Steel rolling production has higher requirements for automation equipment, and the level of automation system and automation equipment has the greatest impact on the quality of the final product. Therefore, special attention should be paid to the application of automation technology in steel mills. This article introduces some automation technologies and cases that have been successfully applied in steel mills.
1. Intelligent stock yard
The intelligentization of the material yard covers applications such as intelligent batching, unattended stackers and reclaimers, intelligent storage and transportation, and unattended belts. Existing relatively complete cases include Jinnan Iron and Steel Co., Ltd. and China Metallurgical South Co., Ltd. successfully put into use the intelligent material yard technology, Baosteel built Zhanjiang intelligent environmental protection raw material yard with the assistance of MCC CCID, etc.
Taking Baosteel’s Zhanjiang stockyard as an example, through intelligent means, the stockyard can save about 5 million kWh of electric energy every year, improve operating efficiency by 20%, and reduce labor costs by 70%. And from the perspective of environmental protection, by reducing material loss, reducing material moisture content, reducing production energy consumption, etc., the company can save hundreds of millions of dollars in costs every year.
1) Stacker-reclaimer automation
Taking the application of stackers and reclaimers in Masteel Port Raw Materials General Plant as an example, it has realized fine management of the stockyard; the production efficiency has increased by 20%, and the utilization rate of the shoreline of the self-provided wharf is more than 2 times higher than the average value; the stability index of the mixed ore is at The best level in the industry.
2) Digital 3D stock yard
The intelligent stockyard technology independently developed by MCC South has been successfully put into use in the Jinnan Iron and Steel Raw Material Field, including 3D digital stockyards, which can realize remote monitoring and virtual roaming of the stockyard, and freely view the operation of the stockyard. By reading the point cloud data of the digital stockyard, the three-dimensional outline of the stockyard can be displayed in real time; by interacting with the on-site data, the type and weight information of the stockpiles can be displayed in real time, and the operation status of the stockpiling and reclaiming equipment can be displayed in real time in three dimensions. By displaying key equipment status parameters and historical trends of key parameters, it lays the foundation for remote operation and maintenance.
3) Digitalization of storage and transportation
Taking JISCO’s storage and transportation intelligent material yard as an example, the project has completed the post optimization and allocation of 45 people, resulting in direct economic benefits of 4.5 million yuan; the storage and transportation department saves about 400,000 yuan in inventory and shipping costs every year; it can reduce losses and quality every year The fee for objection sampling inspection, objection disposal, and re-inspection is 5-6 million yuan.
The application of Donghai Special Steel’s intelligent storage and transportation stock yard has achieved a good effect of improving the level of environmental friendliness. Large-scale fully enclosed environmental protection material sheds and supporting operation systems are deployed in the factory. More than 20 micron-level dry fog suppressors are installed inside each material shed. Dust equipment + 8 sets of wheel washing machines are installed in the access driveway. A year can reduce the emission of 40 tons of carbon monoxide, 50 tons of nitrogen oxides, and 100 tons of suspended particles.
2. Digitalization of sintering and pelletizing process
1) Intelligent monitoring and diagnosis of sintering process
Ansteel Group developed an intelligent online monitoring system for the air leakage rate of sintering machines. After it was put into use, the air leakage rate of No. 1 sintering machine decreased significantly, and the average monthly cost was reduced by nearly one million yuan. At the same time, Ansteel and Northeastern University jointly developed the sintering system mixer intelligent spot inspection online monitoring system, which can collect vibration, temperature, speed, and image signals of key parts of the equipment in real time, realize intelligent fault diagnosis, and effectively reduce the incidence of equipment accidents.
2) Intelligent control system
Taking Ninggang sintering intelligent control system as an example, after the optimization of the original system, the platform provides a unified inter-process communication method, an efficient log management method, and completes functions such as a first-level data read and write interface, fast data collection, and efficient data compression algorithms. . Under the development environment provided by the platform, through large-scale reuse, it supports the research and development of process control systems, ensures stable, efficient and rapid construction of metallurgical process control systems, reduces development risks, and optimizes production processes.
3) Digitalization of desulfurization and denitrification process
The technology and application cases include the ultra-low emission transformation project of sintering machine flue gas-desulfurization and denitrification project realized by Sinosteel Tiancheng and Xingang Group; the desulfurization and denitrification project created by Qingxin Environment for Yukun Iron and Steel; Steel companies such as Wuhan Iron and Steel, Yongyang and other steel companies have applied the MCC Changtian flue gas circulation sintering technology; and some functions of the Ramon intelligent desulfurization system have been applied to Meishan Iron and Steel and Baosteel.
