(65ar) Quantifying the Importance of Accurate Physical Property Data in Dispersion Modeling

Modeling discharge and dispersion of materials from processing vessels is an important part of a facility siting study. Here we investigate the dependence of dispersion modeling on physical property data accuracy, including the impact of uncertainty in the lower flammability limit, heat of vaporization, liquid density, and vapor pressure data.  Vapor pressure is further analyzed by comparing correlations obtained from the Design Institute for Physical Properties (DIPPR) to the Clausius-Clapeyron equation using the normal boiling point as the reference. 

Overall, the predicted dispersion distances are relatively resilient to uncertainty in physical properties. However, errors in dispersion distances can be large under the right conditions and it is important to have accurate data for these cases. To ensure data accuracy, we recommend using a modern, critically reviewed database such as the latest DIPPR database, which contains thermophysical data for a large number of compounds and routinely employs rigorous analysis and consistency checks to ensure the reliability of the data.