Mechanism and product characteristics of pyrolysis-activation coupling reaction of Shenfu coal

The characteristics of products from Shenfu coal pyrolysis-activation coupling reaction were investigated in a two-stage fixed bed reactor.The effect of pyrolysis temperature and activating agents (H₂O (g), CO₂ and H₂O (g)/CO₂) on the characteristics of products was analyzed.The mechanism of pyrolysis-activation coupling reaction was revealed.The results show that the pyrolysis temperature has little effect on the CO₂ chemical reactivity of the chars.The tar yield of Shenfu coal pyrolysis is significantly increased by using pyrolysis-activation coupling process, and the tar yield is up to 17.8%.The effect of different activating agents on the yield of mixed coal gases (MCG) and tar is in the order of H₂O (g)>H₂O (g)/CO₂>CO₂ and the main components of tar are saturates and aromatics.The specific surface area of activated carbon can be effectively improved by using H₂O (g)/CO₂ as the activating agents, and the BET specific surface area reaches to 845.37 m²/g.The mechanism of pyrolysis-activation coupling process is that the synthesis gases (SG) from the activation section can provide hydrogen source for coal hydropyrolysis in pyrolysis section, and the rich hydrogen radicals can promote the reaction and change the product distribution and properties.