Thermal-chemical reaction characteristics of Ni/Al2O3 catalytic porous material filled solar reactor for dry reforming of methane process

Abstract

In solar thermochemical systems, the interaction between heat transport characteristics and chemical reaction characteristics has significant impacts on the system energy conversion and storage efficiency. For the purpose of investigating the thermochemical performance of a catalytic porous material filled solar reactor under multi-field coupling, this study established a numerical model by combining the computational fluid dynamics (CFD) method with dry reforming of methane (DRM) reaction kinetics. The Wu model is adopted to predict the momentum dissipation resulted from the non-Darcy flow in the porous zone, and the DRM reaction kinetics including four side reactions are programmed into the Fluent software via user-defined functions. The numerical results indicate that the reaction temperature presents a linear relationship with the incident peak heat flux, and a quadratic relationship with the inlet flow rate. From the perspectives of feedstock conversion efficiency, syngas yield and carbon deposition degree, the optimal operating conditions are determined to achieve the highest profit. Within the current operating parameters, increasing the heat flux of incident radiation contributes to improving the CO2 conversion and CO yield, but has the disadvantage of aggravating the carbon deposition in the front of the porous ceramic, while appropriately increasing the inlet flow rate can effectively alleviate this contradiction. Additionally, choosing a CH4/CO2-feed ratio over 2.0 cannot help improve the conversion rate and syngas yield, but will greatly increase the amount of carbon deposition.