Multi-dimensional cooperative control method for reducing power consumption of refining process

Abstract

The invention discloses a multi-dimensional cooperative control method for reducing power consumption of a refining procedure, which belongs to the technical field of metallurgical automation and energy-saving control, and comprises the following steps of: optimizing a slag system, namely adding lime, a slagging agent and circulating slag into a steel ladle when refining enters a station, and increasing the slag quantity to be more than 120mm; submerged arc control: adding a foaming agent during refining entering; feeding by stages, only adding low-melting-point refining slag during tapping of a primary smelting furnace, and adding lime in the early stage of LF refining; power is supplied in a segmented mode, LF refining is divided into a slag melting period and a temperature rising period, power supply control of different time periods is executed according to the time sequence in the slag melting period, and temperature rising control is conducted according to a preset temperature rising function in the temperature rising period; and continuous casting waste heat recovery: recovering the continuous casting waste heat, and transferring to a refining station.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical automation and energy-saving control technology, and in particular relates to a multi-dimensional collaborative control method for reducing power consumption in refining processes. Background Technology

[0002] The steel refining process (such as LF furnaces and RH furnaces) is one of the most energy-intensive stages in steelmaking, accounting for a significant proportion of energy consumption in the entire steel production process. Traditional refining processes have several problems in actual operation, specifically as follows: (1) The submerged arc is unstable. Due to insufficient slag layer thickness or poor foaming performance, the arc shielding effect is not ideal, the heat loss is serious, the arc thermal efficiency is significantly reduced, and the steel heating rate is slow, usually only maintained at 3-4°C / min, which seriously affects the production rhythm. (2) The power supply strategy is relatively crude and fails to dynamically optimize electrical parameters according to the process characteristics of different stages in the refining process (such as slag formation, heating, composition adjustment and temperature maintenance), resulting in low power utilization and increased ineffective energy consumption. (3) Poor coordination between processes: The production scheduling and steel connection between the three major links of converter, refining and continuous casting are not close enough, resulting in the steel waiting time between processes being too long and the temperature drop being severe (usually reaching 5-10°C / min). In order to compensate for the temperature loss, the power supply time needs to be increased, which further increases energy consumption. (4) The continuous casting residue has not been efficiently recycled and utilized. A large amount of casting residue and slag with high total iron content is discarded, which not only causes steel material loss, but also increases the cost of solid waste treatment, and at the same time leads to the waste of lime, fluorite and other slag materials.

[0003] Taking the actual production data of a certain enterprise's 180-ton ladle refining furnace as an example, its refining power consumption is as high as 25 kWh / t, and the average power supply time is as long as 12-18 minutes per furnace, which keeps the production cost at a high level. Although existing technologies have attempted to make local improvements by optimizing slag composition or improving power supply curves, most of them are still limited to single equipment or process links, lacking systematic and coordinated optimization of the entire process from converter tapping to continuous casting, thus the overall energy-saving effect is limited. Summary of the Invention

[0004] The technical problem to be solved by this invention is to achieve a significant reduction in refining power consumption through slag system optimization, power supply strategy, and casting residue recovery.

[0005] The purpose of this invention is to provide a multi-dimensional collaborative control method for reducing power consumption in refining processes, comprising the following steps: Slag system optimization: When the slag enters the refining station, the amount of slag added to the ladle, including quicklime, slag-forming agent and circulating slag, is increased to more than 120 mm. Submerged arc control involves adding foaming agent when the material enters the refining station; The material is added in stages: only low-melting-point refining slag is added when the primary furnace taps out steel, and lime is added in the early stage of LF refining. Segmented power supply divides LF refining into a slag-forming period and a heating period. During the slag-forming period, power supply control is executed for different time periods according to the time sequence. During the heating period, heating control is performed according to a preset heating function. Continuous casting waste recovery involves recovering the waste heat from continuous casting and transferring it to the refining station.

[0006] Preferably, the slag system optimization includes adding 150 kg / furnace of quicklime to the ladle.

[0007] Preferably, the slag-reducing agent comprises fluorite and a modifier.

[0008] Preferably, the recycled slag is the slag recovered from the previous furnace run.

[0009] Preferably, the foaming agent comprises: 50 kg / furnace of silicon carbide or 30 kg / furnace of calcium carbide.

[0010] Preferably, in the staged feeding process, the low-melting-point refining slag includes 40% to 50% calcium oxide and 35% to 45% aluminum oxide. In the early stage of LF refining, 200 kg of lime is added to each batch.

[0011] Preferably, during the slag-forming period, power supply control for different time periods is executed in chronological order, including: Within 0–2 minutes: Low-pressure long-arc slag formation is used with a power factor cosφ=0.85, voltage 344V, and current 475A. Within 2-4 minutes: add 50% lime, and adjust to cosφ=0.75, voltage 376V, and current 520A; At 4–8 minutes: add the remaining lime, maintaining cosφ = 0.75 and current 520A.

[0012] Preferably, during the heating period, the optimal heating time for the heating function is t: t=(T0 T1) / V; Where T0 is the target temperature, T1 is the end temperature of the first stage, and V is the heating rate. The temperature is rapidly increased using cosφ=0.75, voltage 394V, and current 544A, and then naturally cooled to the target temperature.

