Desulfurization Characteristics of Waste Cement Particles as a Sorbent in Dry Desulfurization

Dry desulfurization characteristics of waste cement particles were examined with laboratory-scale experimental apparatus based on the weight change of the sample exposed to a gas flow containing SO2. The waste cement particles, a byproduct of recycling aggregates from waste concrete, are fine particles with diameters ranging from 10 to 200 mu m and an average diameter of 105 pm. The effects of the operation parameters, i.e., the reaction temperature (650-950 degrees C), SO2 concentration (61-1543 ppm), oxygen concentration (0-10%), NO2 concentration (0-500 ppm), absolute humidity (0-15000 ppm), and particle size (10-200 mu m), on the desulfurization performance were investigated. The desulfurization rates were found to depend on the 1.26th order of the SO2 concentration and to slightly depend on the absolute humidity and the particle size, but they were almost independent of the concentrations of oxygen and NO2 in the gas flow. Arrhenius type temperature dependence was observed up to 850 degrees C with activation energy of 12 kJ/mol. The observed dry desulfurization rates of the waste cement particle were almost equivalent to those of the conventional sorbents such as limestone and calcium hydroxide. Therefore, it is confirmed that the waste cement particles could be applicable in dry desulfurization as an inexpensive sorbent derived from wastes.