A 2-PHASE RELEASE MODEL FOR QUANTIFYING RISK REDUCTION FOR MODIFIED HF ALKYLATION CATALYSTS

This paper describes a two-phase jet model for predicting the HF raino ut (capture) in HF/additive releases. The parent droplets of the relea se mixture constitute the first phase. The second phase is a vapor-liq uid fog. The drops are not in equilibrium with the fog phase with whic h they exchange mass and energy. The fog at any location is assumed to be in local equilibrium. The fog-phase calculations account for HF ol igomerization and HF-water complex equilibria in the vapor phase and v apor-liquid equilibrium in the fog. The model incorporates jet traject ory calculations and hence can predict liquid 'rainout' and the captur e distance. The model HF capture predictions are in agreement with sma ll and large scale HF/additive release experiments. The fog properties and flow rate may be used to initialize atmospheric fog dispersion mo dels for use in risk assessment calculations.