Proposal of a parabolic-trough-oriented photo-thermo-reactor with coaxial baffles and dual-bed for high-efficient solar-driven hydrogen production from methanol steam reforming

Abstract

A novel tubular photo-thermo-reactor with coaxial baffles and dual (photo-thermo- and thermo-) catalyst beds is proposed, integrated with the commercially-mature parabolic trough concentrators (EuroTrough ET-100 model) with high scalability for high-efficient H2 production from solar-driven methanol steam reforming. The optical-flow-thermal-chemical multiphysics coupled model, which incorporates the experimental data of photo-thermo-catalytic reaction kinetics, have been established to optimize the geometric and operational conditions of the proposed reactor. It is demonstrated that the systematic solar hydrogen production efficiency up to 21.2% considering the pumping power and the solar-to-hydrogen efficiency up to 30.6 % without considering the energy cost have been achieved in the best case. The reason for the excellent performance is two-fold. On the one hand, the existence of coaxial baffles guides multiple penetrations of the gaseous reactants through the catalyst beds thus guarantees sufficient contact between them. On the other hand, the design of coaxial dual-bed guarantees cascaded utilizations of both photo-thermo-catalysis and thermo-catalysis thus realizes higher utilization efficiency of full-spectrum solar energy. Considering the compatibility to the commercially-mature optical concentrator, this work exemplifies a practically promising route of effective full-spectrum solar-to-chemical conversion.