Catalytic effects on the ignition temperature of coal

The effects on the ignition temperature of coal are investigated for various catalysts including alkali salts, alkaline earth salts, and transition metal, salts. The results show that the catalytic activity of alkali salts and alkaline earth salts is determined by the first ionization energy of the metal: the lower the first ionization energy, the higher the catalytic activity. In general, the salts with the water of crystallization are more effective catalysts. Transition metal salts show excellent catalytic activities: they reduce the ignition temperature, raise the volume of volatile, and strengthen the homogenous combustion. For certain catalyst series in which each member has the same cation, but different anions, catalytic activities increase with the decrease of the anion acidity. (C) 1998 Elsevier Science Ltd. All rights reserved.