The combustion characteristics of Huadian oil shale and its semicoke are comparatively studied using a thermobalance (TB) and a drop-tube furnace (DTF). It is found that the ignition mechanism of oil shale and semicoke is hetero-homogeneous and heterogeneous, respectively. Drop-tube furnace experiments with both oil shale and semicoke show that the carbon (C) conversion proceeds almost simultaneously with the particle burnout, while the hydrogen (H) conversion is faster and that of nitrogen (N) and sulphur (S) slower than the particle burnout. The kinetic behavior of semicoke combustion is analyzed by drop-tube furnace experiments based on the first-order reaction model, and the kinetic model with known pre-exponential factor Aa 26.3 g.cm-2 S-1.atm-1 and apparent active energy E-a (65.8 kJ/mol) is obtained.
- Oil shale characteristics
- Semicoke combustion kinetics
- Carbon conversion
- Emission of sulphur and nitrogen