Abstract: Based on rigorous thermodynamic modeling, a dynamic process simulation system for multiphase flow in a debutanizer tower was developed using Aspen HYSYS Dynamic. This system enabled quantitative analysis of safety valve relief processes. Subsequent investigations examined the transient pressure, temperature, and relief flowrate characteristics of the debutanizer tower under fire scenarios when equipped with different safety valve types.the results demonstrate that the dynamic model provides more accurate predictions of overpressure peaks and instantaneous relief rates compared to conventional methods. Engineering design parameters for debutanizer towers must account for thermodynamic state variations upon fire relief termination. Comparative analysis of valve specifications revealed: larger throat areas accelerate system pressure stabilization during relief events.Among valves with different flow characteristics (quick-opening, linear, equal-percentage), quick-opening valves exhibited optimal relief performance.

Key words: debutanizer tower, dynamic simulation, fire scenario, safety valve, relief characteristics, valve selection