Ignition Mechanism of Oil Shale and Semi-coke in Different Combustion Reactors

Ignition characteristics of oil shale and semi-coke were performed on thermogravimetric analyzer (TGA), fixed bed and fluidized bed combustion reactors respectively. In the fixed bed and fluidized bed experiment, the ignition temperature is evaluated from gas evolution (CO, CO₂) and bed temperature profiles. The results show that with the increasing of particle size, ignition temperature increases from TGA experiment and fluidized bed experiment with once feed. There is a lower ignition temperature for fixed bed experiment than others. For fluidized bed experiment with once feed, ignition temperature of semi-coke significantly depends on feed temperature. Oil shale ignition mechanism from fluidized bed experiment with once feed may shifts from homogeneous to heterogeneous one. The ignition of semi-coke belongs to heterogeneous ignition.