HIGH-SURFACE-AREA CALCIUM-CARBONATE - PORE STRUCTURAL-PROPERTIES AND SULFATION CHARACTERISTICS

Limestone or calcium carbonate (CaCO3) used as a sorbent in the remova l of acid gas precursors (SO2) from combustion systems suffers from po or pore structural properties which causes low reactivity and incomple te utilization. The surface area and pore size distribution of CaCO3, if tailored appropriately, can considerably enhance its reactivity for SO2. This study focuses on the optimization of pore properties of CaC O3 particles and the enhancement of SO2 reactivity and ultimate utiliz ation. The carbonate is produced by precipitation from an aqueous susp ension of calcium hydroxide by injecting CO2. The influence of operati ng parameters, suspension concentration, gas flow rate, and additives (surfactant) on the surface area and pore volume is investigated. The surface area of the carbonate powder can be controlled in the range of 10-70 m(2)/g by varying the operating parameters. The SO2 reactivity and the ultimate utilization of the calcium carbonate indicate a drama tic improvement and can be correlated with the surface area and pore v olume characteristics of the particles.