Study on co-pyrolysis characteristics of rice straw and Shenfu bituminous coal blends in a fixed bed reactor

• Gas components and yields of the blends were compared with their parent fuels.
• Concentrations of the main components in blended tar were studied.
• The yields, structure and elements of blended char were studied.
• The interactions between biomass and coal for the pyrolysis behavior were discussed.

Co-pyrolysis behaviors of rice straw and Shenfu bituminous coal were studied in a fixed bed reactor under nitrogen atmosphere. The pyrolysis temperatures were 700 °C, 800 °C and 900 °C, respectively. Six different biomass ratios were used. Gas, tar components were analyzed by a gas chromatograph and a gas chromatography–mass spectrometry respectively. Under co-pyrolysis conditions, the gas volume yields are higher than the calculated values. Co-pyrolysis tar contains more phenolics, less oxygenate compounds than calculated values. The addition of biomass changes the atmosphere during the pyrolysis process and promotes tar decomposition. The SEM results show that the differences between the blended char and their parents char are not significant. The results of char yields and ultimate analysis also show that no significant interactions exist between the two kinds of particles. The changes of gas yield and components are caused by the secondary reactions and tar decomposition.