The thermogravimetric characteristics and pyrolysis kinetics of high-density-aquacultured Saccharina japonica were investigated using a thermogravimetric analyzer and micro-tubing reactor, respectively. The effect of water washing S. japonica samples on pyrolysis product distribution was studied at 360, 370 and 380 degrees C with various residence times from 1.0 to 3.0 min. The kinetic rate constants of pyrolysis for untreated and water-washed S. japonica samples were determined using nonlinear least-squares regression of experimental data assuming first-order kinetics. The predominant reaction pathway of water-washed S. japonica was liquid to gas product (k(3)) at each temperature, while that of untreated S. japonica was biomass to liquid product (k(2)) at 360 and 370 C, then liquid to gas product (k(3)) at 380 degrees C. However, the k(2)/k(1) ratio of water-washed S. japonica (1.2166-1.3247) was more than two times that of untreated S. japonica (0.5763-0.6346). (C) 2016 Elsevier Ltd. All rights reserved.