Development of Detailed Surface Reaction Mechanism for Methanation Process Based on Experiments

 

The pressure to reduce greenhouse gas emissions is growing, which demands new and innovative technologies to produce mobile as well as stationary energy. The CO2 methanation offers a pathway to reduce greenhouse gas emissions by directly converting CO2 to CH4 . This also plays a crucial role in “power-to-gas” (P2G) technologies by providing an approach to store excess renewable energy in the form of methane in an existing natural gas infrastructure. However, methanation is a complex process due to its exothermic nature, interaction of the gas species with the catalyst, and possible catalyst degradation. Therefore, a deeper understanding is required for the methanation reaction, its different reaction pathways, and side reactions. In this work, we aim to understand the direct production of synthetic natural gas from CO2 and H2 in a Sabatier process with the help of experiments over a Ni/Al2⁢O3 catalyst. A detailed surface reaction mechanism is developed to extend the study numerically by validating the simulation results with the experimental data. A one-dimensional model, LOGEcat, based on a single-channel catalyst model, is used for kinetic modeling. Experiments as well as simulations have been performed at various conditions, such as temperature variation and N2 dilution to the inlet composition. We have successfully captured the experimental trends using the kinetic model developed for the conditions considered for the analysis.