SIS Design For A Phenol Project

In the process industry, safety instrumented systems are widely used in various processes and equipment protection cases, reducing the probability of occurrence of accidents on site to protect the safety of personnel and the environment, as well as to reduce economic losses. However, the current domestic safety instrumented system design process is not perfect, because the system architecture configuration issues, hardware and software security issues, such as the occurrence of improper operation and maintenance of safety hazards, accidents often happen due to safety instrumented system can not run proper security features. How to design a safe and effective safety instrumented systems has become a serious problem.The project puts Safety instrumented system(SIS) into use for safety monitoring of the process, and to increase the project’s safety performance.This paper briefly describes the project’s control system and the SIS design principles, which the design procedure should follow as well as the functional safety standards. The design of the SIS is under the frame of the safety life cycle. Hazard and risk analysis was to be implemented and the HAZOP study report was completed. Then the Safety Instrument Function (SIF) of the system and their Safety Integrity Level (SIL) were defined in the phenol area which is the main process of the project. The SIL Verification Study should to be done using Markov model, which was implemented by exSILentia software for this project. Any SIF verification results that do not meet the requirements of risk analysis should be reconfiguration and written down. After all these work, the instrument datasheets containing SIL requirements and other safety related requirements should to be built in the INTOOLS, for the stand-alone and redundant configurations of the field instrumentation and system.In addition, the paper also describes DeltaV SIS system, which can meet SIL3requirements and have the certificate. The configuration of DeltaV SIS system for safety-related functions was completed by vendor.