Metallurgical furnace

Abstract

The present invention relates to a metallurgical process and equipment, and more particularly to a metallurgical furnace capable of operating with a wide range of raw materials and fuels. For this purpose, the metallurgical furnace of the present invention comprises (i) at least one upper stack (1), (ii) at least one lower stack (2), (iii) at least one fuel inlet (10) located between the at least one upper stack (1) and the at least one lower stack (2), (iv) at least one charging inlet (3) located on the at least one upper stack (1), (v) at least one physical means (5) for internal separation of the upper stack (1) extending longitudinally downward from the top of the upper stack (1), the physical means (5) being suitable for dividing the upper stack (1) into a central portion (6) and a peripheral portion (7), and (vi) at least one gas outlet (4) located above the peripheral portion (7) of the at least one upper stack (1). The gas outlet (4) plays a role in generating a charge preheating region (7) that increases the operational flexibility of the furnace.

Description

Technical Field

[0001]

[0001] The present invention relates to metallurgical processes and equipment. More specifically, the present invention relates to a metallurgical furnace for the production of pig iron.

Background Art

[0002]

[0002] Mining is an important activity for a country's economic development and accounts for approximately 20% of Brazil's exports in 2022. The mining sector contributes to revenue generation, job creation, and the improvement of the country's infrastructure. However, it is important to highlight that mining also has environmental and social impacts, and therefore, mining must be carried out responsibly and sustainably.

[0003]

[0003] In order to seek solutions that use less mineral raw materials, one trend in the steel production market is based on the use of by-products generated throughout the steel production chain. The conventional steel production route uses a blast furnace (BF) as a reduction furnace to obtain iron, and then this iron is sent to a steelworks for steel production in a basic oxygen furnace (BOF). When using the BF-BOF route, an average of 500 kg of waste is generated per ton of molten steel produced. Furthermore, approximately 185 kg of waste is generated per ton of molten steel obtained from an electric arc furnace that uses scrap as a major charge.

[0004]

[0004] The recycling of iron scrap in Brazil is estimated to reach tens of millions of tons per year. If all of this material is sent to landfill, it will surely cause serious environmental problems. Recycling and reusing this by-product helps to reduce the amount of waste released into the environment, prevent soil and water pollution, and in addition, conserve natural resources and energy.

[0005]

[0005] Currently, there are no metallurgical furnaces on the market that can operate with a wide range of raw materials and fuels. Generally, new structural and operational configurations are required to adapt the reduction process of iron sources to the fuels used. Therefore, it is very important to develop flexible technologies aimed at reusing and recycling materials with the aim of reducing the environmental impact without affecting the productivity of the process or the quality of the products produced.

[0006]

[0006] Document BR 10 2013 033702 1 A2, owned by the same applicant, describes the insertion of a burner into a self-reducing furnace, which enables greater versatility in the use of pulverized solid carbonaceous fuels, liquid fuels, and gaseous fuels. Despite their versatility, these fuels are considered auxiliary fuels and their use is limited.

[0007]

[0007] Patent BR 11 2017 012467 0 B1, owned by the same applicant, describes a self-reducing metallurgical furnace operating with a preferential central hot airflow due to the presence of a hood (curtain wall) located within the upper stack, extending longitudinally through the furnace, which allows for the use of lower quality iron materials than ore, such as scrap, by appropriate control of the gas flow to enable uniform reduction of the iron charge. However, the stack is sealed so that air cannot pass through the sides of the equipment, which prevents backflow of hot air in the charge and consequently prevents its preheating in the upper stack.

[0008]

[0008] The present invention proposed herein solves the problems of the above-mentioned technical status in a simple and efficient manner. [Overview of the project]

[0009]

[0009] The first object of the present invention is to provide a metallurgical furnace for producing pig iron from various raw materials, such as self-reducing briquettes produced from iron oxide sources such as ore and steelmaking by-products, as well as scrap, scrap briquettes, and HBI (hot briquette iron).

