The fly ash generated from the burning of low sulfur coals is featured by high alkalinity, which alone or mixed with CaCO3 can be used as the absorbent for desulfurization. The desulfurization performance of fly ash and CaCO3 compound absorbent is experimentally investigated in a bubbling desulfurization reactor. Results show that the desulfurization rate of CaCO3 is improved by adding fly ash at Ca/S mole ratio of 1.024. The maximum desulfurization rate of the compound absorbent could reach 94%. The optimum ratio of fly ash and CaCO3 in the compound absorbent is 1:1. (C) 2016 Elsevier B.V. All rights reserved.