Multi-circuit variable-current submerged arc furnace and multi-circuit variable-current submerged arc furnace system

Abstract

The present invention provides a multi-circuit variable-current submerged arc furnace and a multi-circuit variable-current submerged arc furnace system, comprising: a variable-current device, a multi-electrode device, a furnace body, a molten bath and an electric furnace transformer; wherein, the electric furnace transformer, the variable-current device, the multi-electrode device and the molten bath are connected in sequence; the molten bath is a space inside the furnace body for containing furnace charge; the electric furnace transformer is used to transmit power-frequency electric energy to the variable-current device; the variable-current device is used to convert the power-frequency electric energy into electric energy with a frequency of 0 Hz - 20 Hz and then transmit it to the molten bath through the multi-electrode device, so as to establish a plurality of current circuits between the variable-current device, through the multi-electrode device and the molten bath, and smelt the furnace charge in the molten bath. The present invention can improve the drawbacks of the existing submerged arc furnace and improve the adaptability and versatility of the submerged arc furnace smelting.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical engineering, and particularly to a multi-circuit variable-current submerged arc furnace and a multi-circuit variable-current submerged arc furnace system. Background Art

[0002] Submerged arc furnaces are mainly used for reducing and smelting ores, carbonaceous reducing agents, solvents and other raw materials, and are important equipment in the metallurgical industry. At present, there are three types of submerged arc furnaces: AC submerged arc furnaces powered by three-phase industrial frequency, submerged arc furnaces powered by bottomless electrodes with direct current, and submerged arc furnaces powered by three-phase low frequency. However, the AC submerged arc furnace powered by three-phase industrial frequency has the disadvantages of high reactance of the conductive circuit, large eddy current loss of the ferromagnetic components of the electric furnace, difficulty in inputting electric energy into the molten pool of the electric furnace, serious skin effect leading to a decrease in the current-carrying capacity of the line and a reduction in the power consumption efficiency of the system, high number of times of repeated ignition and extinction of the arc resulting in large consumption of electrode breakage, low natural power factor of the system, high ore consumption per ton of product and high power consumption per ton of product; when producing certain products, the submerged arc furnace powered by bottomless electrodes with direct current shows an anode effect, resulting in uneven distribution of the heat source in the molten pool; the submerged arc furnace powered by three-phase low frequency has the problem of operating with ultra-low frequency electric energy, which easily causes long-term uneven distribution of the electrothermal source in the molten pool and affects the orderly progress of the electrothermal chemical reduction reaction of the furnace charge. Therefore, the existing submerged arc furnaces have various disadvantages, and their industrial applicability and versatility are poor. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a multi-circuit variable-current submerged arc furnace and a multi-circuit variable-current submerged arc furnace system to improve the disadvantages of the existing submerged arc furnaces and improve the adaptability and versatility of submerged arc furnace smelting.

[0004] To achieve the above purpose, the technical solutions adopted in the embodiments of the present invention are as follows:

[0005] In the first aspect, the embodiments of the present invention provide a multi-circuit variable-current submerged arc furnace, including: a variable-current device, a multi-electrode device, a furnace body, a molten pool and an electric furnace transformer; wherein, the electric furnace transformer, the variable-current device, the multi-electrode device and the molten pool are connected in sequence; the molten pool is a space inside the furnace body for containing furnace charge; the electric furnace transformer is used to deliver industrial frequency electric energy to the variable-current device; the variable-current device is used to convert the industrial frequency electric energy into electric energy with a frequency of 0 Hz - 20 Hz and then deliver it to the molten pool through the multi-electrode device, so as to establish multiple current circuits between the variable-current device and the molten pool through the multi-electrode device, and smelt the furnace charge in the molten pool.

[0006] In an embodiment, the variable-current device includes a plurality of current converters; wherein, the number of current circuits output by the variable-current device is the same as the number of current converters.

[0007] In an embodiment, the number of electrodes provided in the multi-electrode device is an even number greater than 2, and the number of electrodes is the same as the number of current converters.

[0008] In one embodiment, each converter includes a first output terminal and a second output terminal, and the first output terminal and the second output terminal are connected to the multi-electrode device; wherein, the output voltage between the first output terminal and the second output terminal of each converter has the characteristics of the same frequency, the same phase, and the same amplitude.

[0009] In one embodiment, each electrode is connected to the first output terminals of two converters or the second output terminals of two converters; the distance between each electrode and the adjacent electrode with the opposite current phase is the same.

