Numerical Analysis of Bubble Hydrodynamics in a Steam Reactor Chemical Looping Reforming System
Hydrogen production using a three-reactor chemical looping reforming technology is an innovative process that allows cost-effective carbon capture and storage. A computational fluid dynamics model for the steam reactor of chemical looping reforming (CLR) process has been developed based on kinetic theory of granular flow. The reactive fluid dynamics system of the CLR process has been customized by incorporating the oxidation kinetic of the oxygen carrier into ANSYS Fluent software. An Eulerian multiphase treatment is used to describe the continuum principle of two-fluid model for both gas- and solid-phase models. In the present work, iron oxide and steam are used as oxygen carrier and fuel, respectively, for the reaction kinetic model of the steam reactor. Numerical simulations are carried out to capture the bubble hydrodynamics and the relationship between molar fraction of products and gas phase and bubble formation. The conversion rate of steam has been analyzed for different granular sizes, and the overall performance of a CLR system has been studied. The bubble hydrodynamics in terms of development, rise, growth, and burst of bubbles in the steam reactor has been simulated for unsteady and quasi-steady behavior. The quasi-steady state is also noticed to be achieved faster for finer particles than coarser ones that also ensures faster hydrogen production rate for the former case. Solid volume fraction contour has also been qualitatively compared with similar results available in the open literature.
KeywordsHydrogen production Chemical looping reforming Oxygen carrier Reaction kinetics Bubble hydrodynamics CFD
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