PLC Application in dust removal control system of 120 ton ladle furnace of Laigang
Abstract
This paper mainly introduces the application of Programmable Logic Controller (PLC) in the dust removal control system of 120-ton ladle furnace of Laigang, so as to make the control system realize automated, intelligent and Diversified operation. The control system includes processes such as reversing valve control, dust concentration monitoring, anti-blocking alarm and blocked valve alarm. It can automatically control the operation of the dust removal system, which is beneficial to reduce the manual participation and ensure the stability of the dust removal system output. Moreover, compared with the traditional manual control mode, the control accuracy is improved. Therefore, the application of PLC in dust removal control system of 120-ton ladle furnace of Laigangshould be promoted and implemented.
Key words: PLC;120 tons ladle furnace; dust removal control system
1. Introduction
Laigang is one of the largest steel enterprises in China. Its ladle 120-ton ladle furnace is the main source of steel production. In this production process, the high temperature flue gas released by the furnace contains a lot of dust particles, so the dust needs to be removed before emission. The traditional method of dust removal is mechanical dust removal, which needs to be manually operated to control the filter temperature and dust concentration. This method has less control accuracy and requires a lot of manual labor, which affects the dust removal effect and increases the cost. In order to improve dust removal efficiency and reduce operating costs, the Programmable Logic Controller (PLC) is applied to control the dust removal system of 120-ton ladle furnace in Laigang.
2.PLC Application in dust removal control system
2.1 System Structure
The PLC application in the dust removal control system of the 120-ton ladle furnace at Laigang adopts two-level control system. In the upper layer, a man-machine interface is adopted to monitor the operating parameters of the dust removal system. According to the monitoring results, the upper layer manually adjusts the operations of the dust removal system to achieve the optimal dust removal effect. The lower layer of control adopts PLC. It is responsible for executing the instructions received from the man-machine interface and controlling the actuators such as reversing valves, solenoid valves and servo motors in the dust removal system.
2.2 System Control
The lower layer control system of the dust removal control system of 120-ton ladle furnace of Laigang is mainly composed of PLC, valve positioner and electric actuators (servo motor). The PLC uses CAN bus communication to realize the signal transfer in the industrial environment and the coordination control with electric actuators. According to the operating conditions of the dust removal system, the PLC transmits control signals to the valve positioner, solenoid valve and servo motor to control the electric actuators running process. In order to ensure the reliable running of the control system, the PLC and valve positioner are also provided with manual operation mode, which is convenient for the operators to debug and maintain the system.
2.3 System Monitoring
The monitoring part of the PLC application in the 120-ton ladle furnace dust removal control system mainly consists of dust concentration sensor, dust bag pressure sensor and blocking alarm. The dust concentration sensor can realize the real-time collection of dust concentration information in the flue gas, so as to dynamically monitor the running situation of the dust removal system. The dust bag pressure sensor monitors the pressure of the filter bag, and alarms in time when the pressure is too high or too low. The blocking alarm can detect whether the filter material is blocked, so as to protect the normal operation of the dust removal system.
3. Conclusion
In a word, the application of PLC in dust removal control system of 120-ton ladle furnace of Laigang greatly improves the efficiency and accuracy of dust removal control, reduces the cost and workload of manual labor, and improves the reliability and safety of the system.