[0010] In one embodiment, the multi-electrode device includes four electrodes; the four electrodes are arranged in a square or parallelogram layout; wherein, the parallelogram is composed of two identical equilateral triangles.

[0011] In one embodiment, the number of electrodes in the multi-electrode device is an even number greater than 4, and the electrodes are arranged in a rectangular layout; wherein, the rectangle is composed of multiple identical isosceles triangles, and each electrode is located at the vertex of the isosceles triangle.

[0012] In one embodiment, the electrodes are arranged in a parallelogram layout; wherein, the parallelogram is composed of multiple identical equilateral triangles, and each electrode is located at the vertex of the equilateral triangle.

[0013] In one embodiment, the electrodes are arranged in an equilateral triangle layout; wherein, each electrode is located at the vertex and the midpoint of each side of the equilateral triangle.

[0014] In a second aspect, the embodiment of the present invention provides a multi-circuit variable-current submerged arc furnace system, which includes the multi-circuit variable-current submerged arc furnace according to any one of the above first aspects, and further includes an external power source connected to the multi-circuit variable-current submerged arc furnace.

[0015] The embodiments of the present invention bring the following beneficial effects:

[0016] The above-mentioned multi-circuit variable-current submerged arc furnace and multi-circuit variable-current submerged arc furnace system provided by the embodiments of the present invention include: a variable-current device, a multi-electrode device, a furnace body, a molten pool, and an electric furnace transformer; wherein, the electric furnace transformer, the variable-current device, the multi-electrode device, and the molten pool are connected in sequence; the molten pool is a space inside the furnace body for containing furnace charge; the electric furnace transformer is used to deliver power-frequency electric energy to the variable-current device; the variable-current device is used to convert the power-frequency electric energy into electric energy with a frequency of 0 Hz - 20 Hz and then deliver it to the molten pool through the multi-electrode device, so as to establish multiple current circuits between the variable-current device, the multi-electrode device, and the molten pool, and smelt the furnace charge in the molten pool. The variable-current device of the above-mentioned multi-circuit variable-current submerged arc furnace can continuously output within each half cycle, and the electric power obtained by each equivalent load of the molten pool remains basically unchanged within each half cycle, thus being able to avoid the drawbacks of power-frequency power supply; at the same time, since the electrodes of the multi-electrode device can be polarity-swapped within a certain period of time, it can improve the problems of the appearance of the anode effect when smelting some products in the submerged arc furnace and the operation with ultra-low-frequency electric energy, enabling the molten pool to obtain a uniformly distributed electric heat source, promoting the orderly and stable progress of the electro-thermal chemical reaction of the furnace charge, and thus improving the adaptability and versatility of the submerged arc furnace smelting.

[0017] Other features and advantages of the present invention will be described in the subsequent description, and part of them will become obvious from the description, or be understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the description, claims, and drawings.

[0018] To make the above-mentioned objectives, features, and advantages of the present invention more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of a multi-circuit variable-current submerged arc furnace provided by an embodiment of the present invention;

[0021] Figure 2 It is a planar layout structure diagram of four electrodes in a multi-electrode device provided by an embodiment of the present invention;

[0022] Figure 3 It is a planar layout structure diagram of six electrodes in a multi-electrode device provided by an embodiment of the present invention;

[0023] Figure 4The planar structure diagram of a multi-circuit variable-current submerged arc furnace with four electrodes provided by an embodiment of the present invention;

[0024] Figure 5 The equivalent circuit schematic diagram of a multi-circuit variable-current submerged arc furnace with four electrodes provided by an embodiment of the present invention;

[0025] Figure 6 The waveform schematic diagram of voltage and current in the equivalent circuit of a multi-circuit variable-current submerged arc furnace provided by an embodiment of the present invention;

[0026] Figure 7 The planar structure diagram of a multi-circuit variable-current submerged arc furnace with six electrodes provided by an embodiment of the present invention;

[0027] Figure 8 The equivalent circuit schematic diagram of a multi-circuit variable-current submerged arc furnace with six electrodes provided by an embodiment of the present invention;

[0028] Figure 9 The circuit principle schematic diagram of an existing three-phase low-frequency submerged arc furnace provided by an embodiment of the present invention;

[0029] Figure 10 The structure schematic diagram of a multi-circuit variable-current submerged arc furnace system provided by an embodiment of the present invention.

