Studies of fast co-pyrolysis of oil shale and wood in a bubbling fluidized bed

•Thermal conversion process of oil shale was adjusted and optimized through the addition of biomass.•The effect of free radicals escaped from biomass on oil shale pyrolysis was discussed.•The interaction of biomass and oil shale during the fast co-pyrolysis was deeply investigated. Fast co-pyrolysis characteristics of oil shale-wood blends were researched by a bubbling fluidized bed reactor in this paper. An on-line GASMET Fourier transform infrared (FTIR) spectrometer and a gas chromatography-mass spectrometer (GC–MS) were employed for analyzing gas and liquid products. The effect of different blending ratios of oil shale(S)/wood(W) (S:W = 1:0,3:1,1:1,1:3,0:1 in this paper) on the co-pyrolysis products was discussed. The effect of temperature on the characteristics of the co-pyrolysis of S:W = 3:1 was also investigated in this paper. According to the results, the interaction of oil shale and biomass influenced oxygen distribution in volatiles, promoting the generation of CO2 generation and inhibiting the conversion of oxygen-containing compounds like alcohols and acids in pyrolytic oil. The effects of minerals in oil shale and the free radicals generated from wood were concluded according to the experimental results. In addition, as the temperature increased from 430 °C–600 °C, the yield of oil reached maximum at 520 °C with stronger secondary cracking of kerogen and biomass macromolecules.