Integrated Application of Dynamic Risk-Based Inspection and Integrity Operating Windows in Petrochemical Plants

The scientific and reasonable maintenance strategy is critical to ensure the continuous operation of stationary equipment in the petrochemical industry; both risk-based inspection (RBI) and integrity operating windows (IOWs) are effective for stationary equipment maintenance. In traditional static RBI, the risk is assumed to remain constant in whole inspection period, and the latest variations of medium and process parameters are not fed back into risk calculation. Thus, risk value may be overestimated or underestimated, leading to unexpected failures or excessive inspection. Integrated application of dynamic risk-based inspection (DRBI) and IOWs is an advanced direction for this problem. However, due to the complexity of dynamic interaction mechanisms and risk assessment algorithms as well as the deficiency of powerful software, industrial applications of DRBI and IOWs are still limited. By proposing improved dynamic risk indexes and real-time monitoring process parameters as well as utilizing them in DRBI assessment, this article proposes an integrated DRBI-IOWs method and develops a corresponding system. Further, the method and system are applied in a crude distillation unit. The results show that DRBI-IOWs provide direct and real-time insights into the actual risk and give early warning to the process parameter controls, which is important to control the equipment risk of sudden failures.