AN INTEGRAL MODEL FOR POOL SPREADING, VAPORISATION AND DISSOLUTION OF HYDROCARBON MIXTURES

A two-phase or liquid release of flammable or toxic fuel may rainout forming a liquid pool. This represents a major safety hazard as the liquid will evaporate upon contact with the substrate forming a flammable vapour cloud. This paper describes a new robust model for spreading, vaporisation and dissolution of a multi-component pool. The new model is an extended version of the pool model PVAP in the Phast consequence modelling package. The multi-component pool model tracks the mixture composition of the transient pool as a function of time, and employs established mixing rules to estimate overall pool properties. Two distinctive cases for pool vaporisation are studied namely boiling and evaporation. Additionally, the model makes continuous checks for transitions between boiling and evaporation by performing a bubble point calculation at each step of the simulation. The present work introduces for the first time a model for the dissolution of water- soluble chemicals present in a multi-component pool. Predictions using the model are compared against the widely-used HGSYSTEM multi-component pool model, LPOOL, and published experimental data in terms of numerical robustness and accuracy. © 2012 IChemE.