Parametric study on catalytic tri-reforming of methane for syngas production

A two-dimensional numerical model for syngas production from tri-reforming of methane (TRM) in adiabatic tubular fixed-bed reactors was established. From the results obtained, it was found that reactant must be preheated to certain temperatures for TRM activation. Although the delay factor accounting for the varying catalytic bed activities produced different temperature and species mole fraction profiles in the reactor upstream, the reactor performance was delay factor independent if the reactor outlet results were used because nearly identical temperature and species mole fraction variations were obtained at the reactor downstream. The numerical results also indicated that reverse water-gas shift reaction plays an important role for H₂ and CO yields. With higher O₂ in reactant, high temperature resulted, leading to lower H₂/CO ratio. The absence of H₂O in the reactant caused dry reforming of methane as the dominant reaction, resulting in H₂/CO ratio close to unity. With the absence of CO₂ in the reactant, steam reforming of methane was the dominant reaction, resulting in H₂/CO ratio close to 3. Using flue gas from combustion as TRM feedstock, it was found that H₂/CO ratio was enhanced using lower CH₄ amount in reactant. High-temperature flue gas was suggested for TRM for the activation requirement. - Highlights: • Reactant must be preheated to certain temperature for tri-reforming of methane (TRM) activation. • A delay factor is used to account for varying catalytic activity. • TRM performance is delay factor independent when reactor outlet results are used. • Water-gas shift reaction plays an important role in H₂ yield, CO yield and H₂/CO ratio in TRM. • Low CH₄ and high temperature are suggested when flue gas is used in TRM.