[0030] Icon:

[0031] 10 - Converter equipment; 20 - Multi-electrode device; 30 - Furnace body; 40 - Bath; 50 - Electric furnace transformer; 101 - 1# converter; 102 - 2# converter; 103 - 3# converter; 104 - 4# converter; 105 - 5# converter; 106 - 6# converter; 501 - 1# electric furnace transformer; 502 - 2# electric furnace transformer; 503 - 3# electric furnace transformer; 504 - 4# electric furnace transformer; 505 - 5# electric furnace transformer; 506 - 6# electric furnace transformer; 201 - 1-phase electrode; 202 - 2-phase electrode; 203 - 3-phase electrode; 204 - 4-phase electrode; 205 - 5-phase electrode; 206 - 6-phase electrode; 100 - Multi-circuit variable-current submerged arc furnace; 200 - External power supply. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] At present, there are three types of submerged arc furnaces: AC submerged arc furnaces powered by three-phase power frequency, submerged arc furnaces powered by bottomless electrodes with direct current, and submerged arc furnaces powered by three-phase low frequency. AC submerged arc furnaces powered by three-phase power frequency are widely used. They have the characteristics of low voltage and large current load, high reactance of the conductive circuit, large eddy current loss in the ferromagnetic components of the electric furnace, difficulty in inputting electric energy into the molten pool of the electric furnace, serious skin effect, which leads to a decrease in the current-carrying capacity of the line and a reduction in the power consumption efficiency of the system, high frequency of repeated ignition and extinction of the arc, resulting in large consumption of electrode breakage, low natural power factor of the system, large ore consumption per ton of product and high power consumption per ton of product, etc.; Submerged arc furnaces powered by bottomless electrodes with direct current are less used. Because the molten pool load structure of the submerged arc furnace is not the same when smelting each product is not considered, it is easy to cause the appearance of anode effect and uneven distribution of the heat source in the molten pool, restricting its industrial operation adaptability and versatility; Submerged arc furnaces powered by three-phase low frequency are also less used. They do not have very obvious technical advantages compared with power frequency submerged arc furnaces. The best operating effect is achieved when the working frequency is around 5Hz - 10HZ. The reactance of the conductive circuit is reduced by 5 to 10 times compared with power frequency power supply. The output line voltage of the three-phase low frequency power supply is a square wave. To prevent current short-circuit between the three-phase power loops, two 1 / 6 cycle no-output times are set in each cycle of the three-phase line voltage. When the system operates at ultra-low frequency, there will be a large difference in the electric power obtained by each equivalent load in the molten pool for a long time, resulting in uneven distribution of the electrothermal source in the molten pool for a long time, affecting the orderly progress of the electrothermal chemical reduction reaction of the furnace charge, and restricting the technical advantages brought by using ultra-low frequency electric energy.

[0034] Based on this, a multi-circuit variable current submerged arc furnace and a multi-circuit variable current submerged arc furnace system provided by an embodiment of the present invention are used to improve the disadvantages of existing submerged arc furnaces and improve the adaptability and versatility of submerged arc furnace smelting.

[0035] For the convenience of understanding this embodiment, first, a method of a multi-circuit variable current submerged arc furnace disclosed in an embodiment of the present invention will be introduced in detail. See Figure 1 As shown in the structural schematic diagram of a multi-circuit variable current submerged arc furnace, it is shown that the multi-circuit variable current submerged arc furnace includes: a variable current device 10, a multi-electrode device 20, a furnace body 30, a molten pool 40, and an electric furnace transformer 50; among them, the electric furnace transformer 50, the variable current device 10, the multi-electrode device 20, and the molten pool 40 are connected in sequence; the molten pool 40 is a space inside the furnace body 30 for containing furnace charge; the electric furnace transformer 50 is used to transmit power frequency electric energy to the variable current device 10; the variable current device 10 is used to convert the power frequency electric energy into electric energy with a frequency of 0Hz - 20Hz and then transmit it to the molten pool 40 through the multi-electrode device 20, so as to establish multiple current loops between the variable current device and the molten pool 40 through the multi-electrode device 20, and smelt the furnace charge in the molten pool 40.

[0036] In one embodiment, the electric furnace transformer 50 is connected to the current conversion device 10. The current conversion device 10 is connected between the electric furnace transformer 50 and the multi-electrode device 20, and the multi-electrode device 20 is connected between the current conversion device 10 and the molten bath 40; the furnace body 30 is a container capable of containing hot furnace charge, and the molten bath 40 is the space in the furnace body 30 for containing hot furnace charge; the electric furnace transformer 50 is used to supply industrial frequency electric energy of 50 Hz - 60 Hz to the current conversion device 10 after being powered on. The current conversion device 10 is used to convert the input industrial frequency electric energy into 0 Hz - 20 Hz electric energy with a multi-channel output function, and then convey it to the molten bath 40 through the multi-electrode device 20; the current conversion device 10 establishes multiple current loops with the molten bath 40 through the multi-electrode device 20, and generates arc heat and resistance heat in the molten bath 40 to smelt the furnace charge in the molten bath 40.

