Impact of product gas recycling on steam methane reforming performance with Ni and Rh catalysts

Abstract

This study investigates the impact of gas product recycling (GPR) on the performance of the steam methane reforming (SMR) process using nickel (Ni) and rhodium (Rh) catalysts. Hydrogen production, a cleaner alternative to fossil fuels, predominantly employs SMR due to its industrial efficacy. The study utilizes numerical simulations with Cantera software to evaluate the effects of recycling up to 30% of gaseous products at temperatures of 800, 1000, and 1200 Kelvin and a steam-to-methane ratio of 3. Key governing equations, including mass and energy conservation, as well as reaction kinetics described by the Arrhenius equation, are applied. The simulations reveal that GPR at 1200 K with a Ni catalyst enhances syngas production and reduces CO2 leakage, making it a viable option within the 20-30% recycling range. However, GPR at lower temperatures (800 K and 1000 K) for both Ni and Rh catalysts, and at 1200 K for Rh catalysts, results in undesirable increases in carbon deposition and CO2 production. Thus, GPR is generally not recommended for Rh catalysts due to significant coke formation. These findings underscore the potential benefits and limitations of GPR in optimizing SMR processes, particularly highlighting the suitability of Ni catalysts at higher temperatures.