Peanut shell generated from peanut harvesting has a great potential to be converted into an energy resource in developing countries such as China, Vietnam, and Indonesia. The main objective of this study is to investigate the combustion characteristics of peanut shell in a pilot-scale vortexing fluidized-bed combustor with flue gas recirculation. Crushed and pelletized peanut shells are used as the feeding materials. The effects of in-bed stoichiometric oxygen ratio (S-b), particle sizes, and particle shapes on the combustion characteristics as well as pollutant emissions are investigated. Results show that similar temperature profiles are observed in all cases. CO emissions from the combustion of both fuels are all less than 70 ppm. CO emission decreases, while NOx emissions increase with particle sizes. CO and NOx emissions of pellet combustion show an inverse trend from that of crushed shell combustion at different in-bed stoichiometric oxygen ratios. (C) 2014 Elsevier B.V. All rights reserved.