Simulation of dry and steam reforming of methane over a nickel-based catalyst in a fixed-bed tube reactor using COMSOL

At present, most of the world's synthesis gas (syngas), composed of carbon monoxide
(CO) and hydrogen (H₂), originates from methane reforming. Syngas is a crucial
feedstock in the chemical industry for producing various chemicals. In this study, we
developed mathematical models of methane steam reforming and methane dry reforming
in COMSOL Multiphysics. These models were employed to investigate the effects of
operating conditions on product yield, composition, and temperature and concentration
profiles, as well as to determine the optimal temperature and pressure conditions for
maximizing the product yield. The inlet temperature was set from 700 to1000 K, with
pressures ranging from 1 to 50 bar. The results indicated that steam reforming primarily
produced hydrogen, whereas dry reforming predominantly yield carbon monoxide. Both
reactions exhibited high efficiency at high temperatures and low pressures due to their
endothermic nature and the characteristics of gas expansion. The 3D flow behavior
analysis, as illustrated by the flux direction and concentration distribution, revealed that
the flow flux is predominantly aligned parallel to the reactor length.For the concentration
profiles, the reactant concentration was lowest at the reactor center and increased toward
the near-wall region (Fig. 3 and Fig. 5), while the opposite trend was observed for
product concentration due to enhanced reaction efficiency at high temperatures in the
middle of the reactor. The optimal conditions for steam reforming were found to be 900
K at 1 atm, achieving a conversion of 95.26%, while for dry reforming, the optimal
conditions were 1000 K at 1 atm, with a conversion of 88.77%.