SUMMARYThe biomass, coal and their blends at blending ratios (biomass : coal) of 95:5, 90:10, 85:15 and 80:20 were pyrolysed under a nitrogen environment at four different heating rates comprising 5°C, 10°C, 15°C and 20°C per minute to investigate their pyrolytic behaviour and to determine kinetic parameters of thermal decomposition through Kissinger's corrected kinetic equation using the thermogravimetric analysis results. In the kinetic analysis, the activation energy of both types of biomass was less than that of coal, being 168.7 kJ/mol (cypress wood chips), 164.6 kJ/mol (macadamia nut shells) and 199.6 kJ/mol (Australian bituminous coal). The activation energy of the blends of biomass and coal followed that of the weighted average of the individual samples in the blends. Char production of the samples and the blends was also analysed to observe any synergetic effects and thermal interaction between biomass and coal. The char production of the blends corresponded to the sum of the results for the individual samples with the coefficient of determination of 0.999. Thermal decomposition of biomass and coal appeared to take place independently, and thus, the activation energy of the blends can be calculated from that of the two components. There was no evidence for any significant synergetic effects and thermal interaction between either type of biomass and coal during copyrolysis. Copyright © 2013 John Wiley & Sons, Ltd.

SUMMARY The thermal behaviour and kinetic analysis of biomass (cypress wood chips and macadamia nut shells) and Australian bituminous coal during combustion were studies using the thermogravimetric technique with four different heating rates under an air atmosphere. Each type of biomass was blended with coal at mass ratios (biomass:coal) of 95:5, 90:10, 85:15 and 80:20 to investigate the effect of coal as a supplementary fuel on thermal behaviour during the combustion process. Combustion of the individual samples and the blends took place in three steps comprising dehydration, devolatilisation and char oxidation. During co‐combustion, the thermal decomposition behaviour of the blends followed that of the weighted average of the individual samples in the blends. In kinetic analysis, thermal decomposition of biomass and coal appeared to take place independently, and thus, the activation energy of the blends can be calculated from that of the two components. No evidence for any significant synergetic effects or thermal interaction was found between either type of biomass and the coal during co‐combustion based on the lack of deviation from expected behaviour of the blends. Copyright © 2013 John Wiley & Sons, Ltd.