Optimum operating conditions in ethanol steam reforming over a Ni/La2O3-αAl2O3 catalyst in a fluidized bed reactor
2018
Montero, Carolina | Remiro, Aingeru | Benito, Pedro Luis | Bilbao, Javier | Gayubo, Ana G.
This manuscript analyzes the steam reforming of ethanol (SRE) over a Ni/La₂O₃-αAl₂O₃ catalyst in a fluidized bed reactor under a wide range of operating conditions (500–650°C, space time up to 0.35gcₐₜₐₗyₛₜh/gEₜOH, and steam/ethanol (S/E) molar ratio in the feed between 3 and 9) in order to select optimum conditions for maximizing H₂ production. The significance the individual reactions in the reaction mechanism have on products distribution and the role of the catalyst in the extent of these reactions has also been analyzed. Blank runs (without catalyst) have been performed to test the contribution of thermal routes to this mechanism. Ethylene and acetaldehyde are intermediate products in the kinetic scheme, whose presence is only observed when ethanol conversion is not full. The increase in temperature enhances the reforming and decomposition of ethanol and acetaldehyde and, when the catalyst is used, CH₄ reforming and reverse WGS reactions are also promoted, so that the yield of H₂ and CO increases, that of CH₄ decreases and the one of CO₂ remains almost constant with temperature. The increase in S/E molar ratio increases H₂ yield, but attenuates the rate of some reactions involved in the process. 600°C, a space time of 0.35gcₐₜₐₗyₛₜh/gEₜOH and S/E=6 are suitable conditions for maximizing ethanol conversion (100%) and H₂ yield (82%) with high catalyst stability.
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