Kinetics of chemisorption and reduction of NO on coal chars

The kinetics of chemisorption and reduction reaction of NO on coal chars was investigated using a fixed bed reactor. The effect of pyrolysis temperature (500℃~900℃) and mineral matter on the removal of NO by coal chars was also analyzed. The results indicated that coal char and NO both in temperature programmed reaction (TPR) and isothermal reaction experienced a transition from chemisorption to reduction reaction with increasing temperature (30℃~600℃). The kinetics of coal chars and NO at low temperature could be well described by Elovich equation. The initial chemisorption rate of raw coal chars increased with elevated temperature, but the value of demineralized ones first increased and then declined. The activation energy of chemisorption during isothermal process increased with the increase of NO uptakes. The NO conversions during TPR and rate constants in isothermal reduction reaction varied inversely with pyrolysis temperature. Therefore, deactivation of coal char towards NO was caused by pyrolysis at high temperature. Additionally, the mineral matter played a catalytic role both in chemisorption and reduction reaction of NO on coal chars.