A new design of catalytic tube reactor for hydrogen production from ethanol steam reforming

A new design of the catalytic tube system with a crossflow configuration, featured by low catalyst usage and cost, is developed using computational fluid dynamics (CFD). Meanwhile, the kinetics of ethanol steam reforming over a nickel-based catalyst is conducted based on experimental measurements. The effects of six parameters on ethanol conversion and H₂ yield are evaluated; they are the reaction pressure, the Reynolds number (Re), the ratio of catalyst thickness to tube diameter (T/D ratio), the ratio of tube diameter to channel width (D/W ratio), the steam-to-ethanol molar ratio (S/E ratio), and the number of tubes. The results indicate that the higher the reaction pressure, the better the ESR performance, as a result of the dominant kinetic mechanism on ESR in the special geometric structure of this study. Increasing the D/W or T/D ratio can effectively improve the ethanol conversion and H₂ yield, stemming from the diminish of gas hourly space velocity (GHSV). It is observed that the ethanol conversion has no significant growth when the S/E ratio is over 4, revealing the co-effective choice of the S/E ratio below 4. Increasing the number of tubes raises the ethanol conversion and attains 97% conversion when using four tubes. However, the influence of the altered Reynolds number on the performance is insignificant. When the T/D ratio is lifted to 0.33, the ethanol conversion achieves almost 100%. Overall, the newly designed catalytic tube system with low catalyst usage is a promising reactor that can be applied in ESR for efficient hydrogen production.