Sulfation performance of CaO under circulating fluidized bed combustion-like condition

Abstract

As a major air pollutant, SO2 has negative effect on the human health and environment. The desulfurization characteristics of two CaO samples (commercial one and the other one calcined from CaCO3) with high purity were examined by a thermo-gravimetric analyzer under circulating fluidized bed combustion-like condition. The influences of SO2 concentration (1000–4000 ppm), CO2 concentration (0–45%) and temperatures (800–950 °C) on the sulfation conversion degree of CaO samples were addressed, and sulfation kinetic parameters for the two samples were estimated based on the unreacted shrinking core model. The sulfation conversion degree of CaO calcined from CaCO3 at 900 °C and 2000 ppm SO2 was 68% higher than the commercial CaO. The sulfation conversion degree for the commercial CaO at 950 °C with 2000 ppm SO2 was one time higher than at 800 °C, and the sulfation conversion degree for the sample calcined from CaCO3 at 950 °C increased by about 31% compared to that at 800 °C. The calcium conversion degree of the sample calcined from CaCO3 was 0.59 in the absence of CO2, and the conversion degree with the CO2 concentration of 45% reduced by about 31%. The sulfation kinetics of two samples were appropriately described by the shrinking unreacted core model. The sample calcined from CaCO3 had a better sulfation activity than the commercial CaO.