The effect of sawdust on the calcination and the intrinsic rate of the carbonation reaction using a thermogravimetric analyzer (TGA)

The effect of sawdust on the rate of limestone carbonation/calcination reactions was studied in a thermogravimetric analyzer applying a grain model for the calcium-based sorbent, namely Havelock limestone (0.50–1.41 mm). Two samples were employed for calcination under N2 at 850 °C: one containing limestone, and the other a mixture containing limestone and sawdust. The resulting limestone samples were observed under a scanning electron microscope (SEM), while the quantitative influence of calcination conditions was examined by BET surface areas. The presence of sawdust during calcination caused a significant increase in the initial rate of carbonation, which has been attributed to the enhancement of CaO surface area. The presence of H2 which is emitted from sawdust pyrolysis was assumed to be responsible for reduction of limestone sintering.