The Design And Implementation Of Pulverized Coal Injection Automatic Control System In Qian-steel

With the development of iron and steel, the main aim of iron and steel industry has change to increase the comprehensive utilization rate of energy, save the energy and protect environment. Despite the amount of pulverized coal into blast furnace had reached by 1710 million tons and the average annual injection by 125.7 kg P.C/t Fe in 2002, there are still much more difference with the international advanced level.This paper mainly completed the design and optimization of PCI control system for No.3 blast furnace, which combined with the project of the development of PCI (Pulverized coal injection) control system in Qian-steel. The main clue of this paper was to make PCI system stable and increase PCI rate. The main works of this paper are as the follows:(1) In this paper research and analysis on the process characteristics of PCI system was done, requirement analysis for PCI automatic control system of No.3 blast furnace, which having 4000m3 in Qian-Steel, was completed, and PCI control system scheme for No 3 blast furnace was confirmed based on double pot injection process.(2) On the basis of requirement analysis, the general design of PCI system, the design of hardware, the design of safety interlock and the design of software was completed according to system engineering.(3) The selection of PLC and configuration software was accomplished, and the building of system network was completed which combined field bus with power optical fiber key network. Schneider higher-end 6 series PLC was selected to make sure the safety on the measurement and control of PCI system, and Intouch from Wonderware Company was selected for its easy to edit and its friend interface.(4) According to the flow rate of coal cannot be measured correctly, the factors which influence the PCI rate was analyzed. Three methods of computing PCI rate was compared and a mathematic model based on multiple linear regression was built, which has been applied in the industrial process.(5) Research on the measurement of coal weighing and curve of transporting airs was completed for the problem of changing pots in advanced and unreasonable curve of transporting airs, which make the pressure of pulverized pot too high. The improved measurement of coal weighing and curve of optimized transporting airs was proposed in this paper and was applied in the industrial process.After optimization the pulverized coal injection system of No.3 blast furnace has stable operation, the pulverized coal injection rate was raised from 76 t/h to 89 t/h, and the highest ratio of coal was raised to 200kg/t.