Figures (7)  Tables (1)

    • Figure 1. 

      Schematic diagram of the developed internally heated cigar-type pyrolyzer and photograph of the pyrolysis experimental system.

    • Figure 2. 

      Influence of (a) draft direction, (b) air distribution rate, and (c) cooling type on the fixed carbon and ash contents of biochar. Dd: downdraft condition, Du: updraft condition, Rl: low air distribution rate, Rh: high air distribution rate, Cn: air insulation, Cw: water cooling.

    • Figure 3. 

      (a) Van Krevelen diagram for pellets and their products. (b), (c) Probability density of O/C and H/C molar ratios.

    • Figure 4. 

      Influence of (a) draft direction, (b) air distribution rate, and (c) cooling type at different pyrolysis temperatures on the specific surface area (SSA) and pH of biochar. Dd: downdraft condition, Du: updraft condition, Rl: low air distribution rate, Rh: high air distribution rate, Cn: air insulation, Cw: water cooling.

    • Figure 5. 

      Influence of (a) draft direction, (b) air distribution rate, and (c) cooling type at different pyrolysis temperatures on the cation exchange capacity (CEC) and electrical conductivity (EC) of biochar. Dd: downdraft condition, Du: updraft condition, Rl: low air distribution rate, Rh: high air distribution rate, Cn: air insulation, Cw: water cooling.

    • Figure 6. 

      Influence of (a) draft direction, (b) air distribution rate, and (c) cooling type on the polycyclic aromatic hydrocarbon (PAH) content and toxic equivalence quantity (TEQ) of biochar. Dd: downdraft condition, Du: updraft condition, Rl: low air distribution rate, Rh: high air distribution rate, Cn: air insulation, Cw: water cooling.

    • Figure 7. 

      Low heating value and energy distribution of biochar and syngas under different pyrolysis conditions.

    • Index Parameter
      Nominal diameter (mm) 8
      Bulk density (kg/m3) 580
      Natural length (mm) 20–45
      LHV (lower heating value) (MJ/kg) 15.65
      Proximate analysis based on received basis (wt.%)
      Volatile content concentration 62.47
      Fixed carbon concentration 11.14
      Ash concentration 20.64
      Moisture concentration 5.75
      Ultimate analysis based on dry and ash-free basis (wt.%)
      Concentration of C element 51.34
      Concentration of H element 7.01
      Concentration of O element 40.89
      Concentration of N element 0.77

      Table 1. 

      Characteristics of raw material biomass pellets produced from reed straw