Abstract: In order to make full use of the biomass waste nut shells, thermogravimetry(TG) analysis was used to investigate the combustion characteristic and kinetics of Camellia oleifera shells, Juglans regia shells, and Macadamia ternifolia shells. The influences of different heating rates on the combustion behavior of three kinds of shells were analyzed, and the combustion characteristics and the kinetic parameters were determined. The results indicated that the combustion characteristic parameters of three kinds of biomass shells had obvious difference, but they all increased with the increase of heating rate. With the increase of heating rate, the ignition and burnout temperature, the maximum combustion rate, the average burning rate and the integrated combustion characteristic index improved. At the heating rate of 10 ℃/min, the integrated combustion characteristic indexes of Camellia oleifera shells, Juglans regia shells, and Macadamia ternifolia shells were 0.56×10^-7, 1.18×10^-7 and 0.88×10^-7, respectively. The combustion kinetic of biomass shells was studied by using the first order reaction kinetics model. All correlation coefficients of the fitting curves were greater than 0.93. The activation energies of low temperature stage of Camellia oleifera shells, Juglans regia shells, and Macadamia ternifolia shells were 30.40-52.41 kJ/mol, respectively, and the activation energies at high temperature stage were 18.49-40.62 kJ/mol, respectively. And the activation energies of low temperature stage were higher than those of the high temperature stage.

Key words: biomass shell, thermogravimetry analysis, combustion characteristic, kinetic