[0037] The above multi-loop current conversion submerged arc furnace provided by the embodiment of the present invention includes: a current conversion device, a multi-electrode device, a furnace body, a molten bath, and an electric furnace transformer; the current conversion device can continuously output in each half cycle, and the electric power obtained by each equivalent load of the molten bath is basically unchanged in each half cycle, so as to avoid the disadvantages of industrial frequency power supply; at the same time, since the electrodes of the multi-electrode device can be polarity-interchanged within a certain time, it can improve the problems of the appearance of anode effect when smelting some products in the submerged arc furnace and the operation with ultra-low frequency electric energy, so that the molten bath obtains a uniformly distributed electric heat source, promotes the orderly and stable progress of the electro-thermal chemical reaction of the furnace charge, and thus improves the adaptability and versatility of the submerged arc furnace smelting.

[0038] Further, the current conversion device includes a plurality of current converters; wherein, the number of current loops output by the current conversion device is the same as the number of current converters; each current converter is a single-phase output, and each current converter includes a first output terminal and a second output terminal, and the first output terminal and the second output terminal are connected to the multi-electrode device; wherein, the output voltage between the first output terminal and the second output terminal of each current converter has the characteristics of the same frequency, the same phase, and the same amplitude.

[0039] The number of electrodes provided in the multi-electrode device is an even number greater than 2, and the number of electrodes is the same as the number of current converters. The electrodes can be high-temperature resistant carbon electrodes. Specifically, the first output terminal and the second output terminal of each current converter are connected to two electrodes of the multi-electrode device, forming a current loop with the molten bath; each electrode of the multi-electrode device is connected to the first output terminals of two current converters or the second output terminals of two current converters; the distance between each electrode and the adjacent electrode with the opposite current phase is the same. At the same time, each electrode is associated with the loop currents of the two connected current converters, and the number of electrodes connected to the first output terminal of the current converter is the same as the number of electrodes connected to the second output terminal.

[0040] In the embodiment of the present invention, the number of electrodes set in the multi-electrode device is an even number greater than 2. For ease of understanding, taking four electrodes as an example, the embodiment of the present invention provides a planar layout structure diagram of four electrodes in the multi-electrode device, see Figure 2 As shown, the four electrodes are arranged in a square or parallelogram; for details, see Figure 2 As shown in part (a) of FIG. 1 , the center points of the four electrodes are connected to form a square plane layout, or see Figure 2 As shown in part (b), the lines connecting the center points of the four electrodes form a parallelogram plane layout, where the parallelogram is composed of two identical equilateral triangles.

[0041] Furthermore, when the number of electrodes in the multi-electrode device is an even number greater than 4, the electrodes are arranged in a rectangular shape; wherein the rectangle is composed of a plurality of identical isosceles triangles, and each electrode is located at a vertex of the isosceles triangle; or the electrodes are arranged in a parallelogram shape; wherein the parallelogram is composed of a plurality of identical equilateral triangles, and each electrode is located at a vertex of the equilateral triangle; or the electrodes are arranged in an equilateral triangle shape; wherein each electrode is located at a vertex of the equilateral triangle and at the midpoint of each side.

[0042] Taking six electrodes as an example, an embodiment of the present invention provides a planar layout structure diagram of six electrodes in a multi-electrode device, see Figure 3 As shown, the six electrodes can be arranged in a rectangular shape, a parallelogram shape, or an equilateral triangle shape. Figure 3 As shown in part (a) of FIG. 1 , the lines connecting the center points of the six electrodes form a rectangular plane layout, and the rectangle is composed of a plurality of isosceles triangles, and each electrode is located at the vertex of the isosceles triangle; see FIG. Figure 3 As shown in part (b), the lines connecting the center points of the six electrodes form a parallelogram plane layout, and the parallelogram is composed of two equilateral triangles, and each electrode is located at the vertex of the equilateral triangle; see Figure 3 As shown in part (c), the lines connecting the center points of the six electrodes form an equilateral triangle plane layout, and each electrode is located at the vertex of the equilateral triangle and the midpoint of each side. Through the reasonable connection of the above electrode layout and the converter equipment, each electrode can establish a uniformly distributed molten pool load heating source when inserted into the molten pool, promote the orderly and stable electrothermal chemical reaction of the charge, thereby improving the adaptability and versatility of the smelting of the submerged arc furnace.

