Research And Design Of ESD In Hydrocracking Unit Based On PLC

Hydrocracking unit is a category A device with the highest risk of explosion and fire among the oil refining devices, so a only process control system is not enough in this device. In order to safeguard the safety of production equipments and operating personnels, it is necessary to design an emergency shutdown interlock logic protection system.So in this thesis, an emergency shutdown interlock protection system based on S7-400H fault-tolerant of the automation system. the main work content are as follows:(1) Analyzed the environment of hydrocracking process, put forward the necessity of using the emergency shutdown system. Insight into the composition of the classification,advantages and disadvantages of the emergency shutdown system; analysised the reliability parameters of emergency shutdown system.(2) According to the process of hydrocracking unit and setting principles of safety interlock, interlock logic design is created this system for the major equipment,such as new hydrogen compressor, recycle hydrogen compressor and reaction furnace,in the emergency pressure relief systems and devices.(3) Estimate the capacity of system memory and I/O points, according to the I/O points,choose and confirm the number of the various modules suitable for the system, adopts the STEP7software to the hardware configuration of system, including the main control system configuration and redundant I/O module configuration.(4) Through the FBD of STEP7programming language to design the emergency shutdown interlocking logic programming, and use the Siemens PLCSIM simulation software interlocking program for functional testing, to achieve the purpose of the emergency shutdown system.(5) Finally, monitoring interface design based on the WinCC configuration software, Monitoring factors that may affect the equipment normal operation conditions (level, pressure, etc.).