Oxidation Reaction of Calcium Sulfide in an Advanced PFBC Condition(II)

The effects of particle size, O2 concentration, temperature, and sorbent type on sulfation of calcium sulfide were investigated at temperatures of 650 to 850°C Calcium sulfide particle is oxidized to CaSO4 through reaction: CaS + 2O2↑CaSO4 when reaction temperature is below 850°C. CaS particle with a diameter below 0.005 mm was found to achieve complete conversion to CaSO4. However, CaS particle with a diameter above 0.02 mm wasn't be completely converted to CaSO4 due to the pore blockage of sulfate product layer. A kinetic study of the sulfation reaction (CaS + 2O2 ↑CaSO4) has shown its activation energy to be 57.2 kJ/mol. A grain model has been developed to analyze the oxidation reaction within a CaS particle. The effects of temperature, O2 concentration, particle size and type of limestone on the reaction process were discussed.