[0013] Preferably, 2 / 3 of the waste heat from continuous casting is recovered and transferred to the refining station.

[0014] Preferably, it also includes: real-time acquisition of arc current, voltage, frequency and flue gas composition, dynamic prediction of temperature deviation and compensation.

[0015] The advantages and technical effects of this invention are as follows: Significantly reduced power consumption: Through multi-dimensional collaborative control, the overall power saving rate reaches 30% to 50%, significantly reducing energy consumption per ton of steel. It is applicable to various steel types such as ordinary steel, high carbon steel, and alloy steel, and has a wide range of production line adaptability. Full-process collaboration: It organically combines slag ratio optimization, dynamic adjustment of power supply curve, waste heat recovery and utilization, and intelligent control of production rhythm to achieve full-process collaborative management from raw material input to molten steel output, breaking through the limitations of traditional single-point technology optimization and improving overall energy efficiency and stability. Intelligent and low-carbon: Relying on the Internet of Things and big data analysis platform, it realizes digital monitoring and real-time closed-loop control of the refining process, effectively reducing carbon emissions by more than 20%, while supporting the connection with clean energy systems and fully adapting to green steel manufacturing standards and sustainable development requirements. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some examples of the present invention, and not all examples. Obviously, the illustrated embodiments of the present invention demonstrate characteristic technical solutions. Based on the embodiments of the present invention, any other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0017] A multi-dimensional collaborative control method for reducing power consumption in refining processes, specifically including: Slag system optimization: When the slag enters the refining station, the amount of slag added to the ladle, including quicklime, slag-forming agent and circulating slag, is increased to more than 120 mm. When the steel ladle is brought into the refining station, 150 kg of quicklime per furnace, slag-forming agent (including fluorite and modifier), and recycled slag (i.e. slag recovered from the previous furnace) are added to increase the total slag volume to more than 120 mm. This promotes rapid slag formation and increases the slag layer thickness, thereby effectively adsorbing inclusions, improving the purity of the molten steel, and enhancing the slag's fluidity and covering effect, creating more favorable conditions for subsequent refining operations.

[0018] Submerged arc control involves adding foaming agent when the material enters the refining station; During the refining process, operators must simultaneously add a foaming agent (either silicon carbide, 50 kg per furnace, or calcium carbide, 30 kg per furnace) to effectively enhance the foaming effect of the slag layer and significantly improve the stability of the submerged arc. This process optimization increases the heating rate of the arc heating stage from 3–4°C / min to 5–6°C / min, while simultaneously reducing the power supply time per furnace to 11 minutes, thereby significantly improving smelting efficiency and reducing energy consumption.

[0019] The material is added in stages: only low-melting-point refining slag is added when the primary furnace taps out steel, and lime is added in the early stage of LF refining. During the tapping of steel from the primary refining furnace, only low-melting-point refining slag is added. Its composition mainly consists of 40%–50% calcium oxide and 35%–45% alumina to promote rapid slag formation and initial desulfurization. In the early stages of LF refining, specifically during the 2nd to 4th minute of the refining process, 200 kg of lime is added in batches to gradually adjust the slag and increase basicity, avoiding slag agglomeration or uneven reaction due to excessive addition at once. This batch addition method helps maintain slag fluidity, improves submerged arc stability, and thus maximizes submerged arc efficiency, creating favorable conditions for subsequent deep desulfurization and alloying.

[0020] Segmented power supply divides LF refining into a slag-forming period and a heating period. During the slag-forming period, power supply control is executed for different time periods according to the time sequence. During the heating period, heating control is performed according to a preset heating function. The LF refining process is divided into two main stages. The following is the detailed operation procedure for the first stage: First stage (slag formation period, 0-8 minutes): 0-2 minutes: A power supply system with a power factor of cosφ = 0.85, a voltage of 344V, and a current of 475A is adopted. The steel is slowly heated and initially slag is formed in a low-voltage long arc mode, which promotes the formation of initial slag and uniform heating of the molten steel surface.

[0021] 2-4 minutes: Add 50% of the lime to the total slag material in batches, then adjust the electrical parameters to cosφ=0.75, voltage 376V, current 520A, medium voltage and medium arc operation to accelerate lime melting and increase alkalinity.

[0022] 5-8 minutes: Add the remaining 50% lime, keep cosφ = 0.75 and current 520A unchanged, gradually increase the slag basicity and fluidity to promote desulfurization and deoxidation reactions, and at the same time strengthen argon stirring to promote the polymerization and flotation of inclusions.

[0023] During this stage, it is necessary to closely monitor the stability of the electric arc, the state of the molten slag, and the activity level of the molten steel surface. If necessary, the current or argon flow rate should be finely adjusted according to the slag formation.

[0024] Second stage (warming period): Calculate the optimal warming time t based on the formula: t=(T0 T1) / V Where T0 is the target temperature, T1 is the end temperature of the first stage, and V is the heating rate. The heating is achieved by rapidly heating with cosφ=0.75, voltage 394V, and current 544A, followed by natural cooling (rate 1.8°C / min) to the target temperature to avoid high power consumption during the heat preservation period.

