Revaluating Bursting Disk Vent Sizing: The Impact of Temperature Unbalance Between Liquid and Vapor

Bursting disk vent sizing is crucial in process industries to protect pressure vessels from overpressure. A bursting disk is a non-reclosing device that ruptures at a set pressure to safely release excess pressure. Proper sizing ensures system integrity and prevents failures, considering factors like process fluid properties, operating pressure, temperature, and relief rate. Compliance with ASME and API standards is essential, but these assume equilibrium between liquid and vapor phases, which may not hold in industrial accidents like external fires. During a fire, liquid heats up faster than vapor due to radiation, especially without internal stirring. This temperature imbalance causes the liquid to overheat, leading to sudden vaporization when the disk opens. This effect can result in an underestimation of peak vapor flow and venting area. This study experimentally demonstrated this temperature imbalance using a pressure-resistant calorimetric vessel equipped with a relief valve and a moving thermocouple. Findings highlight a need to reconsider vent sizing methods based on equilibrium assumptions in closed vessels for improved process safety.