Structural impact under accidental LNG release on the LNG bunkering ship: Implementation of advanced cryogenic risk analysis

Abstract

The potential risk associated with the accidental release of Liquefied Natural Gas (LNG) is a notable concern during the design phase of gas-handling facilities. One of the risk is an excessive cryogenic exposure to structures or equipment, leading to hazardous situations. This study aims to introduce a novel method that implements Advanced Cryogenic Risk Analysis (ACRA) to enhance the safety of LNG bunkering ship structure in case of cryogenic flow leakage. The method involves evaluating thermal loads based on the preceding simulated LNG release scenarios using Computational Fluid Dynamics (CFD). These thermal parameters are then employed in structural analysis through the Finite Element (FE) approach. The integration of thermal data from CFD simulations into the FE model was achieved using the Random Forest algorithm. The LNG bunkering structure is represented using DH36-grade steel material. Furthermore, to accurately capture the mechanical properties of DH36 steel, cryogenic tensile tests were conducted across a temperature range from 298.15 K to 113.15 K. The resulting stress-strain data from these tests were utilized to establish a reliable material model for conducting FE analysis. This paper comprehensively presents a novel ACRA procedure by utilizing physical parameter of the gas release cosnequence such as the steel temperature profile to identify the brittle failure under the accidental gas release on the LNG bunkering ship. In addition, quantitative risk analysis (QRA) was also presented regarding the cryogenic spill hazard, to link the probability and consequence aspects of the LNG bunkering risk, particularly the results of steel temperature, stress, and strain experienced by the ship's structure. Furthermore, the individual risk was also estimated. The implications of the findings are discussed in detail regarding the cryogenic risk, cryogenic tensile test and numerical analyses. ？ 2024 The Institution of Chemical Engineers