[0025] Continuous casting waste recovery involves recovering the waste heat from continuous casting and transferring it to the refining station.

[0026] Two-thirds of the waste heat from continuous casting is recovered and transferred to the refining station via a dedicated thermal circulation system. This waste heat is utilized in the early stages of refining to promote rapid slag formation and melting, achieving early slag formation, effectively improving the submerged arc effect, and enhancing the thermal efficiency of the electric arc, thereby directly reducing the electricity consumption required for heating. This measure is expected to reduce the loss of 1 kg / t of total iron charge while improving the energy utilization efficiency of the smelting process.

[0027] Process rhythm coordination and temperature control: By implementing a Just-In-Time (JIT) production system, the operational rhythms of the three major processes—converter, refining, and continuous casting—are systematically coordinated and dynamically scheduled, achieving seamless integration between processes. This mechanism effectively increased the refining arrival temperature hit rate from 42.88% to 62.74%, significantly shortening the waiting time of molten steel between processes and reducing temperature drop losses. Simultaneously, through key process optimization measures such as improving the converter endpoint hit rate and implementing full-process ladle insulation, the proportion of non-process refining has been further controlled to 15.68%, reducing ineffective energy consumption and electricity demand from the production source.

[0028] Intelligent control system integration: An information-based control system, including the Q-One power supply system and the Q-Melt smelting model, is introduced to achieve real-time acquisition and dynamic analysis of multi-dimensional data such as electric arc furnace current, voltage, operating frequency, and flue gas composition. Based on data-driven algorithms, the system performs real-time prediction and intelligent compensation for temperature deviations during the smelting process, significantly improving temperature control accuracy and energy efficiency. By adopting low-frequency power supply technology (such as 20Hz) to enhance arc penetration and reduce system inductive reactance, an additional 10% energy saving is achieved while ensuring smelting quality, further promoting green and low-carbon production.

[0029] Specific implementation examples: Taking the production of Q235B steel using a 180t ladle as an example: Add 500 kg of top slag ash from the converter tapping process; After the LF enters the station, add 100kg of quicklime, 50kg of calcium fluoride, and 30kg of calcium carbide. After powering on, operate according to the segmented power supply parameters. The heating curve is monitored by an intelligent system to ensure that the total smelting cycle is ≤32 minutes.

[0030] Result: Power consumption decreased from 25 kWh / t to 15 kWh / t, and power delivery time was shortened by 25%.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-dimensional synergic control method for reducing the electric consumption of a refining process, characterized in that, The method comprises the following steps: Slag system optimization, adding lime, slag modifier and circulating slag into ladle to increase slag amount to 120mm or more at refining entry; Submerged arc control, adding foaming agent at refining entry; Staged charging, adding low melting point refining slag at initial smelting furnace tapping, and adding lime at early stage of LF refining; Sectional power supply, dividing LF refining into slagging period and temperature rising period, performing power supply control in different time periods in time sequence in slagging period, and performing temperature rising control according to preset temperature rising function in temperature rising period; Continuous casting residual heat recovery, transferring residual heat of continuous casting to refining station.

2. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized in that, The slag system optimization comprises adding 150kg of lime per furnace into the ladle.

3. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized in that, The slag modifier comprises fluorite and modified agent.

4. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized by, The circulating slag is recycled slag of previous furnace.

5. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized by, The foaming agent comprises 50kg of silicon carbide per furnace or 30kg of calcium carbide per furnace.

6. The multi-dimensional synergic control method for reducing electric power consumption of a refining process according to claim 1, characterized by, In the staged charging, the low melting point refining slag comprises 40%-50% of calcium oxide and 35%-45% of aluminum oxide, and 200kg of lime is added per batch at early stage of LF refining.

7. The multi-dimensional synergic control method for reducing electric power consumption of a refining process according to claim 1, characterized by, In the slagging period, the power supply control in different time periods in time sequence comprises the following steps: In 0-2 minutes, low voltage long arc slagging is performed with power factor cosφ=0.85, voltage 344V and current 475A; In 2-4 minutes, 50% of lime is added, and cosφ=0.75, voltage 376V and current 520A are adjusted; In 4-8 minutes, the remaining lime is added, and cosφ=0.75 and current 520A are maintained.

8. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized by, In the temperature rising period, the optimal temperature rising time of the temperature rising function is t: t = (T0 T1 ) / V; Wherein, T0 is target temperature, T1 is first stage end temperature, and V is temperature rising speed, cosφ=0.75, voltage 394V and current 544A are used for rapid temperature rising, and then natural cooling to target temperature.

9. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, wherein, The residual heat of continuous casting is recovered by 2 / 3 per furnace and transferred to the refining station.

10. The multi-dimensional synergic control method for reducing power consumption of a refining process according to claim 1, characterized by, The method further comprises the following steps: Real-time acquisition of arc current, voltage, frequency and smoke components, dynamic prediction of temperature deviation and compensation.