Metallurgical furnace

Abstract

The present invention relates to metallurgical processes and apparatuses, and more particularly, to a metallurgical furnace that can be operated using a variety of raw materials and fuels. To this end, the metallurgical furnace according to the invention comprises: (i) at least one upper housing (1); (ii) at least one lower housing (2); (iii) at least one fuel inlet (10) located between the at least one upper housing (1) and the at least one lower housing (2); (iv) at least one charge inlet (3) in the at least one upper housing (1); (v) at least one physical structure (5) for the internal separation of the upper housing (1) extending longitudinally downward from the top of the housing, the physical structure (5) being adapted to divide the upper housing (1) into a central portion (6) and a peripheral portion (7); and (vi) at least one gas outlet (4) on top of the peripheral portion (7) of the at least one upper housing (1). The gas outlet (4) is responsible for creating a charge preheating zone (7) which increases the operational flexibility of the furnace.

Description

Technical Field

[0001] The present invention relates to metallurgical processes and equipment. More particularly, the present invention relates to a metallurgical furnace for producing pig iron. Background Art

[0002] Mining is an important activity for the national economic development, accounting for around 20% of Brazil's exports in 2022. Mining helps generate income, create jobs and improve national infrastructure. However, it is important to note that mining also has environmental and social impacts, so it must be carried out in a responsible and sustainable manner.

[0003] In order to find solutions to use less and less mineral raw materials, one of the trends in the steel production market is based on the use of by-products generated throughout the steel production chain. The traditional steel production route uses a blast furnace (AF) as a reduction reactor to obtain iron, which is then sent to the steel mill for the production of steel in an oxygen furnace (BOF-Basic Oxygen Furnace). Through the AF-BOF route, an average of 500 kg of waste is generated for each ton of liquid steel produced. In addition, about 185 kg of waste is generated for each ton of liquid steel obtained from an electric arc furnace using scrap as the main charge.

[0004] It is estimated that tens of millions of tons of ferrous scrap are recycled in Brazil each year. If all this material were to go to landfill, it would certainly cause serious environmental problems. Recycling and reusing these byproducts helps reduce the amount of waste released into the environment, prevents soil and water contamination, and saves natural resources and energy.

[0005] Currently, there are no metallurgical furnaces on the market that are capable of operating with a wide range of raw materials and fuels. In general, new structural and operating configurations are required to adapt the processes for reducing ferrous resources to the fuels used. Therefore, it is extremely important to develop flexible technologies aimed at reusing and repurposing materials in order to mitigate environmental impact without compromising process productivity and the quality of the products produced.

[0006] Document BR 10 2013 033702 1A2 held by the same applicant describes the insertion of burners in an autoreduction furnace, which allows for more flexible use of pulverized solid carbon fuels, liquid fuels and gaseous fuels. Despite their versatility, these fuels are still considered auxiliary fuels and their use is limited.

[0007] Patent BR 11 2017 012467 0B1 held by the same applicant describes a self-reducing metallurgical furnace that operates with a central preferential hot air flow, thanks to the presence of a hood (curtain wall) located in the upper shaft and extending longitudinally through the furnace, which makes it possible to use ferrous materials of lower quality (such as scrap) since the air flow can be adequately controlled to achieve a uniform reduction of the ferrous charge. However, the shaft is sealed in such a way that it is impossible for air to pass through the sides of the device, thereby hindering the counterflow of hot air in the charge and therefore hindering the preheating of the charge in the upper shaft.

[0008] The present invention solves the above-mentioned problems in the prior art in a simple and effective manner. Summary of the invention

[0009] A 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 ores and steel by-products as well as scrap, scrap briquettes and HBI (hot briquetted iron).

[0010] A second object of the present invention is to provide a metallurgical furnace for producing pig iron which can be operated using different types of fuels such as anthracite, fuel briquettes, coal, charcoal, metallurgical coke, green petroleum coke and additional fuels such as synthesis gas and H2.

[0011] A third object of the present invention is to provide a flexible metallurgical furnace for producing pig iron which can help to reduce environmental impact and improve the energy efficiency of metallurgical production processes.

[0012] In order to achieve the above-mentioned objectives, the present invention provides a metallurgical furnace, comprising: (i) at least one upper furnace shaft; (ii) at least one lower furnace shaft; (iii) at least one fuel inlet located between at least one upper furnace shaft and at least one lower furnace shaft; (iv) at least one charging inlet located in at least one upper furnace shaft; (v) at least one physical structure for internal partition of the upper furnace shaft, which extends longitudinally downward from the top of the furnace shaft, and the physical structure is suitable for dividing the upper furnace shaft into a central part and a peripheral part; (vi) at least one gas outlet located at the top of the peripheral part of at least one upper furnace shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following detailed description refers to the accompanying drawings and their respective reference numerals.

[0014] Figure 1 A preferred embodiment of a metallurgical furnace according to the invention is shown.

[0015] Figure 2 A detailed view of a charge preheating area in a metallurgical furnace according to a preferred embodiment of the present invention is shown.

[0016] Figure 3 A preferred embodiment of a metallurgical furnace according to the invention is shown, in which a plurality of gas outlets and charge inlets are provided. DETAILED DESCRIPTION

[0017] First, it should be noted that the following description will be based on a preferred embodiment of the present invention. However, as will be clear to those skilled in the art, the present invention is not limited to this particular embodiment.