3. Digitization of ironmaking
More successful cases in recent years include the intelligent manufacturing of Longmen Iron and Steel’s ironmaking process, the structural optimization of Baowu Masteel’s ironmaking system, the first ironmaking intelligent manufacturing pilot project of Baotou Steel, and the intelligent smelting of ironmaking blast furnaces at Hesteel Chenggang.
1) Remote furnace front one-button control
Referring to Echeng Iron and Steel’s blast furnace front intelligent project, it has realized the standardized operation of the front furnace, improved the front operation environment, reduced the errors and risks caused by manual operations, optimized the allocation of human resources, optimized the utilization rate of blast furnace clay, and improved production It is a compound application of “one-button opening” and “remote + one-button” to improve efficiency, reduce operating costs, and avoid production safety accidents.
2) Blast furnace expert system
At present, Panzhihua Iron and Steel, Shagang, Kunming Iron and Steel, Chongqing Iron and Steel Co., Ltd. and Nanjing Iron and Steel Co., Ltd. have introduced the blast furnace expert system from VAI; Baosteel and Fudan University have jointly developed a furnace condition monitoring and management system; Wuhan Iron and Steel Co., Ltd. has cooperated with Beijing University of Science and Technology to develop the No. 1 blast furnace expert system; Shougang has developed an artificial intelligence blast furnace smelting expert system; Nangang and Chongqing University have jointly developed a blast furnace operation management system.
4. Intelligent control technology of heating furnace
The regenerative heating furnace automatic control system is a process control system that integrates billet information management, heating process information monitoring, and heating target temperature control. Its application will transform the production of black box heating furnaces into considerable, controllable and predictable modern production process.
5. Ironmaking production automation technology
In the large and medium-sized blast furnaces, the automation of the batching process under the tank, the automation of the feeding and distribution process, the automation of the hot blast furnace combustion process, the automation of pulverized coal injection, the mechanization of tapping before the furnace, and the zero return of large-scale blast furnaces have been realized. Our company is fully equipped with ironmaking Independent development and system integration capabilities of automation systems.
•Blast furnace raw fuel automatic batching, automatic feeding technology
• Large-scale blast furnace high-precision return ore automatic furnace feeding technology
• Automatic combustion and switching control of hot blast stove
• Automatic correction model of a, β, γ angles of cloth distributor
• Fully automatic interlocking cloth model for furnace top equipment
• Automatic compensating furnace top cloth model
• Automatic pulverized coal injection control
•Functions of material change calculation, blast furnace operating parameters, data trend query and electronic report
•Collection and analysis of production core data to realize online guidance of blast furnace operation
6. Steelmaking production automation technology
Integrate frequency conversion drive, PLC control, large-scale network management, computer model technology, etc. into complex working conditions such as converter, refining, continuous casting, etc., to realize full automation of steelmaking production, and have the hardware design and software development of the automation system , The integration ability of the whole process of on-site debugging.
• Tilting oxygen lance control technology
• Efficient feeding control technology
•Safe and stable steelmaking residual energy recovery control technology
• Top and bottom combined blowing control technology
•intelligent steelmaking system integration
• Fully automatic continuous casting control technology
Control system of Jinan Iron and Steel No. 1-5 continuous casting machine
Jinan Iron and Steel No. 1-3 120-ton converter and 210-ton converter control system
7. Automatic control technology of LF ladle refining furnace
As an intermediate link between steelmaking and continuous casting, LF ladle refining furnace is widely used in modern iron and steel enterprises. It can significantly improve the alloy yield and the control accuracy of molten steel composition, and is convenient for temperature adjustment. The automatic control technology of the LF refining furnace can effectively reduce the heating time of the electrodes of the LF refining furnace, provide an optimized alloy ingredient list, and greatly reduce production power consumption and raw material costs.
PLC basic control:
• Ladle argon blowing control;
• Molten steel temperature rise control;
•Alloy feeding control.
• Furnace plan management model
• Energy balance calculation
• Estimation model of ladle outbound time
• Ladle temperature forecast model
• Alloy optimization batching model
• Ladle composition forecast model
•Steel slag composition forecast and slag batching model
•Improved the heating accuracy of the system, shortened the refining heating time, and reduced the power consumption and electrode consumption.