[0043] For ease of understanding, the present invention also provides a plan view of a multi-circuit variable current ore furnace with four electrodes, see Figure 4As shown in the figure, a multi-circuit converter submerged arc furnace is schematically shown to include: Converter 101, Converter 102, Converter 103, Converter 104, Electric furnace transformer 501, Electric furnace transformer 502, Electric furnace transformer 503, Electric furnace transformer 504, Phase 1 electrode 201, Phase 2 electrode 202, Phase 3 electrode 203, and Phase 4 electrode 204. Among them, Converter 101 includes output terminal A1 (the first output terminal) and output terminal B1 (the second output terminal), Converter 102 includes output terminal A2 and output terminal B2, Converter 103 includes output terminal A3 and output terminal B3, Converter 104 includes output terminal A4 and output terminal B4, and the output voltages U A1B1 、U A2B2 、U A3B3 、U A4B4 of the four converters have the output characteristics of the same frequency, the same phase, and the same amplitude. The connecting lines of the center points of Phase 1 electrode 201, Phase 2 electrode 202, Phase 3 electrode 203, and Phase 4 electrode 204 form a square planar layout, and the molten bath load is the arc resistance and the charge resistance in the molten bath.

[0044] As Figure 4 shown, Electric furnace transformer 501 is connected to Converter 101, Electric furnace transformer 502 is connected to Converter 102, Electric furnace transformer 503 is connected to Converter 103, and Electric furnace transformer 504 is connected to Converter 104. Phase 1 electrode 201 is respectively connected to output terminal A1 of Converter 101 and output terminal A4 of Converter 104, and Phase 2 electrode 202 is respectively connected to output terminal B1 of Converter 101 and output terminal B2 of Converter 102. Phase 3 electrode 203 is respectively connected to output terminal A2 of Converter 102 and output terminal A3 of Converter 103, and Phase 4 electrode 204 is respectively connected to output terminal B3 of Converter 103 and output terminal B4 of Converter 104.

[0045] Furthermore, referring to Figure 5The equivalent circuit schematic diagram of a multi-circuit variable-current submerged arc furnace with four electrodes is shown. The output terminal A1 of the 1# converter 101 is connected to the 1-phase electrode 201, and the output terminal B1 is connected to the 2-phase electrode 202. The 1# converter 101 and the bath load form a loop current i1. The output terminal A2 of the 2# converter 102 is connected to the 3-phase electrode 203, and the output terminal B2 is connected to the 2-phase electrode 202. The 2# converter 102 and the bath load form a loop current i2. The output terminal A3 of the 3# converter 103 is connected to the 3-phase electrode 203, and the output terminal B3 is connected to the 4-phase electrode 204. The 3# converter 103 and the bath load form a loop current i3. The output terminal A4 of the 4# converter 104 is connected to the 1-phase electrode 201, and the output terminal B4 is connected to the 4-phase electrode 204. The 4# converter 104 and the bath load form a loop current i4.

[0046] The 1-phase electrode 201 is connected to the output terminal A1 of the 1# converter 101 and the output terminal A4 of the 4# converter 104. This electrode is associated with two loop currents, i1 and i4, and has the same distance from the adjacent 2-phase electrode 202 and 4-phase electrode 204 with opposite current phases.

[0047] The 2-phase electrode 202 is connected to the output terminal B1 of the 1# converter 101 and the output terminal B2 of the 2# converter 102. This electrode is associated with two loop currents, i1 and i2, and has the same distance from the adjacent 1-phase electrode 201 and 3-phase electrode 203 with opposite current phases.

[0048] The 3-phase electrode 203 is connected to the output terminal A2 of the 2# converter 102 and the output terminal A3 of the 3# converter 103. This electrode is associated with two loop currents, i2 and i3, and has the same distance from the adjacent 2-phase electrode 202 and 4-phase electrode 204 with opposite current phases.

[0049] The 4-phase electrode 204 is connected to the output terminal B3 of the 3# converter 103 and the output terminal B4 of the 4# converter 104. This electrode is associated with two loop currents, i3 and i4, and has the same distance from the adjacent 3-phase electrode 203 and 1-phase electrode 201 with opposite current phases.