[0018] The present invention provides a metallurgical furnace having an innovative technology allowing full control of the gas flow, thereby being able to operate in a flexible manner and using a variety of raw materials and fuels.

[0019] like Figure 1 and 2 The metallurgical furnace of the invention shown comprises at least one upper furnace shaft 1, where the charge (raw material) is inserted into the reactor. Preferably, the cross section of the furnace shaft 1 is circular or rectangular. However, it should be noted that the invention is not limited to any particular furnace form.

[0020] The metallurgical furnace of the present invention further comprises at least one lower furnace shaft 2, which preferably has a circular or rectangular cross section. The diameter or width of the cross section of the furnace shaft 2 is preferably greater than the diameter or width of the cross section of the furnace shaft 1.

[0021] The invention further comprises at least one fuel inlet 10 between at least one upper furnace shaft 1 and at least one lower furnace shaft 2. A fuel supply pipe may be connected to ensure fuel charging for the hearth, avoiding charge drag when using fines.

[0022] Preferably, the upper furnace body 1 comprises a set of upper vents 8 and the lower furnace body 2 comprises a set of lower vents 9 for injecting hot or cold air into the metallurgical furnace. The injected air can eventually be enriched with O2. Solid powder, liquid or gaseous fuel can also be injected through the vents to partially burn the fuel, produce gas and provide the heat energy required for reducing and / or melting the charge. If hot air is to be injected into the vents, an injection assembly 11 can also be used, such as Figure 1 As shown, it can be connected to an air heating system (not shown) known in the prior art.

[0023] The metallurgical furnace of the present invention further comprises at least one charging inlet 3 , which is preferably located on the upper side of the upper furnace shaft 1 .

[0024] In addition, the metallurgical furnace of the present invention further comprises a physical structure 5 for internal partitioning of the upper furnace shaft 1, which extends longitudinally downward from the top of the furnace shaft, and the physical structure 5 is suitable for dividing the upper furnace shaft 1 into a central part 6 and a peripheral part 7. Preferably, the physical structure 5 is a curtain wall extending longitudinally from the top of the upper furnace shaft 1 to half of its length, such as Figure 1 and Figure 2 shown.

[0025] Preferably, the physical structure 5 is adapted to receive the permeable fuel from the top to form at least one permeable fuel column located in the central portion 6 .

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

[0027] Preferably, each gas outlet 4 is provided with an adjacent charging inlet 3. Figure 3 In the preferred embodiment shown, the metallurgical furnace of the invention has a set of at least thirty-six charge inlets 3 and gas outlets 4 .

[0028] The use of gas outlets 4 in the metallurgical furnace of the present invention greatly improves its efficiency. This is because the gas outlets 4 allow the hot air from the lower furnace body 2 to flow upwards and also through the peripheral area, thus creating a charge preheating area. These gas outlets help to form new convection in the furnace, thereby improving the efficiency of heat exchange and increasing operating control. This allows the furnace to be operated with a variety of raw materials and fuels. Therefore, the metallurgical furnace of the present invention uses the heat generated inside it more efficiently, thereby reducing the energy demand of the production process.

[0029] The metallurgical furnace of the present invention may be operated with any permeable fuel from the group consisting of:

[0030] anthracite,

[0031] Fuel lumps,

[0032] coal,

[0033] charcoal,

[0034] Metallurgical coke,

[0035] Green petroleum coke,

[0036] Synthesis gas,

[0037] H2.

[0038] The metallurgical furnace of the present invention can be operated with any charge consisting of self-reducing agglomerates produced from iron oxide sources such as steel ore and by-products as well as scrap, scrap agglomerates and HBI (hot briquetted iron).

[0039] The metallurgical furnace of the present invention has flexibility in the control of pressure, temperature and gas mixture in different zones of the furnace, enabling the same plant to be operated with different qualities of ferrous metal and fuel charges.

[0040] It is possible to make many changes within the scope of protection of the present claims. It is further indicated that the present invention is not limited to the above configurations / embodiments.

Claims

1. A metallurgical furnace comprising: at least one upper furnace shaft (1); at least one lower furnace shaft (2); at least one fuel inlet (10) located between at least one upper furnace shaft (1) and at least one lower furnace shaft (2); at least one charging inlet (3) located in at least one upper furnace shaft (1); as well as at least one physical structure (5) for the internal division of the upper furnace shaft (1), which extends longitudinally downward from the top of the furnace shaft, the physical structure (5) being suitable for dividing the upper furnace shaft (1) into a central part (6) and a peripheral part (7), Characterized in that the metallurgical furnace also includes: at least one gas outlet (4) located in the upper part of said peripheral portion (7) of said at least one upper furnace shaft (1) to create a charge preheating zone; Wherein, for each of the at least one gas outlet (4), a charge inlet (3) of the at least one charge inlet (3) is arranged adjacently so that the inserted charge meets the charge preheating area.

2. The metallurgical furnace according to claim 1, characterized in that: The physical structure (5) is adapted to receive a permeable fuel from above in the central portion (6) to form at least one permeable fuel column.

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

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 a self-reducing agglomerate produced from an iron oxide source such as ores and steel by-products, and scrap, scrap agglomerates, and HBI (hot briquetted iron).

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

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

7. The metallurgical furnace according to any one of claims 1 to 6, characterized in that The injection assembly (11) is connected to the ventilation assembly (8, 9) to inject hot air into the metallurgical furnace.

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