RBI技术应用于LNG设备上的改进研究

Study on improvement for application of RBI technology in LNG equipment

基于API581的风险评估技术（RBI）是近年来石化行业逐渐采用并得到认可的一种新的评估设备经济可行性和安全性的技术。但是由于LNG的温度一般低至-162℃,使得LNG设备在应用API581时受到了限制。低温脆性断裂是LNG设备需考虑的一项主要的失效模式,API在评估脆断损伤因子时的温度范围是-73-38℃。为了能够评估LNG设备在低温环境下的风险,通过遗传算法将温度扩展至-209℃。扩展得到的脆断损伤因子曲线同夏比冲击试验的冲击功随温度变化曲线的趋势基本一致,因此扩展的损伤因子可以满足低温环境下LNG设备的风险评估。

Recently, Risk-Based Inspection （ RBI） technology based on API 581 has been gradually adopted and become a new technology to determine economic feasibility and safety of equipment in petrochemical plants.Howev-er, there are limitations of applying API 581 to LNG equipment because the temperature of LNG is usually under-162℃.Low temperature brittle fracture is a major failure mode of LNG equipment need to be considered, but API code considers the temperature range of about -73-38℃to evaluate the brittle fracture damage factor.To evalu-ate the risk of LNG equipment in low temperature environment, the temperature region was extended to about -209℃with genetic algorithm.The tendency of extended brittle fracture damage factor （ BFDF） curve was similar with the curve of impact energy against temperature change in Charpy impact tests.Therefore, the extend BFDF can satisfy the risk assessment of LNG equipment in cryogenic environment.