Thermodynamic analysis of hydrogen production via methanol steam reforming reation using Gibbs free energy minimization method

In this paper, the thermodynamic equilibrium of the methanol steam reforming process (MSR) for hydrogen production was studied by Gibbs free energy minimization method. The effect of operating parameters such as temperature and steam/methanol ratio in feed stream (Steam/Carbon) on product distribution was evaluated. In order to investigate the amount of undesirable by-product in the equilibrium state, the side-reactions progress in the hydrogen-rich stream were analyzed in the certain operating range (temperature: 300-600 K and Steam/Carbon: 0.1-3). The optimum conditions were determined for maximizing methanol conversion, high hydrogen production yield and minimizing undesirable products such as CO and DME. In order to investigate the effect of presence of methane in the reaction medium on the hydrogen production yield and products selectivity, two separate thermodynamic analyses were performed assuming the presence or absence of methane in the product stream. In the presence of methane (case 2), the maximum hydrogen yield was about 10%. The results showed that in the absence of methane in the reaction medium, the suitable operation conditions limit for obtain the highest hydrogen yield and decrease of undesirable by-products were 450-600 K and a Steam/Carbon ratio above 1.5.