Pyrolysis of coal hydroliquefaction residue in a dual loop reaction system

Chao Wang ; Shaoping Xu; Guangyong Wang; Yahui Xiao

Abstract：To utilize the coal hydroliquefaction residue (CHR), a dual loop reaction system (DLRS) has been developed andupon which the pyrolysis of CHR was conducted under atmospheric pressure. The DLRS combines three reactors,i.e. a fluidized bed pyrolyzer, a radial-flow moving bed filter and a riser combustor followed by a particlesgrading cyclone. These three reactors form two parallel circulating loops, i.e. pyrolysis loop and filtration loopwith small and big quartz sand particles as circulating bed materials, respectively. CHR mixed with quartz sandwas injected into the fluidized bed pyrolyzer rapidly by a gas driven feeder, which makes it possible to disposethe CHR continuously. Under optimized blending ratio of CHR/quartz sand (1:4) and pyrolysis temperature from500 °C to 550 °C, a dust-free pyrolysis tar with the yield of 20 wt% could be obtained, which was about two timesof the Fischer Assay yield. The hexane soluble part (HS) and the hexane insoluble but toluene soluble part (asphaltene, A) account for nearly 94 wt% of the tar. Almost all the HS in the CHR was transferred into the tar during the pyrolysis.

Keywords：Coal hydroliquefaction residue, Pyrolysis, Fluidized bed, Caking