LF furnace voltage and current gear parameter determination method capable of reducing power consumption

Abstract

The invention discloses an LF furnace voltage and current gear parameter determination method capable of reducing power consumption. The method comprises the following steps: step 1, determining a selection range of arc current; 2, acquiring circuit resistance r and arc resistance Rarc, and calculating to obtain operation reactance Xop; 3, calculating to obtain an operation resistance Rop and an operation impedance Zop; 4, working current I, active power P, reactive power Q, apparent power S, arc power Parc, electric efficiency eta and temperature rise speed v are obtained through calculation; and fifthly, an electrical characteristic curve is drawn through matalab software, the most economical current and the current with the fastest temperature rising speed are selected, and therefore the power consumption of the LF furnace can be effectively reduced in actual production. The database technology is utilized, the economic current and the current with the fastest heating speed under each voltage gear are obtained, the reasonable power supply system can not only improve the production efficiency, but also reduce the energy consumption and save the energy, and the method has important significance for saving the refining cost, shortening the smelting time, saving energy and reducing emission.

Description

Technical Field

[0001] The invention belongs to the field of LF refining, and in particular is a method for determining voltage and current gear parameters of an LF furnace for reducing power consumption. Background Art

[0002] LF furnace is a commonly used equipment for refining operation in the current steelmaking process. The main cost consumption of LF furnace is electricity consumption, and the formulation of its power supply system is very critical. However, the power supply system used by various factories is relatively simple, and most of them use the set value when the equipment leaves the factory. Many LF furnaces are in a low-efficiency and high-power consumption working point for a long time, lacking the combination of process and electrical professional selection of working points. In the LF furnace smelting process, by analyzing the electrical characteristic curve and formulating a reasonable power supply system, it is beneficial to reduce power consumption, electrode loss and refractory consumption, which is of great significance to shorten the smelting cycle and improve the thermal efficiency of the LF furnace.

[0003] At present, the traditional method of optimizing the power supply system requires experienced professional electrical engineers to manually draw electrical diagrams on coordinate paper based on the electrical characteristic parameters of the LF furnace, and select appropriate working points by analyzing and comparing a large number of electrical diagrams. When the LF furnace has many working gears, the workload of this manual drawing is very large, and the search for the best working point on the coordinate paper is based on experience and lacks quantitative calculation standards. Summary of the invention

[0004] The present invention provides a method for determining voltage and current gear parameters of an LF furnace for reducing power consumption, so as to solve the defects in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption comprises the following steps:

[0007] Step 1: Determine the selection range of arc current;

[0008] Step 2: Obtain the circuit resistance r and arc resistance R arc And calculate the operating reactance X op ;

[0009] Step 3: Calculate the operating resistance R op And the operating impedance Z op ;

[0010] Step 4: Calculate the working current I, active power P, reactive power Q, apparent power S, and arc power P arc , electrical efficiency η and heating rate v;

[0011] Step 5: Use matalab software to draw the electrical characteristic curve and select the most economical current and the fastest heating rate current, so as to effectively reduce the power consumption of the LF furnace in actual production.

[0012] In the above-mentioned method for determining the voltage and current gear parameters of an LF furnace for reducing power consumption, the selection of the arc current in step 1 needs to meet the following conditions:

[0013] (1) The apparent power does not exceed the allowable capacity of the transformer: S ≤ SF;

[0014] (2) The working current does not exceed the allowable current of the transformer: I≤In;

[0015] (3) Stable arc burning: cosΦ range is 0.707-0.86;

[0016] (4) Good power utilization: cosΦ≥0.65, η≥0.90;

[0017] (5) Avoid the peak area of ​​resistant material corrosion index RE.

[0018] As described above, the method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption, the circuit resistance r and the arc resistance R arc is a fixed known value; the operating reactance X op The calculation formula or method is:

[0019] As described above, the method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption, the operating resistor R op The calculation formula is: op =[(cos 2 Φ·X 2 op ) / (1-cos 2 Φ)] 1 / 2 The operating impedance Z op The calculation formula is: op =[(r+R arc ) 2 +X 2 op ] 1 / 2 .

