Designing Wet Scrubbers for SO2 Absorption into Fairly Concentrated Sulfuric Acid Solutions Containing Hydrogen Peroxide

Absorption of SO₂, diluted with nitrogen up to concentrations of 500 Pa, was performed at 20 °C and 1 atm, with water and sulfuric acid solutions containing hydrogen peroxide in two different contactors: a packed column and a cable scrubber. The absorption rate was determined for various SO₂ partial pressures, as well as different concentrations of sulfuric acid (up to 40 wt %) and of hydrogen peroxide in the scrubbing liquid. It was found that the SO₂ absorption rate increases with the hydrogen peroxide concentration, and decreases as the acidity of the scrubbing liquid increases. Taking into account hydrodynamic and mass transfer characteristics of the packing for both scrubbers, a practical enhancement factor depending on the liquid phase H₂SO₄ and H₂O₂ contents, was deduced from semi‐continuous tests. As a good concordance was observed between results determined for both contactors, a single correlation is proposed, allowing the computation of this kinetic factor for quite simple simulation or design of SO₂ scrubbers, provided the gas and liquid phase mass transfer coefficients k_Ga and k_La are known.