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Chemical Looping Reforming of Glycerol for Continuous H2 Production by Moving-Bed Reactors: Simulation and Experiment
journal contribution
posted on 2020-01-16, 13:09 authored by Bo Jiang, Lin Li, Qian Zhang, Jing Ma, Haotian Zhang, Jun Bai, Zhoufeng Bian, Binlin Dou, Sibudjing Kawi, Dawei TangChemical
looping reforming of biomass is a promising avenue for
hydrogen generation. Both the design of reactor configurations and
the screening of oxygen carriers represent major challenges in chemical
looping technologies. Here, we synthesize three oxygen carriers (referred
to as Ni–Al, NiW–Al, and W–Al) by a continuous
coprecipitation method and first test them in a fixed-bed reactor.
The NiW–Al showed the highest coke resistance, reducibility,
and glycerol conversion. We employ an Ellingham diagram to explain
the superior performance of the NiW–Al and screen operational
temperatures from the standpoint of thermodynamics. Then, using the
NiW–Al oxygen carriers, we investigate the effect of Ni-to-glycerol
ratio, fuel reactor temperature, and steam-to-glycerol ratio in moving-bed
reactors. Establishing two sets of five-stage equilibrium models in
Aspen Plus, we compare the experimental results with simulations,
discovering good agreement with each other. An isothermal and coke-free
operational window was optimized at a fuel reactor temperature of
650 °C, a Ni-to-glycerol ratio of 0.9, and a steam-to-glycerol
ratio of 4.5, achieving an average H2 yield of 1.5 mol-H2/mol-C. This work highlights the promise of combining moving-bed
reactors with oxygen carriers with high oxygen storage capacity to
utilize biomass by chemical looping reforming for continuous H2 generation.