A method for reducing power consumption in LF refining production stage

Abstract

The present invention relates to a method for reducing power consumption in the LF refining production stage, and belongs to the technical field of LF refining production methods and devices. The technical solution of the present invention is: based on the existing electrical characteristic parameters of the LF refining furnace power supply equipment, the characterization power, useful power and useless power corresponding to different currents under the relevant gear voltage are cyclically calculated, and then a linear search is performed to obtain the set current corresponding to the maximum ratio of the corresponding useful work to the characterization power. Finally, the automatic adjustment of the set current at the production site is realized by a computer. The beneficial effect of the present invention is: it realizes the optimal matching of the unit voltage and the set current in the LF refining production process. Thereby, it is ensured that the characterization power is lowest while meeting the production requirements, and the energy consumption is reduced to the greatest extent, so as to achieve the purpose of green and energy-saving production of LF refining.

Description

Technical Field

[0001] The invention relates to a method for reducing power consumption in LF refining production stages, belonging to the technical field of LF refining production methods and devices. Background Art

[0002] In recent years, from both economic and social perspectives, people have increasingly demanded green and energy-saving production in the steelmaking field.

[0003] LF refining furnaces are crucial equipment in the steelmaking process and a major consumer of electricity. Vast quantities of electricity are consumed annually during the LF refining process. Therefore, how to meet on-site production needs, ensuring the production of qualified molten steel in a short period of time while also reducing power consumption and achieving energy conservation, emission reduction, cost reduction, and efficiency improvement is the future direction of LF refining power supply development and a challenging challenge facing process technicians.

[0004] Generally, the power consumption of AC equipment is mainly reflected by the following technical indicators:

[0005] (1) “Representative power” refers to the product of voltage and current in a circuit with resistance and reactance. This indicator is the most important indicator used by the market to measure the amount of electricity consumption in steel companies. Therefore, effectively reducing electricity consumption actually means reducing the amount of representative power per unit time.

[0006] (2) “Useful power” refers to the AC energy actually generated or consumed per unit time, which is the average power within a cycle. This indicator is the most important indicator for measuring the actual production effect at the LF refining production site.

[0007] (3) "Useless power": This refers to the situation in an AC circuit with reactance where the electric or magnetic field absorbs energy from the power supply during part of a cycle and releases energy during another part. The average power over the entire cycle is zero, but energy is constantly exchanged between the power supply and the reactance components (capacitors and inductors) and consumed. Therefore, this indicator is the most important indicator for measuring wasted electrical energy at LF refining production sites.

[0008] Therefore, the main task of effectively reducing the power consumption of the LF refining process is to find the optimal matching relationship between the current and voltage of the power supply equipment, so as to effectively control the output of useless power per unit time on the basis of meeting the temperature rise of the molten steel, and increase the proportion of useful power in the representative power per unit time, thereby reducing the size of the representative power per unit time, achieving the goal of reducing power consumption in the LF refining production process, reducing production costs, and achieving green and energy-saving production.

[0009] Typically, LF refining equipment suppliers divide current and voltage into several ranges and provide steel mills with a list of voltage and current matching requirements for specific power supply equipment. During production, steel mill operators manually select voltage and current according to the voltage and current mappings on the list. However, the supplier's set currents are not fully compatible with the corresponding range voltages. As a result, during the molten steel heating process, the useful power is low and the unused power is high. This leads to a series of problems, including high power consumption in the power supply system, slow molten steel heating, and high production costs for the steel mill.

[0010] To address these issues, on-site operators often rely on experience to manually adjust the set current and gear voltage to ensure the optimal match between the two. While this approach can sometimes achieve results, it often lacks stability, making it difficult to achieve long-term, green, energy-saving production in LF refining.

[0011] Furthermore, the LF refining process involves several stages, including slagging and heating, requiring current and voltage adjustments at each stage. Manual control of these adjustments would not only fail to accurately guarantee these adjustments, but also reduce operational efficiency and place a significant workload on operators.

[0012] Furthermore, steelmaking sites often employ thermal insulation measures to reduce power consumption during the LF refining phase. This involves optimizing the thermal insulation properties of the ladle lining and the steel coating to reduce the extent of the molten steel's cooling, thereby reducing power consumption during the LF refining phase. However, this approach, while primarily a management measure, mitigates power consumption issues during the LF refining phase to a certain extent, but does not fundamentally resolve the problem. Summary of the Invention

[0013] The object of the present invention is to provide a method for reducing the power consumption in the LF refining production stage, namely: on the premise of ensuring that the temperature rise rate of molten steel meets the production requirements, that is, on the basis of ensuring the useful power size, intelligently select the current that matches the gear voltage and realize automatic control of the current, thereby effectively reducing the size of the representative power in the production process, achieving the purpose of reducing the power consumption in the LF refining production stage, and effectively solving the above-mentioned problems existing in the background technology.

