Seismic Analysis and Calculation of LNG Ultra-low Temperature Ball Valve

Cryogenic top-entry ball valves are widely employed in low-temperature engineering applications such as LNG transportation and serve as critical equipment for the stable operation of LNG receiving terminals. To ensure reliable valve performance under severe seismic conditions, a novel cryogenic top-entry ball valve structure was designed. To verify whether the structural strength meets design requirements during cryogenic operation under various working conditions, a simulation model was developed. This enabled the execution of seismic simulation analyses under low-temperature conditions, followed by comprehensive evaluation of the results.The research findings demonstrate that the proposed seismic simulation model accurately calculates the temperature distribution across all valve components. Furthermore, the developed stress evaluation method effectively assesses whether the valve structure complies with stress acceptance criteria under different classification levels （O, A, B, C, D）. Simulation results confirm that the designed valve structure satisfies the Level O stress acceptance criteria for design conditions under the most severe postulated accident conditions （Level D）. This serves as a valuable reference for subsequent seismic calculation and stress evaluation of cryogenic valves, offering significant practical implications.