Using Process Simulators to Quantify Flashing Two Phase Release Conditions

Process simulators are a readily available tool for making complex thermodynamic calculations which are necessary for quantifying the conditions for flashing two-phase flow under sudden depressurization. Many common toxic industrial chemicals (TICs) such as chlorine and ammonia are stored as liquids at ambient temperature, and these materials will flash when depressurized to atmospheric pressure forming an aerosol. This paper considers how to use a process simulator to estimate the mass flow rate from a simple hole for flashing two-phase flow. Analysis shows that the typical approach for determining the flash fraction underestimates the amount of vapor formation for realistic release conditions. Previously published data are considered to demonstrate the effectiveness of this approach. The result of this work is the development of a general approach for quantifying the mass release rate of flashing two phase releases for TICs and other flashing liquids such as cryogenics.