The combustion of biomass fuel provides efficient and inexpensive utilization of solid biomass. Biomass particles generally exhibit non-spherical shapes, which affect the heat and mass transfer and further the char surface reactions. The prolate and oblate spheroidal particles are considered presently. The energy balance is employed for the gas phase near the particle in spheroidal coordinate system. A theoretical study is conducted on the char combustion of the spheroidal particles under either static conditions or forced convection. The expressions for the Nusselt numbers of both prolate and oblate spheroids are obtained. The char combustion rates for the spheroidal particles are affected by the Nusselt number and the particle surface area. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.