Abstract :
The present computation determines the phase-compositions (partial pressures, molalities or activities) and respective amounts of gaseous, aqueous, and solid phases occurring in the equilibrium system; the method is illustrated by the wet flue-gas (power-plants, furnaces) desulfurization system that employs a slurry of lime and natural waters. Hot flue-gas consisting of N2, O2, CO2, H2O(g), NO, N2O, SO2, SO3, and HCl is scrubbed with the Ca(OH)2-slurry to convert sulfur oxides to sulfite (CaSO3.1/2H2O) and sulfate (CaSO4.2H2O) products. The calculation considers 10 gaseous species — SO2, SO3, HCl, CO2, NO, N2O, N2, O2, H2O(g) and HNO2 — 11 non-ionic aqueous species — SO2(aq), SO3(aq), HCl(aq), CO2(aq), NO(aq), N2O(aq), N2(aq), O2(aq), H2O(aq), HNO2(aq) and HNO3(aq) — 11 ionic aqueous species — HSO3−(aq), SO42−(aq), Cl−(aq), HCO3−(aq), CO32−(aq), NO3−(aq), NO2−(aq), OH−(aq), H+(aq), Ca2+(aq) and SO32−(aq) — and two solid phases. The effect of the Ca(OH)2-content on sulfur-partition between the sulfite and sulfate phases was investigated.
