Decoupling of volatile-char interaction in co-pyrolysis of cow manure and bituminous coal and deactivation mechanism of coal char reactivity

In this study, the volatile-char interaction in coal and cow manure co-pyrolysis process was decoupled by adding internals in a two-stage fixed bed reactor, and the effect of vapor-residence time on coal char reactivity at 850 degrees C was investigated. The results indicated that the volatile-char interaction inhibited coal char reactivity, but the inhibition showed an opposite rule with the vapor-residence time in different co-pyrolysis modes. The reformed gas-phase volatiles entered the macromolecular framework of coal and generated PAHs, increasing the aromatization degree and large aromatic rings numbers of char, resulting in the reduction of the O-containing functional groups and the behavioral effects of C-O and C=O being particularly pronounced. The interaction promoted the release of Na/K, and the release behavior changed when only volatile-volatile interaction existed in the co-pyrolysis samples. The reduction of O-containing functional groups resulted in the loss of active sites number after the interaction, AAEM showed limited catalytic behavior. The O-containing functional groups and cross-linking structure act as active sites in the interaction process. This work is beneficial to enrich and develop the synergistic transformation theoretical system of carbon-containing energy materials, and provides theoretical support for promoting the industrial application of related technologies. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the volatile-char interaction in coal and cow manure co-pyrolysis process and its effect on coal char reactivity. The results showed that the interaction inhibited coal char reactivity, but the inhibition varied depending on the vapor-residence time and co-pyrolysis mode.