Impact of using calcium oxide as a bed material on hydrogen production in two-stage fluidized bed gasification

This paper describes the effect of equivalence ratio and steam/biomass ratio on the gas production of a two-stage fluidized bed gasifier. The calcium oxide was employed as bed material in the second stage to evaluate the influence of gasification efficiency. The result shows the H-2 molar percentage increased by approximately 2-3 mol% at the end of the second stage fluidized bed reactor without adding CaO. The second stage fluidized bed gasifier plays an important role of cracking and reforming of tar which generated from the first stage one. On the other hand, when the calcium oxide was used as the bed material in the second stage, it enhanced the generation of H2 under most parameters. Highest H-2 molar percentage in syngas was observed as 37 mol% at ER and S/B ratio is 0.3 and 2, respectively. Generally, more H-2 generation through second stage gasifier was found than that in first stage by 6.1-12.8%. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.