SO2 solubility in 50 wt % H2SO4 at elevated temperatures and pressures

Abstract

The SO2 solubility at various temperatures and pressures was evaluated to determine the SO2 content in a 50 wt % H2SO4 acid solution adding new experimental solubility data for the SO2−H2SO4 binary system currently available in literature. A setup was designed and commissioned to measure the SO2 solubility at temperatures ranging from 30 °C to 80 °C and pressures up to 1000 kPa in 50 wt % H2SO4. SO2 solubility measurements in water were used to benchmark the accuracy of the setup. According to the results, the solubility of SO2 in 50 wt % H2SO4 decreased with increasing temperature despite the increase in the system pressure found at higher temperatures. The highest amount of SO2 soluble in 50 wt % H2SO4 was attained at 30 °C and 3.658 kPa with 13.11 g of SO2 per 100 g of H2SO4 solution. A heat of solution of −36 kJ·mol−1 (uncertainty u(ΔH) = 5 kJ·mol−1) was determined