Flue gas desulfurization by limestone and hydrated lime slurries

The sulfation properties of six different natural limestone and hydrated lime slurries were investigated. Sulfation experiments were carried out at the temperatures of 323 K and 298 K in a gaseous mixture consisting of 5% O ₂, 10% CO₂, 0.5% SO₂ and a balance of nitrogen by volume. Total sulfation capacities of the slurries were found to vary depending on sulfation temperature, sorbent properties and the sorbent content of the slurry. It was determined that the total sulfation capacities of all slurries shifted to higher values as the CaCO₃ and Ca(OH)₂ contents of sorbents and sorbent content of slurries increases and sulfation temperature decreases. Depending on sulfation conditions and the sorbent properties, the total sulfation capacities of limestone and hydrated lime slurries varied between 14.0-33.1 (mg SO₃/ml slurry) and 17.4-40.4 (mg SO₃/ml slurry), respectively. Regression analysis was used to relate the total sulfation capacity values to the CaCO₃ and Ca(OH)₂ contents of sorbents and linear empirical equations were developed.