Ignition and kinetics analysis of coal combustion in low oxygen concentration

The combustion of coals in low oxygen concentration, which exists widely in industry combustion, was investigated by the use of thermogravimetry. Experimental results show that thermogravity/differential thermogravity/ differential scanning calorimetry curves of four studied coals shift to a higher temperature zone in lower oxygen concentration. The ignition temperature is almost constant for each coal and increases with the increased coal rank. The burnout temperature and peak temperature increase with the decreased oxygen concentration. The kinetic parameters were calculated using the Coats-Redfern method for coal combustion in low oxygen concentration. The apparent activation energy increases linearly with oxygen concentration, and high rank coal has a high apparent activation energy. An intensive compensation effect exists between the apparent activation energy E and pre-exponential factor A, and the corresponding compensation coefficients are obtained.