Advanced Technology and Manufacturing Institute (ATAMI)

Numerical modeling of methane-steam reforming is performed in a micro/mini-channel with heat input through catalytic channel walls. The low-Mach number, variable density Navier-Stokes equations together with multicomponent reactions are solved using a parallel numerical framework. Methane-steam reforming is modeled by three reduced-order reactions occurring on the reactor walls. The surface reactions in the presence of a catalyst are modeled as Neumann boundary conditions to the governing equations. Two catalysts are investigated: a porous Nickel substrate and a porous felt with deposited Palladium nanoparticles. The reduced-order mechanism kinetics model is coupled with the flow solver to resolve the chemical species field within the reactor geometry. The effects of the total heat input, heat flux profile, flow rate and inlet steam-methane molar concentration on production of hydrogen are investigated in detail. The results of the parametric study give performance evaluations. An increase of hydrogen production of 10% (molar fraction) is observed when increasing the heat flux from no heat flux to a wall heat flux of 3 kW/m². The results from the three heat flux profiles study (constant, linear increasing, and linear decreasing) are increased hydrogen production between the linear decreasing profile (worst performer) and the linear increasing profile (best performer) of 3.5% on a molar basis. Varying flow rate from 800 ml/min to 100 ml/min results in an increase of hydrogen mole fraction of 16%. Hydrogen production is non-linearly related to the steam-methane ratio. Maximum hydrogen production is observed near a ratio of 3.0. The reaction rates may be increased by the introduction of hydrogen extraction.