[0014] The technical solution of the present invention is: a method for reducing power consumption in the LF refining production stage, comprising the following steps: (1) before the start of LF refining production, an on-site operator maintains the basic electrical parameters of the LF refining power supply equipment and the molten steel process parameters in a computer built-in system; at the same time, based on work experience, a gear voltage setting table for different production stages is entered into the system;

[0015] (2) After the LF refining production begins, the on-site operator clicks the system start button on the computer and the system starts running;

[0016] (3) Start accumulating refining production time;

[0017] (4) Compare the current refining production time with the production time in the setting table, and the PLC controls the electrical equipment to complete the setting of the gear voltage value according to the comparison result;

[0018] (5) Analyze the set current by combining the gear voltage value and electrical characteristic parameters to obtain the corresponding useful power, useless power, representative power and set current respectively; by adjusting the size of the power factor, obtain several sets of ratios of useful power to representative power;

[0019] (6) Perform a linear search on several sets of ratios of useful power to representation power and find the set with the largest ratio;

[0020] (7) The corresponding set current is obtained by the ratio of useful power to representative power, and the value is transmitted to the PLC to realize the control of the set current at the current moment;

[0021] (8) Continue to perform the operations of step (3) to step (7), record the LF refining time, and send the set gear voltage value to the PLC within the specified time according to the gear voltage setting table, and send the corresponding set current value to the PLC through model calculation, so as to continuously achieve the optimized control of the gear voltage and the set current, and ensure the lowest power consumption in the LF refining production process;

[0022] (9) After the LF refining production is completed, the on-site operator clicks the system shutdown button on the computer to shut down the system.

[0023] In the step (1), the basic electrical parameters include the line resistance, rated power, rated voltage, and short-circuit impedance of the power supply equipment.

[0024] In step (3), the formula for the cumulative refining production time is:

[0025]

[0026] in: The refining production time at the current moment, in seconds; is the refining production time at the previous moment, in seconds; Δt is the unit time, in seconds.

[0027] In the step (4), if the current refining production time The production time t of a row in the setting table 设定表 When the error is within ±5s, that is: When t 设定表 The corresponding gear setting voltage value is input into the PLC.

[0028] In step (5), the calculation formula of useful power is:

[0029]

[0030] Where: P is the useful power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment; n is the power factor, and n∈(0,1];

[0031] The calculation formula for useless power is:

[0032]

[0033] In the formula: Q is the useless power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment;

[0034] The calculation formula for characterizing power is:

[0035]

[0036] In the formula: S is the representative power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment;

[0037] The ratio of useful power to representative power:

[0038] η=P / S

[0039] Where: η is the ratio of useful power to representative power;

[0040] The calculation formula for setting current is:

[0041]

[0042] In the formula: I is the set current, unit is A; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment.

[0043] In step (6), the ratio of the maximum useful power to the characterization power, η max ∈[η1,η2,η3,……,η m ], where m is the number of power factors set in step (5).

[0044] The present invention has the beneficial effect of achieving optimal matching between unit voltage and set current in the LF refining production process. This ensures the lowest representative power while meeting production requirements, ensuring the greatest reduction in power consumption, and achieving the goal of green and energy-saving LF refining production. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the invention implementation cases clearer, the technical solutions in the invention implementation cases are clearly and completely described below. Obviously, the implementation cases described are only a small part of the implementation cases of the invention, rather than all the implementation cases. Based on the implementation cases in the invention, all other implementation cases obtained by ordinary technicians in this field without making creative work are within the scope of protection of the invention.

[0046] A method for reducing power consumption during LF refining production comprises the following steps: (1) before LF refining production begins, an on-site operator maintains basic electrical parameters of LF refining power supply equipment and molten steel process parameters in a computer-built-in system; and at the same time, based on work experience, a voltage setting table for different production stages is entered into the system;

[0047] (2) After the LF refining production begins, the on-site operator clicks the system start button on the computer and the system starts running;

[0048] (3) Start accumulating refining production time;

[0049] (4) Compare the current refining production time with the production time in the setting table, and the PLC controls the electrical equipment to complete the setting of the gear voltage value according to the comparison result;

[0050] (5) Analyze the set current by combining the gear voltage value and electrical characteristic parameters to obtain the corresponding useful power, useless power, representative power and set current respectively; by adjusting the size of the power factor, obtain several sets of ratios of useful power to representative power;

[0051] (6) Perform a linear search on several sets of ratios of useful power to representation power and find the set with the largest ratio;

[0052] (7) The corresponding set current is obtained by the ratio of useful power to representative power, and the value is transmitted to the PLC to realize the control of the set current at the current moment;

[0053] (8) Continue to perform the operations of step (3) to step (7), record the LF refining time, and send the set gear voltage value to the PLC within the specified time according to the gear voltage setting table, and send the corresponding set current value to the PLC through model calculation, so as to continuously achieve the optimized control of the gear voltage and the set current, and ensure the lowest power consumption in the LF refining production process;

[0054] (9) After the LF refining production is completed, the on-site operator clicks the system shutdown button on the computer to shut down the system.

