Papers by Keyword: Risk-Based Inspection (RBI)

Abstract: Three propylene spherical tanks which have both the same manufacturing parameters and conditions have been assessed based on risk assessment and non-destructive testing technology. One of the spherical tanks is stopped for comprehensive inspection, and the result of inspection verifies the reliability of risk assessment, which is applied to other two unopened propylene spherical tanks. Meanwhile, in order to make overall inspection level meet the requirements of the risk assessment and so reduce spherical tanks assessing risk, ultrasonic diffraction detection (TOFD) with high detection rate and fluorescent magnetic surface detection technology are adopted to ensure comprehensive test meeting the risk assessment requirements, which can also provide significant guidance for future complete equipment inspection.

Abstract: The risk- and condition-based dynamic inspection proposed to decrease losses and costs caused by accidents which is not only a decision-making and optimal method for inspection strategies, but is also a soft measurement system for fixed equipment safety status. In the risk- and condition-based dynamic inspection method, data collection is standardized to decrease the impact of personal factors on the data. Moreover, a procedure in which experts approve the data collected from plants is supplemented to amend error and supplement omission of data in time. A relevant inspection strategy is adopted based on the different damage types and its initiation and growth for the aspect of inspection decision-making. In the meantime, the cost-risk efficiency of the inspection is regarded as an objective function to optimize inspection strategies according to the risk status of equipment. Finally, a model is established to assess the frequency of in-service inspection and ensure equipment safety during the end of equipment life based on the fitted linear relationship between the corrosion rate and stress energy.

Abstract: Risk-based inspection (RBI) guideline based on API 581 provides a methodology for calculating the risks of equipment in refinery or petrochemical plant. However, there is a major limitation of its application to the petrochemical plant directly since only a representative material is considered in calculating the risk, especially in part of the consequence of failure, even though the equipment is composed of numerous materials. The objectives of this paper are to develop an enhanced RBI program to resolve shortcoming inclusive of the above issue and to evaluate the risks of equipment in petrochemical plant using the program. In this respect, the mole fractions of materials were used to fully incorporate the characteristics of different materials. The proposed RBI program consists of qualitative, semi-quantitative and quantitative risk evaluation modules in which toxic materials as well as representative materials were selected automatically for comparison with those in the current guideline. The RBI program has been applied to evaluate the risks of equipment in Naphtha Cracking Center (NCC) which is a typical facility of petrochemical plant. Thereby, promising evaluation results were obtained and applicability of the proposed RBI program was proven.

Abstract: Recently, regulatory bodies quite often encourage to adopt risk-based inspection (RBI) and management programs because they can enhance safety simultaneously with deregulation in Korea. RBI is an integrated methodology that factors risk into inspection and maintenance decision making. This paper describes an example of how to use known risk assessment codes (API 580, API 581 BRD) to address such safety analysis requirements for risk management in the refining industry. Specifically, this paper reports the methodology and the results of application to the refinery units using the KGS-RBITM program, developed by the Korea Gas Safety Corporation in reference of API Codes and ASME PC (Post Construction) with a suitable consideration of Korean situation. The results of the risk and reliability assessment using KGS-RBITM program are useful in determining whether the detected defects are tolerable or required to be repaired. The subsequent decisions are to manage the future inspection, repair and maintenance planning in the risk reduction control.