[0010]

[0010] A second object of the present invention is to provide a metallurgical furnace for pig iron production that can operate with various types of fuel, which may be anthracite, fuel briquettes, mineral coal, charcoal, metallurgical coke, green petroleum coke, and additional fuels such as synthesis gas and H2.

[0011]

[0011] The third objective of the present invention is to provide a flexible metallurgical furnace for pig iron production that can contribute to reducing environmental impact and improving the energy efficiency of the metallurgical manufacturing process.

[0012]

[0012] To achieve the above objectives, the present invention provides a metallurgical furnace comprising: (i) at least one upper stack; (ii) at least one lower stack; (iii) at least one fuel inlet located between the at least one upper stack and the at least one lower stack; (iv) at least one charge inlet located on the at least one upper stack; (v) at least one physical means for internal separation of the upper stack, extending longitudinally downward from the top of the upper stack, and being adapted to divide the upper stack into a central portion and a peripheral portion; and (vi) at least one gas outlet located on the upper part of the peripheral portion of the at least one upper stack.

[0013]

[0013] The detailed description presented below will be based on the attached drawings and their respective reference numerals. [Brief explanation of the drawing]

[0014] [Figure 1]

[0014] Figure 1 shows a preferred embodiment of the metallurgical furnace according to the present invention. [Figure 2]

[0015] Figure 2 shows a detailed view of the charge preheating region in a metallurgical furnace according to a preferred embodiment of the present invention. [Figure 3]

[0016] Figure 3 shows a preferred embodiment of the metallurgical furnace according to the present invention, which is provided with multiple gas outlets and charging ports. [Modes for carrying out the invention]

[0015]

[0017] It should be emphasized that the following description is based on preferred embodiments of the present invention. However, as will be apparent to those skilled in the art, the present invention is not limited to these particular embodiments.

[0016]

[0018] The present invention provides a metallurgical furnace equipped with innovations that enable proper control of gas flow and allow operation to be carried out in a general-purpose manner and with a wide range of raw materials and fuels.

[0017]

[0019] The metallurgical furnace of the present invention, shown in Figures 1 and 2, comprises at least one upper stack 1 into which the charge (raw material) is inserted into the reactor. Preferably, the cross-section of the stack 1 is circular or rectangular. However, it should be emphasized that the present invention is not limited to any particular shape of the furnace.

[0018]

[0020] The metallurgical furnace of the present invention preferably further comprises at least one lower stack 2 having a circular or rectangular cross-section. The diameter or width of the cross-section of stack 2 is preferably larger than that of stack 1.

[0019]

[0021] The present invention further comprises at least one fuel inlet 10 positioned between at least one upper stack and at least one lower stack 2. The fuel supply duct is coupled to ensure that fuel is supplied to the hearth and can prevent charge carryover when fine materials are used.

[0020]

[0022] Preferably, the upper stack 1 comprises a set 8 of upper tuyeres, and the lower stack 2 comprises a set 9 of lower tuyeres, which function to blow high-temperature or low-temperature air into the metallurgical furnace. The blown air may optionally be enriched with O2. Solid powder fuel, liquid fuel, or gaseous fuel may be further injected through the tuyeres for partial combustion of the fuel, generating gas and providing the thermal energy required for reduction and / or melting of the charge. When high-temperature air is blown into the tuyeres, as shown in FIG. 1, it is further possible to use a blower set 11, which may be connected to an air heating system (not shown) known in the state of the art.

[0021]

[0023] The metallurgical furnace of the present invention preferably further comprises at least one charging port 3 positioned laterally above the upper stack 1.

[0022]

[0024] Furthermore, the metallurgical furnace of the present invention comprises physical means 5 for internal separation of the upper stack 1 extending longitudinally downward from the top of the upper stack 1, and this physical means 5 is adapted to divide the upper stack 1 into a central portion 6 and a peripheral portion 7. Preferably, the physical means 5 is a hood (curtain wall) extending longitudinally from the top of the upper stack 1 to half of its length, as shown in FIGS. 1 and 2.

[0023]

[0025] Preferably, the physical means 5 is adapted to receive permeated fuel from above so as to form at least one column of permeated fuel located in the central portion 6.