[0055] In the step (1), the basic electrical parameters include the line resistance, rated power, rated voltage, and short-circuit impedance of the power supply equipment.

[0056] In step (3), the formula for the cumulative refining production time is:

[0057]

[0058] in: The refining production time at the current moment, in seconds; is the refining production time at the previous moment, in seconds; Δt is the unit time, in seconds.

[0059] In the step (4), if the current refining production time The production time t of a row in the setting table 设定表 When the error is within ±5s, that is: When t 设定表 The corresponding gear setting voltage value is input into the PLC.

[0060] In step (5), the calculation formula of useful power is:

[0061]

[0062] Where: P is the useful power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment; n is the power factor, and n∈(0,1];

[0063] The calculation formula for useless power is:

[0064]

[0065] In the formula: Q is the useless power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment;

[0066] The calculation formula for characterizing power is:

[0067]

[0068] In the formula: S is the representative power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment;

[0069] The ratio of useful power to representative power:

[0070] η=P / S

[0071] Where: η is the ratio of useful power to representative power;

[0072] The calculation formula for setting current is:

[0073]

[0074] In the formula: I is the set current, unit is A; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment.

[0075] In step (6), the ratio of the maximum useful power to the characterization power, η max ∈[η1,η2,η3,……,η m ], where m is the number of power factors set in step (5).

[0076] In practical applications, the present invention is implemented by an intelligent current analysis device and a regulation execution device. The intelligent current analysis device consists of a computer with internally stored information on the basic electrical parameters of the LF refining power supply equipment, including: line resistance (unit: Ω), rated power (unit: KVA), rated voltage (unit: V), and short-circuit impedance (%); molten steel process parameters, including: molten steel weight (unit: ton), molten steel temperature loss per unit time (unit: °C / min); and a table of voltage settings for different production stages. Furthermore, the computer also contains an intelligent current analysis model.

[0077] The regulating execution device consists of a PLC, which is used to realize online regulating control of the voltage and current of the gears in different production stages.

[0078] The present invention comprises the following steps:

[0079] Step 1: Before LF refining production begins, on-site operators maintain the basic electrical parameters of the LF refining power supply equipment, including the power supply equipment's line resistance (unit: Ω), rated power (unit: KVA), rated voltage (unit: V), short-circuit impedance (%), and molten steel process parameters, into the computer's built-in system. At the same time, based on work experience, a voltage setting table for different production stages is entered into the system, as shown in Table 1:

[0080] Table 1 Voltage setting table for different production stages

[0081] Production time (unit: S) Gear setting voltage (unit: V) …… …… …… ……

[0082] Step 2: After the LF refining production starts, the on-site operator clicks the system start button on the computer and the system starts running.

[0083] Step 3: Start accumulating refining production time:

[0084]

[0085] in: The refining production time at the current moment, in seconds; is the refining production time at the previous moment, in seconds; Δt is the unit time, in seconds.

[0086] Step 4: The computer continuously compares the current refining time with the production time in the setting table. If the current refining time The production time t of a row in the setting table 设定表 When the error is within ±5s, that is: When the computer 设定表 The corresponding gear setting voltage U value is input into the PLC, and the PLC controls the electrical equipment to complete the setting of the gear voltage value.

[0087] Step 5: The computer analyzes the set current based on the gear voltage value and electrical characteristic parameters to obtain the corresponding useful power, useless power, representative power and set current, where:

[0088]

[0089] Where: P is useful power, unit: KW;

[0090] U is the gear voltage value, unit is V;

[0091] a is the rated power of the power supply equipment, KVA;

[0092] b is the rated voltage of the power supply equipment, V;

[0093] c is the short-circuit impedance of the power supply equipment.

[0094] n is the power factor, and n∈(0,1]

[0095]

[0096] Where: Q is useless power, unit: KW;

[0097] U is the gear voltage value, unit is V;

[0098] a is the rated power of the power supply equipment, KVA;

[0099] b is the rated voltage of the power supply equipment, V;

[0100] c is the short-circuit impedance of the power supply equipment.

