The Design Of Control System For Supporting Ammonia Station Of 450-square-meter Flue Gas Purification Using Activated Coke Flue

During the sintering process of iron and steel,a large amount of harmful smoke will be produced.Nitrogen oxides and sulfides are the main components of exhaust gases.Untreated waste gas discharged directly into the air will cause irreparable impact on environment.Ammonia is an important raw material for the treatment of waste gas,which can remove nitrogen oxides in the exhaust gas and produce harmless water and nitrogen.Ammonia station is one of the most important facilities in the sintering exhaust gas treatment system,which has the function of liquid ammonia storage and the preparation of mixed gas.In this paper,the design of ammonia station system for the flue gas purification of sintering machine is to achieve automation of liquid ammonia storage and ammonia preparation.This is a project of Lianfeng Steel(Zhangjiagang)Co.,Ltd.The ammonia station is build for NO.2 450-square-meters sintering machine flue gas purification project.And the ammonia station has put into operation.Based on the idea of centralized management and decentralized control,relying on advanced control technology,the control system including IPC and PLC is designed.The lower computer is designed basing on PLC.The type and the modules of PLC are chosen according to the types of physical measurement and the number of points which need to be measured.The hardware configuration is achieved by the hareware component of STEP7.The corresponding program has been designed to achieve the functions like analog conversion,flow accumulation,chain alarm,PID control and so on.The upper computer is developed by using configuration software WinCC.Monitor screen was designed includeing real-time data flow picture and real-time curve,historical data archiving and alarm summary screen.The flow chart can visually display the running status of the system currently.Historical data archiving can view historical data or output data tabulation to provide relevant data for process improvement.The alarm summary is able to respond to the alarm and record it.It can also help technicians to troubleshoot.PLC communicate with WinCC through industrial Ethernet TCP/IP protocol.With the help of the WebNavigator of WinCC,process monitoring pictures and alarm summary screen are sent to the mobile worekstation in plant via wireless net or sent to the control room of steel plant via LAN to provide convenience for manager to debug and manage.The actual operation proves that the system design is reasonable and reliable,and it can meet the control requirements of ammonia plant.