Syngas production by bi-reforming of methane on a bimetallic Ni-ZnO doped zeolite 13X

Abstract

Ennoblement of carbon dioxide, particularly the one produced by anaerobic digestion or by biomass combustion, is a motivation to develop novel or improving already existing processes. In this context, an interesting idea is to use carbon dioxide combined together with methane and water. Therefore, bi-reforming of methane (BRM) for syngas production appears to be a good choice. In this work, BRM was studied over a Ni-catalyst supported on a ZnO-doped zeolite 13X in the temperature range 300 to 900 ◦C. This material was deeply characterized by different techniques. The pure zeolite 13X shows relative good sorption capacity for CO2 at low temperatures (<100 ◦C). The ZnO phase introduced on zeolite 13X did not show a significant improvement for BRM, while 13X zeolite material impregnated with Ni and ZnO showed promising activities, achieving CO2 conversions in the range of 50–60% at a maximum operating temperature of 800 ◦C and atmospheric pressure. The results obtained suggest that ZnO acts as an oxygen supplier when methane is activated by surface nickel, thus destabilizing the feed in the following order: methane, water and carbon dioxide. The influence of the operating conditions in the reactants conversion and products distribution was also analyzed, and it can be concluded that the molar ratios of hydrogen-to-carbon monoxide are close to two at high temperatures.