Catalytic Cracking of Coal Pyrolysis Product for Oil Upgrading over Char Solid Heat Carrier

摘要

Coal char can provide active surfaces for the decomposition of hydrocarbons. The fast pyrolysisrnof Shendong coal using coal char as the solid heat carrier was investigated in a fixed bed reactor to upgrade thernliquid oil. Coal chars pyrolyzed from four different ranks of coals were chosen as the solid heat carrier in thisrnstudy and quartz sand as the reference. For the solid heat carrier in pyrolysis, its activity and stability are anrnimportant factors. The recycle experiments of Shendong coal char were conducted to investigate the stability ofrnsolid heat carrier. The results showed that all coal chars selected as solid heat carrier had catalytic cracking effectrnon coal pyrolysis. During pyrolysis process, tar yield decreased, while gas yield and light oil (hexane soluble)rnfraction in the tar increased. Moreover, the yield of light oil using low-rank coal char was higher than that usingrnhigh-rank coal char. It is indicated that the cracking activity of low-rank coal char was superior to the high-rankrncoal char. The product distribution, gas composition and the char gasification reactivity changed little during thernrecycle experiments, which is demonstrated that the cracking activity and stability of Shendong char werernrelatively good as the solid heat carrier in coal fast pyrolysis.