[0020] In the above-mentioned method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption, the calculation formula of the working current I is: I = U / (3 1 / 2 ·Z op ); The calculation formula of active power P is: P = 3I 2 R op ; The calculation formula of reactive power Q is: Q = 3I2 X op ; The calculation formula of apparent power S is: S=(P 2 +Q 2 ) 1 / 2 ; Arc power P arc The calculation formula is: arc =P-3I 2 r; the calculation formula of electrical efficiency η is: η=(P arc / P)·100%.

[0021] In the above-mentioned method for determining the voltage and current gear parameters of an LF furnace for reducing power consumption, the calculation formula of the heating rate v is:

[0022] As described above, a method for determining the voltage and current gear parameters of an LF furnace for reducing power consumption, the most economical current is obtained in the following manner: the active power P and the heating rate v calculated under different working currents I, the active power P of different working currents I divided by the heating rate v, the working current with the smallest corresponding value is the most economical current.

[0023] In the above-mentioned method for determining the voltage and current gear parameters of an LF furnace for reducing power consumption, the working current is selected within the selection range of the arc current determined in step 1, and the most economical current is obtained with 0.1A as the working current selection interval.

[0024] As described above, a method for determining the voltage and current gear parameters of an LF furnace for reducing power consumption, the fastest heating speed current is the arc power P in the electrical characteristic curve. arc The operating current corresponding to the highest value of the curve within the selection range of the arc current is the current with the fastest heating rate.

[0025] The advantages of the present invention are as follows: the present invention utilizes database technology to obtain the economic current and the fastest heating rate current under each voltage level; a reasonable power supply system can not only improve production efficiency and ensure the quality of steel products, but also reduce energy loss and save energy, which is of great significance for saving refining costs, shortening smelting time, and saving energy and reducing emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1is a schematic diagram of a heating circuit of an LF furnace according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of electrical characteristic curve of an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption comprises the following steps:

[0031] Step 1: Determine the selection range of arc current;

[0032] Step 2: Obtain the circuit resistance r and arc resistance R arc And calculate the operating reactance X op ;

[0033] Step 3: Calculate the operating resistance R op And the operating impedance Z op ;

[0034] Step 4: Calculate the working current I, active power P, reactive power Q, apparent power S, and arc power P arc , electrical efficiency η and heating rate v;

[0035] Step 5: Use matalab software to draw the electrical characteristic curve and select the most economical current and the fastest heating rate current, so as to effectively reduce the power consumption of the LF furnace in actual production.

[0036] Specifically, the selection of the arc current in step 1 of this embodiment needs to meet the following conditions:

[0037] (1) The apparent power does not exceed the allowable capacity of the transformer: S ≤ SF;

[0038] (2) The working current does not exceed the allowable current of the transformer: I≤In;

[0039] (3) Stable arc burning: cosΦ range is 0.707-0.86;

[0040] (4) Good power utilization: cosΦ≥0.65, η≥0.90;

[0041] (5) Avoid the peak area of ​​resistant material corrosion index RE.

[0042] Specifically, the circuit resistance r and arc resistance R described in this embodiment are arc is a fixed known value; the operating reactance X op The calculation formula or method is: The actual value of the operating reactance is calculated based on the specific values ​​of reactive power and operating current measured on site.

[0043] More specifically, the operating resistor R op The calculation formula is: op =[(cos 2 Φ·X 2 op ) / (1-cos 2 Φ)] 1 / 2 The operating impedance Z op The calculation formula is: op =[(r+R arc ) 2 +X 2 op ] 1 / 2 .

[0044] More specifically, the calculation formula of the working current I described in this embodiment is: I = U / (3 1 / 2 ·Z op ); The calculation formula of active power P is: P = 3I 2 R op ; The calculation formula of reactive power Q is: Q = 3I 2 X op ; The calculation formula of apparent power S is: S=(P 2 +Q 2 ) 1 / 2 ; Arc power P arc The calculation formula is: arc =P-3I 2 r; the calculation formula of electrical efficiency η is: η=(P arc / P)·100%.

[0045] Furthermore, the calculation formula of the heating rate v described in this embodiment is:

[0046] Furthermore, the method for obtaining the most economical current described in this embodiment is: the active power P and the heating rate v are calculated under different working currents I, and the active power P of different working currents I is divided by the heating rate v. The working current with the smallest corresponding value is the most economical current.

