Industrial & Engineering Chemistry Research, Vol.57, No.9, 3128-3137, 2018
Kinetics of Steam Gasification of Glucose as a Biomass Surrogate over Ni/Ce Mesoporous Al2O3 in a Fluidized Bed Reactor
This study reports the kinetics of steam gasification of glucose as a biomass surrogate over a new Ni(x)/Ce-doped Al2O3 (x = 5, 10, 15, and 20 wt %) catalyst in a fluidized bed reactor. The presence of ceria plus successive nickel impregnation helped in conserving the catalysts high surface area (i.e., 102 m(2)/g at 20 wt % nickel loading). Incorporation of ceria dopant suppressed coke formation during steam gasification of 15 wt % glucose in the fluidized bed reactor at 650 degrees C and 1 atm in the order Ni(20) < Ni(15) < Ni(10) < Ni(5)/Ce-doped Al2O3. The detailed kinetic model comprises reactant adsorption, surface reaction, and product desorption steps, involving the water gas shift reaction (WGS), steam reforming of methane (SRM), and reverse dry reforming of methane (RDRM). Ni(20)/Ce-doped Al2O3 with the best performance in terms of syngas production, and the least tendency for coking, was used for the kinetic studies (for T = 550-700 degrees C and t = 5-25 s). The results of the model simulation indicate that the rate of water gas shift was the highest (7.76 x 10(-2) mmol/g of cat.s bar(2)) followed by steam reforming of methane (4.13 x 10(-2) mmol/g of cat. s bar(2)) and then reverse dry reforming of methane (3.57 x 10(-2) mmol/g of cat. s bar(2)). The high reaction rates signify the suitability of the new Ni(x)/Ce-mesoporous Al2O3 catalytic system applied in this work. The modeling procedure could be applied conveniently for a different catalytic system in a similar reactor to obtain the necessary kinetic parameters.