[0024]

[0026] The metallurgical furnace of the present invention further comprises at least one gas outlet 4 positioned above the peripheral portion 7 of the upper stack 1. Preferably, the metallurgical furnace of the present invention comprises a plurality of gas outlets 4 and a plurality of charging ports 3.

[0025]

[0027] Preferably, for each gas outlet 4, an air inlet 3 is provided adjacent thereto. In this preferred embodiment shown in FIG. 3, the metallurgical furnace of the present invention has at least 36 sets of charging ports 3 and gas outlets 4.

[0026]

[0028] The use of the gas outlet 4 in the metallurgical furnace of the present invention significantly improves its efficiency. This is because the gas outlet 4 allows the upward flow of hot air from the lower stack 2 to also pass through the peripheral area, generating a charge preheating area therein. These gas outlets contribute to the formation of a new convection inside the furnace, improving the heat exchange efficiency and expanding the operation control. As a result, the furnace can be operated with a wide range of raw materials and fuels. Therefore, the metallurgical furnace of the present invention more efficiently utilizes the heat generated inside, thereby reducing the energy demand of the manufacturing process.

[0027]

[0029] The metallurgical furnace of the present invention can be operated with any of the permeable fuels from the following group: Anthracite, Fuel briquettes, Mineral coal, Charcoal, Metallurgical coke, Green petroleum coke, Synthesis gas, H2.

[0028]

[0030] The metallurgical furnace of the present invention can be operated with any charge consisting of self-reducing briquettes produced from iron oxide sources such as iron ore and steelmaking by-products, as well as scrap, scrap briquettes, and HBI (hot briquetted iron).

[0029]

[0031] The metallurgical furnace of the present invention shows flexibility in controlling the pressure, temperature, and gas mixture in different regions of the furnace, enabling the same equipment to operate with various qualities of iron charges and fuels.

[0030]

[0032] Numerous modifications affecting the scope of protection of this application are permitted. Thus, it is emphasized that the present invention is not limited to the specific configurations / embodiments described above.

Claims

1. It is a metallurgical furnace, At least one upper stack (1), At least one lower stack (2), At least one fuel inlet (10) is located between the at least one upper stack (1) and the at least one lower stack (2), At least one loading port (3) positioned on the at least one upper stack (1), A physical means (5) for internal separation of the upper stack (1) extending longitudinally downward from the top of the upper stack (1), the physical means (5) being suitable for dividing the upper stack (1) into a central portion (6) and a peripheral portion (7), The metallurgical furnace is equipped with, To generate a charge preheating region, the system further comprises at least one gas outlet (4) positioned above the upper part (7) of the at least one upper stack (1), One of the at least one charging port (3) is provided adjacent to each of the at least one gas outlet (4) and brings the inserted charge into contact with the charge preheating area. A metallurgical furnace characterized by the following features.

2. The metallurgical furnace according to claim 1, characterized in that the physical means (5) is adapted to receive permeation fuel from above in the central portion (6) so as to form at least one column of permeation fuel.

3. The permeable fuels include anthracite, fuel briquettes, mineral coal, charcoal, metallurgical coke, green petroleum coke, and synthesis gas and H2. ２ The metallurgical furnace according to claim 1 or 2, characterized in that it is at least one of the group consisting of additional fuels such as the following.

4. The metallurgical furnace according to any one of claims 1 to 3, characterized in that the charge is at least one of the group consisting of self-reducing briquettes produced from iron oxide sources such as ore and steelmaking by-products, and scrap, scrap briquettes, and HBI (hot briquette iron).

5. The metallurgical furnace according to any one of claims 1 to 4, characterized in that the at least one physical means (5) extends longitudinally from the top of the upper stack (1) to half its length.

6. The metallurgical furnace according to any one of claims 1 to 5, characterized in that the upper stack (1) comprises an upper tuyere set (8), and the lower stack (2) comprises a lower tuyere set (9).

7. The metallurgical furnace according to any one of claims 1 to 6, characterized in that a blower set (11) is connected to the tuyere set (8, 9) for blowing high-temperature air into the metallurgical furnace.

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