Co-pyrolysis performance of coal and its direct coal liquefaction residue with solid heat carrier

This paper focuses on uncovering the mechanism between nascent volatiles and solid heat carrier (SHC) in the cascade utilization of low rank coal pyrolysis. Besides the roles of heat storage and transfer, SHC has some cracking activity to regulate tar components. The interaction of volatiles and SHC led to the cracking of hydroxyl in phenols to form aromatics, as well as to the influence of final pyrolysis products distribution. Co-pyrolysis of coal and direct coal liquefaction residue (DCLR) showed inhibitory effect on coal pulverization and an interactive effect on tar yield increasing. Ultimate analysis of the co-char SHC indicates that the content of O decreased slightly, while C and H had a modest increase. The rapid heating rate through SHC leads to an extensive thermal breakdown of macromolecular fragments of coal and DCLR, which outweighs the cracking effect of SHC. Experimental research on co-char SHC circulation in the co-pyrolysis of Shendong coal and DCLR indicated the feasibility of the process combining classification utilization of low rank coal with resource reuse of direct coal liquefaction residue. (C) 2017 Elsevier B.V. All rights reserved.