Application Research Of Safety Interlock System In Heating Furnace Control System

Safety Interlock Systems(SIS)are also called the Emergency Shutdown System(ESD),In the equipments of Petrochemical Corporation,they are filled with poisonous,inflammable and explosive dangerous materials.It's prone to go dangerous,so it is very urgent to design an Safety Interlock Systems to protect equipments and workers.In this paper,an Safety Interlock Systems was researched and designed aim at diesel oil with hydrogen equipment such as fresh hydrogen compressor,recycle hydrogen compressor,feed stock pump and heating furnace,after realizing its processes and characteristics of equipments.And the choice of hardware and configuration,network configuration,the realization of redundancy control and communication between host computer and PLC;and design of HMI were introduced in detail.The main work includes:(1)After analyzing the interlock relationship among the equipments among diesel oil with hydrogen equipment,emergency shutdown interlock logic were designed in this paper,to protect the Thermal oil furnace,Incinerator.(2)Compared with the different structures of SIS in this paper,two modules of SIEMENS' CPU315-2DP were chosen as the key controller of the system,and constituted a redundancy SIS system,its CPU,ET200M remote I/O station and PROFII3US network were redundancy structure,promoted reliability of the system.(3)The design of hardware in this paper includes:calculated I/O according tothe equipments and the demand of emergency shutdown interlock logic andcalculated memory according to the experience formula;selected SIEMENS' S7-300module PLC to build model of system(hardware configuration)and the 485 Field bus connection between two PLC based on MPI protocol and the Ethernet connection between PLC and PC based on OPC protocol.(4)FBD program has been designed based on interlocking logic and symbolic variables.Through the emulator PLCSIM simulate and test program constantly,the ultimately guarantee the ammonia plant timely interlock park when accident occurs.(5)Use WinCC HMI components for configuration,programming,and data management in its friendly interface.Design the required operation screen,the monitor screen,the control screen,alarm screen and so on.