Automatic control of electric arc furnace steelmaking

The electric arc furnace automation control system mainly includes three aspects: the electric arc furnace body system, the Consteel horizontal feeding system, and the furnace door furnace wall oxygen lance system. In addition, there are other peripheral auxiliary equipment, water circulation system and fan dust removal system. The process control is realized by the integration of electrical control, instrument control and computer automatic control, which improves the safety and reliability of the control system.

Electric arc furnace body system

The main control system of the electric arc furnace adopts the SIMATIC S7-300 PLC of Siemens of Germany as the host, configures local/remote expansion racks, and adopts the iconic bus PROFIBUS of Siemens as the system network protocol for global data communication. The whole system consists of a CPU15-2DP CPU as the master station, and other slave stations include the operation console ET200M station, the water cooling and limit ET200 station, the transformer ET200 station, the hydraulic station ET200M station and the feeding ET200M station, of which the master station I completes the furnace body, Hydraulic station, high-voltage switchgear, transformer control and measurement monitoring signal acquisition, transmission and alarm, the main station II mainly completes the electrode adjustment control. Its configuration mainly includes main frame, extension frame, power supply, CPU, interface module, digital input and output modules, and analog input and output modules.

The main body of the electric arc furnace body system lies in the furnace body tilting system and the electrode lifting control system. Both systems are controlled by PLC to drive hydraulic proportional valves to adjust the furnace body and electrodes.

Consteel horizontal feeding system of arc furnace

Although the Consteel horizontal feeding system is an auxiliary equipment for electric arc furnace steelmaking, it plays a vital role in steelmaking rhythm, production process flow, and waste heat utilization. This system mainly includes three parts: tail shock part, water cooling circulation system and horizontal feeding trolley. The PLC control system adopts Siemens S7-300 as the master station, and the slave station part adopts the SDP module to collect digital and analog signals, which are unified into the S7-300CPU. To achieve remote information transmission and execution.

The horizontal feeding system has always been the top priority in Consteel's electric arc furnace smelting. The normal operation of the horizontal feeding system can completely control the production rhythm of the electric furnace, and achieve advance preheating before scrap addition and reduce temperature loss.

Furnace door oxygen lance control system of electric furnace

The furnace door oxygen blowing carbon injection system is an important auxiliary equipment for electric arc furnace steelmaking, and the foam slag is obtained through the carbon injection gun. Foaming slag process is an important means of electric arc furnace steelmaking process. The control of the oxygen lance of the furnace door is completed by two parts, pneumatic and hydraulic. The lifting of the oxygen lance and the swinging up, down, left, right, back and forth are completed by hydraulic control. The oxygen and carbon injection of the furnace door oxygen lance is controlled by an electric solenoid valve and an intelligent valve regulating valve to realize the size and speed of the carbon injection and the oxygen injection.

In the production of the past few years, problems such as water leakage of the furnace door oxygen lance, wear of the chemical gun, furnace door carbon injection tube, and burnout of the hydraulic system line frequently occurred, resulting in the furnace door oxygen lance often failing to meet the requirements for use and unable to perform foam slag. craft. As a result, it will lead to a series of interlocking reactions such as furnace cover and furnace wall arc burning, water leakage, etc. The electric furnace has a high accident rate and cannot reach the designed production capacity. 

By improving the inclination angle of the oxygen lance of the furnace door and improving the control method of the hydraulic valve table, the lifting of the oxygen lance of the furnace door and the swinging back and forth left and right can be controlled by remote control. Realize remote automatic control. In order to improve the disadvantages of the original toner canister, the toner system uses the new version of s7-200smartPLC, and the screen configuration uses the WINCC system to implant the original furnace door gun system to achieve one-key master-standby switching. 

When a powder spraying tank fails, switch to another powder spraying system with one key. Through the technical improvement of the furnace door oxygen gun and the furnace door carbon powder gun, the carbon spraying efficiency has been greatly improved, and the original manual carbon spraying has been converted into fully automatic powder spraying carbon spraying, which reduces labor intensity and improves work efficiency. The slag process is effectively implemented.