Research and application of a dynamic risk management system for the petrochemical unit in extended service

A large number of pressure vessels and pipelines in China's refining and chemical industry will soon enter the extended service period (more than 20 years). It is estimated that by 2025, the growth rate of pressure vessels in extended service will increase from the current 10 thousand units/year to 100 thousand units/year, thus the safety of these aging equipment is the focus of current attention. It is necessary to accurately evaluate and early warn the failure risk of these equipment, especially considering the complex influences, high uncertainty and suddenness of the failure in long-term service. On the other hand, the risk management methods of pressure vessels and pipelines are well-established based on API 571, API 581 and API 584. The commercial software is also developed for risk assessment and integrity management by some institutions and companies. However, at present, the risk assessment and control of equipment in refining and chemical industry are mainly based on the static data and static assessment methods, which have little correlations with the dynamic data from equipment operation and corrosion inspection. Based on the above requirements of corrosion management and risk control for the equipment in extended service, this study developed a dynamic risk management method and system, included the dynamic data interaction with Laboratory Information Management System (LIMS), Distributed Control System (DCS) and corrosion inspection systems, the damage identification diagnosis, the dynamic risk and residual life assessment, and the application of Integrity Operating Windows (IOWs). This paper also introduces the application of the system in crude distillation units as an example to explain the method in detail. The results show that the dynamic risk management system can effectively identify the real-time risks of aging equipment and give early warning to state parameters, which is important to avoid the failure of aging equipment.