[0101]

[0102] Where: S is the representative power, unit: KW;

[0103] U is the gear voltage value, unit is V;

[0104] a is the rated power of the power supply equipment, KVA;

[0105] b is the rated voltage of the power supply equipment, V;

[0106] c is the short-circuit impedance of the power supply equipment.

[0107] η=P / S

[0108] Where: η is the ratio of useful power to representative power.

[0109]

[0110] Where: I is the set current, unit: A;

[0111] U is the gear voltage value, unit is V;

[0112] a is the rated power of the power supply equipment, KVA;

[0113] b is the rated voltage of the power supply equipment, V;

[0114] c is the short-circuit impedance of the power supply equipment.

[0115] The computer adjusts the size of the power factor n, that is, sets several power factors n, to obtain several sets of ratios η of useful power to representative power.

[0116] Step 6: The computer performs a linear search on several sets of ratios η of useful power to representative power to find the largest set of η values, namely: η max ∈[η1,η2,η3,……,ηm ]. Wherein, m is the power factor number set in step 5.

[0117] Step 7: The computer uses the η value to correspond to the corresponding set current I and transmits this value to the PLC to realize the control of the set current at the current moment.

[0118] Step 8: The computer continues to execute the operations of steps 3 to 7, by recording the LF refining time and sending the set gear voltage value to the PLC within the specified time according to the gear voltage setting table, and sending the corresponding set current value to the PLC through model calculation, thereby continuously realizing the optimized control of the gear voltage and set current, ensuring the lowest energy consumption in the LF refining production process.

[0119] Step 9: When the LF refining production is completed, the on-site operator clicks the system shutdown button on the computer to shut down the system.

Claims

1. A method for reducing power consumption in the LF refining production stage, characterized in that The following steps are involved: (1) Before the start of LF refining production, the on-site operator maintains the basic electrical parameters of the LF refining power supply equipment and the molten steel process parameters into the computer built-in system; at the same time, based on work experience, the gear voltage setting table for different production stages is entered into the system; (2) After the LF refining production begins, the on-site operator clicks the system start button on the computer and the system starts running; (3) Start accumulating refining production time; (4) Compare the current refining production time with the production time in the setting table, and the PLC controls the electrical equipment to complete the setting of the gear voltage value according to the comparison result; (5) Analyze the set current by combining the gear voltage value and electrical characteristic parameters to obtain the corresponding useful power, useless power, representative power and set current respectively; by adjusting the size of the power factor, obtain several sets of ratios of useful power to representative power; (6) Perform a linear search on several sets of ratios of useful power to representation power and find the set with the largest ratio; (7) The corresponding set current is obtained by the ratio of useful power to representative power, and the value is transmitted to the PLC to realize the control of the set current at the current moment; (8) Continue to perform the operations of step (3) to step (7), record the LF refining time, and send the set gear voltage value to the PLC within the specified time according to the gear voltage setting table, and send the corresponding set current value to the PLC through model calculation, so as to continuously achieve the optimized control of the gear voltage and the set current, and ensure the lowest power consumption in the LF refining production process; (9) After the LF refining production is completed, the on-site operator clicks the system shutdown button on the computer to shut down the system.

2. The method for reducing power consumption in the LF refining production stage according to claim 1, characterized in that: In the step (1), the basic electrical parameters include the line resistance, rated power, rated voltage, and short-circuit impedance of the power supply equipment.

3. The method for reducing power consumption in the LF refining production stage according to claim 1, characterized in that: In step (3), the formula for the cumulative refining production time is: in: The refining production time at the current moment, in seconds; is the refining production time at the previous moment, in seconds; Δt is the unit time, in seconds.

4. The method for reducing power consumption in the LF refining production stage according to claim 1, characterized in that: In the step (4), if the current refining production time The production time t of a row in the setting table 设定表 When the error is within ±5s, that is: When t 设定表 The corresponding gear setting voltage value is input into the PLC.

5. The method for reducing power consumption in the LF refining production stage according to claim 1, characterized in that: In step (5), the calculation formula of useful power is: Where: P is useful power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment; n is the power factor, and n∈(0,1]; The calculation formula for useless power is: Where: Q is useless power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment; The calculation formula for characterizing power is: Where: S is the representative power, unit is KW; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment; The ratio of useful power to representative power: η=P / S Where: η is the ratio of useful power to representative power; The calculation formula for setting current is: Where: I is the set current, unit is A; U is the gear voltage value, unit is V; a is the rated power of the power supply equipment, unit is KVA; b is the rated voltage of the power supply equipment, unit is V; c is the short-circuit impedance of the power supply equipment.

6. The method for reducing power consumption in the LF refining production stage according to claim 1, characterized in that: In step (6), the ratio of the maximum useful power to the characterization power, η max ∈[η1,η2,η3,……,η m ], where m is the number of power factors set in step (5).

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