34.7%, H ₂ content is 3.9%, Fe content in slag is 8.3% , the total fuel ratio is 520.5kg/t.

Example 3:

Spray 500 tons of coal powder and 10.58×10 ⁵ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) into the molten pool through the coal-oxygen lance, and inject 2,000 tons of iron ore powder and 530 tons of coal powder into the molten pool through the material spray gun , 322 tons of flux, 1.41×10 ⁶ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) was blasted from the top of the molten pool reactor, and after full reaction, 1,227 tons of molten iron and 481 tons of slag were produced, of which the temperature of molten iron was 1,425 ℃, the composition and mass percentage of the generated furnace top gas are: N ₂ content is 36.7%, CO ₂ content is 23.1%, CO content is 36.1%, H ₂ content is 4.1%, Fe content in slag is 7.2% , the total fuel ratio is 515.2kg/t.

Example 4:

Spray 600 tons of pulverized coal and 12.7×10 ⁵ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) into the molten pool through a coal-oxygen spray gun, and inject 2,000 tons of iron ore powder and 434 tons of pulverized coal into the molten pool through a material spray gun , 322 tons of flux, 1.1×10 ⁶ Nm ³ of oxygen-enriched hot air (containing 30% O ₂ ) is blasted from the top of the molten pool reactor, and after full reaction, 1,237 tons of molten iron and 475 tons of slag are produced. Among them, the temperature of molten iron 1440°C, the composition and mass percentage of the generated furnace top gas are: N ₂ content 35.1%, CO ₂ content 23.0%, CO content 37.6%, H ₂ content 4.2%, Fe content in slag 6.0 %, the total fuel ratio is 516.8kg/t.

According to the data of each reaction raw material and output product in the comparative example and the embodiment, arrange and summarize the following table 1.

The data summary table of each reaction raw material and output product in table 1 comparative example and embodiment

By analyzing the data in Table 1, it can be seen that by gradually increasing the pulverized coal and oxygen-enriched hot air injection volume of the oxygen coal lance, reducing the pulverized coal injection volume of the mixed material spray gun and the oxygen-enriched hot air injection volume of the furnace top, the temperature of the molten iron increases, and the slag The ratio of medium iron and total fuel decreases, and the calorific value of gas increases.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still It is possible to modify the technical solutions recorded in the foregoing embodiments, or to perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. within the spirit and principles of the present invention shall be included in the within the protection scope of the present invention.

Claims (10)

1. a high-efficiency heat exchange smelting reduction ironmaking method, is characterized in that, described method comprises the steps: Adjust the ratio of pulverized coal and oxygen-enriched hot air; Spray the adjusted proportion of pulverized coal and oxygen-enriched hot air into the molten pool, and react to form the first substance; The materials are sprayed into the molten pool, and the materials react with each other and with the first material to generate molten iron and top gas. 2. A kind of high-efficiency heat exchange smelting reduction ironmaking method according to claim 1, is characterized in that, described method also comprises the following steps: When the temperature of the molten pool has a sufficient temperature heat source, gradually reduce the amount of oxygen-enriched hot air blown into the top of the molten pool to 0. 3. A kind of high-efficiency heat exchange smelting reduction ironmaking method according to claim 1 or 2, characterized in that the ratio of said adjustment of pulverized coal and oxygen-enriched hot air is specifically: Adjust the mass ratio of C in pulverized coal to O ₂ in oxygen-enriched hot air: C:O ₂ ≥ 2:1. 4. A high-efficiency heat-exchanging smelting reduction ironmaking method according to claim 1, wherein the materials include: iron ore powder, coal powder, dolomite and lime. 5 . The high-efficiency heat exchange smelting reduction ironmaking method according to claim 1 , wherein the first substance is high-temperature CO; or high-temperature CO and pulverized coal. 6. A method for high-efficiency heat exchange smelting reduction ironmaking according to claim 1, wherein the composition and volume percentage of the top gas are: The _N2 content is 35.1%-41.4%, the _CO2 content is 23.0%-24.2%, the CO content is 30.8%-37.6%, and the _H2 content is 3.6%-4.3%. 7. A high-efficiency heat exchange smelting reduction ironmaking device, characterized in that the device includes: an oxygen-coal spray gun, a material spray gun and a molten pool; The oxygen-coal spray gun is used for spraying the adjusted proportion of coal powder and oxygen-enriched hot air into the molten pool together; The material spray gun is used to spray the material into the molten pool; The melting pool is used to provide a reaction site for the adjusted ratio of coal powder and oxygen-enriched hot air, and react to form the first substance; And it is used to provide a reaction place between materials and materials and the first substance, and react to generate molten iron and top gas. 8. A high-efficiency heat exchange smelting reduction ironmaking device according to claim 7, characterized in that: The top of the melting pool is provided with an air inlet and an air outlet. 9. A high-efficiency heat exchange smelting reduction ironmaking device according to claim 7, characterized in that, m oxygen-coal spray guns and n material spray guns are arranged on the circumferential surface of the melting pool. 10. A high-efficiency heat exchange smelting reduction ironmaking device according to claim 7, characterized in that: A slag port and an iron port are provided at the bottom of the melting pool.

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