Interaction between Shenmu coal and different caking coals during co-pyrolysis

The pyrolysis characteristic of blended coal and the interaction between Shenmu coal (SMC) and caking coals(Fat coal-FM, gas coal-QM, coking coal-JM) were studied by temperature-programmed thermobalance. The pyrolysis kinetics were analyzed using distributed activation energy model (DAEM). The results indicate that the concentrated release rate of moisture increases and temperature corresponding to the release peak of volatile matter(t_max) for coal blends decreases as increasing SMC blending ratio. The inhibition of blended coal is reduced as increasing SMC blending ratio when pyrolysis temperature surpasses the solidified temperature of metaplast (>460-480 ℃), indicating a poor bonding behavior of metaplast. In addition, the inhibition of blended coal is enhanced and its bonding behavior is improved with increasing heating rate. The effects of relieving swelling pressure and improving dispersity of metaplast gradually reduce as deepening the metamorphic degree of caking coal from QM, FM to JM, since the corresponding temperature for promoting interaction (release of volatile) is below, within, above the plastic temperature range of caking coals, respectively. A comparison of experimental and calculated distributed activation energy model confirms the interaction mechanism of blended coal during co-pyrolysis.