[0050] For the above-mentioned multi-circuit variable-current submerged arc furnace with four electrodes, refer to Figure 6 The schematic diagram of the voltage and current waveforms in the equivalent circuit of a multi-circuit variable-current submerged arc furnace shown. The four converters of the variable-current equipment have uninterrupted output in each half electrical cycle. The loop voltage drop U A1B1 +U B2A2 +U A3B3 +U B4A4= 0, and there is no current short - circuit phenomenon among the four converter loops; when the multi - loop converter submerged - arc furnace operates with 0Hz electric energy, with the loads in the molten bath remaining unchanged, the electric power obtained by each load in the molten bath remains unchanged at any time; when the multi - loop converter submerged - arc furnace operates with ultra - low - frequency electric energy, with the loads in the molten bath remaining unchanged, the electric power obtained by each load in the molten bath remains unchanged every half - electric - cycle time. Thus, it can improve the drawbacks of the existing submerged - arc furnace, enabling the molten bath to obtain a uniformly distributed electro - thermal source, promoting the orderly and stable progress of the electro - thermal chemical reaction of the furnace charge, and enhancing the adaptability and versatility of the submerged - arc furnace smelting.

[0051] The embodiment of the present invention also provides a planar structure diagram of a multi - loop converter submerged - arc furnace with six electrodes. Refer to Figure 7 As shown, it shows that the multi - loop converter submerged - arc furnace includes: 1# converter 101, 2# converter 102, 3# converter 103, 4# converter 104, 5# converter 105, 6# converter 106, 1# electric furnace transformer 501, 2# electric furnace transformer 502, 3# electric furnace transformer 503, 4# electric furnace transformer 504, 5# electric furnace transformer 505, 6# electric furnace transformer 506, 1 - phase electrode 201, 2 - phase electrode 202, 3 - phase electrode 203, 4 - phase electrode 204, 5 - phase electrode 205, and 6 - phase electrode 206; among them, 1# converter 101 includes output terminal A1 and output terminal B1, 2# converter 102 includes output terminal A2 and output terminal B2, 3# converter 103 includes output terminal A3 and output terminal B3, 4# converter 104 includes output terminal A4 and output terminal B4, 5# converter 105 includes output terminal A5 and output terminal B5, 6# converter 106 includes output terminal A6 and output terminal B6, and the output voltages U A1B1 、U A2B2 、U A3B3 、U A4B4 、U A5B5 、U A6B6 of the four converters have the output characteristics of the same frequency, the same phase, and the same amplitude. The connecting lines of the center points of the 1 - phase electrode 201, 2 - phase electrode 202, 3 - phase electrode 203, 4 - phase electrode 204, 5 - phase electrode 205, and 6 - phase electrode 206 form a rectangular planar layout composed of multiple isosceles triangles, and the molten - bath load is the arc resistance and the charge resistance in the molten bath.

[0052] As Figure 7 shown, 1# electric furnace transformer 501 is connected to 1# converter 101, 2# electric furnace transformer 502 is connected to 2# converter 102, 3# electric furnace transformer 503 is connected to 3# converter 103, 4# electric furnace transformer 504 is connected to 4# converter 104, 5# electric furnace transformer 505 is connected to 5# converter 105, and 6# electric furnace transformer 506 is connected to 6# converter 106.

[0053] Further, referring to Figure 8 the equivalent circuit schematic diagram of a multi-circuit current-converting submerged arc furnace with six electrodes as shown. The output terminal A1 of the 1# converter 101 is connected to the 1-phase electrode 201, and the output terminal B1 is connected to the 2-phase electrode 202. The 1# converter 101 and the bath load form a loop current i1; the output terminal B2 of the 2# converter 102 is connected to the 2-phase electrode 202, and the output terminal A2 is connected to the 3-phase electrode 203. The 2# converter 102 and the bath load form a loop current i2; the output terminal A3 of the 3# converter 103 is connected to the 3-phase electrode 203, and the output terminal B3 is connected to the 4-phase electrode 204. The 3# converter 103 and the bath load form a loop current i3; the output terminal B4 of the 4# converter 104 is connected to the 4-phase electrode 204, and the output terminal A4 is connected to the 5-phase electrode 205. The 4# converter 104 and the bath load form a loop current i4; the output terminal A5 of the 5# converter 105 is connected to the 5-phase electrode 205, and the output terminal B5 is connected to the 6-phase electrode 206. The 5# converter 105 and the bath load form a loop current i5; the output terminal B6 of the 6# converter 106 is connected to the 6-phase electrode 206, and the output terminal A6 is connected to the 1-phase electrode 201. The 6# converter 106 and the bath load form a loop current i6.

