Prediction of coke formation over a catalyst particle for dry reforming of methane

Nowadays, global warming is a significant environmental problem causing various impacts across the globe. Dry reforming of methane (DRM) is one of the reactions that can utilize CO2 effectively. However, the major problem of DRM process is the deactivation of catalysts caused by coke formation over the catalyst particle which mainly occurs from CH4 decomposition reaction. Coke formation leads to a decrease in catalytic performance by blocking the pores and active sites. In this study, the spatial catalyst deactivation caused by coke formation over a spherical alumina-supported nickel catalyst (Ni/Al2O3) particle in dry reforming of methane (DRM) was investigated using computational fluid dynamics (CFD). Firstly, a spherical geometry was developed as the simulation domain to replicate the shape of an actual catalyst. The validation result indicated that both coke accumulation and deactivation on a catalyst particle showed a good agreement with the experimental data. The coke was initially formed at the surface of the catalyst and gradually formed at the center. As the reaction progressed, the concentration of coke at the center was higher than at the surface. Secondly, the effect of CH4/CO2 ratio and temperature on the coke formation was considered. These developed concentration profiles can be further used for a better understanding of coke formation behavior, leading to an improvement of the overall efficiency for the DRM process.