[0047] Furthermore, the working current selection described in this embodiment is within the selection range of the arc current determined in step 1, and the most economical current is obtained with 0.1A as the working current selection interval.

[0048] Furthermore, the fastest heating rate current described in this embodiment is the arc power P in the electrical characteristic curve. arc The operating current corresponding to the highest value of the curve within the selection range of the arc current is the current with the fastest heating rate.

[0049] Example:

[0050] The present invention takes 400V voltage as an example (LF furnace heating circuit as shown in Figure 1 The operation of data verification is as follows:

[0051] Taking the working voltage as 400V, the operating reactance as 3.05mΩ, the operating resistance as 0.24mΩ, and the working current as a variable, the results of calculating various data are shown in Table 1. The electrical characteristic curve is as follows: Figure 2 As shown:

[0052]

[0053] Table 1

[0054] Through Table 1 and Figure 2 It can be seen from the data that the LF furnace voltage and current gear parameter determination method for reducing power consumption of the present invention can quickly and accurately determine the most economical current and the fastest heating rate current. Compared with the traditional F furnace voltage and current gear adjustment method, its power consumption is reduced by 3%, and its refining efficiency is increased by 5%, thereby improving production efficiency and ensuring the quality of steel products. At the same time, it can also reduce energy loss and save energy.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption, characterized in that: The steps include: Step 1: Determine the selection range of arc current; Step 2: Obtain the circuit resistance r and arc resistance R arc And calculate the operating reactance X op ; Step 3: Calculate the operating resistance R op And the operating impedance Z op ; Step 4: Calculate the working current I, active power P, reactive power Q, apparent power S, and arc power P arc , electrical efficiency η and heating rate v; Step 5: Use matalab software to draw the electrical characteristic curve and select the most economical current and the fastest heating rate current, so as to effectively reduce the power consumption of the LF furnace in actual production.

2. The method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption according to claim 1, characterized in that: The selection of arc current in step 1 needs to meet the following conditions: (1) The apparent power does not exceed the allowable capacity of the transformer: S ≤ SF; (2) The working current does not exceed the allowable current of the transformer: I≤In; (3) Stable arc burning: cosΦ range is 0.707-0.86; (4) Good power utilization: cosΦ≥0.65, η≥0.90; (5) Avoid the peak area of ​​resistant material corrosion index RE.

3. The method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption according to claim 1, characterized in that: The circuit resistance r and arc resistance R arc is a fixed known value; the operating reactance X op The calculation formula or method is:

4. The method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption according to claim 1, characterized in that: The operating resistance R op The calculation formula is: op =[(cos 2 Φ·X 2 op ) / (1-cos 2 Φ)] 1 / 2 The operating impedance Z op The calculation formula is: op =[(r+R arc ) 2 +X 2 op ] 1 / 2 .

5. The method for determining the voltage and current gear parameters of a LF furnace for reducing power consumption according to claim 1, characterized in that: The calculation formula of the working current I is: I = U / (3 1 / 2 ·Z op ); The calculation formula of active power P is: P = 3I 2 R op ; The calculation formula of reactive power Q is: Q = 3I 2 X op ; The calculation formula of apparent power S is: S=(P 2 +Q 2 ) 1 / 2 ; Arc power P arc The calculation formula is: arc =P-3I 2 r; the calculation formula of electrical efficiency η is: η=(P arc / P)·100%.

6. A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption according to claim 1, characterized in that: The calculation formula of the heating rate v is:

7. A method for determining voltage and current gear parameters of a LF furnace for reducing power consumption according to claim 1, characterized in that: The most economical current is obtained by calculating the active power P and the heating rate v under different working currents I, dividing the active power P under different working currents I by the heating rate v, and the working current with the smallest corresponding value is the most economical current.

8. A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption according to claim 9, characterized in that: The working current is selected within the selection range of the arc current determined in step 1, and the most economical current is obtained with 0.1A as the working current selection interval.

9. A method for determining voltage and current gear parameters of an LF furnace for reducing power consumption according to claim 1, characterized in that: The fastest heating speed current is the arc power P in the electrical characteristic curve. arc The operating current corresponding to the highest value of the curve within the selection range of the arc current is the current with the fastest heating rate.

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