[0054] The 1-phase electrode 201 is connected to the output terminal A6 of the 6# converter 106 and the output terminal A1 of the 1# converter 101. This electrode is associated with two loop currents, i6 and i1, and has the same distance from the adjacent 6-phase electrode 206 and 2-phase electrode 202 with opposite current phases.

[0055] The 2-phase electrode 202 is connected to the output terminal B1 of the 1# converter 101 and the output terminal B2 of the 2# converter 102. This electrode is associated with two loop currents, i1 and i2, and has the same distance from the adjacent 1-phase electrode 201, 3-phase electrode 203, and 5-phase electrode 205 with opposite current phases.

[0056] The 3-phase electrode 203 is connected to the output terminal A2 of the 2# converter 102 and the output terminal A3 of the 3# converter 103. This electrode is associated with two loop currents, i2 and i3, and has the same distance from the adjacent 2-phase electrode 202 and 4-phase electrode 204 with opposite current phases.

[0057] The 4-phase electrode 204 is connected to the output terminal B3 of the 3# converter 103 and the output terminal B4 of the 4# converter 104. This electrode is associated with two loop currents, i3 and i4, and has the same distance from the adjacent 3-phase electrode 203 and 5-phase electrode 205 with opposite current phases.

[0058] The 5-phase electrode 205 is connected to the output terminal A4 of the 4# converter 104 and the output terminal A5 of the 5# converter 105. This electrode is associated with two loop currents i4 and i5, and has the same distance from the adjacent 4-phase electrode 204, 2-phase electrode 202, and 6-phase electrode 206 with opposite current phases.

[0059] The 6-phase electrode 206 is connected to the output terminal B5 of the 5# converter 105 and the output terminal B6 of the 6# converter 106. This electrode is associated with two loop currents i5 and i6, and has the same distance from the adjacent 5-phase electrode 205 and 1-phase electrode 201 with opposite current phases.

[0060] For the above multi-loop converter submerged arc furnace with six electrodes, the six converters of the converter equipment have uninterrupted output in each half electrical cycle, and the loop voltage drops U A1B1 +U B2A2 +U A3B3 +U B4A4 +U A5B5 +U B6A6 = 0, and there is no current short circuit phenomenon between the six converter loops; when the multi-loop converter submerged arc furnace operates with 0Hz electric energy, with the loads in the molten pool remaining unchanged, the electric power obtained by each load in the molten pool remains unchanged at any time; when the multi-loop converter submerged arc furnace operates with ultra-low frequency electric energy, with the loads in the molten pool remaining unchanged, the electric power obtained by each load in the molten pool remains unchanged in each half electrical cycle time, thereby being able to improve the drawbacks of the existing submerged arc furnace, enabling the molten pool to obtain a uniformly distributed electric heat source, promoting the orderly and stable progress of the electrothermal chemical reaction of the furnace charge, and improving the adaptability and versatility of the submerged arc furnace smelting.

[0061] In summary, when the multi-loop converter submerged arc furnace provided by the embodiment of the present invention operates with ultra-low frequency electric energy, it can avoid various weaknesses of the existing submerged arc furnace using power frequency electric energy, avoid the weaknesses of the existing three-phase low-frequency submerged arc furnace using ultra-low frequency electric energy, and avoid the weaknesses of the existing bottomless electrode DC submerged arc furnace showing anode effects when producing certain products, enabling the molten pool to obtain a uniformly distributed electric heat source and promoting the orderly and stable progress of the electrothermal chemical reaction of the furnace charge; when the multi-loop converter submerged arc furnace provided by the embodiment of the present invention operates with 0Hz electric energy, it can smelt some products without showing anode effects; in addition, the present invention can improve the smelting technical indexes of the submerged arc furnace production, and at the same time has good adaptability and versatility in submerged arc furnace smelting, improving the actual industrial operation value of the submerged arc furnace.

[0062] In addition, referring to Figure 9The following is a schematic diagram of the circuit principle of an existing three-phase low-frequency submerged arc furnace. The line voltage output by the three-phase low-frequency power supply is a square wave. To prevent current short circuits between the three-phase power loops, two 1 / 6-cycle no-output times are set in each cycle of the three-phase line voltage. When the system operates at ultra-low frequency, there will be a large difference in the electric power obtained by each equivalent load in the molten bath for a long time. Compared with the prior art, see Figure 6 As shown, the current conversion device provided by the present invention can continuously output in each half cycle, and the electric power obtained by each equivalent load in the molten bath is basically unchanged in each half cycle, thereby being able to avoid the disadvantages of power frequency power supply.

