Low Temperature Production of SO2 from H2SO4 In the Si Thermochemical Cycle by Using Iron(III) Sulfate Intermediate

Decomposition of sulphuric acid is the highest temperature step in the sulphur iodine water splitting thermochemical cycle. We propose a variation based on the following reactions:

3 H2SO4(acq,conc) + Fe2O3 -> Fe2(SO4)3 (300 °C)

Fe2(SO4)3 -> Fe2O3 + x SO2 + ySO3 + y/2 O2 (650 °C, where x+y=3)

In comparison with direct sulphuric acid decomposition the maximum temperature is lowered, there is no more need for catalysts and the material costs for the reactor is drastically reduced. One disadvantage is the increase of energy demand.

Experimental and theoretical modeling results are presented and discussed.