Effect of gasified semi-coke on coal pyrolysis in the poly-generation of CFB gasification combined with coal pyrolysis

•A coal pyrolysis process with gasified semi-coke as solid heat carrier was simulated.•The tar was analyzed by simulated distillation GC and the catalytic effect of gasified semi-coke on tar cracking was significant.•Gasified semi-coke with larger surface area and pore volume exhibited better catalytic performance.

A simulated coal pyrolysis with solid heat carrier was carried out, and the effects of solid heat carrier and temperature on coal pyrolysis were experimentally investigated. Compared with quartz sand, the gasified semi-coke exhibited better catalytic effects: the content of light tar with boiling point below 360 °C was largely enhanced (43% at 600 °C) and more gaseous products were produced. The gasified semi-coke with larger surface area and pore volume exhibited better catalytic performance. Other than thermal cracking, adsorption and catalytic effect of mineral matters, high specific surface and pore volume of gasified semi-coke are likely the main factors for tar cracking.