•Through the implementation of alloy feeding optimization calculation, the narrow composition control rate of molten steel is improved.
• Improve the temperature and composition accuracy of molten steel refining, stabilize the casting speed of the casting machine, and reduce the cracks and inclusions of the slab.
Application of LF refining furnace (40t) in steelworks.
8. Thickness test of solidified shell of continuous casting slab
By testing the thickness of the solidification shell during the cooling process of the continuous casting slab, we can accurately understand the solidification change law of different parts of the continuous casting slab during the solidification and cooling process. Through the test, it is possible to calculate the comprehensive solidification coefficient of the casting machine, the length of the liquid core or the solidification terminal position, verify the reliability of the solidification prediction expert system introduced by the continuous casting machine, evaluate the comprehensive cooling capacity of the continuous casting machine, optimize the secondary cooling system, and accurately control The solidification terminal position under the condition of high casting speed provides an important basis for realizing high-efficiency continuous casting.
The “nail shooting method” was used to measure the thickness of the solidified slab shell of the continuous casting slab at different positions in the secondary cooling zone. The nail shooting method is to drive a steel nail with tracer material into the solidifying billet shell. The liquidus temperature of the steel nail is lower than the liquidus temperature of the test steel type, and the nail in the liquid phase zone is completely melted, and the two-phase The nail is partially melted in the region of the solid phase, and the nail is not melted in the solid phase region. The shell thickness of the solidified slab can be directly measured by cutting the slab with nails, and then samples are taken at the corresponding position of the slab for sulfur printing, low-magnification inspection, result analysis, and parameter calculation.
9. Steel rolling production automation technology
Adopting advanced transmission technologies such as AC-AC and AC-DC-AC, complex and accurate model control technology, and a fast and stable data processing system, the fully automatic production of steel rolling in various processes from thick plates to thin plates, and from wire rods to plates has been realized.
•Optimized combustion of heating furnace, tracking of rolled parts in the furnace, automatic furnace loading and discharge control
•Black box testing technology, digital-analog system
• Zero-speed down converter runaway motor current increase suppression technology
• Public DC bus frequency conversion control technology
• Twelve-phase rectification technology, inverter vector control
•Pulse amplification, isolation and interference suppression technology
• Inverter network control technology
•Three-axis transmission rolling cutting double-sided shear automatic control technology
• Load balancing technology, “Δ-Y” group current balancing technology
• Cascading control, four-roll mill automatic roll change control technology
•Shearing and finishing automatic control
Control system of straightening machine, heating furnace, bilateral shears and cooling bed in Jinan Iron and Steel Plate Plant
JISCO Heating Furnace Control System
10. Continuous Casting Solidification End Tracking (TSS) System
Slab center segregation and center porosity will lead to quality problems such as steel cracks, reduced mechanical properties, and reduced welding performance. Dynamic soft reduction is currently an ideal technology to eliminate the problems of slab center segregation and center porosity. According to Fourier’s law and the law of energy conservation, the system develops a program to solve the heat transfer mathematical model of the slab, dynamically determines the position of the soft reduction and determines the fan-shaped section of the reduction, optimizes the amount of water sprayed in the secondary cooling zone, reduces the segregation of the slab center, and thus improves the casting process. billet quality.
•Establish a slab heat transfer mathematical model consisting of continuous casting heat conduction differential equations, boundary conditions, thermophysical parameters, geometric conditions, etc., and apply the finite difference algorithm to solve the model.
•Dynamically calculate the distribution of solidified layer thickness and the length of liquid phase cavity, so as to dynamically determine the position of light reduction and determine the segment of reduction.
•Dynamic graphical display of the calculation results of the model, the curves can be used to display the temperature change trend of the upper and lower surfaces of the slab and the center point, and the cloud map can be used to display the temperature distribution of the slab cross section.
•According to the calculation results of the model, dynamically display the change diagram of the thickness of the solidified slab shell along the length direction of the slab, and dynamically display the positions of the liquid phase, solid phase and two phases.
•Real-time online calculation: The system operation sequence is synchronized with the steel pouring, real-time calculation of the slab temperature field, and real-time simulation of the solidification process of the slab.
• Graphical result analysis: express the model operation results in the form of curves and cloud diagrams.
• Concise output: According to user needs, customize output reports that meet specifications.