Kinetic modelling of low-temperature steam methane reforming over Ni-Ru/CeO2: sequential WGS-SMR parameter identification within a reduced LHHW framework

Biogas and biomethane enable sustainable hydrogen production through low-temperature Steam Methane Reforming (SMR). To design membrane reactors for this process, low-temperature kinetic models tailored to catalytic formulations are required. Existing kinetic models often suffer from overparameterisation and limited identifiability. In this work, a simplified and physically consistent kinetic model was developed for low-temperature SMR over Ni-Ru/CeO2 catalyst. Experiments were conducted in a fixed-bed reactor under kinetically controlled conditions (673-823 K, 2-5 bar). A sequential parameter estimation strategy was adopted by first identifying Water Gas Shift (WGS) kinetics and integrating them into the SMR model. The kinetic model neglecting hydrogen adsorption provided the best compromise between goodness-of-fit (R2 ≈ 0.97) and numerical stability. The estimated kinetic parameters reveal enhanced methane activation on Ni-Ru active sites and the CeO2 promoting role in water-assisted pathways. Overall, the proposed model provides a reliable basis for modelling and scaling up low-temperature SMR processes.