Development of a thermodynamic model for the HF/H2SO4 /HFSO3 /H2O System Integrating Chemical Equilibrium

Abstract

Hydrogen fluoride (HF) is the starting material for many fluorine-containing materials, such as refrigerants, fluorinated plastics, and battery electrolytes. BussChemTech licenses processes for the production of anhydrous HF. During HF production, mixtures of HF and H2SO4 occur. Mixing of HF and H2SO4 leads to the following equilibrium reaction: HF + H2SO4 ⇌ HFSO3 + H2O. In previous work involving HF and H2SO4, the concentrations of components were measured with NMR to determine the equilibrium of the reaction. These measurements were carried out with various concentrations of HF and H2SO4. The goal of this work was: • Understand the thermodynamic equilibrium of HF/H2SO4/HFSO3/H2O system • Modelling of the equilibrium to determine HF vapour pressure • Improvement of HF production processes with the developed model