The kinetic parameters (activation energy, pre-exponential factor and reaction order) of volatile and char of deinking sludge are determined by thermogravimetric analysis. From the Arrhenius plot, the activation energy and the pre-exponential factor of char are determined. The reaction order is found to be 0.7 with respect to oxygen partial pressures of 507 - 3040 Pa. The effects of riser gas velocity, solid feeding rate and annulus air on combustion efficiency have been determined in an internally circulating fluidized bed (ICFB). The combustion efficiency decreases with increasing riser gas velocity and solid feeding rate, while it increases with increasing annulus air. High combustion efficiency is obtained when the annulus air is injected.