The Control System Design Of Gas Station With Natural Gas Revamping In Baosteel 2050mm HSM.

The Gas mixing and pressing process is an important tache in the iron and steel producing.The steel quality and output is affected by the mixed gas quality directly.The Gas mixing process,which is influenced by numerous factors,is complex.The actual production needs an effective control method urgently.The calorific value and pressure control of gas station is nonlinear,time-varying and large delay process and contains many uncertain factors that the traditional control algorithm can't completely solve.Once bad control,heating furnace will shock process under over-oxygen and under-oxygen,leading black smoke or over-burning problem.So how to control mixture problems,especially how to control the increase of natural gas,is an urgent problem to be solved.This paper designs the cascade parallel double cross limit control algorithm to cope with the coupling of calorific value and pressure,as the pressure as the main control loop,meeting the pressure demand,and BFG and COG as two auxiliary control loop to meet the calorific value control by high and low limit selector.After adding Natural gas(NG),the replacement of NG and COG runs by proportional ratio with cross limiting control.NG also needs to meet the requirements of pressure and flow control.On this basis,the algorithms of low flow control,second mixture pressure control,and bypass flow control for protecting the compressor are also included.Because the DCS system itself can provide fault tolerance mechanism in all directions,it effectively reduce the loss of production caused by the malfunction.We select ABB AC800M as the controller to realize the function and algorithms.We design DCS with OPC network communication,and also HMI,realizing the man-machine operation,history record,trend alarm,statistical statements,the abnormal diagnosis etc..The design has been applied in Baosteel 2050mm HSM.During the tunning,the NG pressure control and external disturbance issues has been analyzed deeply.,According to external causes disturbance,by analyzing changes in heating furnace,we build feed-forward compensation algorithm,improving the response speed of the system and will improve optimization..The result of real-time control shows the method is advanced and accord with industrial requirement.The system,which is steady-going and reliable,effectively restrain undulation of the calorific value and pressure.At the same time,the system creates huge economic and social benefit for the enterprise.