[0063] For the aforementioned multi-loop current conversion submerged arc furnace, the embodiment of the present invention also provides a multi-loop current conversion submerged arc furnace system. See Figure 10 The following is a schematic diagram of the structure of a multi-loop current conversion submerged arc furnace system, showing that the system includes: a multi-loop current conversion submerged arc furnace 100, and also includes an external power supply 200 connected to the multi-loop current conversion submerged arc furnace 100.

[0064] In the multi-loop current conversion submerged arc furnace system provided by the embodiment of the present invention, the current conversion device of the multi-loop current conversion submerged arc furnace can continuously output in each half cycle, and the electric power obtained by each equivalent load in the molten bath is basically unchanged in each half cycle, thereby being able to avoid the disadvantages of power frequency power supply; at the same time, since the electrodes of the multi-electrode device can be polarity-swapped within a certain time, it is possible to improve the problems of the appearance of the anode effect when smelting some products in the submerged arc furnace and the operation with ultra-low frequency electric energy, so that the molten bath obtains a uniformly distributed electric heat source, promotes the orderly and stable progress of the electrothermal chemical reaction of the furnace charge, and thus improves the adaptability and versatility of the submerged arc furnace smelting.

[0065] In all the examples shown and described here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0066] In addition, in the description of the embodiments of the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. The terms "A" and "B" are only used to describe and distinguish the two output terminals of each converter. The terms "A1", "A2", "A3", "A4", "A5", "A6" are only used to describe and distinguish the output terminal A of each converter. The terms "B1", "B2", "B3", "B4", "B5", "B6" are only used to describe and distinguish the output terminal B of each converter. Therefore, it should not be construed as a limitation to the present application.

[0067] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions recorded in the foregoing embodiments or easily conceive of changes, or equivalently replace some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A multi-circuit variable-current submerged arc furnace, characterized in that, Comprising: A current conversion device, a multi-electrode device, a furnace body, a molten bath, and an electric furnace transformer; wherein, the electric furnace transformer, the current conversion device, the multi-electrode device, and the molten bath are connected in sequence; the molten bath is a space inside the furnace body for containing furnace charge. The electric furnace transformer is used to transmit power frequency electric energy to the current conversion device. The current conversion device is used to convert the power frequency electric energy into electric energy with a frequency of 0Hz - 20Hz and then transmit it to the molten bath through the multi-electrode device, so as to establish a plurality of current loops between the current conversion device and the molten bath through the multi-electrode device, and smelt the furnace charge in the molten bath. The current conversion device includes a plurality of current converters; the number of electrodes provided in the multi-electrode device is an even number greater than 2, and the number of electrodes is the same as the number of current converters; each current converter includes a first output terminal and a second output terminal, and the first output terminal and the second output terminal are connected to the multi-electrode device; wherein, the output voltage between the first output terminal and the second output terminal of each current converter has the characteristics of the same frequency, the same phase, and the same amplitude; the distance between each electrode and the adjacent electrode with the opposite current phase is the same.

2. The multi-circuit variable-current submerged arc furnace according to claim 1, wherein The number of current loops output by the current conversion device is the same as the number of current converters.

3. The multi-circuit variable-current submerged arc furnace according to claim 1, characterized in that, Each electrode is connected to the first output terminals of two current converters or the second output terminals of two current converters.

4. The multi-loop variable-current submerged arc furnace according to claim 3, wherein The multi-electrode device includes four electrodes. The four electrodes are arranged in a square or parallelogram layout; wherein, the parallelogram is composed of two identical equilateral triangles.

5. The multi-circuit variable-current submerged arc furnace according to claim 3, characterized in that, The number of electrodes in the multi-electrode device is an even number greater than 4, and the electrodes are arranged in a rectangular layout; wherein, the rectangle is composed of a plurality of identical isosceles triangles, and each electrode is located at the vertex of the isosceles triangle.

6. The multi-circuit variable-current submerged arc furnace according to claim 5, wherein The electrodes are arranged in a parallelogram layout; wherein, the parallelogram is composed of a plurality of identical equilateral triangles, and each electrode is located at the vertex of the equilateral triangle.

7. The multi-circuit variable-current submerged arc furnace according to claim 5, wherein, The electrodes are arranged in an equilateral triangle layout; wherein, each electrode is located at the vertex and the midpoint of each side of the equilateral triangle.

8. A multi-circuit variable-current submerged arc furnace system, characterized in that, Comprising the multi-loop current conversion submerged arc furnace according to any one of claims 1 to 7, and further comprising an external power source connected to the multi-loop current conversion submerged arc furnace.

Images