Measurement and computation of pressure and temperature of real gases in vessels, columns and storage tanks during transient pressure relief into the meta-stable 2-phase zone.
Emergency relief of vessels with gases (e.g. ethylene) is associated with cold and wet conditions. Temperatures in the range of -40°C and hundreds of liters of condensate are typical. The steel used in these vessels must be capable of withstanding these temperatures – cryogenic steels are however expensive. Intelligent safety devices should regulate venting to ensure that “typical” steels are sufficient for such vessels. To achieve this, one needs a state equation for gases which models condensation and heat transfer on the tank wall properly. Complex computation programs like VeVent – under development of CSE institute – are capable of realizing this.