Pyrolysis characteristics and kinetics of the alga Saccharina japonica

Saccharina japonica can be converted to bio-oil, gas, and char through pyrolysis. In this study, the pyrolysis characteristics of S. japonica were investigated using a thermogravimetric analyzer. Most of the materials decomposed between 200 °C and 350 °C at heating rates of 10–20 °C/min. The apparent activation energy increased from 102.5 kJ mol−1 to 269.7 kJ mol−1 with increasing pyrolysis conversion. The kinetic parameters of S. japonica pyrolysis were determined using nonlinear least-squares regression of the experimental data assuming first-order kinetics. The kinetic rate constants indicated that the predominant reaction pathway was B (bio-oil) to C (gas; C1–C4), rather than A (S. japonica) to B (bio-oil) and/or to C (gas; C1–C4). The proposed lumped kinetics of S. japonica pyrolysis offers a guide for the scale-up of the process at the research and industrial level.